Bipolar disorder and the pseudoautosomal region: An association study

Energy Technology Data Exchange (ETDEWEB)

Parsian, A.; Todd, R.D. [Washington Univ. School of Medicine, St. Louis, MO (United States)

1994-03-15

From family, adoption, and twin studies it is clear that genetic factors play an important role in the etiology of bipolar disorder (McGuffin and Katz: The Biology of Depression, Gaskell, London, 1986). Recently Yoneda et al. reported an association between an allele (A4) of a VNTR marker (DXYS20) for the pseudoautosomal region and bipolar disorder in a Japanese population. In order to test for this association in a Caucasian population, we have typed a sample of 52 subjects with bipolar disorder and 61 normal controls. The bipolar subjects are probands of multiple incidence families. The normal controls are an epidemiologically ascertained sample of middle-aged, unrelated individuals. The two groups were matched for sex and ethnic background. There were no significant differences in the allele or genotype frequencies of DXYS20 between the two groups. In particular, there was no significant difference in the frequency of the A4 allele in normal controls and bipolar patients (0.377 vs. 0.317, respectively). The prevalence of the A4 allele in bipolar patients and normal controls was 0.567 and 0.622, respectively. We were not able to replicate the results of the 1992 Yoneda et al. study. 15 refs., 2 tabs.

Assessing the germplasm of Laminaria (phaeophyceae) with random amplified polymorphic DNA (RAPD) method

Science.gov (United States)

He, Yingjun; Zou, Yuping; Wang, Xiaodong; Zheng, Zhiguo; Zhang, Daming; Duan, Delin

2003-06-01

Eighteen gametophytes including L. japonica, L. ochotensis and L. longissima, were verified with random amplified polymorphic DNA (RAPD) technique. Eighteen ten-base primers were chosen from 100 primers selected for final amplification test. Among the total of 205 bands amplified, 181 (88.3%) were polymorphic. The genetic distance among different strains ranged from 0.072 to 0.391. The dendrogram constructed by unweighted pair-group method with arithmetic (UPGMA) method showed that the female and male gametophytes of the same cell lines could be grouped in pairs respectively. It indicated that RAPD analysis could be used not only to distinguish different strains of Laminaria, but also to distinguish male and female gametophyte within the same cell lines. There is ambiguous systematic relationship if judged merely by the present data. It seems that the use of RAPD marker is limited to elucidation of the phylogenetic relationship among the species of Laminaria.

Molecular Identification of Date Palm Cultivars Using Random Amplified Polymorphic DNA (RAPD) Markers.

Science.gov (United States)

Al-Khalifah, Nasser S; Shanavaskhan, A E

2017-01-01

Ambiguity in the total number of date palm cultivars across the world is pointing toward the necessity for an enumerative study using standard morphological and molecular markers. Among molecular markers, DNA markers are more suitable and ubiquitous to most applications. They are highly polymorphic in nature, frequently occurring in genomes, easy to access, and highly reproducible. Various molecular markers such as restriction fragment length polymorphism (RFLP), amplified fragment length polymorphism (AFLP), simple sequence repeats (SSR), inter-simple sequence repeats (ISSR), and random amplified polymorphic DNA (RAPD) markers have been successfully used as efficient tools for analysis of genetic variation in date palm. This chapter explains a stepwise protocol for extracting total genomic DNA from date palm leaves. A user-friendly protocol for RAPD analysis and a table showing the primers used in different molecular techniques that produce polymorphisms in date palm are also provided.

Inheritance of restriction fragment length polymorphisms, random amplified polymorphic DNAs and isozymes in coastal Douglas-fir

Science.gov (United States)

K.D. Jermstad; A.M. Reem; J.R. Henifin; N.C. Wheeler; D.B Neale

1994-01-01

A total of 225 new genetic loci [151 restriction fragment length polymorphisms (RFLP) and 74 random amplified polymorphic DNAs (RAPD)] in coastal Douglas- fir [Pseudotsuga menziesii (Mirb.) Franco var. menziesii] have been identified using a three-generation outbred pedigree. The Mendelian inheritance of 16 RFLP loci and 29...

Random amplified polymorphic DNA markers of the Brassica alboglabra chromosome of a B. campestris-alboglabra addition line

DEFF Research Database (Denmark)

Bagger Jørgensen, Rikke; Chen, B.Y.; Cheng, B.F.

1996-01-01

The alien C-genome chromosome in a Brassica campestris-alboglabra monosomic addition line was characterized by random amplified polymorphic DNA (RAPD) analysis. The alien chromosome carried three loci, E(c), W-c and Lap-1C, controlling synthesis of erucic acid, white flower colour and a fast...

Synaptonemal complex aberrations in the pseudoautosomal region of X, Y chromosomes in irradiated hamsters

Energy Technology Data Exchange (ETDEWEB)

Allen, J.W.; Collins, B.W. [Environmental Protection Agency, Research Triangle Park, NC (United States); Poorman-Allen, P. [Wellcome Research Lab., Research Triangle Park, N.C. (United States); Sontag, M.R. [Duke Univ., Durham, NC (United States). Medical Center

1994-05-01

The effects of X-radiation, bleomycin and amsacrine (m-AMSA) on the meiotic chromosomes of male Armenian hamsters were determined by electron microscopic analysis of synaptonemal complex (SC) damage. Pachytene stage cells were analyzed 5 or 6 days following their treatment at putative preleptotene-leptotene stages of meiosis. Of the multiple types of SC aberrations observed to be significantly increased over control levels, lateral element breakage and synaptic anomalies were most prevalent. The focus of these studies was on the sex chromosomes which, in the Armenian hamster, reveal an unusally well-defined pseudoautosomal region. In the XY pair, radiation and chemical treatments caused certain forms of structural and synaptic anomalies which appeared to be preferentially localized to telomeric and/or crossover regions. The nature of these specific aberrations, involving breakage, bridge formation and asynapsis, is not well understood; however, their distributions are suggestive of possible relationships with sites and processes of crossing over. (author).

Recombination in the human Pseudoautosomal region PAR1.

Directory of Open Access Journals (Sweden)

Anjali G Hinch

2014-07-01

Full Text Available The pseudoautosomal region (PAR is a short region of homology between the mammalian X and Y chromosomes, which has undergone rapid evolution. A crossover in the PAR is essential for the proper disjunction of X and Y chromosomes in male meiosis, and PAR deletion results in male sterility. This leads the human PAR with the obligatory crossover, PAR1, to having an exceptionally high male crossover rate, which is 17-fold higher than the genome-wide average. However, the mechanism by which this obligatory crossover occurs remains unknown, as does the fine-scale positioning of crossovers across this region. Recent research in mice has suggested that crossovers in PAR may be mediated independently of the protein PRDM9, which localises virtually all crossovers in the autosomes. To investigate recombination in this region, we construct the most fine-scale genetic map containing directly observed crossovers to date using African-American pedigrees. We leverage recombination rates inferred from the breakdown of linkage disequilibrium in human populations and investigate the signatures of DNA evolution due to recombination. Further, we identify direct PRDM9 binding sites using ChIP-seq in human cells. Using these independent lines of evidence, we show that, in contrast with mouse, PRDM9 does localise peaks of recombination in the human PAR1. We find that recombination is a far more rapid and intense driver of sequence evolution in PAR1 than it is on the autosomes. We also show that PAR1 hotspot activities differ significantly among human populations. Finally, we find evidence that PAR1 hotspot positions have changed between human and chimpanzee, with no evidence of sharing among the hottest hotspots. We anticipate that the genetic maps built and validated in this work will aid research on this vital and fascinating region of the genome.

Genomic relations among 31 species of Mammillaria haworth (Cactaceae) using random amplified polymorphic DNA.

Science.gov (United States)

Mattagajasingh, Ilwola; Mukherjee, Arup Kumar; Das, Premananda

2006-01-01

Thirty-one species of Mammillaria were selected to study the molecular phylogeny using random amplified polymorphic DNA (RAPD) markers. High amount of mucilage (gelling polysaccharides) present in Mammillaria was a major obstacle in isolating good quality genomic DNA. The CTAB (cetyl trimethyl ammonium bromide) method was modified to obtain good quality genomic DNA. Twenty-two random decamer primers resulted in 621 bands, all of which were polymorphic. The similarity matrix value varied from 0.109 to 0.622 indicating wide variability among the studied species. The dendrogram obtained from the unweighted pair group method using arithmetic averages (UPGMA) analysis revealed that some of the species did not follow the conventional classification. The present work shows the usefulness of RAPD markers for genetic characterization to establish phylogenetic relations among Mammillaria species.

Mid-infrared optical parametric oscillator pumped by an amplified random fiber laser

Science.gov (United States)

Shang, Yaping; Shen, Meili; Wang, Peng; Li, Xiao; Xu, Xiaojun

2017-01-01

Recently, the concept of random fiber lasers has attracted a great deal of attention for its feature to generate incoherent light without a traditional laser resonator, which is free of mode competition and insure the stationary narrow-band continuous modeless spectrum. In this Letter, we reported the first, to the best of our knowledge, optical parametric oscillator (OPO) pumped by an amplified 1070 nm random fiber laser (RFL), in order to generate stationary mid-infrared (mid-IR) laser. The experiment realized a watt-level laser output in the mid-IR range and operated relatively stable. The use of the RFL seed source allowed us to take advantage of its respective stable time-domain characteristics. The beam profile, spectrum and time-domain properties of the signal light were measured to analyze the process of frequency down-conversion process under this new pumping condition. The results suggested that the near-infrared (near-IR) signal light `inherited' good beam performances from the pump light. Those would be benefit for further develop about optical parametric process based on different pumping circumstances.

Composting oily sludges: Characterizing microflora using randomly amplified polymorphic DNA

International Nuclear Information System (INIS)

Persson, A.; Quednau, M.; Ahrne, S.

1995-01-01

Laboratory-scale composts in which oily sludge was composted under mesophilic conditions with amendments such as peat, bark, and fresh or decomposed horse manure, were studied with respect to basic parameters such as oil degradation, respirometry, and bacterial numbers. Further, an attempt was made to characterize a part of the bacterial flora using randomly amplified polymorphic DNA (RAPD). The compost based on decomposed horse manure showed the greatest reduction of oil (85%). Comparison with a killed control indicated that microbial degradation actually had occurred. However, a substantial part of the oil was stabilized rather than totally broken down. Volatiles, on the contrary, accounted for a rather small percentage (5%) of the observed reduction. RAPD indicated that a selection had taken place and that the dominating microbial flora during the active degradation of oil were not the same as the ones dominating the different basic materials. The stabilized compost, on the other hand, had bacterial flora with similarities to the ones found in peat and bark

Meiotic Consequences of Genetic Divergence Across the Murine Pseudoautosomal Region.

Science.gov (United States)

Dumont, Beth L

2017-03-01

The production of haploid gametes during meiosis is dependent on the homology-driven processes of pairing, synapsis, and recombination. On the mammalian heterogametic sex chromosomes, these key meiotic activities are confined to the pseudoautosomal region (PAR), a short region of near-perfect sequence homology between the X and Y chromosomes. Despite its established importance for meiosis, the PAR is rapidly evolving, raising the question of how proper X / Y segregation is buffered against the accumulation of homology-disrupting mutations. Here, I investigate the interplay of PAR evolution and function in two interfertile house mouse subspecies characterized by structurally divergent PARs, Mus musculus domesticus and M. m. castaneus Using cytogenetic methods to visualize the sex chromosomes at meiosis, I show that intersubspecific F 1 hybrids harbor an increased frequency of pachytene spermatocytes with unsynapsed sex chromosomes. This high rate of asynapsis is due, in part, to the premature release of synaptic associations prior to completion of prophase I. Further, I show that when sex chromosomes do synapse in intersubspecific hybrids, recombination is reduced across the paired region. Together, these meiotic defects afflict ∼50% of spermatocytes from F 1 hybrids and lead to increased apoptosis in meiotically dividing cells. Despite flagrant disruption of the meiotic program, a subset of spermatocytes complete meiosis and intersubspecific F 1 males remain fertile. These findings cast light on the meiotic constraints that shape sex chromosome evolution and offer initial clues to resolve the paradox raised by the rapid evolution of this functionally significant locus. Copyright © 2017 by the Genetics Society of America.

A pronounced evolutionary shift of the pseudoautosomal region boundary in house mice.

Science.gov (United States)

White, Michael A; Ikeda, Akihiro; Payseur, Bret A

2012-08-01

The pseudoautosomal region (PAR) is essential for the accurate pairing and segregation of the X and Y chromosomes during meiosis. Despite its functional significance, the PAR shows substantial evolutionary divergence in structure and sequence between mammalian species. An instructive example of PAR evolution is the house mouse Mus musculus domesticus (represented by the C57BL/6J strain), which has the smallest PAR among those that have been mapped. In C57BL/6J, the PAR boundary is located just ~700 kb from the distal end of the X chromosome, whereas the boundary is found at a more proximal position in Mus spretus, a species that diverged from house mice 2-4 million years ago. In this study we used a combination of genetic and physical mapping to document a pronounced shift in the PAR boundary in a second house mouse subspecies, Mus musculus castaneus (represented by the CAST/EiJ strain), ~430 kb proximal of the M. m. domesticus boundary. We demonstrate molecular evolutionary consequences of this shift, including a marked lineage-specific increase in sequence divergence within Mid1, a gene that resides entirely within the M. m. castaneus PAR but straddles the boundary in other subspecies. Our results extend observations of structural divergence in the PAR to closely related subspecies, pointing to major evolutionary changes in this functionally important genomic region over a short time period.

Quantum random number generator

Science.gov (United States)

Pooser, Raphael C.

2016-05-10

A quantum random number generator (QRNG) and a photon generator for a QRNG are provided. The photon generator may be operated in a spontaneous mode below a lasing threshold to emit photons. Photons emitted from the photon generator may have at least one random characteristic, which may be monitored by the QRNG to generate a random number. In one embodiment, the photon generator may include a photon emitter and an amplifier coupled to the photon emitter. The amplifier may enable the photon generator to be used in the QRNG without introducing significant bias in the random number and may enable multiplexing of multiple random numbers. The amplifier may also desensitize the photon generator to fluctuations in power supplied thereto while operating in the spontaneous mode. In one embodiment, the photon emitter and amplifier may be a tapered diode amplifier.

Application of randomly amplified polymorphic DNA (RAPD ...

African Journals Online (AJOL)

Jane

2011-10-10

Oct 10, 2011 ... and T7-010 based on functional markers according to He et al. (2007). These primers were constructed by Invitrogen GmbH,. Karlsruhe, Germany, and used to amplify the polyphenol oxidases genes. The sequences of these primers were as follows: T3-001: 5`-CCA TTA ACC CTC ACT AAA GGG ACC GTA ...

Studies of the LBL CMOS integrated amplifier/discriminator for randomly timed inputs from fixed target experiments

International Nuclear Information System (INIS)

Russ, J.S.; Yarema, R.J.; Zimmerman, T.

1988-12-01

A group at Lawrence Berkeley Laboratory has reported an elegant CMOS VLSI circuit for amplifying, discriminating, and encoding the signals from highly-segmented charge output devices, e.g., silicon strip detectors or pad readout structures in gaseous detectors. The design exploits switched capacitor circuits and the well-known time structure of data acquisition in colliding beam accelerators to cancel leakage effects and switching noise. For random inputs, these methods are not directly applicable. However, the high speed of the reset switches makes possible a mode of operation for fixed target experiments that uses fast resets to erase unwanted data from random triggers. Data acquisition in this mode has been performed. Details of operation and measurements of noise and rate capability will be presented. 8 refs., 6 figs

A two primers random amplified polymorphic DNA procedure to obtain polymerase chain reaction fingerprints of bacterial species.

Science.gov (United States)

Rivas, R; Velázquez, E; Valverde, A; Mateos, P F; Martínez-Molina, E

2001-04-01

Polymerase chain reation (PCR) fingerprints are used to characterize and recognize bacteria and are generally obtained using universal primers that generate an array of DNA amplicons, which can be separated by electrophoresis. Universal primers 8F and 1491 R have been used to amplify specifically 16S rDNA. We have used these primers at an annealing temperature of 50 degrees C. Agarose gel electrophoresis of PCR products revealed several bands. The band pattern of each bacterial species was different and the strains belonging to the same species shared an identical pattern. The patterns obtained did not show variations with plasmid DNA content or the growth stage of the bacteria. The peculiarity of the randomly amplified polymorphic DNA (RAPD) described in this work lies in the use of two large primers (proximately 20 nt) to obtain the pattern, since normally a only smaller primer is used, and in the new application for the primers used to amplify 16S rDNA. This new procedure, called two primers (TP)-RAPD fingerprinting, is thus rapid, sensitive, reliable, highly reproducible and suitable for experiments with a large number of microorganisms, and can be applied to bacterial taxonomy, ecological studies and for the detection of new bacterial species.

Genetic alterations of hepatocellular carcinoma by random amplified polymorphic DNA analysis and cloning sequencing of tumor differential DNA fragment

Science.gov (United States)

Xian, Zhi-Hong; Cong, Wen-Ming; Zhang, Shu-Hui; Wu, Meng-Chao

2005-01-01

AIM: To study the genetic alterations and their association with clinicopathological characteristics of hepatocellular carcinoma (HCC), and to find the tumor related DNA fragments. METHODS: DNA isolated from tumors and corresponding noncancerous liver tissues of 56 HCC patients was amplified by random amplified polymorphic DNA (RAPD) with 10 random 10-mer arbitrary primers. The RAPD bands showing obvious differences in tumor tissue DNA corresponding to that of normal tissue were separated, purified, cloned and sequenced. DNA sequences were analyzed and compared with GenBank data. RESULTS: A total of 56 cases of HCC were demonstrated to have genetic alterations, which were detected by at least one primer. The detestability of genetic alterations ranged from 20% to 70% in each case, and 17.9% to 50% in each primer. Serum HBV infection, tumor size, histological grade, tumor capsule, as well as tumor intrahepatic metastasis, might be correlated with genetic alterations on certain primers. A band with a higher intensity of 480 bp or so amplified fragments in tumor DNA relative to normal DNA could be seen in 27 of 56 tumor samples using primer 4. Sequence analysis of these fragments showed 91% homology with Homo sapiens double homeobox protein DUX10 gene. CONCLUSION: Genetic alterations are a frequent event in HCC, and tumor related DNA fragments have been found in this study, which may be associated with hepatocarcin-ogenesis. RAPD is an effective method for the identification and analysis of genetic alterations in HCC, and may provide new information for further evaluating the molecular mechanism of hepatocarcinogenesis. PMID:15996039

Identification of three randomly amplified polymorphic DNA-polymerase chain reaction markers for distinguishing Asian and North American Gypsy Moths (Lepidoptera: Lymantriidae)

Science.gov (United States)

David E. Schreiber; Karen J. Garner; James M. Slavicek

1997-01-01

Gypsy moths originating in Asia have recently been introduced into North America, making it necessary to develop markers for distinguishing the Asian strain from the established North American population. We have identified 3 randomly amplified polymorphic DNA-polymerase chain reaction generated (RAPD-PCR) markers which are specific for either Asian or North American...

Optimizing learning of a locomotor task: amplifying errors as needed.

Science.gov (United States)

Marchal-Crespo, Laura; López-Olóriz, Jorge; Jaeger, Lukas; Riener, Robert

2014-01-01

Research on motor learning has emphasized that errors drive motor adaptation. Thereby, several researchers have proposed robotic training strategies that amplify movement errors rather than decrease them. In this study, the effect of different robotic training strategies that amplify errors on learning a complex locomotor task was investigated. The experiment was conducted with a one degree-of freedom robotic stepper (MARCOS). Subjects were requested to actively coordinate their legs in a desired gait-like pattern in order to track a Lissajous figure presented on a visual display. Learning with three different training strategies was evaluated: (i) No perturbation: the robot follows the subjects' movement without applying any perturbation, (ii) Error amplification: existing errors were amplified with repulsive forces proportional to errors, (iii) Noise disturbance: errors were evoked with a randomly-varying force disturbance. Results showed that training without perturbations was especially suitable for a subset of initially less-skilled subjects, while error amplification seemed to benefit more skilled subjects. Training with error amplification, however, limited transfer of learning. Random disturbing forces benefited learning and promoted transfer in all subjects, probably because it increased attention. These results suggest that learning a locomotor task can be optimized when errors are randomly evoked or amplified based on subjects' initial skill level.

True random numbers from amplified quantum vacuum.

Science.gov (United States)

Jofre, M; Curty, M; Steinlechner, F; Anzolin, G; Torres, J P; Mitchell, M W; Pruneri, V

2011-10-10

Random numbers are essential for applications ranging from secure communications to numerical simulation and quantitative finance. Algorithms can rapidly produce pseudo-random outcomes, series of numbers that mimic most properties of true random numbers while quantum random number generators (QRNGs) exploit intrinsic quantum randomness to produce true random numbers. Single-photon QRNGs are conceptually simple but produce few random bits per detection. In contrast, vacuum fluctuations are a vast resource for QRNGs: they are broad-band and thus can encode many random bits per second. Direct recording of vacuum fluctuations is possible, but requires shot-noise-limited detectors, at the cost of bandwidth. We demonstrate efficient conversion of vacuum fluctuations to true random bits using optical amplification of vacuum and interferometry. Using commercially-available optical components we demonstrate a QRNG at a bit rate of 1.11 Gbps. The proposed scheme has the potential to be extended to 10 Gbps and even up to 100 Gbps by taking advantage of high speed modulation sources and detectors for optical fiber telecommunication devices.

Use of random amplified polymorphic DNA (RAPD) for generating specific DNA probes for oxyuroid species (Nematoda).

Science.gov (United States)

Jobet, E; Bougnoux, M E; Morand, S; Rivault, C; Cloarec, A; Hugot, J P

1998-03-01

Random amplified DNA markers (RAPD; Williams et al., 1990) were used to obtained specific RAPD fragments characterising different species of oxyuroids. We tested six species of worms parasitizing vertebrates or invertebrates: Passalurus ambiguus Rudolphi, 1819, parasite of Leporids; Syphacia obvelata (Rudolphi, 1802) Seurat, 1916, a parasite of rodents; Blatticola blattae (Graeffe, 1860) Chitwood, 1932 parasite of the cockroach Blattella germanica; Hammerschmidtiella diesingi (Hammerschmidt, 1838) Chitwood, 1932 and Thelastoma bulhoesi (Magalhaes, 1990) Travassos, 1929, parasites of the cockroach Periplaneta americana, and an undescribed parasite species of a passalid insect from New Caledonia. Among 15 oligonucleotides tested, nine produced several specific bands allowing the interspecific discrimination.

Molecular characterization with random amplified microsatellites (RAMs of Inchi (Caryodendron orinocense K.

Directory of Open Access Journals (Sweden)

Ana Cruz Morillo Coronado

2015-01-01

Full Text Available The Inchi or Cacay (Caryodendron orinocense Karsten is one of the most promising species of the Amazon and Orinoco Colombian. The main product of Cacay are its almonds, from extracted oil cosmetic, phytotherapeutic and food applications, also has a high content of antioxidants such as Omega 3, 6 and 9 and vitamins like A and E. There are no studies on the molecular characterization of this plant genetic resource; therefore the objective of this research was to characterize the genetic diversity using Random Amplified Microsatellite markers (RAMs. The similarity analysis to 0.50 formed four groups according to geographical location, being materials from Putumayo, Cacayal 19, Pauna and Castilla lowest similarity. Estimated heterozygosity values were 0.16 and 0.28 for the primers CGA and GT, respectively. The percentage of polymorphic loci ranged from 55% for the primer CGA and 90% for the GT. The average Fst value for the 27 materials studied was 0.35, showing the space-temporal dynamics of materials Caryodendron tend toward genetic differentiation, due to their own evolutionary processes and domestication incidence.

Evolution of finger millet: evidence from random amplified polymorphic DNA.

Science.gov (United States)

Hilu, K W

1995-04-01

Finger millet (Eleusine coracana ssp. coracana) is an annual tetraploid member of a predominantly African genus. The crop is believed to have been domesticated from the tetraploid E. coracana ssp. africana. Cytogenetic and isozyme data point to the allopolyploid nature of the species and molecular information has shown E. indica to be one of the genomic donors. A recent isozyme study questioned the proposed phylogenetic relationship between finger millet and its direct ancestor subspecies africana. An approach using random amplified polymorphic DNA (RAPD) was employed in this study to examine genetic diversity and to evaluate hypotheses concerning the evolution of domesticated and wild annual species of Eleusine. Unlike previous molecular approaches, the RAPD study revealed genetic diversity in the crop. The pattern of genetic variation was loosely correlated to geographic distribution. The allotetraploid nature of the crop was confirmed and molecular markers that can possibly identify the other genomic donor were proposed. Genotypes of subspecies africana did not group closely with those of the crop but showed higher affinities to E. indica, reflecting the pattern of similarity revealed by the isozyme study. The multiple origin of subspecies africana could explain the discrepancy between the isozyme-RAPD evidence and previous information. The RAPD study showed the close genetic affinity of E. tristachya to the E. coracana--E. indica group and understood the distinctness of E. multiflora.

Random amplified polymorphic DNA analysis of Anopheles nuneztovari (Diptera: Culicidae from Western and Northeastern Colombia

Directory of Open Access Journals (Sweden)

Carmen Elisa Posso

2003-06-01

Full Text Available Random amplified polymorphic DNA (RAPD markers were used to analyze 119 DNA samples of three Colombian Anopheles nuneztovari populations to study genetic variation and structure. Genetic diversity, estimated from heterozygosity, averaged 0.34. Genetic flow was greater between the two populations located in Western Colombia (F ST: 0.035; Nm: 6.8 but lower between these two and the northeastern population (F ST: 0.08; Nm: 2.8. According to molecular variance analysis, the genetic distance between populations was significant (phiST 0.1131, P < 0.001. The variation among individuals within populations (phiST 0.8869, P < 0.001was also significant, suggesting a greater degree of population subdivision, not considered in this study. Both the parameters evaluated and the genetic flow suggest that Colombian An. nuneztovari populations are co-specific.

Fiber Amplifiers

DEFF Research Database (Denmark)

Rottwitt, Karsten

2017-01-01

The chapter provides a discussion of optical fiber amplifiers and through three sections provides a detailed treatment of three types of optical fiber amplifiers, erbium doped fiber amplifiers (EDFA), Raman amplifiers, and parametric amplifiers. Each section comprises the fundamentals including...... the basic physics and relevant in-depth theoretical modeling, amplifiers characteristics and performance data as a function of specific operation parameters. Typical applications in fiber optic communication systems and the improvement achievable through the use of fiber amplifiers are illustrated....

Population structure of a lodgepole pine (Pinus contorta) and jack pine (P. banksiana) complex as revealed by random amplified polymorphic DNA.

Science.gov (United States)

Ye, Terrance Z; Yang, Rong-Cai; Yeh, Francis C

2002-06-01

We studied the population structure of a lodgepole (Pinus contorta Dougl.) and jack pine (Pinus banksiana Lamb.) complex in west central Alberta and neighboring areas by assessing random amplified polymorphic DNA (RAPD) variability in 23 lodgepole pine, 9 jack pine, and 8 putative hybrid populations. Of 200 random primers screened, 10 that amplified 39 sharp and reproducible RAPDs were chosen for the study. None of the 39 RAPDs were unique to the parental species. RAPD diversity ranged from 0.085 to 0.190 among populations and averaged 0.143 for lodgepole pine, 0.156 for jack pine, 0.152 for hybrids, and 0.148 for all 40 populations. The estimated population differentiation based on G(ST) was 0.168 for hybrids, 0.162 for lodgepole pine, 0.155 for jack pine, and 0.247 across all 40 populations. Cluster analysis of genetic distances generally separated jack pine from lodgepole pine and hybrids, but no division could be identified that further separated lodgepole pine from hybrids. The observed weak to mild trend of "introgression by distance" in the complex and neighbouring areas was consistent with the view that introgressive hybridization between lodgepole and jack pines within and outside the hybrid zone may have been through secondary contact and primary intergradation, respectively.

Characterization of Malaysian Trichoderma isolates using random amplified microsatellites (RAMS).

Science.gov (United States)

Siddiquee, Shafiquzzaman; Tan, Soon Guan; Yusuf, Umi Kalsom; Fatihah, Nur Hasan Nudin; Hasan, Md Mainul

2012-01-01

Trichoderma species are commercially applied as biocontrol agents against numerous plant pathogenic fungi due to their production of antifungal metabolites, competition for nutrients and space, and mycoparasitism. However, currently the identification of Trichoderma species from throughout the world based on micro-morphological descriptions is tedious and prone to error. The correct identification of Trichoderma species is important as several traits are species-specific. The Random Amplified Microsatellites (RAMS) analysis done using five primers in this study showed different degrees of the genetic similarity among 42 isolates of this genus. The genetic similarity values were found to be in the range of 12.50-85.11% based on a total of 76 bands scored in the Trichoderma isolates. Of these 76 bands, 96.05% were polymorphic, 3.95% were monomorphic and 16% were exclusive bands. Two bands (250 bp and 200 bp) produced by primer LR-5 and one band (250 bp) by primer P1A were present in all the Trichoderma isolates collected from healthy and infected oil palm plantation soils. Cluster analysis based on UPGMA of the RAMS marker data showed that T. harzianum, T. virens and T. longibrachiatum isolates were grouped into different clades and lineages. In this study we found that although T. aureoviride isolates were morphologically different when compared to T. harzianum isolates, the UPGMA cluster analysis showed that the majority isolates of T. aureoviride (seven from nine) were closely related to the isolates of T. harzianum.

Random-matrix theory of amplifying and absorbing resonators with PT or PTT' symmetry

International Nuclear Information System (INIS)

Birchall, Christopher; Schomerus, Henning

2012-01-01

We formulate Gaussian and circular random-matrix models representing a coupled system consisting of an absorbing and an amplifying resonator, which are mutually related by a generalized time-reversal symmetry. Motivated by optical realizations of such systems we consider a PT or a PTT ' time-reversal symmetry, which impose different constraints on magneto-optical effects, and then focus on five common settings. For each of these, we determine the eigenvalue distribution in the complex plane in the short-wavelength limit, which reveals that the fraction of real eigenvalues among all eigenvalues in the spectrum vanishes if all classical scales are kept fixed. Numerically, we find that the transition from real to complex eigenvalues in the various ensembles display a different dependence on the coupling strength between the two resonators. These differences can be linked to the level spacing statistics in the Hermitian limit of the considered models. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Quantum physics with non-Hermitian operators’. (paper)

Compound heterozygous deletions in pseudoautosomal region 1 in an infant with mild manifestations of langer mesomelic dysplasia.

Science.gov (United States)

Tsuchiya, Takayoshi; Shibata, Minoru; Numabe, Hironao; Jinno, Tomoko; Nakabayashi, Kazuhiko; Nishimura, Gen; Nagai, Toshiro; Ogata, Tsutomu; Fukami, Maki

2014-02-01

Haploinsufficiency of SHOX on the short arm pseudoautosomal region (PAR1) leads to Leri-Weill dyschondrosteosis (LWD), and nullizygosity of SHOX results in Langer mesomelic dysplasia (LMD). Molecular defects of LWD/LMD include various microdeletions in PAR1 that involve exons and/or the putative upstream or downstream enhancer regions of SHOX, as well as several intragenic mutations. Here, we report on a Japanese male infant with mild manifestations of LMD and hitherto unreported microdeletions in PAR1. Clinical analysis revealed mesomelic short stature with various radiological findings indicative of LMD. Molecular analyses identified compound heterozygous deletions, that is, a maternally inherited ∼46 kb deletion involving the upstream region and exons 1-5 of SHOX, and a paternally inherited ∼500 kb deletion started from a position ∼300 kb downstream from SHOX. In silico analysis revealed that the downstream deletion did not affect the known putative enhancer regions of SHOX, although it encompassed several non-coding elements which were well conserved among various species with SHOX orthologs. These results provide the possibility of the presence of a novel enhancer for SHOX in the genomic region ∼300 to ∼800 kb downstream of the start codon. © 2013 Wiley Periodicals, Inc.

Phase noise in RF and microwave amplifiers.

Science.gov (United States)

Boudot, Rodolphe; Rubiola, Enrico

2012-12-01

Understanding amplifier phase noise is a critical issue in many fields of engineering and physics, such as oscillators, frequency synthesis, telecommunication, radar, and spectroscopy; in the emerging domain of microwave photonics; and in exotic fields, such as radio astronomy, particle accelerators, etc. Focusing on the two main types of base noise in amplifiers, white and flicker, the power spectral density of the random phase φ(t) is Sφ(f) = b(0) + b(-1)/f. White phase noise results from adding white noise to the RF spectrum in the carrier region. For a given RF noise level, b(0) is proportional to the reciprocal of the carrier power P(0). By contrast, flicker results from a near-dc 1/f noise-present in all electronic devices-which modulates the carrier through some parametric effect in the semiconductor. Thus, b(-1) is a parameter of the amplifier, constant in a wide range of P(0). The consequences are the following: Connecting m equal amplifiers in parallel, b(-1) is 1/m times that of one device. Cascading m equal amplifiers, b(-1) is m times that of one amplifier. Recirculating the signal in an amplifier so that the gain increases by a power of m (a factor of m in decibels) as a result of positive feedback (regeneration), we find that b(-1) is m(2) times that of the amplifier alone. The feedforward amplifier exhibits extremely low b(-1) because the carrier is ideally nulled at the input of its internal error amplifier. Starting with an extensive review of the literature, this article introduces a system-oriented model which describes the phase flickering. Several amplifier architectures (cascaded, parallel, etc.) are analyzed systematically, deriving the phase noise from the general model. There follow numerous measurements of amplifiers using different technologies, including some old samples, and in a wide frequency range (HF to microwaves), which validate the theory. In turn, theory and results provide design guidelines and give suggestions for CAD and

Molecular characterization of 93 genotypes of cocoa (Theobroma cacao L. with random amplified microsatellites RAMs

Directory of Open Access Journals (Sweden)

Yacenia Morillo C.

2014-12-01

Full Text Available Random amplified microsatellite (RAMs markers six were used to characterize 93 genotypes of cocoa in Tumaco (Colombia. Hundred twenty seven bands were generated. The number of polymorphic loci varied between 11 and 25 for the AG and TG primers, respectively. This study differentiated the 93 genotypes into six groups with a 0.53 similarity, 0.28 mean heterozygosity (He for the population, and 0.12±0.02 genetic differentiation coefficient or Fst. A significant level of genetic diversity was evident in the T. cacao genotypes. This resource would benefit selection programs of individual trees or plant breeding programs. The genotypes clustered in a large proportion in accordance with the collection zone. This characteristic was associated with collection zones and along the rivers in the municipality of Tumaco. The RAM technique proved to be a useful tool for the determination of genetic diversity in Theobroma species.

Development of a sequence characterized amplified region (SCAR ...

African Journals Online (AJOL)

The varieties of rice are difficult to be distinguished because of their similar morphological characters, therefore rice variety identification or differentiation is very important. The authentication by using molecular marker or DNA fingerprinting is the most accurate method. In this study, random amplified polymorphic DNA ...

Comparison of Ribotyping, Randomly Amplified Polymorphic DNA Analysis, and Pulsed-Field Gel Electrophoresis in Typing of Lactobacillus rhamnosus and L. casei Strains

OpenAIRE

Tynkkynen, Soile; Satokari, Reetta; Saarela, Maria; Mattila-Sandholm, Tiina; Saxelin, Maija

1999-01-01

A total of 24 strains, biochemically identified as members of the Lactobacillus casei group, were identified by PCR with species-specific primers. The same set of strains was typed by randomly amplified polymorphic DNA (RAPD) analysis, ribotyping, and pulsed-field gel electrophoresis (PFGE) in order to compare the discriminatory power of the methods. Species-specific primers for L. rhamnosus and L. casei identified the type strain L. rhamnosus ATCC 7469 and the neotype strain L. casei ATCC 33...

Stabilization of the outputs of pulse amplifiers utilizing non-linear feedback networks. Application to nuclear spectrometer amplifiers

International Nuclear Information System (INIS)

Henein, K.L.

1978-02-01

In nuclear spectroscopy, baseline instability and random fluctuations at the output of the amplifier create imperfectly solved problems mainly at high counting rates. After a critical examination of current systems, solutions are proposed which surpass existing ones. It is shown that restorers and stabilizers of baselines have their own preferential application. Considering natural limits of performance the proposed solutions give entirely satisfactory results [fr

Operation amplifier

NARCIS (Netherlands)

Tetsuya, Saito; Nauta, Bram

2008-01-01

To provide an operation amplifier which improves power source voltage removal ratios while assuring phase compensation characteristics, and therefore can be realized with a small-scale circuit and low power consumption. SOLUTION: The operation amplifier comprises: a differential amplifier circuit 1;

Amplifier Distortion

Science.gov (United States)

Keeports, David

2006-12-01

By definition, a high fidelity amplifier's instantaneous output voltage is directly proportional to its instantaneous input voltage. While high fidelity is generally valued in the amplification of recorded music, nonlinearity, also known as distortion, is desirable in the amplification of some musical instruments. In particular, guitar amplifiers exploit nonlinearity to increase both the harmonic content and sustain of a guitar's sound. I will discuss how both modifications in sound result from saturation of triode tubes and transistors. Additionally, I will describe the difference in the symmetry of saturation curves for transistors and tubes and the reason why tube guitar amplifiers are generally considered to be superior to solid-state amplifiers. Finally, I will discuss attempts to use solid-state electronics to replicate the sound of tube amplifiers.

Physical-layer security analysis of PSK quantum-noise randomized cipher in optically amplified links

Science.gov (United States)

Jiao, Haisong; Pu, Tao; Xiang, Peng; Zheng, Jilin; Fang, Tao; Zhu, Huatao

2017-08-01

The quantitative security of quantum-noise randomized cipher (QNRC) in optically amplified links is analyzed from the perspective of physical-layer advantage. Establishing the wire-tap channel models for both key and data, we derive the general expressions of secrecy capacities for the key against ciphertext-only attack and known-plaintext attack, and that for the data, which serve as the basic performance metrics. Further, the maximal achievable secrecy rate of the system is proposed, under which secrecy of both the key and data is guaranteed. Based on the same framework, the secrecy capacities of various cases can be assessed and compared. The results indicate perfect secrecy is potentially achievable for data transmission, and an elementary principle of setting proper number of photons and bases is given to ensure the maximal data secrecy capacity. But the key security is asymptotically perfect, which tends to be the main constraint of systemic maximal secrecy rate. Moreover, by adopting cascaded optical amplification, QNRC can realize long-haul transmission with secure rate up to Gb/s, which is orders of magnitude higher than the perfect secrecy rates of other encryption systems.

Comparing interfertility data with random amplified microsatellites DNA (RAMS) studies in Ganoderma Karst. Taxonomy.

Science.gov (United States)

Nudin, Nur Fatihah Hasan; S, Siddiquee

2012-03-01

The taxonomy of the causal pathogen of basal stem rot of oil palms, Ganoderma is somewhat problematic at present. In order to determine the genetic distance relationship between G. boninense isolates and non-boninense isolates, a random amplified microsatellites DNA (RAMS) technique was carried out. The result was then compared with interfertility data of G. boninense that had been determined in previous mating studies to confirm the species of G. boninense. Dendrogram from cluster analysis based on UPGMA of RAMS data showed that two major clusters, I and II which separated at a genetic distance of 0.7935 were generated. Cluster I consisted of all the biological species G. boninense isolates namely CNLB, GSDK 3, PER 71, WD 814, GBL 3, GBL 6, OC, GH 02, 170 SL and 348781 while all non-boninense isolates namely G. ASAM, WRR, TFRI 129, G. RES, GJ, and CNLM were grouped together in cluster II. Although the RAMS markers showed polymorphisms in all the isolates tested, the results obtained were in agreement with the interfertility data. Therefore, the RAMS data could support the interfertility data for the identification of Ganoderma isolates.

Randomly amplified polymorphic-DNA analysis for detecting genotoxic effects of Boron on maize (Zea mays L.).

Science.gov (United States)

Sakcali, M Serdal; Kekec, Guzin; Uzonur, Irem; Alpsoy, Lokman; Tombuloglu, Huseyin

2015-08-01

This study was carried out to investigate the genotoxic effect of boron (B) on maize using randomly amplified polymorphic DNA (RAPD) method. Experimental design was conducted under 0, 5, 10, 25, 50, 100, 125, and 150 ppm B exposures, and physiological changes have revealed a sharp decrease in root growth rates from 28% to 85%, starting from 25 ppm to 150 ppm, respectively. RAPD-polymerase chain reaction (PCR) analysis shows that DNA alterations are clearly observed from beginning to 100 ppm. B-induced inhibition in root growth had a positive correlation with DNA alterations. Total soluble protein, root and stem lengths, and B content analysis in root and leaves encourage these results as a consequence. These preliminary findings reveal that B causes chromosomal aberration and genotoxic effects on maize. Meanwhile, usage of RAPD-PCR technique is a suitable biomarker to detect genotoxic effect of B on maize and other crops for the future. © The Author(s) 2013.

Application of random amplified polymorphic DNA (RAPD) markers ...

African Journals Online (AJOL)

SAM

2014-06-11

Jun 11, 2014 ... variety share an identical genome. In this field one of the most successful techniques is random ... To each minced sample, 350 µL of the same extraction buffer was added and the samples were ..... using fingerprints produced by random primers. J. Hort. Sci. 69:123-. 130. Levi A, Rowland LJ, Hartung JS ...

Genetic relationships among Rosa species based on random ...

African Journals Online (AJOL)

To investigate the genetic diversity of Rosa accessions, random amplified polymorphism DNA (RAPD) approach was employed. Nine of ten primers amplified 138 scorable RAPD loci with 111 polymorphic bands (80%). Percentages of polymorphic bands ranged from 75 to 100%. Sizes of amplified DNA fragments ranged ...

Auto-Zero Differential Amplifier

Science.gov (United States)

Quilligan, Gerard T. (Inventor); Aslam, Shahid (Inventor)

2017-01-01

An autozero amplifier may include a window comparator network to monitor an output offset of a differential amplifier. The autozero amplifier may also include an integrator to receive a signal from a latched window comparator network, and send an adjustment signal back to the differential amplifier to reduce an offset of the differential amplifier.

Portable musical instrument amplifier

Science.gov (United States)

Christian, David E.

1990-07-24

The present invention relates to a musical instrument amplifier which is particularly useful for electric guitars. The amplifier has a rigid body for housing both the electronic system for amplifying and processing signals from the guitar and the system's power supply. An input plug connected to and projecting from the body is electrically coupled to the signal amplifying and processing system. When the plug is inserted into an output jack for an electric guitar, the body is rigidly carried by the guitar, and the guitar is operatively connected to the electrical amplifying and signal processing system without use of a loose interconnection cable. The amplifier is provided with an output jack, into which headphones are plugged to receive amplified signals from the guitar. By eliminating the conventional interconnection cable, the amplifier of the present invention can be used by musicians with increased flexibility and greater freedom of movement.

Generalized randomly amplified linear system driven by Gaussian noises: Extreme heavy tail and algebraic correlation decay in plasma turbulence

International Nuclear Information System (INIS)

Steinbrecher, Gyoergy; Weyssow, B.

2004-01-01

The extreme heavy tail and the power-law decay of the turbulent flux correlation observed in hot magnetically confined plasmas are modeled by a system of coupled Langevin equations describing a continuous time linear randomly amplified stochastic process where the amplification factor is driven by a superposition of colored noises which, in a suitable limit, generate a fractional Brownian motion. An exact analytical formula for the power-law tail exponent β is derived. The extremely small value of the heavy tail exponent and the power-law distribution of laminar times also found experimentally are obtained, in a robust manner, for a wide range of input values, as a consequence of the (asymptotic) self-similarity property of the noise spectrum. As a by-product, a new representation of the persistent fractional Brownian motion is obtained

Operation Amplifier

NARCIS (Netherlands)

Tetsuya, Saito; Nauta, Bram

2011-01-01

PROBLEM TO BE SOLVED: To provide an operation amplifier which improves power source voltage removal ratios while assuring phase compensation characteristics, and therefore can be realized with a small-scale circuit and low power consumption. SOLUTION: The operation amplifier comprises: a

Operation Amplifier

NARCIS (Netherlands)

Tetsuya, S.; Nauta, Bram

2007-01-01

PROBLEM TO BE SOLVED: To provide an operation amplifier which improves power source voltage removal ratios while assuring phase compensation characteristics, and therefore can be realized with a small-scale circuit and low power consumption. ; SOLUTION: The operation amplifier comprises: a

Distributed feedback laser amplifiers combining the functions of amplifiers and channel filters

DEFF Research Database (Denmark)

Wang, Z.; Durhuus, T.; Mikkelsen, Benny

1994-01-01

A dynamic model for distributed feedback amplifiers, including the mode coupled equations and the carrier rate equation, is established. The presented mode coupled equations have taken into account the interaction between fast changing optical signal and the waveguide with corrugations. By showin...... the possibility of amplifying 100 ps pulses without pulse broadening, we anticipate that a distributed feedback amplifier can be used as a combined amplifier and channel filter in high bit rate transmission systems....

Design and Development of Advanced Lock-in Amplifier and its Application

Directory of Open Access Journals (Sweden)

Bhagyajyothi

2013-06-01

Full Text Available Lock-in amplifiers are used to process the analog signals even in the presence of noise sources of greater amplitude. In the present study, an attempt is made to design a C8051F060 microcontroller based lock-in amplifier. The microcontroller contains all the on-chip features to design a single-chip lock-in amplifier. The reference signal for lock-in amplifier is generated by on-chip digital-to-analog converter (DAC and timer. The signal whose amplitude is to be measured is acquired by on-chip ADC. The ADC values are directly stored on to XRAM through on-chip DMA controller. Later, these stored values are processed by using quadrature sampling method to get amplitude and phase of the 100 waves. The amplitude and phase values of 100 waves are averaged to eliminate the random noise of the signal and are displayed on the LCD module. The amplitude and phase are sent to the PC through on-chip serial port (UART to store/plot the graph. The proposed lock-in amplifier is applied to study the phase transitions of sulfur sample by varying the temperature at slow rate (0.3 °C/min using microcontroller based temperature control system.

Identification of internal variation in the pseudoautosomal VNTR DXYS17, with nonrandom distribution of the alleles on the X and the Y chromosomes

Energy Technology Data Exchange (ETDEWEB)

Decorte, R.; Wu, R.; Marynen, P.; Cassiman, J.J.

1994-03-01

The PCR technique was used to analyze the DXYS17 locus in the pseudoautosomal region of the X and the Y chromosomes. Analysis on an automated DNA sequencer allowed for sensitive and highly accurate typing of 16 different alleles with a size between 480 and 1,100 bp. Two DXYS17 alleles migrated with the same size on agarose or denaturing polyacrylamide gels but with different mobilities on nondenaturing polyacrylamide gels. Sequence analysis showed that, while an identical number of repeats were present in both alleles, differences in the composition of the units were observed. The origin of these differences was found in the 28- and 33-bp units, which only had a specific repeat pattern at the 5' and 3' ends of the region. The genotype distribution for DXYS17 in a Caucasian population did not deviate from the values expected under Hardy-Weinberg equilibrium. However, the frequency of one allele and one genotype was significantly different between males and females. Segregation analysis showed that this difference was the result of a nonrandom distribution of certain alleles on the sex chromosomes in males. 31 refs., 4 figs., 2 tabs.

Evaluation of genetic diversity in Chinese kale (Brassica oleracea L. var. alboglabra Bailey) by using rapid amplified polymorphic DNA and sequence-related amplified polymorphism markers.

Science.gov (United States)

Zhang, J; Zhang, L G

2014-02-14

Chinese kale is an original Chinese vegetable of the Cruciferae family. To select suitable parents for hybrid breeding, we thoroughly analyzed the genetic diversity of Chinese kale. Random amplified polymorphic DNA (RAPD) and sequence-related amplified polymorphism (SRAP) molecular markers were used to evaluate the genetic diversity across 21 Chinese kale accessions from AVRDC and Guangzhou in China. A total of 104 bands were detected by 11 RAPD primers, of which 66 (63.5%) were polymorphic, and 229 polymorphic bands (68.4%) were observed in 335 bands amplified by 17 SRAP primer combinations. The dendrogram showed the grouping of the 21 accessions into 4 main clusters based on RAPD data, and into 6 clusters based on SRAP and combined data (RAPD + SRAP). The clustering of accessions based on SRAP data was consistent with petal colors. The Mantel test indicated a poor fit for the RAPD and SRAP data (r = 0.16). These results have an important implication for Chinese kale germplasm characterization and improvement.

Molecular Diversity of Antagonistic Streptomyces spp. against Botrytis allii, the agent of onion gray mold using Random Amplified Polymorphic DNA (RAPD Markers

Directory of Open Access Journals (Sweden)

M. Jorjandi

2014-08-01

Full Text Available As an aim in sustainable agriculture, biological control of plant diseases has received intensive attention mainly as a response to public concern about the use of chemical fungicides in the environment. Soil Actinomycetes particularly Streptomyces spp. enhance soil fertility and have antagonistic activity against wide range of plant pathogens. To investigate for biocontrol means against the pathogen, 30 isolates of Actinomycetes have been isolated from agricultural soils of Kerman province of Iran and assayed for antagonistic activity against Botrytis allii, the agent of onion gray mold. RAPD DNA analysis has been used to determine the relatedness of active and non-active isolates based on their RAPD-PCR fingerprints. PCR amplifiable DNA samples have been isolated using the CTAB method and amplified fragments have been obtained from 5 random 10-mer primers. Different DNA fingerprinting patterns have been obtained for all of the isolates. Electrophoretic and cluster analysis of the amplification products has revealed incidence of polymorphism among the isolates. A total of 138 bands, ranging in size from 150-2800 bp, have been amplified from primers which 63.7% of the observed bands have been polymorphic. Genetic distances among different varieties have been analyzed with a UPGMA (Unweighted pair-group method, arithmetic average-derived dendrogram. Resulting dendrogram has showed from 0.65 to 0.91 similarities among varieties and divided the isolates into five major groups. Isolates which haven’t had any antagonistic activity against B. allii have been separated into a group and other isolates classified into four groups. The results indicate that RAPD is an efficient method for discriminating and studying genetic diversity of Streptomyces isolates.

Development of an optimized random amplified polymorphic DNA protocol for fingerprinting of Klebsiella pneumoniae.

Science.gov (United States)

Ashayeri-Panah, M; Eftekhar, F; Feizabadi, M M

2012-04-01

To develop an optimized random amplified polymorphic DNA (RAPD) protocol for fingerprinting clinical isolates of Klebsiella pneumoniae. Employing factorial design of experiments, repeatable amplification patterns were obtained for 54 nosocomial isolates using 1 μmol 1(-1) primer, 4 mmol 1(-1) MgCl(2), 0·4 mmol 1(-1) dNTPs, 2·5 U Taq DNA polymerase and 90 ng DNA template in a total volume of 25 μl. The optimum thermocycling program was: initial denaturation at 94°C for 4 min followed by 50 cycles of 1 min at 94°C, 2 min at 34°C, 2 min at 72°C and a final extension at 72°C for 10 min. The optimized RAPD protocol was highly discriminatory (Simpson's diversity index, 0·982), and all isolates were typable with repeatable patterns (Pearson's similarity coefficient ≈ 100%). Seven main clusters were obtained on a similarity level of 70% and 32 distinct clusters on a similarity level of 85%, reflecting the heterogeneity of the isolates. Systematic optimization of RAPD generated reliable DNA fingerprints for nosocomial isolates of K. pneumoniae. This is the first report on RAPD optimization based on factorial design of experiments for discrimination of K. pneumoniae. © 2012 The Authors. Letters in Applied Microbiology © 2012 The Society for Applied Microbiology.

Genetic diversity of edible mushroom pleurotus spp. revealed by randomly amplified polymorphic dna fingerprinting

International Nuclear Information System (INIS)

Khan, N. A.; Awan, F. S.; Khan, A. I.; Waseem, M.

2017-01-01

The Oyster mushroom (Pleurotus) cultivation is a profitable agribusiness and having high significance due its nutritive and therapeutic value. Due to deficient knowledge on Pleurotus mushroom genetics seven strains of Oyster mushroom, two local and five exotic were studied for their genetic diversity through RAPD markers. It was clear from similarity matrix that similarity index ranges from 45 to 72%. The cluster analysis of combined data set of all the markers resulted in three major clades, while isolate P-17 remains ungrouped and shown to be the most diverse strain of the seven. During amplification of genomic DNA yielded 70 fragments that could be scored, of which 41 were polymorphic, with an average of 2.73 polymorphic fragments per primer. Number of amplified fragments with random primers ranged from three to six. Polymorphism ranged from 0% to 83.33%, with an overall 58% polymorphism. The allele frequency of RAPD primers ranged from 0.71 to 1.00 while the polymorphic information content highest for the primer GL-C-20 (0.29) followed by the primers GL A-20 and GL C-16 that is zero, indicating medium level of polymorphism among the strains of Oyster mushroom. The objective of the study was to characterize Pleurotus strains collected from different origins and to find out the variability at molecular level. (author)

Antares laser power amplifier

International Nuclear Information System (INIS)

Stine, R.D.; Ross, G.F.; Silvernail, C.

1979-01-01

The overall design of the Antares laser power amplifier is discussed. The power amplifier is the last stage of amplification in the 100-kJ Antares laser. In the power amplifier a single, cylindrical, grid-controlle, cold-cathode electron gun is surrounded by 12 large-aperture CO 2 electron-beam sustained laser discharge sectors. Each power amplifier will deliver 18 kJ and the six modules used in Antares will produce the required 100 kJ for delivery to the target. A large-scale interaction between optical, mechanical, and electrical disciplines is required to meet the design objectives. Significant component advances required by the power amplifier design are discussed

Estimation of genetic variability among elite wheat genotypes using random amplified polymorphic DNA (RAPD) analysis

International Nuclear Information System (INIS)

BIBI, S.; Khan, I.A.; Naqvi, M.H.; Siddiqui, M.A.; Yasmeen, S.; Seema, M.

2012-01-01

Twenty four wheat varieties/lines were assessed through RAPD for genetic diversity. Of forty primers, thirteen were able to amplify the genomic DNA and yielded 269 polymorphic bands. The percentage of the polymorphic loci was 86.22%. Nei's genetic diversity (h) ranged from 0.248 to 0.393, with an average of 0.330. Shanon's index ranged from 0.382 to 0.567, with an average of 0.487. The proportion of genetic variation among the populations ( Ds) accounted for 28.58 % of the whole genetic diversity. The level of gene flow (Nm) was 1.25. Some specific RAPD bands were also identified, variety C-591, and QM-4531 contain a specific segment of 4.9 kbp. Whereas SARC-1 and PKV-1600 amplified a specific DNA segment with primer A-09. Marvi-2000 contains two specific segments of 3.2 kb and 200 bp amplified with primer B-07. Genetically most similar genotypes were C-591 and Pasban-90 (76%) and most dissimilar genotypes were Rawal-87 and Khirman (36.1%). On the basis of results, 24 wheat varieties under study could be divided into 'two' groups and five clusters 'A' to 'E. (author)

Amplification factor variable amplifier

NARCIS (Netherlands)

Akitsugu, Oshita; Nauta, Bram

2007-01-01

PROBLEM TO BE SOLVED: To provide an amplification factor variable amplifier capable of achieving temperature compensation of an amplification factor over a wide variable amplification factor range. ; SOLUTION: A Gilbert type amplification factor variable amplifier 11 amplifies an input signal and

Amplification factor variable amplifier

NARCIS (Netherlands)

Akitsugu, Oshita; Nauta, Bram

2010-01-01

PROBLEM TO BE SOLVED: To provide an amplification factor variable amplifier capable of achieving temperature compensation of an amplification factor over a wide variable amplification factor range. ;SOLUTION: A Gilbert type amplification factor variable amplifier 11 amplifies an input signal and can

CMOS Current-mode Operational Amplifier

DEFF Research Database (Denmark)

Kaulberg, Thomas

1992-01-01

current-mode feedback amplifier or a constant bandwidth in a transimpedance feedback amplifier. The amplifier is found to have a gain bandwidth product of 8 MHz, an offset current of 0.8 ¿A (signal-range ±700¿A) and a (theoretically) unlimited slew-rate. The amplifier is realized in a standard CMOS 2......A fully differential-input differential-output current-mode operational amplifier (COA) is described. The amplifier utilizes three second generation current-conveyors (CCII) as the basic building blocks. It can be configured to provide either a constant gain-bandwidth product in a fully balanced...

Operational amplifiers

CERN Document Server

Dostal, Jiri

1993-01-01

This book provides the reader with the practical knowledge necessary to select and use operational amplifier devices. It presents an extensive treatment of applications and a practically oriented, unified theory of operational circuits.Provides the reader with practical knowledge necessary to select and use operational amplifier devices. Presents an extensive treatment of applications and a practically oriented, unified theory of operational circuits

CMOS Current-mode Operational Amplifier

OpenAIRE

Kaulberg, Thomas

1992-01-01

A fully differential-input differential-output current-mode operational amplifier (COA) is described. The amplifier utilizes three second generation current-conveyors (CCII) as the basic building blocks. It can be configured to provide either a constant gain-bandwidth product in a fully balanced current-mode feedback amplifier or a constant bandwidth in a transimpedance feedback amplifier. The amplifier is found to have a gain bandwidth product of 8 MHz, an offset current of 0.8 ¿A (signal-r...

Simplified design of IC amplifiers

CERN Document Server

Lenk, John

1996-01-01

Simplified Design of IC Amplifiers has something for everyone involved in electronics. No matter what skill level, this book shows how to design and experiment with IC amplifiers. For experimenters, students, and serious hobbyists, this book provides sufficient information to design and build IC amplifier circuits from 'scratch'. For working engineers who design amplifier circuits or select IC amplifiers, the book provides a variety of circuit configurations to make designing easier.Provides basics for all phases of practical design.Covers the most popular forms for amplif

Improved-Bandwidth Transimpedance Amplifier

Science.gov (United States)

Chapsky, Jacob

2009-01-01

The widest available operational amplifier, with the best voltage and current noise characteristics, is considered for transimpedance amplifier (TIA) applications where wide bandwidth is required to handle fast rising input signals (as for time-of-flight measurement cases). The added amplifier inside the TIA feedback loop can be configured to have slightly lower voltage gain than the bandwidth reduction factor.

Millimeter-wave power amplifiers

CERN Document Server

du Preez, Jaco

2017-01-01

This book provides a detailed review of millimeter-wave power amplifiers, discussing design issues and performance limitations commonly encountered in light of the latest research. Power amplifiers, which are able to provide high levels of output power and linearity while being easily integrated with surrounding circuitry, are a crucial component in wireless microwave systems. The book is divided into three parts, the first of which introduces readers to mm-wave wireless systems and power amplifiers. In turn, the second focuses on design principles and EDA concepts, while the third discusses future trends in power amplifier research. The book provides essential information on mm-wave power amplifier theory, as well as the implementation options and technologies involved in their effective design, equipping researchers, circuit designers and practicing engineers to design, model, analyze, test and implement high-performance, spectrally clean and energy-efficient mm-wave systems.

Oscillators and operational amplifiers

OpenAIRE

Lindberg, Erik

2005-01-01

A generalized approach to the design of oscillators using operational amplifiers as active elements is presented. A piecewise-linear model of the amplifier is used so that it make sense to investigate the eigenvalues of the Jacobian of the differential equations. The characteristic equation of the general circuit is derived. The dynamic nonlinear transfer characteristic of the amplifier is investigated. Examples of negative resistance oscillators are discussed.

FLUIDIC AC AMPLIFIERS.

Science.gov (United States)

Several fluidic tuned AC Amplifiers were designed and tested. Interstage tuning and feedback designs are considered. Good results were obtained...corresponding Q’s as high as 12. Element designs and test results of one, two, and three stage amplifiers are presented. AC Modulated Carrier Systems

Device-independent randomness amplification with a single device

International Nuclear Information System (INIS)

Plesch, Martin; Pivoluska, Matej

2014-01-01

Expansion and amplification of weak randomness with untrusted quantum devices has recently become a very fruitful topic of research. Here we contribute with a procedure for amplifying a single weak random source using tri-partite GHZ-type entangled states. If the quality of the source reaches a fixed threshold R=log 2 ⁡(10), perfect random bits can be produced. This technique can be used to extract randomness from sources that can't be extracted neither classically, nor by existing procedures developed for Santha–Vazirani sources. Our protocol works with a single fault-free device decomposable into three non-communicating parts, that is repeatedly reused throughout the amplification process. - Highlights: • We propose a protocol for device independent randomness amplification. • Our protocol repeatedly re-uses a single device decomposable into three parts. • Weak random sources with min-entropy rate greater than 1/4 log 2 ⁡(10) can be amplified. • Security against all-quantum adversaries is achieved

A simple strategy for subcloning and amplifying random multimegabase subchromosomal acentric DNA fragments as double minute chromosomes

International Nuclear Information System (INIS)

Hahn, P.J.; Giddings, L.; Lane, M.J.

1989-01-01

Restriction mapping of relatively large genomes (e.g. human) utilizing randomly generated DNA segments requires high mapping redundancy to successfully organize 'contigs' to represent the entire genome. The number of independent DNA segment maps required is dependent on the average size of a mapping segment; the larger the segment, the fewer required. The authors have developed a strategy for subcloning intact multimegabase subchromosomal fragments as double minute chromosomes. Such fragments could serve as primary mapping elements or as adjunct (linking) fragments to rapidly connect already existent contigs generated using yeast artificial chromosomes or cosmids. They present several lines of evidence supporting the viability of this approach. (1) X-ray treated EMT-6 mouse cells (7.5 Gr.) which are selected over several months with increasing levels of methotrexate (MTX) contain highly amplified circular DNA molecules (double minutes) which include the dihydrofolate reductase (DHFR) gene in a size range between 1,000 and 3,500 kilobases as determined by pulsed-field gel electrophoresis and these acentric chromosomal fragments have been stably maintained in culture for at least a year. (2) Preliminary data based on experiments involving fusion of X-irradiated Chinese Hamster Ovary (CH0 DG44) cells containing randomly inserted cotransfected Neomycin resistance and DHFR genes to mouse EMT-6 cells shows that the linked genes can be readily cotransferred as acentric subchromosomal fragment(s) suitable for gene amplification. (3) The studies of CHO cells with cell fusion transferred X-ray induced chromosomal fragments containing the natural CHO DHFR gene suggest that transferred chromosome fragments undergo gene amplification much more readily than nonfragmented endogenous DHFR genes

A CMOS current-mode operational amplifier

DEFF Research Database (Denmark)

Kaulberg, Thomas

1993-01-01

current-mode feedback amplifier or a constant bandwidth in a transimpedance feedback amplifier. The amplifier is found to have a gain-bandwidth product of 3 MHz, an offset current of 0.8 μA (signal range ±700 μA), and a (theoretically) unlimited slew rate. The amplifier is realized in a standard CMOS 2......A fully differential-input, differential-output, current-mode operational amplifier (COA) is described. The amplifier utilizes three second-generation current conveyors (CCIIs) as the basic building blocks. It can be configured to provide either a constant gain-bandwidth product in a fully balanced...

Ames and random amplified polymorphic DNA tests for the validation of the mutagenic and/or genotoxic potential of the drinking water disinfection by-products chloroform and bromoform.

Science.gov (United States)

Khallef, Messaouda; Cenkci, Süleyman; Akyil, Dilek; Özkara, Arzu; Konuk, Muhsin; Benouareth, Djamel Eddine

2018-01-28

Chloroform and Bromoform are two abundant trihalomethanes found in Algerian drinking water. The investigation of the mutagenic hazard of these disinfection by-products was studied by Ames test as prokaryotic bioassay to show their mutagenic effects. For this, Salmonella typhimurium TA98 and TA100 strains were employed. Both chloroform and bromoform showed a direct mutagenic effect since the number of revertant colonies gradually increase in dose-dependent manner with all concentrations tested with the two bacterial strains and these were both in the absence and presence of S9 metabolic activation. The genotoxic hazard was also studied by random amplified polymorphic DNA test on the root cells of Allium cepa as eukaryotic bioassay. DNA extracted from the roots of the onion were incubated at different concentrations of chloroform and bromoform and then amplified by polymerase chain reaction. This was based on demonstrating a major effect of disappearance of bands compared to roots incubated in the negative control (distilled water). The results showed that these two compounds affected genomic DNA by breaks although by mutations.

Modeling of semiconductor optical amplifiers

DEFF Research Database (Denmark)

Mørk, Jesper; Bischoff, Svend; Berg, Tommy Winther

We discuss the modelling of semiconductor optical amplifiers with emphasis on their high-speed properties. Applications in linear amplification as well as ultrafast optical signal processing are reviewed. Finally, the possible role of quantum-dot based optical amplifiers is discussed.......We discuss the modelling of semiconductor optical amplifiers with emphasis on their high-speed properties. Applications in linear amplification as well as ultrafast optical signal processing are reviewed. Finally, the possible role of quantum-dot based optical amplifiers is discussed....

NASA developments in solid state power amplifiers

Science.gov (United States)

Leonard, Regis F.

1990-01-01

Over the last ten years, NASA has undertaken an extensive program aimed at development of solid state power amplifiers for space applications. Historically, the program may be divided into three phases. The first efforts were carried out in support of the advanced communications technology satellite (ACTS) program, which is developing an experimental version of a Ka-band commercial communications system. These first amplifiers attempted to use hybrid technology. The second phase was still targeted at ACTS frequencies, but concentrated on monolithic implementations, while the current, third phase, is a monolithic effort that focusses on frequencies appropriate for other NASA programs and stresses amplifier efficiency. The topics covered include: (1) 20 GHz hybrid amplifiers; (2) 20 GHz monolithic MESFET power amplifiers; (3) Texas Instruments' (TI) 20 GHz variable power amplifier; (4) TI 20 GHz high power amplifier; (5) high efficiency monolithic power amplifiers; (6) GHz high efficiency variable power amplifier; (7) TI 32 GHz monolithic power amplifier performance; (8) design goals for Hughes' 32 GHz variable power amplifier; and (9) performance goals for Hughes' pseudomorphic 60 GHz power amplifier.

HIGH AVERAGE POWER OPTICAL FEL AMPLIFIERS

International Nuclear Information System (INIS)

2005-01-01

Historically, the first demonstration of the optical FEL was in an amplifier configuration at Stanford University [l]. There were other notable instances of amplifying a seed laser, such as the LLNL PALADIN amplifier [2] and the BNL ATF High-Gain Harmonic Generation FEL [3]. However, for the most part FELs are operated as oscillators or self amplified spontaneous emission devices. Yet, in wavelength regimes where a conventional laser seed can be used, the FEL can be used as an amplifier. One promising application is for very high average power generation, for instance FEL's with average power of 100 kW or more. The high electron beam power, high brightness and high efficiency that can be achieved with photoinjectors and superconducting Energy Recovery Linacs (ERL) combine well with the high-gain FEL amplifier to produce unprecedented average power FELs. This combination has a number of advantages. In particular, we show that for a given FEL power, an FEL amplifier can introduce lower energy spread in the beam as compared to a traditional oscillator. This properly gives the ERL based FEL amplifier a great wall-plug to optical power efficiency advantage. The optics for an amplifier is simple and compact. In addition to the general features of the high average power FEL amplifier, we will look at a 100 kW class FEL amplifier is being designed to operate on the 0.5 ampere Energy Recovery Linac which is under construction at Brookhaven National Laboratory's Collider-Accelerator Department

Electrospun amplified fiber optics.

Science.gov (United States)

Morello, Giovanni; Camposeo, Andrea; Moffa, Maria; Pisignano, Dario

2015-03-11

All-optical signal processing is the focus of much research aiming to obtain effective alternatives to existing data transmission platforms. Amplification of light in fiber optics, such as in Erbium-doped fiber amplifiers, is especially important for efficient signal transmission. However, the complex fabrication methods involving high-temperature processes performed in a highly pure environment slow the fabrication process and make amplified components expensive with respect to an ideal, high-throughput, room temperature production. Here, we report on near-infrared polymer fiber amplifiers working over a band of ∼20 nm. The fibers are cheap, spun with a process entirely carried out at room temperature, and shown to have amplified spontaneous emission with good gain coefficients and low levels of optical losses (a few cm(-1)). The amplification process is favored by high fiber quality and low self-absorption. The found performance metrics appear to be suitable for short-distance operations, and the large variety of commercially available doping dyes might allow for effective multiwavelength operations by electrospun amplified fiber optics.

Suppression of genetic recombination in the pseudoautosomal region and at subtelomeres in mice with a hypomorphic Spo11 allele.

Science.gov (United States)

Smagulova, Fatima; Brick, Kevin; Pu, Yongmei; Sengupta, Uttara; Camerini-Otero, R Daniel; Petukhova, Galina V

2013-07-22

Homologous recombination is the key process that generates genetic diversity and drives evolution. SPO11 protein triggers recombination by introducing DNA double stranded breaks at discreet areas of the genome called recombination hotspots. The hotspot locations are largely determined by the DNA binding specificity of the PRDM9 protein in human, mice and most other mammals. In budding yeast Saccharomyces cerevisae, which lacks a Prdm9 gene, meiotic breaks are formed opportunistically in the regions of accessible chromatin, primarily at gene promoters. The genome-wide distribution of hotspots in this organism can be altered by tethering Spo11 protein to Gal4 recognition sequences in the strain expressing Spo11 attached to the DNA binding domain of the Gal4 transcription factor. To establish whether similar re-targeting of meiotic breaks can be achieved in PRDM9-containing organisms we have generated a Gal4BD-Spo11 mouse that expresses SPO11 protein joined to the DNA binding domain of yeast Gal4. We have mapped the genome-wide distribution of the recombination initiation sites in the Gal4BD-Spo11 mice. More than two hundred of the hotspots in these mice were novel and were likely defined by Gal4BD, as the Gal4 consensus motif was clustered around the centers in these hotspots. Surprisingly, meiotic DNA breaks in the Gal4BD-Spo11 mice were significantly depleted near the ends of chromosomes. The effect is particularly striking at the pseudoautosomal region of the X and Y chromosomes - normally the hottest region in the genome. Our data suggest that specific, yet-unidentified factors influence the initiation of meiotic recombination at subtelomeric chromosomal regions.

Fast pulse amplifier

International Nuclear Information System (INIS)

Lepetit, J.; Poussier, E.

1984-01-01

This amplifier comprises an inverter transformer, the primary circuit of which receives a pulse and the secondary circuit of which is connected to several amplifying elements in parallel. The inverter transformer is made of coaxial cable segments winded around a magnetic torus; the cable cores connected in series constitute the primary circuit and the braiding of cables, connected in parallel, are the secondary circuit. The transformer comprises, besides, delay lines in series with each braiding of the secondary circuit, these ones are such that pulses issued from each braiding arrive together to the secondary circuit connectors. This invention applies, noticeably in the case of a high voltage amplifier, to the control of deflection blocks of particles used in medicine or in particle accelerators [fr

A fluidic/pneumatic interface amplifier

Science.gov (United States)

Limbert, D. E.; Kegel, T. M.

The development of a low cost, reliable, linear pressure amplifier to interface Laminar Proportional Amplifiers (LPA) to pneumatic controllers is presented. The amplifier consists of an LPA input stage and an output stage consisting of a venturi in series with a bellows nozzle valve. The LPA output drives the bellows nozzle valve thereby altering the flowrate through the venturi. The pressure within the venturi throat region, which is the amplifier output, changes with the flowrate. Non-linear characteristics, due to supersonic flow within the venturi, are altered through the use of feedback to the LPA input. A computer based model, to aid in optimizing the amplifier design, is developed. This model incorporates the effects of shock waves and boundary layers within the venturi. Good correspondence between the model and an experimental prototype is shown.

Amplifier for nuclear spectrometry

International Nuclear Information System (INIS)

Suarez Canner, E.

1996-01-01

The spectroscopy amplifier model AE-020 is designed to adjust suitable the pulses coming from nuclear radiation detectors. Due to is capacity and specifications, the amplifier can be used together with high and medium resolution spectroscopy system

Modeling FWM and impairments aware amplifiers placement technique for an optical MAN/WAN: Inline amplifiers case

Science.gov (United States)

Singh, Gurpreet; Singh, Maninder Lal

2015-08-01

A new four wave mixing (FWM) model for an optical network with amplifiers and a comparative analysis among three proposed amplifiers placement techniques have been presented in this paper. The FWM model is validated with the experimental measured data. The novelty of this model is its uniqueness that on direct substitutions of network parameters like length, it works even for unequal inter amplifier separations. The novelty of the analysis done among three schemes is that it presents fair choice of amplifiers placement methods for varied total system length. The appropriateness of these three schemes has been analyzed on the basis of critical system length, critical number of amplifiers and critical bit error rate (10-9) in presence of four wave mixing (FWM) and amplified spontaneous emission noise (ASE). The implementation of analysis done has been given with the help of an example of a regenerative metropolitan area network (MAN). The results suggest that the decreasing fiber section scheme should be avoided for placements of amplifiers and schemes IUFS and EFS shows their importance interchangeably for different set of parameters.

Realistic noise-tolerant randomness amplification using finite number of devices

Science.gov (United States)

Brandão, Fernando G. S. L.; Ramanathan, Ravishankar; Grudka, Andrzej; Horodecki, Karol; Horodecki, Michał; Horodecki, Paweł; Szarek, Tomasz; Wojewódka, Hanna

2016-04-01

Randomness is a fundamental concept, with implications from security of modern data systems, to fundamental laws of nature and even the philosophy of science. Randomness is called certified if it describes events that cannot be pre-determined by an external adversary. It is known that weak certified randomness can be amplified to nearly ideal randomness using quantum-mechanical systems. However, so far, it was unclear whether randomness amplification is a realistic task, as the existing proposals either do not tolerate noise or require an unbounded number of different devices. Here we provide an error-tolerant protocol using a finite number of devices for amplifying arbitrary weak randomness into nearly perfect random bits, which are secure against a no-signalling adversary. The correctness of the protocol is assessed by violating a Bell inequality, with the degree of violation determining the noise tolerance threshold. An experimental realization of the protocol is within reach of current technology.

Semiconductor quantum-dot lasers and amplifiers

DEFF Research Database (Denmark)

Hvam, Jørn Märcher; Borri, Paola; Ledentsov, N. N.

2002-01-01

-power surface emitting VCSELs. We investigated the ultrafast dynamics of quantum-dot semiconductor optical amplifiers. The dephasing time at room temperature of the ground-state transition in semiconductor quantum dots is around 250 fs in an unbiased amplifier, decreasing to below 50 fs when the amplifier...... is biased to positive net gain. We have further measured gain recovery times in quantum dot amplifiers that are significantly lower than in bulk and quantum-well semiconductor optical amplifiers. This is promising for future demonstration of quantum dot devices with high modulation bandwidth...

NIF/LMJ prototype amplifier mechanical design

International Nuclear Information System (INIS)

Horvath, J.

1996-10-01

Amplifier prototypes for the National Ignition Facility and the Laser Megajoule will be tested at Lawrence Livermore National Laboratory. The prototype amplifier, which is an ensemble of modules from LLNL and Centre d'Etudes de Limeil-Valenton, is cassette-based with bottom access for maintenance. A sealed maintenance transfer vehicle which moves optical cassettes between the amplifier and the assembly cleanroom, and a vacuum gripper which holds laser slabs during cassette assembly will also be tested. The prototype amplifier will be used to verify amplifier optical performance, thermal recovery time, and cleanliness of mechanical operations

A low-voltage sense amplifier with two-stage operational amplifier clamping for flash memory

Science.gov (United States)

Guo, Jiarong

2017-04-01

A low-voltage sense amplifier with reference current generator utilizing two-stage operational amplifier clamp structure for flash memory is presented in this paper, capable of operating with minimum supply voltage at 1 V. A new reference current generation circuit composed of a reference cell and a two-stage operational amplifier clamping the drain pole of the reference cell is used to generate the reference current, which avoids the threshold limitation caused by current mirror transistor in the traditional sense amplifier. A novel reference voltage generation circuit using dummy bit-line structure without pull-down current is also adopted, which not only improves the sense window enhancing read precision but also saves power consumption. The sense amplifier was implemented in a flash realized in 90 nm flash technology. Experimental results show the access time is 14.7 ns with power supply of 1.2 V and slow corner at 125 °C. Project supported by the National Natural Science Fundation of China (No. 61376028).

Novel Bacteriocinogenic Lactobacillus plantarum Strains and Their Differentiation by Sequence Analysis of 16S rDNA, 16S-23S and 23S-5S Intergenic Spacer Regions and Randomly Amplified Polymorphic DNA Analysis

Directory of Open Access Journals (Sweden)

Morteza Shojaei Moghadam

2010-01-01

Full Text Available Six strains of bacteriocinogenic Lactobacillus plantarum (TL1, RG11, RS5, UL4, RG14 and RI11 isolated from Malaysian foods were investigated for their structural bacteriocin genes. A new combination of plantaricin EF and plantaricin W bacteriocin structural genes was successfully amplified from all studied strains, suggesting that they were novel bacteriocin-producing L. plantarum strains. A four-base pair variable region was detected in the short 16S-23S intergenic spacer regions of the studied strains by a comparative analysis with 17 L. plantarum strains deposited in the GenBank, implying they were new genotypes. The studied L. plantarum strains were subsequently differentiated into four groups on the basis of the detected four-base pair variable region of the short 16S-23S intergenic spacer region. Further analysis of the DNA sequence of 23S-5S intergenic spacer region revealed only one type of 23S-5S intergenic spacer region present in the studied strains, indicating it was highly conserved among the studied L. plantarum strains. Three randomly amplified polymorphic DNA experiments using three different combinations of arbitrary primers successfully differentiated the studied L. plantarum strains from each other, confirming they were different strains. In conclusion, the studied L. plantarum strains were shown to be novel bacteriocin producers and high level of strain discrimination could be achieved with a combination of randomly amplified polymorphic DNA analysis and the analysis of the variable region of short 16S-23S intergenic spacer region present in L. plantarum strains.

Molecular Typing of Borrelia burgdorferi Sensu Lato by Randomly Amplified Polymorphic DNA Fingerprinting Analysis

Science.gov (United States)

Wang, Guiqing; van Dam, Alje P.; Spanjaard, Lodewijk; Dankert, Jacob

1998-01-01

To study whether pathogenic clusters of Borrelia burgdorferi sensu lato strains occur, we typed 136 isolates, cultured from specimens from patients (n = 49) with various clinical entities and from ticks (n = 83) or dogs (n = 4) from different geographic regions, by randomly amplified polymorphic DNA (RAPD) fingerprinting with four arbitrary primers. The RAPD patterns were reproducible up to the 95% similarity level as shown in duplicate experiments. In these experiments the purified DNAs prepared on different days, from different colonies, and after various passages were used as templates. With an intergroup difference of 55%, the 136 strains could be divided into seven genetic clusters. Six clusters comprised and corresponded to the established species B. burgdorferi sensu stricto (n = 23), Borrelia garinii (n = 39), Borrelia afzelii (n = 59), Borrelia japonica (n = 1), Borrelia valaisiana (n = 12), and genomic group DN127 (n = 1). One strain from a patient with erythema migrans (EM) did not belong to any of the species or genomic groups known up to now. The RAPD types of B. burgdorferi sensu stricto, B. garinii, and B. afzelii isolates, which may give rise to human Lyme borreliosis (LB), were associated with their geographic origins. A high degree of genetic diversity was observed among the 39 B. garinii strains, and six subgroups could be recognized. One of these comprised eight isolates from patients with disseminated LB only and no tick isolates. B. afzelii strains from patients with EM or acrodermatitis chronica atrophicans were not clustered in particular branches. Our study showed that RAPD analysis is a powerful tool for discriminating different Borrelia species as well as Borrelia isolates within species. PMID:9508310

Assembly and maintenance of full scale NIF amplifiers in the amplifier module prototype laboratory (AMPLAB)

International Nuclear Information System (INIS)

Horvath, J. A.

1998-01-01

Mechanical assembly and maintenance of the prototype National Ignition Facility amplifiers in the Amplifier Module Prototype Laboratory (AMPLAB) at Lawrence Livermore National Laboratory requires specialized equipment designed to manipulate large and delicate amplifier components in a safe and clean manner. Observations made during the operation of this assembly and maintenance equipment in AMPLAB provide design guidance for similar tools being built for the National Ignition Facility. Fixtures used for amplifier frame installation, laser slab and flashlamp cassette assembly, transport, and installation, and in-situ blastshield exchange are presented. Examples include a vacuum slab gripper, slab handling clean crane, slab cassette assembly fixture, sealed transport vehicle for slab cassette movement between the cleanroom and amplifier, slab cassette transfer fixture between the cleanroom and transport vehicle, and equipment needed for frame assembly unit, blastshield, an d flashlamp cassette installation and removal. The use of these tools for amplifier assembly, system reconfiguration, reflector replacement, and recovery from an abnormal occurrence such as a flashlamp explosion is described. Observations are made on the design and operation of these tools and their contribution to the final design

All-optical clocked flip-flops and random access memory cells using the nonlinear polarization rotation effect of low-polarization-dependent semiconductor optical amplifiers

Science.gov (United States)

Wang, Yongjun; Liu, Xinyu; Tian, Qinghua; Wang, Lina; Xin, Xiangjun

2018-03-01

Basic configurations of various all-optical clocked flip-flops (FFs) and optical random access memory (RAM) based on the nonlinear polarization rotation (NPR) effect of low-polarization-dependent semiconductor optical amplifiers (SOA) are proposed. As the constituent elements, all-optical logic gates and all-optical SR latches are constructed by taking advantage of the SOA's NPR switch. Different all-optical FFs (AOFFs), including SR-, D-, T-, and JK-types as well as an optical RAM cell were obtained by the combination of the proposed all-optical SR latches and logic gates. The effectiveness of the proposed schemes were verified by simulation results and demonstrated by a D-FF and 1-bit RAM cell experimental system. The proposed all-optical clocked FFs and RAM cell are significant to all-optical signal processing.

European Research on THz Vacuum Amplifiers

DEFF Research Database (Denmark)

Brunetti, F.; Cojocarua, C.-S.; de Rossi, A.

2010-01-01

The OPTHER (OPtically Driven TeraHertz AmplifiERs) project represents a considerable advancement in the field of high frequency amplification. The design and realization of a THz amplifier within this project is a consolidation of efforts at the international level from the main players...... of the European research, academy and industry in vacuum electronics. This paper describes the status of the project and progress towards the THz amplifier realization....

Integrated amplifying circuit with MOS transistors

Energy Technology Data Exchange (ETDEWEB)

Baylac, B; Merckel, G; Meunier, P

1974-01-25

The invention relates to a feedback-pass-band amplifier with MOS-transistors. The differential stage of conventional amplifiers is changed into an adding state, whereas the differential amplification stages are changed into amplifier inverter stages. All MOS transistors used in that amplifier are of similar configuration and are interdigitized, whereby the operating speed dispersion is reduced. This can be applied to obtaining a measurement channel for proportional chambers.

Giant Pulse Phenomena in a High Gain Erbium Doped Fiber Amplifier

Science.gov (United States)

Li, Stephen X.; Merritt, Scott; Krainak, Michael A.; Yu, Anthony

2018-01-01

High gain Erbium Doped Fiber Amplifiers (EDFAs) are vulnerable to optical damage when unseeded, e.g. due to nonlinear effects that produce random, spontaneous Q-switched (SQS) pulses with high peak power, i.e. giant pulses. Giant pulses can damage either the components within a high gain EDFA or external components and systems coupled to the EDFA. We explore the conditions under which a reflective, polarization-maintaining (PM), core-pumped high gain EDFA generates giant pulses, provide details on the evolution of normal pulses into giant pulses, and provide results on the transient effects of giant pulses on an amplifier's fused-fiber couplers, an effect which we call Fiber Overload Induced Leakage (FOIL). While FOIL's effect on fused-fiber couplers is temporary, its damage to forward pump lasers in a high gain EDFA can be permanent.

Genetic relatedness of artichoke (Cynara scolymus L.) hybrids using random amplified polymorphic DNA (RAPD) fingerprinting.

Science.gov (United States)

Sharaf-Eldin, M A; Al-Tamimi, A; Alam, P; Elkholy, S F; Jordan, J R

2015-12-28

The artichoke (Cynara scolymus L.) is an important food and medicinal crop that is cultivated in Mediterranean countries. Morphological characteristics, such as head shape and diameter, leaf shape, and bract shape, are mainly affected by environmental conditions. A molecular marker approach was used to analyze the degree of polymorphism between artichoke hybrid lines. The degree of genetic difference among three artichoke hybrids was evaluated using random amplified polymorphic DNA-PCR (RAPD-PCR). In this study, the DNA fingerprints of three artichoke lines (A13-010, A11-018, and A12-179) were generated, and a total of 10 decamer primers were applied for RAPD-PCR analyses. Polymorphism  (16.66 to 62.50%) was identified using eight arbitrary decamers and total genomic DNA extracted from the hybrids. Of the 59 loci detected, there were 25 polymorphic and 34 monomorphic loci. Jaccard's similarity index (JSI) ranged between 1.0 and 0.84. Based on the unweighted pair group method with arithmetic mean (UPGMA) similarity matrix and dendrogram, the results indicated that two hybrids (A13-010 and A11-018) were closely related to each other, and the A12-179 line showed more divergence. When identifying correct accessions, consideration of the genetic variation and genetic relationships among the genotypes are required. The RAPD-PCR fingerprinting of artichoke lines clearly showed that it is possible to analyze the RAPD patterns for correlation between genetic means and differences or resemblance between close accessions (A13-010 and A11- 018) at the genomic level.

In-flight auscultation during medical air evacuation: comparison between traditional and amplified stethoscopes.

Science.gov (United States)

Fontaine, Emmanuelle; Coste, Sébastien; Poyat, Chrystelle; Klein, Céline; Lefort, Hugues; Leclerc, Thomas; Dubourdieu, Stéphane; Briche, Frédérique; Jost, Daniel; Maurin, Olga; Domanski, Laurent; Tourtier, Jean-Pierre

2014-01-01

The aim of this study was to evaluate the capacity of a traditional stethoscope versus an electronically amplified one (expected to reduce background and ambient noise) to assess heart and respiratory sounds during medical transport. It was a prospective, double-blinded, randomized performed study. One traditional stethoscope (Littmann Cardiology III; 3M, St Paul, MN) and 1 electronically amplified stethoscope (Littmann 3200, 3M) were used for our tests. Heart and lung auscultation during real medical evacuations aboard a medically configured Falcon 50 aircrafts were studied. The quality of auscultation was ranged using a numeric rating scale from 0 to 10 (0 corresponding to "I hear nothing" and 10 to "I hear perfectly"). Data collected were compared using a t-test for paired values. A total of 40 comparative evaluations were performed. For cardiac auscultation, the value of the rating scale was 4.53 ± 1.91 and 7.18 ± 1.88 for the traditional and amplified stethoscope, respectively (paired t-test: P auscultation was estimated at 3.1 ± 1.95 for a traditional stethoscope and 5.10 ± 2.13 for the amplified one (paired t-test: P < .0001). This study showed that practitioners would be better helped in hearing cardiac and respiratory sounds with an electronically amplified stethoscope than with a traditional one during air medical transport in a medically configured Falcon 50 aircraft. Copyright © 2014 Air Medical Journal Associates. Published by Elsevier Inc. All rights reserved.

Power Amplifiers in CMOS Technology: A contribution to power amplifier theory and techniques

NARCIS (Netherlands)

Acar, M.

2011-01-01

In order to meet the demands from the market on cheaper, miniaturized mobile communications devices realization of RF power amplifiers in the mainstream CMOS technology is essential. In general, CMOS Power Amplifiers (PAs) require high voltage to decrease the matching network losses and for high

Enhanced performance CCD output amplifier

Science.gov (United States)

Dunham, Mark E.; Morley, David W.

1996-01-01

A low-noise FET amplifier is connected to amplify output charge from a che coupled device (CCD). The FET has its gate connected to the CCD in common source configuration for receiving the output charge signal from the CCD and output an intermediate signal at a drain of the FET. An intermediate amplifier is connected to the drain of the FET for receiving the intermediate signal and outputting a low-noise signal functionally related to the output charge signal from the CCD. The amplifier is preferably connected as a virtual ground to the FET drain. The inherent shunt capacitance of the FET is selected to be at least equal to the sum of the remaining capacitances.

Random amplified polymorphic DNA (RAPD analysis of Lutzomyia longipalpis laboratory populations

Directory of Open Access Journals (Sweden)

DiaS Edelberto S.

1998-01-01

Full Text Available The phlebotomine sand fly Lutzomyia longipalpis has been incriminated as a vector of American visceral leishmaniasis, caused by Leishmania chagasi. However, some evidence has been accumulated suggesting that it may exist in nature not as a single but as a species complex. Our goal was to compare four laboratory reference populations of L. longipalpis from distinct geographic regions at the molecular level by RAPD-PCR. We screened genomic DNA for polymorphic sites by PCR amplification with decamer single primers of arbitrary nucleotide sequences. One primer distinguished one population (Marajó Island, Pará State, Brazil from the other three (Lapinha Cave, Minas Gerais State, Brazil; Melgar, Tolima Department, Colombia and Liberia, Guanacaste Province, Costa Rica. The population-specific and the conserved RAPD-PCR amplified fragments were cloned and shown to differ only in number of internal repeats.

Transmission characteristics of acoustic amplifier in thermoacoustic engine

International Nuclear Information System (INIS)

Sun Daming; Qiu Limin; Wang Bo; Xiao Yong

2008-01-01

Thermoacoustic engines are promising in practical applications for the merits of simple configuration, reliable operation and environmentally friendly working gas. An acoustic amplifier can increase the output pressure amplitude of a thermoacoustic engine (TE) and improve the matching between the engine and its load. In order to make full use of an acoustic amplifier, the transmission characteristics are studied based on linear thermoacoustic theory. Computational and experimental results show that the amplifying ability of an acoustic amplifier is mainly determined by its geometry parameters and output resistance impedance. The amplifying ability of an acoustic amplifier with appropriate length and diameter reaches its maximum when the output resistance impedance is infinite. It is also shown that the acoustic amplifier consumes an amount of acoustic power when amplifying pressure amplitude and the acoustic power consumption increases with amplifying ratio. Furthermore, a novel cascade acoustic amplifier is proposed, which has a much stronger amplifying ability with reduced acoustic power consumption. In experiments, a two-stage cascade acoustic amplifier amplifies the pressure ratio from 1.177 to 1.62 and produces a pressure amplitude of 0.547 MPa with nitrogen of 2.20 MPa as working gas. Good agreements are obtained between the theoretical analysis and experimental results. This research is instructive for comprehensively understanding the mechanism and making full use of the acoustic amplifier

Reverse transcription using random pentadecamer primers increases yield and quality of resulting cDNA

DEFF Research Database (Denmark)

Stangegaard, Michael; Dufva, I.H.; Dufva, Hans Martin

2006-01-01

oligonucleotides (pentadecamers) consistently, yielded at least 2 fold as much cDNA as did random hexamers using either-poly(A) RNA or an amplified version of messenger RNA (aRNA) as a template. The cDNA generated using pentadecamers did not differ in size distribution or the amount of incorporated label compared...... with cDNA generated with random hexamers. The increased efficiency of priming using random pentadecamers resulted in reverse transcription of > 80% of the template aRNA, while random hexamers induced reverse transcription of only 40% of the template aRNA. This suggests a better coverage...... that random pentadecamers can replace random hexamers in reverse transcription reactions on both poly(A) RNA and amplified RNA, resulting in higher cDNA yields and quality....

Genetic variability of Amorphophallus muelleri Blume in Java based on Random Amplified Polymorphic DNA

Directory of Open Access Journals (Sweden)

DIYAH MARTANTI

2008-10-01

Full Text Available Amorphophallus muelleri Blume (Araceae is valued for its glucomanan content for use in food industry (healthy diet food, paper industry, pharmacy and cosmetics. The species is triploid (2n=3x=39 and the seed is developed apomictically. The present research is aimed to identify genetic variability of six population of A. muelleri from Java (consisted of 50 accessions using random amplified polymorphic DNA (RAPD. The six populations of the species are: East Java: (1 Silo-Jember, (2 Saradan-Madiun, (3 IPB (cultivated, from Saradan-Madiun, (4 Panti-Jember, (5 Probolinggo; and Central Java: (6 Cilacap. The results showed that five RAPD primers generated 42 scorable bands of which 29 (69.05% were polymorphic. Size of the bands varied from 300bp to 1.5kbp. The 50 accessions of A. muelleri were divided into two main clusters, some of them were grouped based on their populations, and some others were not. The range of individual genetic dissimilarity was from 0.02 to 0.36. The results showed that among six populations investigated, Saradan population showed the highest levels of genetic variation with mean values of na = 1.500+ 0.5061, ne = 1.3174 + 0.3841, PLP = 50% and He = 0, 0.1832+0.2054, whereas Silo-Jember population showed the lowest levels of genetic variation with mean values na = 1.2619+ 0.4450, ne = 1.1890 + 0.3507, PLP = 26.19% and He = 0.1048+0.1887. Efforts to conserve, domesticate, cultivate and improve genetically should be based on the genetic properties of each population and individual within population, especially Saradan population which has the highest levels of genetic variation, need more attention for its conservation.

Evidence of transmission of Mycobacterium tuberculosis by random amplified polymorphic DNA (RAPD) fingerprinting in Taipei City, Taiwan.

Science.gov (United States)

Harn, H J; Shen, K L; Ho, L I; Yu, K W; Liu, G C; Yueh, K C; Lee, J H

1997-01-01

AIMS: To determine, by strain identification of Mycobacterium tuberculosis, whether transmission has occurred between individuals or whether new strains are present. METHODS: A rapid protocol for random amplified polymorphic DNA (RAPD) analysis was developed. This protocol was applied to 64 strains of M tuberculosis that had been confirmed by culture and microbiological methods. RESULTS: There are five groups of M tuberculosis prevalent in Taipei city, Taiwan. The major types are groups I and III. Groups I and II had been prevalent until the end of last year when, according to our group analysis, they had been eradicated. However, group III was continuously present from the middle of 1995 to the middle of 1996, and group IV was present at the end of both years, which indicated that both groups were transmitted continuously. These clustered strains had demographic characteristics consistent with a finding of transmission tuberculosis. Also, there were 13 of 64 strains with unique RAPD fingerprints that were inferred to be due primarily to the reactivation of infection. In the drug resistance analysis, the major type represented included group III and part of group IV. CONCLUSIONS: Our preliminary data imply, not only that the prevalence of M tuberculosis in Taipei city is due to transmission rather than reactivation, but that drug resistance also may play a role in tuberculosis transmission. Images PMID:9378819

Estimating Genetic Conformism of Korean Mulberry Cultivars Using Random Amplified Polymorphic DNA and Inter-Simple Sequence Repeat Profiling

Directory of Open Access Journals (Sweden)

Sunirmal Sheet

2018-03-01

Full Text Available Apart from being fed to silkworms in sericulture, the ecologically important Mulberry plant has been used for traditional medicine in Asian countries as well as in manufacturing wine, food, and beverages. Germplasm analysis among Mulberry cultivars originating from South Korea is crucial in the plant breeding program for cultivar development. Hence, the genetic deviations and relations among 8 Morus alba plants, and one Morus lhou plant, of different cultivars collected from South Korea were investigated using 10 random amplified polymorphic DNA (RAPD and 10 inter-simple sequence repeat (ISSR markers in the present study. The ISSR markers exhibited a higher polymorphism (63.42% among mulberry genotypes in comparison to RAPD markers. Furthermore, the similarity coefficient was estimated for both markers and found to be varying between 0.183 and 0.814 for combined pooled data of ISSR and RAPD. The phenogram drawn using the UPGMA cluster method based on combined pooled data of RAPD and ISSR markers divided the nine mulberry genotypes into two divergent major groups and the two individual independent accessions. The distant relationship between Dae-Saug (SM1 and SangchonJo Sang Saeng (SM5 offers a possibility of utilizing them in mulberry cultivar improvement of Morus species of South Korea.

Final amplifier design and mercury

International Nuclear Information System (INIS)

Rose, E.A.; Hanson, D.E.

1991-01-01

The final amplifier for the Mercury KrF excimer facility is being designed. The design exercise involves extensive modeling to predict amplifier performance. Models of the pulsed-power system, including a Child-Langmuir diode with closure, electron-beam energy deposition, KrF laser kinetics, amplified spontaneous emission (ASE), a time-dependent laser extraction in the presence of ASE are presented as a design package. The design exercise indicates that the energy objective of Phase I -- 100 joules -- will be met

A pulse amplifier for nuclear instrumentation

International Nuclear Information System (INIS)

Martin, D.; Cliff, P.

1987-01-01

A Class-A 1 Watt amplifier has been designed and optimized for nanosecond pulses. Spanning .01MHz to 1300Mhz, signal gain is 26dB with gain flatness of 1dB. The amplifier drive +- 10 volts across 500 with 350ps risetime. Each amplifier is housed in a 2-wide NIM

An Implantable CMOS Amplifier for Nerve Signals

DEFF Research Database (Denmark)

Nielsen, Jannik Hammel; Lehmann, Torsten

2003-01-01

In this paper, a low noise high gain CMOS amplifier for minute nerve signals is presented. The amplifier is constructed in a fully differential topology to maximize noise rejection. By using a mixture of weak- and strong inversion transistors, optimal noise suppression in the amplifier is achieved....... A continuous-time current-steering offset-compensation technique is utilized in order to minimize the noise contribution and to minimize dynamic impact on the amplifier input nodes. The method for signal recovery from noisy nerve signals is presented. A prototype amplifier is realized in a standard digital 0...

Fast logarithmic amplifier

International Nuclear Information System (INIS)

Tai, I.; Hasegawa, K.

1975-01-01

This paper reports on the improvement of frequency characteristics of a logarithmic amplifier with a Paterson transdiode connection. The improvement of the response speed has been achieved by using a phase compensation technique. Small signal response analyses of the logging circuit revealed the effects of a series resistor Rsub(p) and a parallel capacitance Csub(p) on the response of the circuit. The improvement of the frequency characteristics are remarkable at higher current levels. These facts were proved by the practical logarithmic amplifier. (auth.)

Stochastic phenomena in a fiber Raman amplifier

Energy Technology Data Exchange (ETDEWEB)

Kalashnikov, Vladimir [Aston Institute of Photonic Technologies, Aston University, Birmingham (United Kingdom); Institute of Photonics, Vienna University of Technology (Austria); Sergeyev, Sergey V. [Aston Institute of Photonic Technologies, Aston University, Birmingham (United Kingdom); Ania-Castanon, Juan Diego [Instituto de Optica CSIC, Madrid (Spain); Jacobsen, Gunnar [Acreo, Kista (Sweden); Popov, Sergei [Royal Institute of Technology (KTH), Stockholm (Sweden)

2017-01-15

The interplay of such cornerstones of modern nonlinear fiber optics as a nonlinearity, stochasticity and polarization leads to variety of the noise induced instabilities including polarization attraction and escape phenomena harnessing of which is a key to unlocking the fiber optic systems specifications required in high resolution spectroscopy, metrology, biomedicine and telecommunications. Here, by using direct stochastic modeling, the mapping of interplay of the Raman scattering-based nonlinearity, the random birefringence of a fiber, and the pump-to-signal intensity noise transfer has been done in terms of the fiber Raman amplifier parameters, namely polarization mode dispersion, the relative intensity noise of the pump laser, fiber length, and the signal power. The obtained results reveal conditions for emergence of the random birefringence-induced resonance-like enhancement of the gain fluctuations (stochastic anti-resonance) accompanied by pulse broadening and rare events in the form of low power output signals having probability heavily deviated from the Gaussian distribution. (copyright 2016 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Flashlamp excited fluid laser amplified

International Nuclear Information System (INIS)

1976-01-01

The patent describes a laser amplifier with chambers for containing and amplifying an intensifier medium. It serves the need for a large impulse repetition rate and high intensities as required e.g. for laser isotope separation

Design considerations for RF power amplifiers demonstrated through a GSM/EDGE power amplifier module

NARCIS (Netherlands)

Baltus, P.G.M.; Bezooijen, van A.; Huijsing, J.H.; Steyaert, M.; Roermund, van A.H.M.

2002-01-01

This paper describes the design considerations for RF power amplifiers in general, including trends in systems, linearity and efficiency, the PA environment, implementation is sues and technology. As an example a triple-band (900/1800/1900MHz) dual mode (GSMIEdge) power amplifier module is described

Comparison of ribotyping, randomly amplified polymorphic DNA analysis, and pulsed-field gel electrophoresis in typing of Lactobacillus rhamnosus and L. casei strains.

Science.gov (United States)

Tynkkynen, S; Satokari, R; Saarela, M; Mattila-Sandholm, T; Saxelin, M

1999-09-01

A total of 24 strains, biochemically identified as members of the Lactobacillus casei group, were identified by PCR with species-specific primers. The same set of strains was typed by randomly amplified polymorphic DNA (RAPD) analysis, ribotyping, and pulsed-field gel electrophoresis (PFGE) in order to compare the discriminatory power of the methods. Species-specific primers for L. rhamnosus and L. casei identified the type strain L. rhamnosus ATCC 7469 and the neotype strain L. casei ATCC 334, respectively, but did not give any signal with the recently revived species L. zeae, which contains the type strain ATCC 15820 and the strain ATCC 393, which was previously classified as L. casei. Our results are in accordance with the suggested new classification of the L. casei group. Altogether, 21 of the 24 strains studied were identified with the species-specific primers. In strain typing, PFGE was the most discriminatory method, revealing 17 genotypes for the 24 strains studied. Ribotyping and RAPD analysis yielded 15 and 12 genotypes, respectively.

S-band low noise amplifier and 40 kW high power amplifier subsystems of Japanese Deep Space Earth Station

Science.gov (United States)

Honma, K.; Handa, K.; Akinaga, W.; Doi, M.; Matsuzaki, O.

This paper describes the design and the performance of the S-band low noise amplifier and the S-band high power amplifier that have been developed for the Usuda Deep Space Station of the Institute of Space and Astronautical Science (ISAS), Japan. The S-band low noise amplifier consists of a helium gas-cooled parametric amplifier followed by three-stage FET amplifiers and has a noise temperature of 8 K. The high power amplifier is composed of two 28 kW klystrons, capable of transmitting 40 kW continuously when two klystrons are combined. Both subsystems are operating quite satisfactorily in the tracking of Sakigake and Suisei, the Japanese interplanetary probes for Halley's comet exploration, launched by ISAS in 1985.

Small signal microwave amplifier design

CERN Document Server

Grosch, Theodore

2000-01-01

This book explains techniques and examples for designing stable amplifiers for high-frequency applications in which the signal is small and the amplifier circuit is linear. An in-depth discussion of linear network theory provides the foundation needed to develop actual designs. Examples throughout the book will show you how to apply the knowledge gained in each chapter leading to the complex design of low noise amplifiers. Many exercises at the end of each chapter will help students to practice their skills. The solutions to these design problems are available in an accompanying solutions book

Analysis of the background noise of field effect transistors in MOS complementary technology and application in the construction of a current-sensitive integrated amplifier

International Nuclear Information System (INIS)

Beuville, E.

1989-10-01

A low noise amplifier for use in high energy physics is developed. The origin and the mechanisms of the noise in MOSFET transistors is carried out with the aim of minimizing such effects in amplifiers. The research is applied in the construction of a current-sensitive integrated amplifier. The time scale continuous filtering principle is used and allows the detection of particles arriving in the counter in a random distribution. The rules which must be taken into account in the construction of an analog integrated circuit are shown [fr

Noise in Optical Amplifiers

DEFF Research Database (Denmark)

Jeppesen, Palle

1997-01-01

Noise in optical amplifiers is discussed on the basis of photons and electromagntic fields. Formulas for quantum noise from spontaneous emission, signal-spontaneous beat noise and spontaneous-spontaneous beat noise are derived.......Noise in optical amplifiers is discussed on the basis of photons and electromagntic fields. Formulas for quantum noise from spontaneous emission, signal-spontaneous beat noise and spontaneous-spontaneous beat noise are derived....

Amplified spontaneous emissions in a high-gain laser amplifier

International Nuclear Information System (INIS)

Osada, Hidenori; Gamo, Hideya.

1978-01-01

The gain and line-narrowing of the amplified spontaneous emissions(ASE) in a partially homogeneous high-gain Xe 3.51 μm laser amplifier were studied theoretically and experimentally with emphasis of saturation effect. The unidirectionally travelling ASE was generated by conveniently using optical isolators and used as a broadband radiation source. It has properties of 10 μW/mm 2 in intensity with fluctuation of less than 1% in 5 hours, 43.5 MHz of the linewidth and 1.0 x 10 -3 radians of beam divergence. The measured saturation intensity was 4.85 μW/mm 2 and a small signal gain was 0.1 cm -1 . The theoretical prediction of the line-narrowing shows reasonablly good agreement with the measured one. (author)

Dual-range linearized transimpedance amplifier system

Science.gov (United States)

Wessendorf, Kurt O.

2010-11-02

A transimpedance amplifier system is disclosed which simultaneously generates a low-gain output signal and a high-gain output signal from an input current signal using a single transimpedance amplifier having two different feedback loops with different amplification factors to generate two different output voltage signals. One of the feedback loops includes a resistor, and the other feedback loop includes another resistor in series with one or more diodes. The transimpedance amplifier system includes a signal linearizer to linearize one or both of the low- and high-gain output signals by scaling and adding the two output voltage signals from the transimpedance amplifier. The signal linearizer can be formed either as an analog device using one or two summing amplifiers, or alternately can be formed as a digital device using two analog-to-digital converters and a digital signal processor (e.g. a microprocessor or a computer).

Detection of Non-Amplified Genomic DNA

CERN Document Server

Corradini, Roberto

2012-01-01

This book offers a state-of-the-art overview on non amplified DNA detection methods and provides chemists, biochemists, biotechnologists and material scientists with an introduction to these methods. In fact all these fields have dedicated resources to the problem of nucleic acid detection, each contributing with their own specific methods and concepts. This book will explain the basic principles of the different non amplified DNA detection methods available, highlighting their respective advantages and limitations. The importance of non-amplified DNA sequencing technologies will be also discussed. Non-amplified DNA detection can be achieved by adopting different techniques. Such techniques have allowed the commercialization of innovative platforms for DNA detection that are expected to break into the DNA diagnostics market. The enhanced sensitivity required for the detection of non amplified genomic DNA has prompted new strategies that can achieve ultrasensitivity by combining specific materials with specifi...

Is there a role for amplifiers in sexual selection?

Science.gov (United States)

Gualla, Filippo; Cermelli, Paolo; Castellano, Sergio

2008-05-21

The amplifier hypothesis states that selection could favour the evolution of traits in signallers that improve the ability of receivers to extract honest information from other signals or cues. We provide a formal definition of amplifiers based on the receiver's mechanisms of signal perception and we present a game-theoretical model in which males advertise their quality and females use sequential-sampling tactics to choose among prospective mates. The main effect of an amplifier on the female mating strategy is to increase her mating threshold, making the female more selective as the effectiveness of the amplifier increases. The effects of the amplifier on male advertising strategy depends both on the context and on the types of the amplifier involved. We consider two different contexts for the evolution of amplifiers (when the effect of amplifiers is on signals and when it is on cues) and two types of amplifiers (the 'neutral amplifier', when it improves quality assessment without altering male attractiveness, and the 'attractive amplifier', when it improves both quality assessment and male attractiveness). The game-theoretical model provides two main results. First, neutral and attractive amplifiers represent, respectively, a conditional and an unconditional signalling strategy. In fact, at the equilibrium, neutral amplifiers are displayed only by males whose advertising level lays above the female acceptance threshold, whereas attractive amplifiers are displayed by all signalling males, independent of their quality. Second, amplifiers of signals increase the differences in advertising levels between amplifying and not-amplifying males, but they decrease the differences within each group, so that the system converges towards an 'all-or-nothing' signalling strategy. By applying concepts from information theory, we show that the increase in information transfer at the perception level due to the amplifier of signals is contrasted by a decrease in information

An Implantable CMOS Amplifier for Nerve Signals

DEFF Research Database (Denmark)

Nielsen, Jannik Hammel; Lehmann, Torsten

2001-01-01

In this paper, a low noise high gain CMOS amplifier for minute nerve signals is presented. By using a mixture of weak- and strong inversion transistors, optimal noise suppression in the amplifier is achieved. A continuous-time offset-compensation technique is utilized in order to minimize impact...... on the amplifier input nodes. The method for signal recovery from noisy nerve signals is presented. A prototype amplifier is realized in a standard digital 0.5 μm CMOS single poly, n-well process. The prototype amplifier features a gain of 80 dB over a 3.6 kHz bandwidth, a CMRR of more than 87 dB and a PSRR...

Operational amplifiers theory and design

CERN Document Server

Huijsing, Johan

2017-01-01

This proven textbook guides readers to a thorough understanding of the theory and design of operational amplifiers (OpAmps). The core of the book presents systematically the design of operational amplifiers, classifying them into a periodic system of nine main overall configurations, ranging from one gain stage up to four or more stages. This division enables circuit designers to recognize quickly, understand, and choose optimal configurations. Characterization of operational amplifiers is given by macro models and error matrices, together with measurement techniques for their parameters. Definitions are given for four types of operational amplifiers depending on the grounding of their input and output ports. Many famous designs are evaluated in depth, using a carefully structured approach enhanced by numerous figures. In order to reinforce the concepts introduced and facilitate self-evaluation of design skills, the author includes problems with detailed solutions, as well as simulation exercises. Provides te...

Wideband Low Noise Amplifiers Exploiting Thermal Noise Cancellation

NARCIS (Netherlands)

Bruccoleri, F.; Klumperink, Eric A.M.; Nauta, Bram

2005-01-01

Low Noise Amplifiers (LNAs) are commonly used to amplify signals that are too weak for direct processing for example in radio or cable receivers. Traditionally, low noise amplifiers are implemented via tuned amplifiers, exploiting inductors and capacitors in resonating LC-circuits. This can render

Enhanced Gain in Photonic Crystal Amplifiers

DEFF Research Database (Denmark)

Ek, Sara; Semenova, Elizaveta; Hansen, Per Lunnemann

2012-01-01

We experimentally demonstrate enhanced gain in the slow-light regime of quantum well photonic crystal amplifiers. A strong gain enhancement is observed with the increase of the group refractive index, due to light slow-down. The slow light enhancement is shown in a amplified spontaneous emission....... These results are promising for short and efficient semiconductor optical amplifiers. This effect will also benefit other devices, such as mode locked lasers....

A system for biasing a differential amplifier

International Nuclear Information System (INIS)

Barbier, Daniel; Ittel, J.M.; Poujois, Robert

1975-01-01

This invention concerns a system for biasing a differential amplifier. It particularly applies to the integrated differential amplifiers designed with MOS field effect transistors. Variations in the technological parameters may well cause the amplifying transistors to work outside their usual operational area, in other words outside the linear part of the transfer characteristic. To ensure that these transistors function correctly, it is necessary that the value of the voltage difference at the output be equally null. To do this and to centre on the so called 'rest' point of the amplifier transfer charateristic, the condition will be set that the output potentials of each amplifier transistor should have a zero value or a constant value as sum. With this in view, the bias on the source (generally a transistor powered by its grid bias voltage) supplying current to the two amplifying transistors fitted in parallel, is permanently adjusted in a suitable manner [fr

Solid-state disk amplifiers for fusion-laser systems

Energy Technology Data Exchange (ETDEWEB)

Martin, W.E.; Trenholme, J.B.; Linford, G.J.; Yarema, S.M.; Hurley, C.A.

1981-09-01

We review the design, performance, and operation of large-aperture (10 to 46 cm) solid-state disk amplifiers for use in laser systems. We present design data, prototype tests, simulations, and projections for conventional cylindrical pump-geometry amplifiers and rectangular pump-geometry disk amplifiers. The design of amplifiers for the Nova laser system is discussed.

Molecular diversity among Turkish oaks (QUERCUS) using random ...

African Journals Online (AJOL)

aykut

2013-11-06

Nov 6, 2013 ... using random amplified polymorphic DNA (RAPD) ... 1Department of Molecular Biology and Genetics, Faculty of Science and Arts, Uşak University, 64200 Uşak, Turkey. ..... University Directorate of Scientific Research Projects.

Multi-pass amplifier architecture for high power laser systems

Science.gov (United States)

Manes, Kenneth R; Spaeth, Mary L; Erlandson, Alvin C

2014-04-01

A main amplifier system includes a first reflector operable to receive input light through a first aperture and direct the input light along an optical path. The input light is characterized by a first polarization. The main amplifier system also includes a first polarizer operable to reflect light characterized by the first polarization state. The main amplifier system further includes a first and second set of amplifier modules. Each of the first and second set of amplifier modules includes an entrance window, a quarter wave plate, a plurality of amplifier slablets arrayed substantially parallel to each other, and an exit window. The main amplifier system additionally includes a set of mirrors operable to reflect light exiting the first set of amplifier modules to enter the second set of amplifier modules and a second polarizer operable to reflect light characterized by a second polarization state.

Design of an 1800nm Raman amplifier

DEFF Research Database (Denmark)

Svane, Ask Sebastian; Rottwitt, Karsten

2013-01-01

We present the experimental results for a Raman amplifier that operates at 1810 nm and is pumped by a Raman fiber laser at 1680 nm. Both the pump laser and the Raman amplifier is polarization maintaining. A challenge when scaling Raman amplifiers to longer wavelengths is the increase...... in transmission loss, but also the reduction in the Raman gain coefficient as the amplifier wavelength is increased. Both polarization components of the Raman gain is characterized, initially for linearly co-polarized signal and pump, subsequently linearly polarized orthogonal signal and pump. The noise...

Amplification or reduction of backscattering in a coherently amplifying or absorbing disordered chain

International Nuclear Information System (INIS)

Sen, A.K.

1997-09-01

We study localization properties of a one-dimensional disordered system characterized by a random non-hermitean hamiltonian where both the randomness and the non-hermiticity arises in the local site-potential; its real part being random, and a constant imaginary Part implying the presence of either a coherent absorption or amplification at each site. While the two-probe transport properties behave seemingly very differently for the amplifying and the absorbing chains, the logarithmic resistance u = ln(1 + R 4 ) where R 4 is the 4-probe resistance gives a unified description of both the cases. It is found that the ensemble-averaged increases linearly with length indicating exponential growth of resistance. While in contrast to the case of Anderson localization (random hermitean matrix), the variance of u could be orders of magnitude smaller in the non-hermitean case, the distribution of u still remains non-Gaussian even in the large length limit. (author)

Remote Acquisition Amplifier For 50-Ohm Cable

Science.gov (United States)

Amador, Jose J.

1995-01-01

Buffer-amplifier unit designed to drive 50-Ohm cables up to 100 ft. (30 m) long, compensating for attenuation in cables and enabling remote operation of oscilloscopes. Variable resistor provides for adjustment of gain of amplifier, such that overall gain from input terminals of amplifier to output end of cable set to unity.

First characterization of Candida albicans by random amplified polymorphic DNA method in Nicaragua and comparison of the diagnosis methods for vaginal candidiasis in Nicaraguan women

Directory of Open Access Journals (Sweden)

Bello Martha Darce

2002-01-01

Full Text Available A total of 106 women with vaginitis in Nicaragua were studied. The positive rate for the identification of Candida species was 41% (44 positive cultures out of 106 women with vaginitis. The sensitivity of microscopic examination of wet mount with the potassium hydroxide (KOH was 61% and 70% with Gram's stain when using the culture of vaginal fluid as gold standard for diagnosis of candidiasis. Among the 44 positives cultures, isolated species of yeast from vaginal swabs were C. albicans (59%, C. tropicalis (23%, C. glabrata (14% and C. krusei (4%. This study reports the first characterization of 26 C. albicans stocks from Nicaragua by the random amplified polymorphic DNA method. The genetic analysis in this small C. albicans population showed the existence of linkage disequilibrium, which is consistent with the hypothesis that C. albicans undergoes a clonal propagation.

Isolation and characterization of a pseudoautosomal region-specific genetic marker in C57BL/6 mice using genomic representational difference analysis.

Science.gov (United States)

Kalcheva, I D; Matsuda, Y; Plass, C; Chapman, V M

1995-12-19

Representational difference analysis was used to identify strain-specific differences in the pseudoautosomal region (PAR) of mouse X and Y chromosomes. One second generation (C57BL/6 x Mus spretus) x Mus spretus interspecific backcross male carrying the C57BL/6 (B6) PAR was used for tester DNA. DNA from five backcross males from the same generation that were M. spretus-type for the PAR was pooled for the driver. A cloned probe designated B6-38 was recovered that is B6-specific in Southern analysis. Analysis of genomic DNA from several inbred strains of laboratory mice and diverse Mus species and subspecies identified a characteristic Pst I pattern of fragment sizes that is present only in the C57BL family of strains. Hybridization was observed with sequences in DBA/2J and to a limited extent with Mus musculus (PWK strain) and Mus castaneus DNA. No hybridization was observed in DNA of different Mus species, M. spretus, M. hortulanus, and M. caroli. Genetic analyses of B6-38 was conducted using C57BL congenic males that carry M. spretus alleles for distal X chromosome loci and the PAR and outcrosses of heterozygous congenic females with M. spretus. These analyses demonstrated that the B6-38 sequences were inherited with both the X and Y chromosome. B6-38 sequences were genetically mapped as a locus within the PAR using two interspecific backcrosses. The locus defined by B6-38 is designated DXYRp1. Preliminary analyses of recombination between the distal X chromosome gene amelogenin (Amg) and the PAR loci for either TelXY or sex chromosome association (Sxa) suggest that the locus DXYRp1 maps to the distal portion of the PAR.

Multiple excitation regenerative amplifier inertial confinement system

International Nuclear Information System (INIS)

George, V.E.; Haas, R.A.; Krupke, W.F.; Schlitt, L.G.

1980-01-01

The invention relates to apparatus and methods for producing high intensity laser radiation generation which is achieved through an optical amplifier-storage ring design. One or two synchronized, counterpropagating laser pulses are injected into a regenerative amplifier cavity and amplified by gain media which are pumped repetitively by electrical or optical means. The gain media excitation pulses are tailored to efficiently amplify the laser pulses during each transit. After the laser pulses have been amplified to the desired intensity level, they are either switched out of the cavity by some switch means, as for example an electro-optical device, for any well known laser end uses, or a target means may be injected into the regenerative amplifier cavity in such a way as to intercept simultaneously the counterpropagating laser pulses. One such well known end uses to which this invention is intended is for production of high density and temperature plasmas suitable for generating neutrons, ions and x-rays and for studying matter heated by high intensity laser radiation

Spectral hole-burning and carrier-heating dynamics in quantum-dot amplifiers: Comparison with bulk amplifiers

DEFF Research Database (Denmark)

Borri, P.; Langbein, W.; Hvam, Jørn Märcher

2001-01-01

The ultrafast gain dynamics in an electrically pumped InAs/InGaAs/GaAs quantum-dot amplifier are measured at room temperature with femtosecond resolution, and compared with results on an InGaAsP bulk amplifier. The role of spectral hole burning and carrier heating in the recovery of the gain...

The OPTHER Project: Progress toward the THz Amplifier

DEFF Research Database (Denmark)

Paoloni, C; Brunetti, F; Di Carlo, A

2011-01-01

This paper describes the status of the OPTHER (OPtically driven TeraHertz AmplifiERs) project and progress toward the THz amplifier realization. This project represents a considerable advancement in the field of high frequency amplification. The design and realization of a THz amplifier within...... this project is a consolidation of efforts at the international level from the leading scientific and industrial European organizations working with vacuum electronics....

Spectroscopic amplifier for pin diode

International Nuclear Information System (INIS)

Alonso M, M. S.; Hernandez D, V. M.; Vega C, H. R.

2014-10-01

The photodiode remains the basic choice for the photo-detection and is widely used in optical communications, medical diagnostics and field of corpuscular radiation. In detecting radiation it has been used for monitoring radon and its progeny and inexpensive spectrometric systems. The development of a spectroscopic amplifier for Pin diode is presented which has the following characteristics: canceler Pole-Zero (P/Z) with a time constant of 8 μs; constant gain of 57, suitable for the acquisition system; 4th integrator Gaussian order to waveform change of exponential input to semi-Gaussian output and finally a stage of baseline restorer which prevents Dc signal contribution to the next stage. The operational amplifier used is the TLE2074 of BiFET technology of Texas Instruments with 10 MHz bandwidth, 25 V/μs of slew rate and a noise floor of 17 nv/(Hz)1/2. The integrated circuit has 4 operational amplifiers and in is contained the total of spectroscopic amplifier that is the goal of electronic design. The results show like the exponential input signal is converted to semi-Gaussian, modifying only the amplitude according to the specifications in the design. The total system is formed by the detector, which is the Pin diode, a sensitive preamplifier to the load, the spectroscopic amplifier that is what is presented and finally a pulse height analyzer (Mca) which is where the spectrum is shown. (Author)

[Study on sequence characterized amplified region (SCAR) markers of Cornus officinalis].

Science.gov (United States)

Chen, Suiqing; Lu, Xiaolei; Wang, Lili

2011-05-01

To establish sequence characterized amplified region markers of Cornus officinalis and provide a scientific basis for molecular identification of C. officinalis. The random primer was screened through RAPD to obtain specific RAPD marker bands. The RAPD marker bands were separated, extracted, cloned and sequenced. Both ends of the sequence of RAPD marker bands were determined. A pair of specific primers was designed for conventional PCR reaction, and SCAR marker was acquired. Four pairs of primers were designed based on the sequence of RAPD marker bands. The DNA of the seven varieties of C. officinalis was amplified by using YST38 and YST43 primer. The results showed that seven varieties of C. officinalis were able to produce a single PCR product. It was an effective way to identify C. officinalis. The varieties with cylindrical and long-pear shape fruits amplified by YST38 showed a specific band, which could be used as the evidence of variety identification. Seven varieties of C. oficinalis were amplified by using primer YST39. But the size of band of the variety with spindly shape fruit (35,0400 bp) was about 300 bp, which was shorter than those of the variety with the other shape fruits of C. officinalis (650-700 bp). The variety with the spindly shape fruit could be identified through this difference. The primer YST92 could produce a fragment from 600-700 bp in the varieties with cylindrical and long-pear shape fruits, a fragment from 200-300 bp in the varieties with oval and short-cylindrical shape fruits and had no fragment in the varieties with long cylindrical, elliptic and short-pear shape fruits, which could be used to select the different shapes of C. officinalis. SCAR mark is established and can be used as the basis for breeding and distinguishing the verieties of C. officinalis.

Automatic error compensation in dc amplifiers

International Nuclear Information System (INIS)

Longden, L.L.

1976-01-01

When operational amplifiers are exposed to high levels of neutron fluence or total ionizing dose, significant changes may be observed in input voltages and currents. These changes may produce large errors at the output of direct-coupled amplifier stages. Therefore, the need exists for automatic compensation techniques. However, previously introduced techniques compensate only for errors in the main amplifier and neglect the errors induced by the compensating circuitry. In this paper, the techniques introduced compensate not only for errors in the main operational amplifier, but also for errors induced by the compensation circuitry. Included in the paper is a theoretical analysis of each compensation technique, along with advantages and disadvantages of each. Important design criteria and information necessary for proper selection of semiconductor switches will also be included. Introduced in this paper will be compensation circuitry for both resistive and capacitive feedback networks

Quantum electronics maser amplifiers and oscillators

CERN Document Server

Fain, V M; Sanders, J H

2013-01-01

Quantum Electronics, Volume 2: Maser Amplifiers and Oscillators deals with the experimental and theoretical aspects of maser amplifiers and oscillators which are based on the principles of quantum electronics. It shows how the concepts and equations used in quantum electronics follow from the basic principles of theoretical physics.Comprised of three chapters, this volume begins with a discussion on the elements of the theory of quantum oscillators and amplifiers working in the microwave region, along with the practical achievements in this field. Attention is paid to two-level paramagnetic ma

Class-E Amplifier Design Improvements for GSM Frequencies

Directory of Open Access Journals (Sweden)

Z. Nadir

2011-06-01

Full Text Available Efficient power amplifiers are essential in portable battery-operated systems such as mobile phones. Also, the power amplifier (PA is the most power-consuming building block in the transmitter of a portable system. This paper investigates how the efficiency of the power amplifier (which is beneficial for multiple applications in communcation sector can be improved by increasing the efficiency of switching mode class E power amplifiers for frequencies of 900 MHz and 1800 MHz. The paper tackles modeling, design improvements and verification through simulation for higher efficiencies. This is the continuation of previous work by the authors. These nonlinear power amplifiers can only amplify constant-envelope RF signals without introducing significant distortion. Mobile systems such as Advanced Mobile Phone System (AMPS and Global System for Mobile communications (GSM use modulation schemes which generate constant amplitude RF outputs in order to use efficient but nonlinear power amplifiers. Improvements in designs are suggested and higher efficiencies are achieved, to the tune of 67.1% (for 900 MHz and 67.0% (1800 MHz.

Amplified OTDR Systems for Multipoint Corrosion Monitoring

Science.gov (United States)

Nascimento, Jehan F.; Silva, Marcionilo J.; Coêlho, Isnaldo J. S.; Cipriano, Eliel; Martins-Filho, Joaquim F.

2012-01-01

We present two configurations of an amplified fiber-optic-based corrosion sensor using the optical time domain reflectometry (OTDR) technique as the interrogation method. The sensor system is multipoint, self-referenced, has no moving parts and can measure the corrosion rate several kilometers away from the OTDR equipment. The first OTDR monitoring system employs a remotely pumped in-line EDFA and it is used to evaluate the increase in system reach compared to a non-amplified configuration. The other amplified monitoring system uses an EDFA in booster configuration and we perform corrosion measurements and evaluations of system sensitivity to amplifier gain variations. Our experimental results obtained under controlled laboratory conditions show the advantages of the amplified system in terms of longer system reach with better spatial resolution, and also that the corrosion measurements obtained from our system are not sensitive to 3 dB gain variations. PMID:22737017

Bandwidth tunable amplifier for recording biopotential signals.

Science.gov (United States)

Hwang, Sungkil; Aninakwa, Kofi; Sonkusale, Sameer

2010-01-01

This paper presents a low noise, low power, bandwidth tunable amplifier for bio-potential signal recording applications. By employing depletion-mode pMOS transistor in diode configuration as a tunable sub pA current source to adjust the resistivity of MOS-Bipolar pseudo-resistor, the bandwidth is adjusted without any need for a separate band-pass filter stage. For high CMRR, PSRR and dynamic range, a fully differential structure is used in the design of the amplifier. The amplifier achieves a midband gain of 39.8dB with a tunable high-pass cutoff frequency ranging from 0.1Hz to 300Hz. The amplifier is fabricated in 0.18εm CMOS process and occupies 0.14mm(2) of chip area. A three electrode ECG measurement is performed using the proposed amplifier to show its feasibility for low power, compact wearable ECG monitoring application.

Sequence-Related Amplified Polymorphism (SRAP Markers: A Potential Resource for Studies in Plant Molecular Biology

Directory of Open Access Journals (Sweden)

Daniel W. H. Robarts

2014-07-01

Full Text Available In the past few decades, many investigations in the field of plant biology have employed selectively neutral, multilocus, dominant markers such as inter-simple sequence repeat (ISSR, random-amplified polymorphic DNA (RAPD, and amplified fragment length polymorphism (AFLP to address hypotheses at lower taxonomic levels. More recently, sequence-related amplified polymorphism (SRAP markers have been developed, which are used to amplify coding regions of DNA with primers targeting open reading frames. These markers have proven to be robust and highly variable, on par with AFLP, and are attained through a significantly less technically demanding process. SRAP markers have been used primarily for agronomic and horticultural purposes, developing quantitative trait loci in advanced hybrids and assessing genetic diversity of large germplasm collections. Here, we suggest that SRAP markers should be employed for research addressing hypotheses in plant systematics, biogeography, conservation, ecology, and beyond. We provide an overview of the SRAP literature to date, review descriptive statistics of SRAP markers in a subset of 171 publications, and present relevant case studies to demonstrate the applicability of SRAP markers to the diverse field of plant biology. Results of these selected works indicate that SRAP markers have the potential to enhance the current suite of molecular tools in a diversity of fields by providing an easy-to-use. highly variable marker with inherent biological significance.

BROADBAND TRAVELLING WAVE SEMICONDUCTOR OPTICAL AMPLIFIER

DEFF Research Database (Denmark)

2010-01-01

Broadband travelling wave semiconductor optical amplifier (100, 200, 300, 400, 800) for amplification of light, wherein the amplifier (100, 200, 300, 400, 800) comprises a waveguide region (101, 201, 301, 401, 801) for providing confinement of the light in transverse directions and adapted...

A modular positive feedback-based gene amplifier

Directory of Open Access Journals (Sweden)

Bhalerao Kaustubh D

2010-02-01

Full Text Available Abstract Background Positive feedback is a common mechanism used in the regulation of many gene circuits as it can amplify the response to inducers and also generate binary outputs and hysteresis. In the context of electrical circuit design, positive feedback is often considered in the design of amplifiers. Similar approaches, therefore, may be used for the design of amplifiers in synthetic gene circuits with applications, for example, in cell-based sensors. Results We developed a modular positive feedback circuit that can function as a genetic signal amplifier, heightening the sensitivity to inducer signals as well as increasing maximum expression levels without the need for an external cofactor. The design utilizes a constitutively active, autoinducer-independent variant of the quorum-sensing regulator LuxR. We experimentally tested the ability of the positive feedback module to separately amplify the output of a one-component tetracycline sensor and a two-component aspartate sensor. In each case, the positive feedback module amplified the response to the respective inducers, both with regards to the dynamic range and sensitivity. Conclusions The advantage of our design is that the actual feedback mechanism depends only on a single gene and does not require any other modulation. Furthermore, this circuit can amplify any transcriptional signal, not just one encoded within the circuit or tuned by an external inducer. As our design is modular, it can potentially be used as a component in the design of more complex synthetic gene circuits.

Realization of OFCC based Transimpedance Mode Instrumentation Amplifier

Directory of Open Access Journals (Sweden)

Neeta Pandey

2016-01-01

Full Text Available The paper presents an instrumentation amplifier suitable for amplifying the current source transducer signals. It provides a voltage output. It has a high gain, common mode rejection ratio and gain independent bandwidth. It uses three Operational Floating Current Conveyors (OFCCs and four resistors. The effect of nonidealities of OFCC on performance of proposed transimpedance instrumentation amplifier (TIA is also analyzed. The proposal has been verified through SPICE simulations using CMOS based schematicThe paper presents an instrumentation amplifier suitable for amplifying the current source transducer signals. It provides a voltage output. It has a high gain, common mode rejection ratio and gain independent bandwidth. It uses three operational floating current conveyors (OFCCs and four resistors. The effect of nonidealities of OFCC on performance of proposed transimpedance instrumentation amplifier (TIA is also analyzed. The proposal has been verified through SPICE simulations using CMOS based schematic.

Quantum-Limited Directional Amplifiers with Optomechanics

Science.gov (United States)

Malz, Daniel; Tóth, László D.; Bernier, Nathan R.; Feofanov, Alexey K.; Kippenberg, Tobias J.; Nunnenkamp, Andreas

2018-01-01

Directional amplifiers are an important resource in quantum-information processing, as they protect sensitive quantum systems from excess noise. Here, we propose an implementation of phase-preserving and phase-sensitive directional amplifiers for microwave signals in an electromechanical setup comprising two microwave cavities and two mechanical resonators. We show that both can reach their respective quantum limits on added noise. In the reverse direction, they emit thermal noise stemming from the mechanical resonators; we discuss how this noise can be suppressed, a crucial aspect for technological applications. The isolation bandwidth in both is of the order of the mechanical linewidth divided by the amplitude gain. We derive the bandwidth and gain-bandwidth product for both and find that the phase-sensitive amplifier has an unlimited gain-bandwidth product. Our study represents an important step toward flexible, on-chip integrated nonreciprocal amplifiers of microwave signals.

Integrated wide-band low-background amplifiers

International Nuclear Information System (INIS)

Il'yushchenko, I.I.

1980-01-01

Ways of increasing stability and reproduction of characteristics of wide-band integral amplifiers that would to the least extent increase their background noises, are discussed. Considered are some certain flowsheets of integral wide-band amplifiers with low background noise of foreign production which differ from one another by construction of inlet cascades as well as by the applied feedback type. The principal flowsheets of the amplifiers and their main performances are presented. The analysis of the data obtained has revealed that microcircuits made of cascades with a common emitter and local combined feedback are most wide-band among all the considered microcircuits [ru

Advances in high-power rf amplifiers

International Nuclear Information System (INIS)

Tallerico, P.J.

1979-01-01

Several powerful accelerators and storage rings are being considered that will require tens or even hundreds of megawatts of continuous rf power. The economics of such large machines can be dictated by the cost and efficiency of the rf amplifiers. The overall design and performance of such narrow-band amplifiers, operating in the 50- to 1500-MHz region, are being theoretically studied as a function of frequency to determine the optimum rf amplifier output power, gain, efficiency, and dc power requirements. The state of the art for three types of amplifiers (gridded tubes, klystrons, and gyrocons) is considered and the development work necessary to improve each is discussed. The gyrocon is a new device, hence its various embodiments are discussed in detail. The Soviet designs are reviewed and the gyrocon's strengths and weaknesses are compared to other types of microwave amplifiers. The primary advantages of the gyrocon are the very large amount of power available from a single device and the excellent efficiency and stable operation. The klystron however, has much greater gain and is simpler mechanically. At very low frequencies, the small size of the gridded tube makes it the optimum choice for all but the most powerful systems

Class D audio amplifiers for high voltage capacitive transducers

DEFF Research Database (Denmark)

Nielsen, Dennis

of high volume, weight, and cost. High efficient class D amplifiers are now widely available offering power densities, that their linear counterparts can not match. Unlike the technology of audio amplifiers, the loudspeaker is still based on the traditional electrodynamic transducer invented by C.W. Rice......Audio reproduction systems contains two key components, the amplifier and the loudspeaker. In the last 20 – 30 years the technology of audio amplifiers have performed a fundamental shift of paradigm. Class D audio amplifiers have replaced the linear amplifiers, suffering from the well-known issues...... with the low level of acoustical output power and complex amplifier requirements, have limited the commercial success of the technology. Horn or compression drivers are typically favoured, when high acoustic output power is required, this is however at the expense of significant distortion combined...

Amplified Policymaking

Science.gov (United States)

Prince, Katherine; Woempner, Carolyn

2010-01-01

This brief examines the policy implications of two drivers of change presented in the "2020 Forecast: Creating the Future of Learning"-- Pattern Recognition and Amplified Organization. These drivers point toward a series of cultural shifts and illuminate how we are developing new ways of organizing, constructing, and managing knowledge.…

Amplified spontaneous emission spectrum and gain characteristic of a two-electrode semiconductor optical amplifier

International Nuclear Information System (INIS)

Wang Hanchao; Huang Lirong; Shi Zhongwei

2011-01-01

A two-electrode multi-quantum-well semiconductor optical amplifier is designed and fabricated. The amplified spontaneous emission (ASE) spectrum and gain were measured and analyzed. It is shown that the ASE spectrum and gain characteristic are greatly influencedby the distribution of the injection current density. By changing the injection current density of two electrodes, the full width at half maximum, peak wavelength, peak power of the ASE spectrum and the gain characteristic can be easily controlled. (semiconductor devices)

CARM and harmonic gyro-amplifier experiments at 17 GHz

International Nuclear Information System (INIS)

Menninger, W.L.; Danly, B.G.; Alberti, S.; Chen, C.; Rullier, J.L.; Temkin, R.J.

1993-01-01

Cyclotron resonance maser amplifiers are possible sources for applications such as electron cyclotron resonance heating of fusion plasmas and driving high-gradient rf linear accelerators. For accelerator drivers, amplifiers or phase locked-oscillators are required. A 17 GHz cyclotron autoresonance maser (CARM) amplifier experiment and a 17 GHz third harmonic gyro-amplifier experiment are presently underway at the MIT Plasma Fusion Center. Using the SRL/MIT SNOMAD II introduction accelerator to provide a 380 kV, 180 A, 30 ns flat top electron beam, the gyro-amplifier experiment has produced 5 MW of rf power with over 50 dB of gain at 17 GHz. The gyro-amplifier operates in the TE 31 mode using a third harmonic interaction. Because of its high power output, the gyro-amplifier will be used as the rf source for a photocathode rf electron gun experiment also taking place at MIT. Preliminary gyro-amplifier results are presented, including measurement of rf power, gain versus interaction length, and the far-field pattern. A CARM experiment designed to operate in the TE 11 mode is also discussed

Characterization of a Common-Gate Amplifier Using Ferroelectric Transistors

Science.gov (United States)

Hunt, Mitchell; Sayyah, Rana; MacLeod, Todd C.; Ho, Fat D.

2011-01-01

In this paper, the empirical data collected through experiments performed using a FeFET in the common-gate amplifier circuit is presented. The FeFET common-gate amplifier was characterized by varying all parameters in the circuit, such as load resistance, biasing of the transistor, and input voltages. Due to the polarization of the ferroelectric layer, the particular behavior of the FeFET common-gate amplifier presents interesting results. Furthermore, the differences between a FeFET common-gate amplifier and a MOSFET common-gate amplifier are examined.

The design of high performance weak current integrated amplifier

International Nuclear Information System (INIS)

Chen Guojie; Cao Hui

2005-01-01

A design method of high performance weak current integrated amplifier using ICL7650 operational amplifier is introduced. The operating principle of circuits and the step of improving amplifier's performance are illustrated. Finally, the experimental results are given. The amplifier has programmable measurement range of 10 -9 -10 -12 A, automatic zero-correction, accurate measurement, and good stability. (authors)

Quantum Dot Semiconductor Optical Amplifiers - Physics and Applications

DEFF Research Database (Denmark)

Berg, Tommy Winther

2004-01-01

This thesis describes the physics and applications of quantum dot semiconductor optical amplifiers based on numerical simulations. These devices possess a number of unique properties compared with other types of semiconductor amplifiers, which should allow enhanced performance of semiconductor...... respects is comparable to those of fiber amplifiers. The possibility of inverting the optically active states to a large degree is essential in order to achieve this performance. Optical signal processing through cross gain modulation and four wave mixing is modeled and described. For both approaches...... and QW devices and to experiments on quantum dot amplifiers. These comparisons outline the qualitative differences between the different types of amplifiers. In all cases focus is put on the physical processes responsible the differences....

Analog circuit design designing high performance amplifiers

CERN Document Server

Feucht, Dennis

2010-01-01

The third volume Designing High Performance Amplifiers applies the concepts from the first two volumes. It is an advanced treatment of amplifier design/analysis emphasizing both wideband and precision amplification.

Intrafamilial, Preferentially Mother-to-Child and Intraspousal, Helicobacter pylori Infection in Japan Determined by Mutilocus Sequence Typing and Random Amplified Polymorphic DNA Fingerprinting.

Science.gov (United States)

Yokota, Shin-ichi; Konno, Mutsuko; Fujiwara, Shin-ichi; Toita, Nariaki; Takahashi, Michiko; Yamamoto, Soh; Ogasawara, Noriko; Shiraishi, Tsukasa

2015-10-01

The infection route of Helicobacter pylori has been recognized to be mainly intrafamilial, preferentially mother-to-child, especially in developed countries. To determine the transmission route, we examined whether multilocus sequence typing (MLST) was useful for analysis of intrafamilial infection. The possibility of intraspousal infection was also evaluated. Clonal relationships between strains derived from 35 index Japanese pediatric patients, and their family members were analyzed by two genetic typing procedures, MLST and random amplified polymorphic DNA (RAPD) fingerprinting. Mostly coincident results were obtained by MLST and RAPD. By MLST, the allele of loci in the isolates mostly matched between the index child and both the father and mother for 9 (25.7%) of the 35 patients, between the index child and the mother for 25 (60.0%) of the 35 patients. MLST is useful for analyzing the infection route of H. pylori as a highly reproducible method. Intrafamilial, especially mother-to-children and sibling, infection is the dominant transmission route. Intraspousal infection is also thought to occur in about a quarter in the Japanese families. © 2015 John Wiley & Sons Ltd.

High power X-band coaxial amplifier experiments

International Nuclear Information System (INIS)

Davis, T.J.; Nation, J.A.

1991-01-01

Studies are continuing on the development of X-band coaxial microwave amplifiers as a source for next generation linear colliders. Coaxial amplifiers employ an annular electron beam propagating between inner and outer drift tube conductors, a configuration which allows large increases in beam current over standard pencil beam amplifiers. Large average diameter systems may still be used without mode competition since TM mode cutoff frequencies are controlled by the separation between conductors. A number of amplifier configurations are being studied, all primed by a driven initial cavity which resonates around 9 GHz. Simple theory of coaxial systems and particle-in-cell simulations are presented, as well as initial experimental results using a 420 keV, 7-8 kA, 9 cm diameter annular beam

Wideband multi-element Er-doped fiber amplifier

International Nuclear Information System (INIS)

Thipparapu, N K; Jain, S; May-Smith, T C; Sahu, J K

2014-01-01

A multi-element Er-doped fiber amplifier (MEEDFA) is demonstrated in which the gain profile is extended into the S and L bands. Each fiber element of the MEEDFA is found to provide a maximum gain of 37 dB and a noise figure of < 4 dB in the C-band. The gain profile of the amplifier is shifted towards longer wavelength by cascading fiber elements. The novel geometry of the multi-element fiber (MEF) could allow for the development of a broadband amplifier in a split-band configuration. The proposed amplifier can operate in the wavelength band of 1520 to 1595 nm (75 nm), with a minimum gain of 20 dB. (letter)

A parallel input composite transimpedance amplifier

Science.gov (United States)

Kim, D. J.; Kim, C.

2018-01-01

A new approach to high performance current to voltage preamplifier design is presented. The design using multiple operational amplifiers (op-amps) has a parasitic capacitance compensation network and a composite amplifier topology for fast, precision, and low noise performance. The input stage consisting of a parallel linked JFET op-amps and a high-speed bipolar junction transistor (BJT) gain stage driving the output in the composite amplifier topology, cooperating with the capacitance compensation feedback network, ensures wide bandwidth stability in the presence of input capacitance above 40 nF. The design is ideal for any two-probe measurement, including high impedance transport and scanning tunneling microscopy measurements.

Unconditionally stable microwave Si-IMPATT amplifiers

International Nuclear Information System (INIS)

Seddik, M.M.

1986-07-01

The purpose of this investigation has been the development of an improved understanding of the design and analysis of microwave reflection amplifiers employing the negative resistance property of the IMPATT devices. Unconditionally stable amplifier circuit using a Silicon IMPATT diode is designed. The problems associated with the design procedures and the stability criterion are discussed. A computer program is developed to perform the computations. The stable characteristics of a reflection-type Si-IMPATT amplifier, such as gain, frequency and bandwidth are examined. It was found that at large signal drive levels, 7 dB gain with bandwidth of 800 MHz at 22,5 mA was obtained. (author)

Low noise amplifier for ZnS(Ag) scintillation chamber

International Nuclear Information System (INIS)

Do Hoang Cuong

1998-01-01

A new pulse amplifier that can be used with standard photomultiplier tubes coupled with Zn(Ag) scintillation chamber is presented. The amplifier based on an IC operational amplifier LF 356N consists of a low-noise charge sensitive preamplifier and pulse shaping circuits for optimization of signal to noise ratio. Temperature instability is ≤ 0.05%/ o C. Dynamic range for linear output signals is equal +7 V. The presented amplifier is used in a measuring head for 0.17 L Lucas chambers developed in Department of Nuclear Instruments and Methods of the INCT in laboratory investigations aimed to develop methods and instruments for measurement of radon concentration in the air. The amplifier can also be employed for measurement of ionizing radiation by means of other scintillators coupled to PM tube. The amplifier is followed by a pulse discriminator with adjustable discrimination level. The amplifier output signal and discriminator output pulses are fed to external devices. (author)

Transpermeance Amplifier Applied to Magnetic Bearings

Directory of Open Access Journals (Sweden)

Jossana Ferreira

2017-02-01

Full Text Available The most conventional approach of controlling magnetic forces in active magnetic bearings (AMBs is through current feedback amplifiers: transconductance. This enables the operation of the AMB to be understood in terms of a relatively simple current-based model as has been widely reported on in the literature. The alternative notion of using transpermeance amplifiers, which approximate the feedback of gap flux rather than current, has been in commercial use in some form for at least thirty years, however is only recently seeing more widespread acceptance as a commercial standard. This study explores how such alternative amplifiers should be modeled and then examines the differences in behavior between AMBs equipped with transconductance and transpermeance amplifiers. The focus of this study is on two aspects. The first is the influence of rotor displacement on AMB force, commonly modeled as a constant negative equivalent mechanical stiffness, and it is shown that either scheme actually leads to a finite bandwidth effect, but that this bandwidth is much lower when transpermeance is employed. The second aspect is the influence of eddy currents. Using a very simple model of eddy currents (a secondary short-circuited coil, it is demonstrated that transpermeance amplifiers can recover significant actuator bandwidth compared with transconductance, but at the cost of needing increased peak current headroom.

A high-power two stage traveling-wave tube amplifier

International Nuclear Information System (INIS)

Shiffler, D.; Nation, J.A.; Schachter, L.; Ivers, J.D.; Kerslick, G.S.

1991-01-01

Results are presented on the development of a two stage high-efficiency, high-power 8.76-GHz traveling-wave tube amplifier. The work presented augments previously reported data on a single stage amplifier and presents new data on the operational characteristics of two identical amplifiers operated in series and separated from each other by a sever. Peak powers of 410 MW have been obtained over the complete pulse duration of the device, with a conversion efficiency from the electron beam to microwave energy of 45%. In all operating conditions the severed amplifier showed a ''sideband''-like structure in the frequency spectrum of the microwave radiation. A similar structure was apparent at output powers in excess of 70 MW in the single stage device. The frequencies of the ''sidebands'' are not symmetric with respect to the center frequency. The maximum, single frequency, average output power was 210 MW corresponding to an amplifier efficiency of 24%. Simulation data is also presented that indicates that the short amplifiers used in this work exhibit significant differences in behavior from conventional low-power amplifiers. These include finite length effects on the gain characteristics, which may account for the observed narrow bandwidth of the amplifiers and for the appearance of the sidebands. It is also found that the bunching length for the beam may be a significant fraction of the total amplifier length

Photonic-band-gap gyrotron amplifier with picosecond pulses

Science.gov (United States)

Nanni, Emilio A.; Jawla, Sudheer; Lewis, Samantha M.; Shapiro, Michael A.; Temkin, Richard J.

2017-12-01

We report the amplification of 250 GHz pulses as short as 260 ps without observation of pulse broadening using a photonic-band-gap circuit gyrotron traveling-wave-amplifier. The gyrotron amplifier operates with a device gain of 38 dB and an instantaneous bandwidth of 8 GHz. The operational bandwidth of the amplifier can be tuned over 16 GHz by adjusting the operating voltage of the electron beam and the magnetic field. The amplifier uses a 30 cm long photonic-band-gap interaction circuit to confine the desired TE03-like operating mode while suppressing lower order modes which can result in undesired oscillations. The circuit gain is >55 dB for a beam voltage of 23 kV and a current of 700 mA. These results demonstrate the wide bandwidths and a high gain achievable with gyrotron amplifiers. The amplification of picosecond pulses of variable lengths, 260-800 ps, shows good agreement with the theory using the coupled dispersion relation and the gain-spectrum of the amplifier as measured with quasi-CW input pulses.

Single conversion stage amplifier - SICAM

Energy Technology Data Exchange (ETDEWEB)

Ljusev, P.

2005-12-15

This Ph.D. thesis presents a thorough analysis of the so called SICAM - SIngle Converter stage AMplifier approach to building direct energy conversion audio power amplifiers. The mainstream approach for building isolated audio power amplifiers today consists of isolated DC power supply and Class D amplifier, which essentially represents a two stage solution, where each of the components can be viewed as separate and independent part. The proposed SICAM solution strives for direct energy conversion from the mains to the audio output, by dedicating the operation of the components one to another and integrating their functions, so that the final audio power amplifier represents a single-stage topology with higher efficiency, lower volume, less board space, lower component count and subsequently lower cost. The SICAM approach is both applicable to non-isolated and isolated audio power amplifiers, but the problems encountered in these two cases are different. Non-isolated SICAM solutions are intended for both AC mains-connected and battery-powered devices. In non-isolated mains-connected SICAMs the main idea is to simplify the power supply or even provide integrated power factor correction (PFC) functions, while still maintaining low component stress and good audio performance by generally decreasing the input voltage level to the Class D audio power amplifier. On the other hand, non-isolated battery-powered SICAMs have to cope with the ever changing battery voltage and provide output voltage levels which are both lower and higher than the battery voltage, while still being simple and single-stage energy conversion solutions. In isolated SICAMs the isolation transformer adjusts the voltage level on the secondary side to the desired level, so the main challenges here are decreasing the size of the magnetic core and reducing the number and size of bulky reactive components as much as possible. The main focus of this thesis is directed towards the isolated SICAMs and

Sequence-related amplified polymorphism (SRAP) markers: A potential resource for studies in plant molecular biology1

Science.gov (United States)

Robarts, Daniel W. H.; Wolfe, Andrea D.

2014-01-01

In the past few decades, many investigations in the field of plant biology have employed selectively neutral, multilocus, dominant markers such as inter-simple sequence repeat (ISSR), random-amplified polymorphic DNA (RAPD), and amplified fragment length polymorphism (AFLP) to address hypotheses at lower taxonomic levels. More recently, sequence-related amplified polymorphism (SRAP) markers have been developed, which are used to amplify coding regions of DNA with primers targeting open reading frames. These markers have proven to be robust and highly variable, on par with AFLP, and are attained through a significantly less technically demanding process. SRAP markers have been used primarily for agronomic and horticultural purposes, developing quantitative trait loci in advanced hybrids and assessing genetic diversity of large germplasm collections. Here, we suggest that SRAP markers should be employed for research addressing hypotheses in plant systematics, biogeography, conservation, ecology, and beyond. We provide an overview of the SRAP literature to date, review descriptive statistics of SRAP markers in a subset of 171 publications, and present relevant case studies to demonstrate the applicability of SRAP markers to the diverse field of plant biology. Results of these selected works indicate that SRAP markers have the potential to enhance the current suite of molecular tools in a diversity of fields by providing an easy-to-use, highly variable marker with inherent biological significance. PMID:25202637

Sequence-related amplified polymorphism (SRAP) markers: A potential resource for studies in plant molecular biology(1.).

Science.gov (United States)

Robarts, Daniel W H; Wolfe, Andrea D

2014-07-01

In the past few decades, many investigations in the field of plant biology have employed selectively neutral, multilocus, dominant markers such as inter-simple sequence repeat (ISSR), random-amplified polymorphic DNA (RAPD), and amplified fragment length polymorphism (AFLP) to address hypotheses at lower taxonomic levels. More recently, sequence-related amplified polymorphism (SRAP) markers have been developed, which are used to amplify coding regions of DNA with primers targeting open reading frames. These markers have proven to be robust and highly variable, on par with AFLP, and are attained through a significantly less technically demanding process. SRAP markers have been used primarily for agronomic and horticultural purposes, developing quantitative trait loci in advanced hybrids and assessing genetic diversity of large germplasm collections. Here, we suggest that SRAP markers should be employed for research addressing hypotheses in plant systematics, biogeography, conservation, ecology, and beyond. We provide an overview of the SRAP literature to date, review descriptive statistics of SRAP markers in a subset of 171 publications, and present relevant case studies to demonstrate the applicability of SRAP markers to the diverse field of plant biology. Results of these selected works indicate that SRAP markers have the potential to enhance the current suite of molecular tools in a diversity of fields by providing an easy-to-use, highly variable marker with inherent biological significance.

Characterization of a Common-Source Amplifier Using Ferroelectric Transistors

Science.gov (United States)

Hunt, Mitchell; Sayyah, Rana; MacLeond, Todd C.; Ho, Pat D.

2010-01-01

This paper presents empirical data that was collected through experiments using a FeFET in the established common-source amplifier circuit. The unique behavior of the FeFET lends itself to interesting and useful operation in this widely used common-source amplifier. The paper examines the effect of using a ferroelectric transistor for the amplifier. It also examines the effects of varying load resistance, biasing, and input voltages on the output signal and gives several examples of the output of the amplifier for a given input. The difference between a commonsource amplifier using a ferroelectric transistor and that using a MOSFET is addressed.

Class-D audio amplifiers with negative feedback

OpenAIRE

Cox, Stephen M.; Candy, B. H.

2006-01-01

There are many different designs for audio amplifiers. Class-D, or switching, amplifiers generate their output signal in the form of a high-frequency square wave of variable duty cycle (ratio of on time to off time). The square-wave nature of the output allows a particularly efficient output stage, with minimal losses. The output is ultimately filtered to remove components of the spectrum above the audio range. Mathematical models are derived here for a variety of related class-D amplifier de...

Differential transimpedance amplifier circuit for correlated differential amplification

Science.gov (United States)

Gresham, Christopher A [Albuquerque, NM; Denton, M Bonner [Tucson, AZ; Sperline, Roger P [Tucson, AZ

2008-07-22

A differential transimpedance amplifier circuit for correlated differential amplification. The amplifier circuit increase electronic signal-to-noise ratios in charge detection circuits designed for the detection of very small quantities of electrical charge and/or very weak electromagnetic waves. A differential, integrating capacitive transimpedance amplifier integrated circuit comprising capacitor feedback loops performs time-correlated subtraction of noise.

Ring cavity for a Raman capillary waveguide amplifier

Science.gov (United States)

Kurnit, N.A.

1981-01-27

A regenerative ring amplifier and regenerative ring oscillator are described which function to feed back a portion of the Stokes signal to complete the ring cavity. The ring cavity configuration allows the CO/sub 2/ laser pump signal and Stokes signal to copropagate through the Raman capillary waveguide amplifier. A Raman capillary waveguide amplifier is also provided in the return leg of the ring cavity to increase gain without increasing the round trip time. Additionally, the ring cavity can be designed such that the amplified Stokes signal is synchronous with the mode-locked spikes of the incoming CO/sub 2/ laser pump signal.

Molecular markers. Amplified fragment length polymorphism

Directory of Open Access Journals (Sweden)

Pržulj Novo

2005-01-01

Full Text Available Amplified Fragment Length Polymorphism molecular markers (AFLPs has been developed combining procedures of RFLPs and RAPDs molekular markers, i.e. the first step is restriction digestion of the genomic DNA that is followed by selective amplification of the restricted fragments. The advantage of the AFLP technique is that it allows rapid generation of a large number of reproducible markers. The reproducibility of AFLPs markers is assured by the use of restriction site-specific adapters and adapter-specific primers for PCR reaction. Only fragments containing the restriction site sequence plus the additional nucleotides will be amplified and the more selected nucleotides added on the primer sequence the fewer the number of fragments amplified by PCR. The amplified products are normally separated on a sequencing gel and visualized after exposure to X-ray film or by using fluorescent labeled primers. AFLP shave proven to be extremely proficient in revealing diversity at below the species level. A disadvantage of AFLP technique is that AFLPs are essentially a dominant marker system and not able to identify heterozygotes.

Virulence properties and random amplification of polymorphic DNA ...

African Journals Online (AJOL)

Genotypic and phenotypic characterization as well as studies on the virulence factors of Candida albicans isolates obtained from oral cavity of patients was carried out using random amplified polymorphic DNA (RAPD) fingerprinting and epithelial cells adherence assay, respectively. RAPD patterns revealed the presence of ...

A high-efficiency superconductor distributed amplifier

Energy Technology Data Exchange (ETDEWEB)

Herr, Q P, E-mail: quentin.herr@ngc.co [Northrop Grumman Corporation, 7323 Aviation Boulevard, Baltimore, MD 21240 (United States)

2010-02-15

A superconductor output amplifier that converts single-flux-quantum signals to a non-return-to-zero pattern is reported using a twelve-stage distributed amplifier configuration. The output amplitude is measured to be 1.75 mV over a wide bias current range of {+-} 12%. The bit error rate is measured using a Delta-Sigma data pattern to be less than 1 x 10{sup -9} at 10 Gb s{sup -1} per channel. Analysis of the eye diagram suggests that the actual bit error rate may be much lower. The amplifier has power efficiency of 12% neglecting the termination resistor, which may be eliminated from the circuit with a small modification. (rapid communication)

Exponential gain of randomness certified by quantum contextuality

Science.gov (United States)

Um, Mark; Zhang, Junhua; Wang, Ye; Wang, Pengfei; Kim, Kihwan

2017-04-01

We demonstrate the protocol of exponential gain of randomness certified by quantum contextuality in a trapped ion system. The genuine randomness can be produced by quantum principle and certified by quantum inequalities. Recently, randomness expansion protocols based on inequality of Bell-text and Kochen-Specker (KS) theorem, have been demonstrated. These schemes have been theoretically innovated to exponentially expand the randomness and amplify the randomness from weak initial random seed. Here, we report the experimental evidence of such exponential expansion of randomness. In the experiment, we use three states of a 138Ba + ion between a ground state and two quadrupole states. In the 138Ba + ion system, we do not have detection loophole and we apply a methods to rule out certain hidden variable models that obey a kind of extended noncontextuality.

Fundamentals of RF and microwave transistor amplifiers

CERN Document Server

Bahl, Inder J

2009-01-01

A Comprehensive and Up-to-Date Treatment of RF and Microwave Transistor Amplifiers This book provides state-of-the-art coverage of RF and microwave transistor amplifiers, including low-noise, narrowband, broadband, linear, high-power, high-efficiency, and high-voltage. Topics covered include modeling, analysis, design, packaging, and thermal and fabrication considerations. Through a unique integration of theory and practice, readers will learn to solve amplifier-related design problems ranging from matching networks to biasing and stability. More than 240 problems are included to help read

Design And Construction Of 300W Audio Power Amplifier For Classroom

Directory of Open Access Journals (Sweden)

Shune Lei Aung

2015-07-01

Full Text Available Abstract This paper describes the design and construction of 300W audio power amplifier for classroom. In the construction of this amplifier microphone preamplifier tone preamplifier equalizer line amplifier output power amplifier and sound level indicator are included. The output power amplifier is designed as O.C.L system and constructed by using Class B among many types of amplifier classes. There are two types in O.C.L system quasi system and complementary system. Between them the complementary system is used in the construction of 300W audio power amplifier. The Multisim software is utilized for the construction of audio power amplifier.

Self-pulsation in Raman fiber amplifiers

DEFF Research Database (Denmark)

Pedersen, Martin Erland Vestergaard; Ott, Johan Raunkjær; Rottwitt, Karsten

2009-01-01

Dynamic behavior caused by Brillouin scattering in Raman fiber amplifiers is studied. Modes of self-pulsation steady state oscillations are found. Their dependence on amplification scheme is demonstrated.......Dynamic behavior caused by Brillouin scattering in Raman fiber amplifiers is studied. Modes of self-pulsation steady state oscillations are found. Their dependence on amplification scheme is demonstrated....

Computer-Aided Design of Microstrip GaAs Mesfet Amplifiers

DEFF Research Database (Denmark)

Nielsen, Niels Ole

1976-01-01

Results on computer-aided design of broadband GaAs MESFET amplifiers in microstrip is presented. The analysis of an amplifier is based on measured scattering parameters and a model of the microstrip structure, which includes parasitics and junction effects. The optimized performance of one stage...... amplifiers with lossless distributed matching elements is presented. Realized amplifiers are in good agreement with the theory. One stage amplifiers with a 1 ¿m FET in chip form exhibit 5.8 dB of gain in the range 8-12 GHz, while a gain of 4.5 dB from 4-8 GHz has been obtained with a packaged 1 ¿m FET....

Note: A high dynamic range, linear response transimpedance amplifier.

Science.gov (United States)

Eckel, S; Sushkov, A O; Lamoreaux, S K

2012-02-01

We have built a high dynamic range (nine decade) transimpedance amplifier with a linear response. The amplifier uses junction-gate field effect transistors (JFETs) to switch between three different resistors in the feedback of a low input bias current operational amplifier. This allows for the creation of multiple outputs, each with a linear response and a different transimpedance gain. The overall bandwidth of the transimpedance amplifier is set by the bandwidth of the most sensitive range. For our application, we demonstrate a three-stage amplifier with transimpedance gains of approximately 10(9)Ω, 3 × 10(7)Ω, and 10(4)Ω with a bandwidth of 100 Hz.

Characterization of Grain Amaranth (Amaranthus spp. Germplasm in South West Nigeria Using Morphological, Nutritional, and Random Amplified Polymorphic DNA (RAPD Analysis

Directory of Open Access Journals (Sweden)

Pamela E. Akin-Idowu

2016-01-01

Full Text Available Efficient utilization of plant genetic resources for nutrition and crop improvement requires systematic understanding of the important traits. Amaranthus species are distributed worldwide with an interesting diversity of landraces and cultivars whose leaves and seeds are consumed. Despite their potential to enhance food security and economic livelihoods, grain amaranth breeding to improve nutritional quality and adoption by farmers in sub-Saharan Africa is scanty. This study assessed the variation among 29 grain amaranth accessions using 27 phenotypic (10 morphological and 17 nutritional characters and 16 random amplified polymorphic DNA (RAPD primers. Multivariate analysis of phenotypic characters showed the first four principal components contributing 57.53% of observed variability, while cluster analysis yielded five groups at 87.5% similarity coefficient. RAPD primers generated a total of 193 amplicons with an average of 12.06 amplicons per primer, 81% of which were polymorphic. Genetic similarities based on Jaccard’s coefficient ranged from 0.61 to 0.88. The RAPD-based unweighted pair group method with arithmetic mean dendrogram grouped the accessions into nine clusters, with the same species clustering together. RAPD primers distinguished the accessions more effectively than phenotypic markers. Accessions in the different clusters as obtained can be exploited for heterotic gain in desired nutritional traits.

Higher order mode optical fiber Raman amplifiers

DEFF Research Database (Denmark)

Rottwitt, Karsten; Friis, Søren Michael Mørk; Usuga Castaneda, Mario A.

2016-01-01

We review higher order mode Raman amplifiers and discuss recent theoretical as well as experimental results including system demonstrations.......We review higher order mode Raman amplifiers and discuss recent theoretical as well as experimental results including system demonstrations....

Genetic variations of Lansium domesticum Corr. accessions from Java, Sumatra and Ceram based on Random Amplified Polymorphic DNA fingerprints

Directory of Open Access Journals (Sweden)

KUSUMADEWI SRI YULITA

2011-07-01

Full Text Available Yulita KS (2011 Genetic variations of Lansium domesticum Corr. accessions from Java, Bengkulu and Ceram based on Random Amplified Polymorphic DNA fingerprints. Biodiversitas 12: 125-130. Duku (Lansium domesticum Corr. is one of popular tropical fruits in SE Asia. The spesies has three varieties, known as duku, langsat and kokosan; and duku is the most popular one for being the sweetiest fruit. Indonesia has several local varieties of duku, such as duku Condet, duku Sumber and duku Palembang. This present study aimed to assess genetic diversity of 47 accessions of duku from Java, Sumatra, and Ceram based on RAPD fingerprints. Ten RAPD’s primers were initially screened and five were selected for the analysis. These five primers (OPA 7, 13, 18, OPB 7, and OPN 12 generated 53 scorable bands with an average of 10.6 polymorphic fragment per primer. Percentage of polymorphism ranged from 16.89% (OPA 7 and OPN 12 to 24.54% (OPB 7 with an average of 20.16% polymorphism. OPB 7 at 450 bp was exclusively possessed by accession 20 (Java, OPA 18 at 500 bp was by accession 6 (Java, 550 bp by 3 clones from Bengkulu. While OPN 12 at 300 bp and OPA 13 at 450 bp were shared among the accessions. Clustering analysis was performed based on RAPD profiles using the UPGMA method. The range of genetic similarity value among accessions was 0.02-0.65 suggesting high variation of gene pool existed among accessions.

Stimulated Brillouin scattering threshold in fiber amplifiers

International Nuclear Information System (INIS)

Liang Liping; Chang Liping

2011-01-01

Based on the wave coupling theory and the evolution model of the critical pump power (or Brillouin threshold) for stimulated Brillouin scattering (SBS) in double-clad fiber amplifiers, the influence of signal bandwidth, fiber-core diameter and amplifier gain on SBS threshold is simulated theoretically. And experimental measurements of SBS are presented in ytterbium-doped double-clad fiber amplifiers with single-frequency hundred nanosecond pulse amplification. Under different input signal pulses, the forward amplified pulse distortion is observed when the pulse energy is up to 660 nJ and the peak power is up to 3.3 W in the pulse amplification with pulse duration of 200 ns and repetition rate of 1 Hz. And the backward SBS narrow pulse appears. The pulse peak power equals to SBS threshold. Good agreement is shown between the modeled and experimental data. (authors)

Low-cost amplifier for alpha detection with photodiode

Energy Technology Data Exchange (ETDEWEB)

Domienikan, Cláudio; Costa, Priscila; Genezini, Frederico A.; Zahn, Guilherme S., E-mail: clanikan@ipen.br, E-mail: pcosta@ipen.br, E-mail: fredzini@ipen.br, E-mail: gzahn@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil)

2017-07-01

A low-cost amplifier for Hamamatsu S3590-09 PIN photodiode to be used in alpha detection is presented. This amplifier consists basically of two circuits: a pulse preamplifier and a shaper-driver. The PIN photodiode is reverse-biased and connected to a charge preamplifier input. Incident alpha particles generate a small current pulse in the photodiode. The integrating circuit of the low noise preamplifier transforms current pulse into a voltage pulse with amplitude proportional to the charge carried by the current pulse. The shaper-driver consists of a differentiator and an integrator and is responsible for filtering and further amplifying the preamplifier signal, generating a NIM-compatible energy pulse. The performance of the set photodiode-amplifier was successively tested through the use of a {sup 243}Am radioactive source. The low-cost photodiode amplifier was designed and constructed at IPEN - CNEN/SP using national components and expertise. (author)

Simulations of longitudinally pumped dye laser amplifier

International Nuclear Information System (INIS)

Takehisa, Kiwamu; Takemori, Satoshi

1995-01-01

Simulations of a copper laser pumped dye laser amplifier and new designs of the longitudinally pumped dye laser amplifier are presented. The simulations take the consideration of the amplified spontaneous emission (ASE). The new designs utilize a center-hole reflector instead of a dichroic mirror. The simulation results indicate that the poor spatial overlap between the pump beam and the dye beam in the transverse pumping not only reduces the laser output power, but also generates ASE strongly. The results also indicate that the longitudinal pumping is as efficient as the transverse pumping. (author)

Pulse shaping amplifier (PSA) for nuclear spectroscopy system

International Nuclear Information System (INIS)

Lombigit, L.; Maslina Mohd Ibrahim; Nolida Yusup; Nur Aira Abdul Rahman; Yong, C.F.

2014-01-01

Pulse Shaping Amplifier (PSA) is an essential components in nuclear spectroscopy system. This networks have two functions; to shape the output pulse and performs noise filtering. In this paper, we describes procedure for design and development of a pulse shaping amplifier which can be used for nuclear spectroscopy system. This prototype was developed using high performance electronics devices and assembled on a FR4 type printed circuit board. Performance of this prototype was tested by comparing it with an equivalent commercial spectroscopy amplifier (Model SILENA 7611). The test results show that the performance of this prototype is comparable to the commercial spectroscopic amplifier. (author)

GaN-based Power amplifiers for microwave applications

Directory of Open Access Journals (Sweden)

Jorge Julián Moreno-Rubio

2016-01-01

Full Text Available This paper presents a discussion about the design strategies of different kind of power amplifiers for RF/Microwave appli- cations, such as the tuned load power amplifier, class F, class F-1 and Doherty. Furthermore, it is shown the continuous wave characterization of the amplifiers above mentioned. A comparison between the obtained results, in terms of gain, efficiency and output power is presented.

Single-mode operation of a coiled multimode fiber amplifier

International Nuclear Information System (INIS)

Koplow, Jeffrey P.; Kliner, Dahv A. V.; Goldberg, Lew

2000-01-01

We report a new approach to obtaining single-transverse-mode operation of a multimode fiber amplifier in which the gain fiber is coiled to induce significant bend loss for all but the lowest-order mode. We demonstrated this method by constructing a coiled amplifier using Yb-doped, double-clad fiber with a core diameter of 25 μm and a numerical aperture of ∼0.1 (V≅7.4) . When the amplifier was operated as an amplified-spontaneous-emission source, the output beam had an M 2 value of 1.09±0.09 ; when seeded at 1064 nm, the slope efficiency was similar to that of an uncoiled amplifier. This technique will permit scaling of pulsed fiber lasers and amplifiers to significantly higher pulse energies and peak powers and cw fiber sources to higher average powers while maintaining excellent beam quality. (c) 2000 Optical Society of America

Implantable neurotechnologies: a review of integrated circuit neural amplifiers.

Science.gov (United States)

Ng, Kian Ann; Greenwald, Elliot; Xu, Yong Ping; Thakor, Nitish V

2016-01-01

Neural signal recording is critical in modern day neuroscience research and emerging neural prosthesis programs. Neural recording requires the use of precise, low-noise amplifier systems to acquire and condition the weak neural signals that are transduced through electrode interfaces. Neural amplifiers and amplifier-based systems are available commercially or can be designed in-house and fabricated using integrated circuit (IC) technologies, resulting in very large-scale integration or application-specific integrated circuit solutions. IC-based neural amplifiers are now used to acquire untethered/portable neural recordings, as they meet the requirements of a miniaturized form factor, light weight and low power consumption. Furthermore, such miniaturized and low-power IC neural amplifiers are now being used in emerging implantable neural prosthesis technologies. This review focuses on neural amplifier-based devices and is presented in two interrelated parts. First, neural signal recording is reviewed, and practical challenges are highlighted. Current amplifier designs with increased functionality and performance and without penalties in chip size and power are featured. Second, applications of IC-based neural amplifiers in basic science experiments (e.g., cortical studies using animal models), neural prostheses (e.g., brain/nerve machine interfaces) and treatment of neuronal diseases (e.g., DBS for treatment of epilepsy) are highlighted. The review concludes with future outlooks of this technology and important challenges with regard to neural signal amplification.

The Nike electron-beam-pumped KrF laser amplifiers

International Nuclear Information System (INIS)

Sethian, J.D.; Pawley, C.J.; Obenschain, S.P.

1997-01-01

Nike is a recently completed multikilojoule krypton-fluoride (KrF) laser that has been built to study the physics of direct-drive inertial confinement fusion. The two final amplifiers of the Nike laser are both electron-beam-pumped systems. This paper describes these two amplifiers, with an emphasis on the pulsed power. The smaller of the two has a 20 x 20 cm aperture, and produces an output laser beam energy in excess of 100 J. This 20 cm Amplifier uses a single 12 kJ Marx generator to inject two 300 kV, 75 kA, 140 ns flat-top electron beams into opposite sides of the laser cell. The larger amplifier in Nike has a 60 x 60 cm aperture, and amplifies the laser beam up to 5 kJ. This 60 cm amplifier has two independent electron beam systems. Each system has a 170 kJ Marx generator that produces a 670 kV, 540 kA, 240 ns flat-top electron beam. Both amplifiers are complete, fully integrated into the laser, meet the Nike system requirements, and are used routinely for laser-target experiments

47 CFR 97.315 - Certification of external RF power amplifiers.

Science.gov (United States)

2010-10-01

.... (2) The amplifier was manufactured before April 28, 1978, and has been issued a marketing waiver by... that operator's station. (3) The amplifier is sold to an amateur radio operator or to a dealer, the amplifier is purchased in used condition by a dealer, or the amplifier is sold to an amateur radio operator...

Pump to signal noise transfer in parametric fiber amplifiers

DEFF Research Database (Denmark)

Lund-Hansen, Toke; Rottwitt, Karsten; Peucheret, Christophe

2010-01-01

Fiber optic parametric amplifiers have been suggested due to their potential low spontaneous emission. However, by nature the parametric amplifier only work in a forward pumped configuration, which result in transfer of relative intensity noise in the pump to the signal.......Fiber optic parametric amplifiers have been suggested due to their potential low spontaneous emission. However, by nature the parametric amplifier only work in a forward pumped configuration, which result in transfer of relative intensity noise in the pump to the signal....

Method for reducing snap in magnetic amplifiers

Science.gov (United States)

Fischer, R. L. E.; Word, J. L.

1968-01-01

Method of reducing snap in magnetic amplifiers uses a degenerative feedback circuit consisting of a resistor and a separate winding on a magnetic core. The feedback circuit extends amplifier range by allowing it to be used at lower values of output current.

Non-Stoichiometric SixN Metal-Oxide-Semiconductor Field-Effect Transistor for Compact Random Number Generator with 0.3 Mbit/s Generation Rate

Science.gov (United States)

Matsumoto, Mari; Ohba, Ryuji; Yasuda, Shin-ichi; Uchida, Ken; Tanamoto, Tetsufumi; Fujita, Shinobu

2008-08-01

The demand for random numbers for security applications is increasing. A conventional random number generator using thermal noise can generate unpredictable high-quality random numbers, but the circuit is extremely large because of large amplifier circuit for a small thermal signal. On the other hand, a pseudo-random number generator is small but the quality of randomness is bad. For a small circuit and a high quality of randomness, we purpose a non-stoichiometric SixN metal-oxide-semiconductor field-effect transistor (MOSFET) noise source device. This device generates a very large noise signal without an amplifier circuit. As a result, it is shown that, utilizing a SiN MOSFET, we can attain a compact random number generator with a high generation rate near 1 Mbit/s, which is suitable for almost all security applications.

Amplifier Design for Proportional Ionization Chambers

Energy Technology Data Exchange (ETDEWEB)

Baker, W. H.

1950-08-24

This paper presents the requirements of a nuclear amplifier of short resolving time, designed to accept pulses of widely varying amplitudes. Data are given which show that a proportional ionization chamber loaded with a 1,000-ohm resistor develops pulses of 0.5 microsecond duration and several volts amplitude. Results indicate that seven basic requirements are imposed on the amplifier when counting soft beta and gamma radiation in the presence of alpha particles, without absorbers. It should, (1) have a fast recovery time, (2) have a relatively good low frequency response, (3) accept pulses of widely varying heights without developing spurious pulsed, (4) have a limiting output stage, (5) preserve the inherently short rise time of the chamber, (6) minimize pulse integration, and (7) have sufficient gain to detect the weak pulses well below the chamber voltage at which continuous discharge takes place. The results obtained with an amplifier which meets these requirements is described. A formula is derived which indicates that redesign of the proportional ionization chamber might eliminate the need for an amplifier. This may be possible if the radioactive particles are collimated parallel to the collecting electrode.

Power Amplifier Design for E-band Wireless System Communications

DEFF Research Database (Denmark)

Hadziabdic, Dzenan; Krozer, Viktor; Johansen, Tom Keinicke

2008-01-01

E-band wireless communications will become important as the microwave backhaul for high-speed data transmission. One of the most critical components is the front-end power amplifier in this system. The paper analyzes different technologies with potential in the E-band frequency range and present...... a power amplifier design satisfying the E-band system specifications. The designed power amplifier achieves a maximum output power of ges 20 dBm with a state-of-the-art power-added efficiency of 15%. The power is realized using InP DHBT technology. To the best of our knowledge it is the highest output...... power and efficiency reported for an InP HBT power amplifier in this frequency range. The predicted power-added efficiency is higher than that of power amplifiers based on SiGe HBT and GaAs pHEMT technologies. The design shows the capabilities of InP DHBT for power amplifier applications...

A new semicustom integrated bipolar amplifier for silicon strip detectors

International Nuclear Information System (INIS)

Zimmerman, T.

1989-01-01

The QPA02 is a four channel DC coupled two stage transimpedance amplifier designed at Fermilab on a semicustom linear array (Quickchip 2S) manufactured by Tektronix. The chip was developed as a silicon strip amplifier but may have other applications as well. Each channel consists of a preamplifier and a second stage amplifier/sharper with differential output which can directly drive a transmission line (90 to 140 ohms). External bypass capacitors are the only discrete components required. QPA02 has been tested and demonstrated to be an effective silicon strip amplifier. Other applications may exist which can use this amplifier or a modified version of this amplifier. For example, another design is now in progress for a wire chamber amplifier, QPA03, to be reported later. Only a relatively small effort was required to modify the design and layout for this application. 11 figs

Clonality Analysis of Helicobacter pylori in Patients Isolated from Several Biopsy Specimens and Gastric Juice in a Japanese Urban Population by Random Amplified Polymorphic DNA Fingerprinting

Directory of Open Access Journals (Sweden)

Nariaki Toita

2013-01-01

Full Text Available Background. The number of Helicobacter pylori clones infecting a single host has been discussed in numerous reports. The number has been suggested to vary depending on the regions in the world. Aim. The purpose of this study was to examine the number of clones infecting a single host in a Japanese urban population. Materials and Methods. Thirty-one Japanese patients undergoing upper gastrointestinal endoscopy were enrolled in this study. H. pylori isolates (total 104 strains were obtained from biopsy specimens (antrum, corpus, and duodenum and gastric juice. Clonal diversity was examined by the random amplified polymorphic DNA (RAPD fingerprinting method. Results. The RAPD fingerprinting patterns of isolates from each patient were identical or very similar. And the isolates obtained from several patients with 5- to 9-year intervals showed identical or very similar RAPD patterns. Conclusion. Each Japanese individual of an urban population is predominantly infected with a single H. pylori clone.

Pulse amplifier with high 'common mode rejection'

International Nuclear Information System (INIS)

Ijlst, P.

1987-01-01

The input signal of a pulse amplifier contains large 'common-mode' signals which have to be suppressed. A transformer, especially constructed for this purpose, is described. It has been tried to optimize the signal to noise ratio of the pulse amplifier by means of noise analysis. (Auth.)

Behavior of MOSFET Amplifier in Radiation Fields

International Nuclear Information System (INIS)

Sharshar, K.A.A.; Ashry, M.

2000-01-01

MOSFET type 2 N 3823 characteristics and its application as an amplifier are analyzed including the effects of gamma, electron beam 1.5 MeV 25 m A and neutron flux. The 1-V characteristics, transfer curve, and the frequency response of the amplifier, and the amplification factor(A v 0 are discussed with MOSFET circuit parameters. The drain current and the amplitude of the output signal decrease as the absorbed dose increases. The measured values of the amplified signal are attenuated by 30% and 6% after exposing the MOSFET to gamma radiation and electron beam at the same dose respectively. Also for exposure to 4x10 13 N/cm 3 neutrons decreased the measured value of the amplified signal by 73% of the initial values. The decrease in the gain of the MOSFET is due to the degradation of the transconductance. It is also noticed that percentage of the decrease depends on the type of radiation

Low-noise audio amplifiers and preamplifier for use with intrinsic thermocouples

International Nuclear Information System (INIS)

Langner, G.C.; Sachs, R.D.; Stewart, F.L.

1979-03-01

Two simple, low-noise audio amplifiers and one low-noise preamplifier for use with intrinsic thermocouples were designed, built, and tested. The amplifiers and the preamplifier have different front end designs. One amplifier uses ultralow-noise operational amplifiers; the other amplifier uses a hybrid component. The preamplifier uses ultralow-noise discrete components. The amplifiers' equivalent noise inputs, at maximum gain, are 4.09 nV and 50 nV; the preamplifier's input is 4.05 μV. Their bandwidths are 15 600 Hz, 550 Hz, and 174 kHz, respectively. the amplifiers' equivalent noise inputs were measured from approx. 0 to 100 Hz, whereas the preamplifier's equivalent noise input was measured from approx. 0 to 174 kHz

Genetic diversity of Kenyan Prosopis populations based on random ...

African Journals Online (AJOL)

To determine whether naturally established stands consist of a single or mixture of species, six populations from Bamburi, Bura, Isiolo, Marigat, Taveta and Turkwel were compared for relatedness with reference to Prosopis chilensis, Prosopis juliflora and Prosopis pallida using random amplified polymorphic DNA markers.

Free-electron laser system with Raman amplifier outcoupling

Energy Technology Data Exchange (ETDEWEB)

Linford, G.J.

1988-05-03

A free-electron laser system is described comprising: a free-electron laser pump beam generator producing a high-power optical output beam in a vacuum environement; a Raman amplifier cell located in the path of the output beam from the pump beam generator; means for generating and introducing a Stokes seed beam into the Raman amplifier cell, a pair of gaseous windows through which the output beam enters and leaves the Raman amplifier cell, each window having a stream of gas moving continuously in a direction generally perpendicular to the beam; and a mirror positioned in the path of the output beam from the Raman amplifier, the mirror functioning to reflect and further direct the output beam, but not the unwanted spectral components.

Modeling and design techniques for RF power amplifiers

CERN Document Server

Raghavan, Arvind; Laskar, Joy

2008-01-01

The book covers RF power amplifier design, from device and modeling considerations to advanced circuit design architectures and techniques. It focuses on recent developments and advanced topics in this area, including numerous practical designs to back the theoretical considerations. It presents the challenges in designing power amplifiers in silicon and helps the reader improve the efficiency of linear power amplifiers, and design more accurate compact device models, with faster extraction routines, to create cost effective and reliable circuits.

Efficient trigger signal generation from wasted backward amplified stimulated emission at optical amplifiers for optical coherence tomography

Directory of Open Access Journals (Sweden)

Kim Seung Taek

2015-01-01

Full Text Available This paper propose an optical structure to generate trigger signals for optical coherence tomography (OCT using backward light which is usually disposed. The backward light is called backward amplified stimulated emission generated from semiconductor optical amplifier (SOA when using swept wavelength tunable laser (SWTL. A circulator is applied to block undesirable lights in the SWTL instead of an isolator in common SWTL. The circulator also diverts backward amplified spontaneous lights, which finally bring out trigger signals for a high speed digitizer. The spectra of the forward lights at SOA and the waveform of the backward lights were measured to check the procedure of the trigger formation in the experiment. The results showed that the trigger signals from the proposed SWTL with the circulator was quite usable in OCT.

Amplifying genetic logic gates.

Science.gov (United States)

Bonnet, Jerome; Yin, Peter; Ortiz, Monica E; Subsoontorn, Pakpoom; Endy, Drew

2013-05-03

Organisms must process information encoded via developmental and environmental signals to survive and reproduce. Researchers have also engineered synthetic genetic logic to realize simpler, independent control of biological processes. We developed a three-terminal device architecture, termed the transcriptor, that uses bacteriophage serine integrases to control the flow of RNA polymerase along DNA. Integrase-mediated inversion or deletion of DNA encoding transcription terminators or a promoter modulates transcription rates. We realized permanent amplifying AND, NAND, OR, XOR, NOR, and XNOR gates actuated across common control signal ranges and sequential logic supporting autonomous cell-cell communication of DNA encoding distinct logic-gate states. The single-layer digital logic architecture developed here enables engineering of amplifying logic gates to control transcription rates within and across diverse organisms.

SPS RF System Amplifier plant

CERN Multimedia

1977-01-01

The picture shows a 2 MW, 200 MHz amplifier plant with feeder lines. The main RF-system of the SPS comprises four cavities: two of 20 m length and two of 16.5 m length. They are all installed in one long straight section (LSS 3). These cavities are of the travelling-wave type operating at a centre frequency of 200.2 MHz. They are wideband, filling time about 700 ns and untuned. The power amplifiers, using tetrodes are installed in a surface building 200 m from the cavities. Initially only two cavities were installed, a third cavity was installed in 1978 and a forth one in 1979. The number of power amplifiers was also increased: to the first 2 MW plant a second 2 MW plant was added and by end 1979 there were 8 500 kW units combined in pairs to feed each of the 4 cavities with up to about 1 MW RF power, resulting in a total accelerating voltage of about 8 MV. See also 7412016X, 7412017X, 7411048X.

Semi-automatic laser beam microdissection of the Y chromosome and analysis of Y chromosome DNA in a dioecious plant, Silene latifolia

International Nuclear Information System (INIS)

Matsunaga, S.; Kawano, S.; Michimoto, T.; Higashiyama, T.; Nakao, S.; Sakai, A.; Kuroiwa, T.

1999-01-01

Silene latifolia has heteromorphic sex chromosomes, the X and Y chromosomes. The Y chromosome, which is thought to carry the male determining gene, was isolated by UV laser microdissection and amplified by degenerate oligonucleotide-primed PCR. In situ chromosome suppression of the amplified Y chromosome DNA in the presence of female genomic DNA as a competitor showed that the microdissected Y chromosome DNA did not specifically hybridize to the Y chromosome, but-hybridized to all chromosomes. This result suggests that the Y chromosome does not contain Y chromosome-enriched repetitive sequences. A repetitive sequence in the microdissected Y chromosome, RMY1, was isolated while screening repetitive sequences in the amplified Y chromosome. Part of the nucleotide sequence shared a similarity to that of X-43.1, which was isolated from microdissected X chromosomes. Since fluorescence in situ hybridization analysis with RMY1 demonstrated that RMY1 was localized at the ends of the chromosome, RMY1 may be a subtelomeric repetitive sequence. Regarding the sex chromosomes, RMY1 was detected at both ends of the X chromosome and at one end near the pseudoautosomal region of the Y chromosome. The different localization of RMY1 on the sex chromosomes provides a clue to the problem of how the sex chromosomes arose from autosomes

Wideband pulse amplifiers for the NECTAr chip

International Nuclear Information System (INIS)

Sanuy, A.; Delagnes, E.; Gascon, D.; Sieiro, X.; Bolmont, J.; Corona, P.; Feinstein, F.; Glicenstein, J-F.; Naumann, C.L.; Nayman, P.; Ribó, M.

2012-01-01

The NECTAr collaboration's FE option for the camera of the CTA is a 16 bits and 1–3 GS/s sampling chip based on analog memories including most of the readout functions. This works describes the input amplifiers of the NECTAr ASIC. A fully differential wideband amplifier, with voltage gain up to 20 V/V and a BW of 400 MHz. As it is impossible to design a fully differential OpAmp with an 8 GHz GBW product in a 0.35 CMOS technology, an alternative implementation based on HF linearized transconductors is explored. The output buffer is a class AB miller operational amplifier, with special non-linear current boost.

Wideband pulse amplifiers for the NECTAr chip

Science.gov (United States)

Sanuy, A.; Delagnes, E.; Gascon, D.; Sieiro, X.; Bolmont, J.; Corona, P.; Feinstein, F.; Glicenstein, J.-F.; Naumann, C. L.; Nayman, P.; Ribó, M.; Tavernet, J.-P.; Toussenel, F.; Vincent, P.; Vorobiov, S.

2012-12-01

The NECTAr collaboration's FE option for the camera of the CTA is a 16 bits and 1-3 GS/s sampling chip based on analog memories including most of the readout functions. This works describes the input amplifiers of the NECTAr ASIC. A fully differential wideband amplifier, with voltage gain up to 20 V/V and a BW of 400 MHz. As it is impossible to design a fully differential OpAmp with an 8 GHz GBW product in a 0.35 CMOS technology, an alternative implementation based on HF linearized transconductors is explored. The output buffer is a class AB miller operational amplifier, with special non-linear current boost.

High-power piezo drive amplifier for large stack and PFC applications

Science.gov (United States)

Clingman, Dan J.; Gamble, Mike

2001-08-01

This paper describes the continuing development of Boeing High Power Piezo Drive Amplifiers. Described is the development and testing of a 1500 Vpp, 8 amp switching amplifier. This amplifier is used to drive a piezo stack driven rotor blade trailing edge flap on a full size helicopter. Also discuss is a switching amplifier designed to drive a Piezo Fiber Composite (PFC) active twist rotor blade. This amplifier was designed to drive the PFC material at 2000 Vpp and 0.5 amps. These amplifiers recycle reactive energy, allowing for a power and weight efficient amplifier design. This work was done in conjunction with the DARPA sponsored Phase II Smart Rotor Blade program and the NASA Langley Research Center sponsored Active Twist Rotor (ATR) blade program.

Traveling-Wave Tube Amplifier for THz Frequencies

DEFF Research Database (Denmark)

Kotiranta, Mikko; Krozer, Viktor; Zhurbenko, Vitaliy

tubes and gas lasers, but the ones available are too expensive or large for many applications. This work is related to the European project OPTHER (Optically driven terahertz amplifiers) which aims to realise a compact, powerful and efficient vacuum tube amplifier for the frequency range of 0.3 – 2...

Introduction to RF power amplifier design and simulation

CERN Document Server

Eroglu, Abdullah

2015-01-01

Introduction to RF Power Amplifier Design and Simulation fills a gap in the existing literature by providing step-by-step guidance for the design of radio frequency (RF) power amplifiers, from analytical formulation to simulation, implementation, and measurement. Featuring numerous illustrations and examples of real-world engineering applications, this book:Gives an overview of intermodulation and elaborates on the difference between linear and nonlinear amplifiersDescribes the high-frequency model and transient characteristics of metal-oxide-semiconductor field-effect transistorsDetails activ

Distributed CMOS Bidirectional Amplifiers Broadbanding and Linearization Techniques

CERN Document Server

El-Khatib, Ziad; Mahmoud, Samy A

2012-01-01

This book describes methods to design distributed amplifiers useful for performing circuit functions such as duplexing, paraphrase amplification, phase shifting power splitting and power combiner applications.  A CMOS bidirectional distributed amplifier is presented that combines for the first time device-level with circuit-level linearization, suppressing the third-order intermodulation distortion. It is implemented in 0.13μm RF CMOS technology for use in highly linear, low-cost UWB Radio-over-Fiber communication systems. Describes CMOS distributed amplifiers for optoelectronic applications such as Radio-over-Fiber systems, base station transceivers and picocells; Presents most recent techniques for linearization of CMOS distributed amplifiers; Includes coverage of CMOS I-V transconductors, as well as CMOS on-chip inductor integration and modeling; Includes circuit applications for UWB Radio-over-Fiber networks.

Resistor-less charge sensitive amplifier for semiconductor detectors

Energy Technology Data Exchange (ETDEWEB)

Pelczar, K., E-mail: krzysztof.pelczar@doctoral.uj.edu.pl; Panas, K.; Zuzel, G.

2016-11-01

A new concept of a Charge Sensitive Amplifier without a high-value resistor in the feedback loop is presented. Basic spectroscopic parameters of the amplifier coupled to a coaxial High Purity Germanium detector (HPGe) are discussed. The amplifier signal input is realized with an n-channel J-FET transistor. The feedback capacitor is discharged continuously by the second, forward biased n-channel J-FET, driven by an RC low–pass filter. Both the analog—with a standard spectroscopy amplifier and a multi-channel analyzer—and the digital—by applying a Flash Analog to Digital Converter—signal readouts were tested. The achieved resolution in the analog and the digital readouts was 0.17% and 0.21%, respectively, at the Full Width at Half Maximum of the registered {sup 60}Co 1332.5 keV gamma line.

Gyrocon: a deflection-modulated, high-power microwave amplifier

International Nuclear Information System (INIS)

Tallerico, P.J.

1977-10-01

A large-signal, relativistic theory of the electron-field interaction in a new class of microwave amplifiers is presented and applied to the analysis of a high-power, 450-MHz amplifier for accelerator applications. The analysis indicates that electronic efficiencies in excess of 90 percent are obtainable and that overall efficiencies of 90 percent are possible. The amplifier is unique in several respects; the electron velocity is perpendicular to the circuit energy flow, the device uses a fast-wave circuit, and the electron beam is deflection modulated

External Peltier Cooler For Low-Noise Amplifier

Science.gov (United States)

Soper, Terry A.

1990-01-01

Inexpensive Peltier-effect cooling module made of few commercially available parts used to reduce thermal noise in microwave amplifier. Retrofitted to almost any microwave low-noise amplifier or receiver preamplifier used in communication, telemetry, or radar. Includes copper or aluminum cold plate held tightly against unit to be cooled by strap-type worm-gear clamps.

Efficiency Optimization in Class-D Audio Amplifiers

DEFF Research Database (Denmark)

Yamauchi, Akira; Knott, Arnold; Jørgensen, Ivan Harald Holger

2015-01-01

This paper presents a new power efficiency optimization routine for designing Class-D audio amplifiers. The proposed optimization procedure finds design parameters for the power stage and the output filter, and the optimum switching frequency such that the weighted power losses are minimized under...... the given constraints. The optimization routine is applied to minimize the power losses in a 130 W class-D audio amplifier based on consumer behavior investigations, where the amplifier operates at idle and low power levels most of the time. Experimental results demonstrate that the optimization method can...... lead to around 30 % of efficiency improvement at 1.3 W output power without significant effects on both audio performance and the efficiency at high power levels....

Wideband pulse amplifiers for the NECTAr chip

Energy Technology Data Exchange (ETDEWEB)

Sanuy, A., E-mail: asanuy@ecm.ub.es [Dept. AM i Dept. ECM, Institut de Ciencies del Cosmos (ICC), Universitat de Barcelona. Marti i Franques 1, E08028, Barcelona (Spain); Delagnes, E. [IRFU/DSM/CEA, CE-Saclay, Bat. 141 SEN Saclay, F-91191, Gif-sur-Yvette (France); Gascon, D. [Dept. AM i Dept. ECM, Institut de Ciencies del Cosmos (ICC), Universitat de Barcelona. Marti i Franques 1, E08028, Barcelona (Spain); Sieiro, X. [Departament d' Electronica, Universitat de Barcelona. Marti i Franques 1, E08028, Barcelona (Spain); Bolmont, J.; Corona, P. [LPNHE, Universite Paris VI and Universite Paris VII and IN2P3/CNRS, Barre 12-22, 1er etage, 4 place Jussieu, 75252 Paris (France); Feinstein, F. [LUPM, Universite Montpellier II and IN2P3/CNRS, CC072, bat. 13, place Eugene Bataillon, 34095 Montpellier (France); Glicenstein, J-F. [IRFU/DSM/CEA, CE-Saclay, Bat. 141 SEN Saclay, F-91191, Gif-sur-Yvette (France); Naumann, C.L.; Nayman, P. [LPNHE, Universite Paris VI and Universite Paris VII and IN2P3/CNRS, Barre 12-22, 1er etage, 4 place Jussieu, 75252 Paris (France); Ribo, M. [Dept. AM i Dept. ECM, Institut de Ciencies del Cosmos (ICC), Universitat de Barcelona. Marti i Franques 1, E08028, Barcelona (Spain); and others

2012-12-11

The NECTAr collaboration's FE option for the camera of the CTA is a 16 bits and 1-3 GS/s sampling chip based on analog memories including most of the readout functions. This works describes the input amplifiers of the NECTAr ASIC. A fully differential wideband amplifier, with voltage gain up to 20 V/V and a BW of 400 MHz. As it is impossible to design a fully differential OpAmp with an 8 GHz GBW product in a 0.35 CMOS technology, an alternative implementation based on HF linearized transconductors is explored. The output buffer is a class AB miller operational amplifier, with special non-linear current boost.

The Dynamics of Semiconductor Optical Amplifiers – Modeling and Applications

DEFF Research Database (Denmark)

Mørk, Jesper; Nielsen, Mads Lønstrup; Berg, Tommy Winther

2003-01-01

The importance of semiconductor optical amplifiers is discussed. A semiconductor optical amplifier (SOA) is a semiconductor laser with anti-reflection coated facets that amplifies an injected light signal by means of stimulated emission. SOAs have a number of unique properties that open up...

Noise and saturation properties of semiconductor quantum dot optical amplifiers

DEFF Research Database (Denmark)

Berg, Tommy Winther; Mørk, Jesper

2002-01-01

We present a detailed theoretical analysis of quantum dot optical amplifiers. Due to the presence of a reservoir of wetting layer states, the saturation and noise properties differ markedly from bulk or QW amplifiers and may be significantly improved.......We present a detailed theoretical analysis of quantum dot optical amplifiers. Due to the presence of a reservoir of wetting layer states, the saturation and noise properties differ markedly from bulk or QW amplifiers and may be significantly improved....

Manhattan equation for the operational amplifier

OpenAIRE

Mishonov, Todor M.; Danchev, Victor I.; Petkov, Emil G.; Gourev, Vassil N.; Dimitrova, Iglika M.; Varonov, Albert M.

2018-01-01

A differential equation relating the voltage at the output of an operational amplifier $U_0$ and the difference between the input voltages ($U_{+}$ and $U_{-}$) has been derived. The crossover frequency $f_0$ is a parameter in this operational amplifier master equation. The formulas derived as a consequence of this equation find applications in thousands of specifications for electronic devices but as far as we know, the equation has never been published. Actually, the master equation of oper...

Integrated circuit amplifiers for multi-electrode intracortical recording.

Science.gov (United States)

Jochum, Thomas; Denison, Timothy; Wolf, Patrick

2009-02-01

Significant progress has been made in systems that interpret the electrical signals of the brain in order to control an actuator. One version of these systems senses neuronal extracellular action potentials with an array of up to 100 miniature probes inserted into the cortex. The impedance of each probe is high, so environmental electrical noise is readily coupled to the neuronal signal. To minimize this noise, an amplifier is placed close to each probe. Thus, the need has arisen for many amplifiers to be placed near the cortex. Commercially available integrated circuits do not satisfy the area, power and noise requirements of this application, so researchers have designed custom integrated-circuit amplifiers. This paper presents a comprehensive survey of the neural amplifiers described in publications prior to 2008. Methods to achieve high input impedance, low noise and a large time-constant high-pass filter are reviewed. A tutorial on the biological, electrochemical, mechanical and electromagnetic phenomena that influence amplifier design is provided. Areas for additional research, including sub-nanoampere electrolysis and chronic cortical heating, are discussed. Unresolved design concerns, including teraohm circuitry, electrical overstress and component failure, are identified.

Series-Tuned High Efficiency RF-Power Amplifiers

DEFF Research Database (Denmark)

Vidkjær, Jens

2008-01-01

An approach to high efficiency RF-power amplifier design is presented. It addresses simultaneously efficiency optimization and peak voltage limitations when transistors are pushed towards their power limits.......An approach to high efficiency RF-power amplifier design is presented. It addresses simultaneously efficiency optimization and peak voltage limitations when transistors are pushed towards their power limits....

Functional Blocks and Biquadratic ARC Filters using Transimpedance Amplifiers

Directory of Open Access Journals (Sweden)

R. Sarman

1997-04-01

Full Text Available The aims of the article are design and analysis of modern circuits including high performance functional blocks and biquadratic filters using transimpedance amplifiers. Here are given various types of these circuits, that works in classical voltage, current or hybrid mode. In this paper are also compared various possibilities of connection of single amplifier filters as for reduction of influence of transimpedance amplifier parasitic elements.

Functional Blocks and Biquadratic ARC Filters using Transimpedance Amplifiers

OpenAIRE

R. Sarman; R. Prokop; T. Dostal

1997-01-01

The aims of the article are design and analysis of modern circuits including high performance functional blocks and biquadratic filters using transimpedance amplifiers. Here are given various types of these circuits, that works in classical voltage, current or hybrid mode. In this paper are also compared various possibilities of connection of single amplifier filters as for reduction of influence of transimpedance amplifier parasitic elements.

Using MEMS Capacitive Switches in Tunable RF Amplifiers

OpenAIRE

Danson John; Plett Calvin; Tait Niall

2006-01-01

A MEMS capacitive switch suitable for use in tunable RF amplifiers is described. A MEMS switch is designed, fabricated, and characterized with physical and RF measurements for inclusion in simulations. Using the MEMS switch models, a dual-band low-noise amplifier (LNA) operating at GHz and GHz, and a tunable power amplifier (PA) at GHz are simulated in m CMOS. MEMS switches allow the LNA to operate with 11 dB of isolation between the two bands while maintaining dB of gain and sub- dB no...

Criterion of transverse coherence of self-amplified spontaneous emission in high gain free electron laser amplifiers

International Nuclear Information System (INIS)

Xie, M.; Kim, K.J.

1995-01-01

In a high gain free electron laser amplifier based on Self-Amplified Spontaneous Emission (SASE) the spontaneous radiation generated by an electron beam near the undulator entrance is amplified many orders of magnitude along the undulator. The transverse coherence properties of the amplified radiation depends on both the amplification process and the coherence of the seed radiation (the undulator radiation generated in the first gain length or so). The evolution of the transverse coherence in the amplification process is studied based on the solution of the coupled Maxwell-Vlasov equations including higher order transverse modes. The coherence of the seed radiation is determined by the number of coherent modes in the phase space area of the undulator radiation. We discuss the criterion of transverse coherence and identify governing parameters over a broad range of parameters. In particular we re-examine the well known emittance criterion for the undulator radiation, which states that full transverse coherence is guaranteed if the rms emittance is smaller than the wavelength divided by 4π. It is found that this criterion is modified for SASE because of the different optimization conditions required for the electron beam. Our analysis is a generalization of the previous study by Yu and Krinsky for the case of vanishing emittance with parallel electron beam. Understanding the transverse coherence of SASE is important for the X-ray free electron laser projects now under consideration at SLAC and DESY

Self-amplifying mRNA vaccines.

Science.gov (United States)

Brito, Luis A; Kommareddy, Sushma; Maione, Domenico; Uematsu, Yasushi; Giovani, Cinzia; Berlanda Scorza, Francesco; Otten, Gillis R; Yu, Dong; Mandl, Christian W; Mason, Peter W; Dormitzer, Philip R; Ulmer, Jeffrey B; Geall, Andrew J

2015-01-01

This chapter provides a brief introduction to nucleic acid-based vaccines and recent research in developing self-amplifying mRNA vaccines. These vaccines promise the flexibility of plasmid DNA vaccines with enhanced immunogenicity and safety. The key to realizing the full potential of these vaccines is efficient delivery of nucleic acid to the cytoplasm of a cell, where it can amplify and express the encoded antigenic protein. The hydrophilicity and strong net negative charge of RNA impedes cellular uptake. To overcome this limitation, electrostatic complexation with cationic lipids or polymers and physical delivery using electroporation or ballistic particles to improve cellular uptake has been evaluated. This chapter highlights the rapid progress made in using nonviral delivery systems for RNA-based vaccines. Initial preclinical testing of self-amplifying mRNA vaccines has shown nonviral delivery to be capable of producing potent and robust innate and adaptive immune responses in small animals and nonhuman primates. Historically, the prospect of developing mRNA vaccines was uncertain due to concerns of mRNA instability and the feasibility of large-scale manufacturing. Today, these issues are no longer perceived as barriers in the widespread implementation of the technology. Currently, nonamplifying mRNA vaccines are under investigation in human clinical trials and can be produced at a sufficient quantity and quality to meet regulatory requirements. If the encouraging preclinical data with self-amplifying mRNA vaccines are matched by equivalently positive immunogenicity, potency, and tolerability in human trials, this platform could establish nucleic acid vaccines as a versatile new tool for human immunization. Copyright © 2015 Elsevier Inc. All rights reserved.

Pulsed hydrogen fluoride laser oscillator-amplifier experiments

International Nuclear Information System (INIS)

Schott, G.L.

1975-01-01

Pulsed HF chemical laser oscillator energies were scaled from millijoules to several kilojoules over the period 1970-1974, reaching approximately 10 J with SF 6 and transverse discharges, and using electron-beam initiation and elemental F 2 above 1000J. This demonstrated scalability to large energy with acceptable electrical efficiency is only one prerequisite for application of this gas laser in fusion; equally important matters are achievement of focusable, approximately 1 ns pulses, couplable to light-element targets, all from an affordable system. Exploratory MOPA experiments are reported which address control of HF laser beam focusability and pulse duration, using SF 6 -based experimental oscillator--amplifier sequences and Pockels' cell switching. Simultaneous multiline lasing with 2.6 less than or equal to lambda less than or equal to 3.1 μm and high specific gain and energy density are particularly important factors encountered with HF, where amplifier pumping and lasing occur in a substantially cw temporal relationship, even in less than 100 ns bursts. Time-resolved SF 6 --HI oscillator spectra contain 27 simultaneous lines from six vibrational bands. An apertured, SF 6 -hydrocarbon pin-discharge oscillator generates approximately 10 mJ of TEM 00 radiation, which is amplified to approximately 1 J in approximately 150 ns by a TEA amplifier and p []opagated tens of meters. A three-stage system coupling these elements through an approximately 1 ns electrooptic gate to a greater than 10 J, e-beam energized amplifier is under development. (auth)

Molecular diversity among Turkish oaks ( QUERCUS ) using random ...

African Journals Online (AJOL)

Turkey is one of the most important region of the world according to oak species number and variation. In this study, species belonging to evergreen oaks in Turkey were investigated to solve taxonomic problems and to design the limit of taxa by using random amplified polymorphic DNA (RAPD) data. Here, three species of ...

Cascade energy amplifier

International Nuclear Information System (INIS)

Barzilov, A.P.; Gulevich, A.V.; Kukharchuk, O.F.

2000-01-01

The technical problem of long-life fission product and minor actinide incineration and production of plutonium fuel in the prospective nuclear systems will arise at significant scales of nuclear power industry development. Subcritical nuclear reactors driven by extemal neutron sources (energy amplifiers) are considered as incinerators of toxicity of complete nuclear industry. In the frames of this concept, the subcritical reactor part consisting of two coupled blanket regions (inner fast neutron spectrum core and outer thermal core) driven by extemal neutron source is discussed. Two types of source are studied: spallation target and 14-MeV fusion bum of micropellets. Liquid metal Pb-Bi is considered as target material and coolant of inner fast core. Thermal core is a heavy-water subcritical reactor of the Candu-type. The fast core is protected from thermal neutrons influence with the boron shield. All reactor technologies used in this concept are tested during years of operation and commercially available. Thus, the cascade energy amplifiers have a set of advantages in comparison with traditional concepts: in energy production, in transmutation efficiency, and in economics. (authors)

Power neodymium-glass amplifier of a repetitively pulsed laser

Energy Technology Data Exchange (ETDEWEB)

Vinogradov, Aleksandr V; Gaganov, V E; Garanin, Sergey G; Zhidkov, N V; Krotov, V A; Martynenko, S P; Pozdnyakov, E V; Solomatin, I I [Russian Federal Nuclear Center ' All-Russian Research Institute of Experimental Physics' , Sarov, Nizhnii Novgorod region (Russian Federation)

2011-11-30

A neodymium-glass diode-pumped amplifier with a zigzag laser beam propagation through the active medium was elaborated; the amplifier is intended for operation in a repetitively pulsed laser. An amplifier unit with an aperture of 20 Multiplication-Sign 25 mm and a {approx}40-cm long active medium was put to a test. The energy of pump radiation amounts to 140 J at a wavelength of 806 nm for a pump duration of 550 {mu}s. The energy parameters of the amplifier were experimentally determined: the small-signal gain per pass {approx}3.2, the linear gain {approx}0.031 cm{sup -1} with a nonuniformity of its distribution over the aperture within 15%, the stored energy of 0.16 - 0.21 J cm{sup -3}. The wavefront distortions in the zigzag laser-beam propagation through the active element of the amplifier did not exceed 0.4{lambda} ({lambda} = 0.63 {mu}m is the probing radiation wavelength).

Power neodymium-glass amplifier of a repetitively pulsed laser

International Nuclear Information System (INIS)

Vinogradov, Aleksandr V; Gaganov, V E; Garanin, Sergey G; Zhidkov, N V; Krotov, V A; Martynenko, S P; Pozdnyakov, E V; Solomatin, I I

2011-01-01

A neodymium-glass diode-pumped amplifier with a zigzag laser beam propagation through the active medium was elaborated; the amplifier is intended for operation in a repetitively pulsed laser. An amplifier unit with an aperture of 20 × 25 mm and a ∼40-cm long active medium was put to a test. The energy of pump radiation amounts to 140 J at a wavelength of 806 nm for a pump duration of 550 μs. The energy parameters of the amplifier were experimentally determined: the small-signal gain per pass ∼3.2, the linear gain ∼0.031 cm -1 with a nonuniformity of its distribution over the aperture within 15%, the stored energy of 0.16 - 0.21 J cm -3 . The wavefront distortions in the zigzag laser-beam propagation through the active element of the amplifier did not exceed 0.4λ (λ = 0.63 μm is the probing radiation wavelength).

GAME EDUKASI PERAKITAN AMPLIFIER BERBASIS ANDROID UNTUK USER UMUM

Directory of Open Access Journals (Sweden)

Fundhi Fanju Hafili

2015-04-01

Full Text Available ABSTRAK Seiring dengan perkembangan dan kebutuhan teknologi saat ini pembelajaran elektro dapat dibuat menjadi lebih praktis dan menarik di ponsel berbasis android Mempelajari elektronika juga memerlukan usaha-usaha nyata yang ber-kesinambungan dan mengarah kepada tumbuhnya kesadaran untuk menjadikan elektronika sebagai perkembangan teknologi. Dengan adanya metode game, merupakan salah satu metode belajar merakit amplifier yang disusun secara praktis dan sistematis sehingga memudahkan setiap orang untuk belajar maupun mengajarkan merancang amplifier. Sementara itu metode pembelajaran yang ada saat ini yaitu melalui buku maupun dengan cara bertatap muka langsung dengan tentor dirasa masih kurang efektif. Untuk mengatasi masalah tersebut maka penulis membuat game edukasi elektro merancang amplifier, karena mudah dipahami dan memudahkan para calon teknisi elektro dalam belajar merancang amplifier. Perancangan ini dilakukan dengan pendekatan metode Research and Development adalah metode penelitian yang digunakan untuk menghasilkan produk tertentu dan menguji keefektifan produk tersebut. Dengan aplikasi ini diharapkan dapat membantu para pengguna yang ingin belajar merakit amplifier berbasis android. . Kata kunci: elektro, game, research and development.

InP Heterojunction Bipolar Transistor Amplifiers to 255 GHz

Science.gov (United States)

Radisic, Vesna; Sawdai, Donald; Scott, Dennis; Deal, William; Dang, Linh; Li, Danny; Cavus, Abdullah; To, Richard; Lai, Richard

2009-01-01

Two single-stage InP heterojunction bipolar transistor (HBT) amplifiers operate at 184 and 255 GHz, using Northrop Grumman Corporation s InP HBT MMIC (monolithic microwave integrated circuit) technology. At the time of this reporting, these are reported to be the highest HBT amplifiers ever created. The purpose of the amplifier design is to evaluate the technology capability for high-frequency designs and verify the model for future development work.

Bevalac injector final stage RF amplifier upgrades

International Nuclear Information System (INIS)

Howard, D.; Calvert, J.; Dwinell, R.; Lax, J.; Lindner, A.; Richter, R.; Ridgeway, W.

1991-01-01

With the assistance of the DOE In-house Energy Management Program, the Bevalac injector final stage RF amplifier systems have been successfully upgraded to reduce energy consumption and operating costs. This recently completed project removed the energy-inefficient plate voltage modulator circuits that were used in conjunction with the final stage RF amplifiers. Construction, design, and operating parameters are described in detail

Effects of entanglement in an ideal optical amplifier

Science.gov (United States)

Franson, J. D.; Brewster, R. A.

2018-04-01

In an ideal linear amplifier, the output signal is linearly related to the input signal with an additive noise that is independent of the input. The decoherence of a quantum-mechanical state as a result of optical amplification is usually assumed to be due to the addition of quantum noise. Here we show that entanglement between the input signal and the amplifying medium can produce an exponentially-large amount of decoherence in an ideal optical amplifier even when the gain is arbitrarily close to unity and the added noise is negligible. These effects occur for macroscopic superposition states, where even a small amount of gain can leave a significant amount of which-path information in the environment. Our results show that the usual input/output relation of a linear amplifier does not provide a complete description of the output state when post-selection is used.

Genetic diversity of two Tunisian sheep breeds using random ...

African Journals Online (AJOL)

Random amplified polymorphic DNA (RAPD) markers were used to study genetic diversity and population structure in six sheep populations belonging to two native Tunisian breeds (the Barbarine and the Western thin tail). A total of 96 samples were typed using eight RAPD primers. 62 bands were scored, of which 44 ...

Design of a high-gain laser diode-array pumped Nd:YAG Alternating Precessive Slab Amplifier (APS-Amplifier)

Science.gov (United States)

Coyle, D. Barry

1991-01-01

In the design of space qualifiable laser systems for ranging and altimetry, such as NASA's Geodynamic Laser Ranging System (GLRS), the transmitter must be kept small, powerful yet efficient, and must consist of as few components as possible. A novel preamplifier design is examined which requires no external beam steering optics, yielding a compact component with simple alignment procedures. The gains achieved are comparable to multipass zigzag amplifiers using two or more sets of external optics for extra passes through the amplifying medium.

Design of a high-gain laser diode-array pumped Nd:YAG alternating precessive slab amplifier (APS amplifier)

Science.gov (United States)

Coyle, D. B.

1991-01-01

In the design of space-qualifiable laser systems for ranging and altimetry, such as NASA's Geodynamic Laser Ranging System (GLRS), the transmitter must be kept small, powerful yet efficient, and must consist of as few components as possible. A novel preamplifier design is examined which requires no external beam steering optics, yielding a compact component with simple alignment procedures. The gains achieved are comparable to multipass zigzag amplifiers using two or more sets of external optics for extra passes through the amplifying medium.

A CMOS Integrating Amplifier for the PHENIX Ring Imaging Cherenkov detector

International Nuclear Information System (INIS)

Wintenberg, A.L.; Jones, J.P. Jr.; Young, G.R.; Moscone, C.G.

1997-11-01

A CMOS integrating amplifier has been developed for use in the PHENIX Ring Imaging Cherenkov (RICH) detector. The amplifier, consisting of a charge-integrating amplifier followed by a variable gain amplifier (VGA), is an element of a photon measurement system comprising a photomultiplier tube, a wideband, gain of 10 amplifier, the integrating amplifier, and an analog memory followed by an ADC and double correlated sampling implemented in software. The integrating amplifier is designed for a nominal full scale input of 160 pC with a gain of 20 mV/pC and a dynamic range of 1000:1. The VGA is used for equalizing gains prior to forming analog sums for trigger purposes. The gain of the VGA is variable over a 3:1 range using a 5 bits digital control, and the risetime is held to approximately 20 ns using switched compensation in the VGA. Details of the design and results from several prototype devices fabricated in 1.2 microm Orbit CMOS are presented. A complete noise analysis of the integrating amplifier and the correlated sampling process is included as well as a comparison of calculated, simulated and measured results

A CMOS Integrating Amplifier for the PHENIX Ring Imaging Cherenkov detector

Energy Technology Data Exchange (ETDEWEB)

Wintenberg, A.L.; Jones, J.P. Jr.; Young, G.R. [Oak Ridge National Lab., TN (United States); Moscone, C.G. [Tennessee Univ., Knoxville, TN (United States)

1997-11-01

A CMOS integrating amplifier has been developed for use in the PHENIX Ring Imaging Cherenkov (RICH) detector. The amplifier, consisting of a charge-integrating amplifier followed by a variable gain amplifier (VGA), is an element of a photon measurement system comprising a photomultiplier tube, a wideband, gain of 10 amplifier, the integrating amplifier, and an analog memory followed by an ADC and double correlated sampling implemented in software. The integrating amplifier is designed for a nominal full scale input of 160 pC with a gain of 20 mV/pC and a dynamic range of 1000:1. The VGA is used for equalizing gains prior to forming analog sums for trigger purposes. The gain of the VGA is variable over a 3:1 range using a 5 bits digital control, and the risetime is held to approximately 20 ns using switched compensation in the VGA. Details of the design and results from several prototype devices fabricated in 1.2 {micro}m Orbit CMOS are presented. A complete noise analysis of the integrating amplifier and the correlated sampling process is included as well as a comparison of calculated, simulated and measured results.

Amplified spontaneous emission in solar-pumped iodine laser

Science.gov (United States)

Cho, Yong S.; Hwang, In H.; Han, Kwang S.; Lee, Ja H.

1992-01-01

The amplified spontaneous emission (ASE) from a long pulse, solar-simulating radiation pumped iodine laser amplifier is studied. The ASE threshold pump intensity is almost proportional to the inverse of the laser gain length when the gas pressure is constant in the laser tube.

Ultrafast Dynamics of Quantum-Dot Semiconductor Optical Amplifiers

DEFF Research Database (Denmark)

Poel, Mike van der; Hvam, Jørn Märcher

2007-01-01

We report on a series of experiments on the dynamical properties of quantum-dot semiconductor optical amplifiers. We show how the amplifier responds to one or several ultrafast (170 fs) pulses in rapid succession and our results demonstrate applicability and ultimate limitations to application...

Self-oscillating modulators for direct energy conversion audio power amplifiers

Energy Technology Data Exchange (ETDEWEB)

Ljusev, P.; Andersen, Michael A.E.

2005-07-01

Direct energy conversion audio power amplifier represents total integration of switching-mode power supply and Class D audio power amplifier into one compact stage, achieving high efficiency, high level of integration, low component count and eventually low cost. This paper presents how self-oscillating modulators can be used with the direct switching-mode audio power amplifier to improve its performance by providing fast hysteretic control with high power supply rejection ratio, open-loop stability and high bandwidth. Its operation is thoroughly analyzed and simulated waveforms of a prototype amplifier are presented. (au)

Design and development of digital seismic amplifier recorder

Energy Technology Data Exchange (ETDEWEB)

Samsidar, Siti Alaa; Afuar, Waldy; Handayani, Gunawan, E-mail: gunawanhandayani@gmail.com [Department of Physics, ITB (Indonesia)

2015-04-16

A digital seismic recording is a recording technique of seismic data in digital systems. This method is more convenient because it is more accurate than other methods of seismic recorders. To improve the quality of the results of seismic measurements, the signal needs to be amplified to obtain better subsurface images. The purpose of this study is to improve the accuracy of measurement by amplifying the input signal. We use seismic sensors/geophones with a frequency of 4.5 Hz. The signal is amplified by means of 12 units of non-inverting amplifier. The non-inverting amplifier using IC 741 with the resistor values 1KΩ and 1MΩ. The amplification results were 1,000 times. The results of signal amplification converted into digital by using the Analog Digital Converter (ADC). Quantitative analysis in this study was performed using the software Lab VIEW 8.6. The Lab VIEW 8.6 program was used to control the ADC. The results of qualitative analysis showed that the seismic conditioning can produce a large output, so that the data obtained is better than conventional data. This application can be used for geophysical methods that have low input voltage such as microtremor application.

Operational amplifier circuits analysis and design

CERN Document Server

Nelson, J C C

1995-01-01

This book, a revised and updated version of the author's Basic Operational Amplifiers (Butterworths 1986), enables the non-specialist to make effective use of readily available integrated circuit operational amplifiers for a range of applications, including instrumentation, signal generation and processing.It is assumed the reader has a background in the basic techniques of circuit analysis, particularly the use of j notation for reactive circuits, with a corresponding level of mathematical ability. The underlying theory is explained with sufficient but not excessive, detail. A range of compu

Amplifying the helicopter drift in a conformal HMD

Science.gov (United States)

Schmerwitz, Sven; Knabl, Patrizia M.; Lueken, Thomas; Doehler, Hans-Ullrich

2016-05-01

Helicopter operations require a well-controlled and minimal lateral drift shortly before ground contact. Any lateral speed exceeding this small threshold can cause a dangerous momentum around the roll axis, which may cause a total roll over of the helicopter. As long as pilots can observe visual cues from the ground, they are able to easily control the helicopter drift. But whenever natural vision is reduced or even obscured, e.g. due to night, fog, or dust, this controllability diminishes. Therefore helicopter operators could benefit from some type of "drift indication" that mitigates the influence of a degraded visual environment. Generally humans derive ego motion by the perceived environmental object flow. The visual cues perceived are located close to the helicopter, therefore even small movements can be recognized. This fact was used to investigate a modified drift indication. To enhance the perception of ego motion in a conformal HMD symbol set the measured movement was used to generate a pattern motion in the forward field of view close or on the landing pad. The paper will discuss the method of amplified ego motion drift indication. Aspects concerning impact factors like visualization type, location, gain and more will be addressed. Further conclusions from previous studies, a high fidelity experiment and a part task experiment, will be provided. A part task study will be presented that compared different amplified drift indications against a predictor. 24 participants, 15 holding a fixed wing license and 4 helicopter pilots, had to perform a dual task on a virtual reality headset. A simplified control model was used to steer a "helicopter" down to a landing pad while acknowledging randomly placed characters.

Spaceflight 2 um Tm Fiber MOPA Amplifier, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Fibertek proposes to design, develop, and test a spaceflight prototype 2051 nm thulium (Tm)-doped fiber amplifier (TDFA) optical master oscillator power amplifier...

Compact solid state radio frequency amplifiers in kW regime for ...

Indian Academy of Sciences (India)

RF amplifier; solid state amplifier; power combiner and divider; .... was designed using planar and coaxial transmission line baluns with minimum lumped variable ..... Cripps S C 1999 RF power amplifiers for wireless communication. Norwood: ...

Distributed amplifier using Josephson vortex flow transistors

International Nuclear Information System (INIS)

McGinnis, D.P.; Beyer, J.B.; Nordman, J.E.

1986-01-01

A wide-band traveling wave amplifier using vortex flow transistors is proposed. A vortex flow transistor is a long Josephson junction used as a current controlled voltage source. The dual nature of this device to the field effect transistor is exploited. A circuit model of this device is proposed and a distributed amplifier utilizing 50 vortex flow transistors is predicted to have useful gain to 100 GHz

PHEMT Distributed Power Amplifier Adopting Broadband Impedance Transformer

DEFF Research Database (Denmark)

Narendra, K.; Limiti, E.; Paoloni, C.

2013-01-01

A non-uniform drain line distributed power amplifier (DPA) employing a broadband impedance transformer is presented. The DPA is based on GaAs PHEMT technology. The impedance transformer employs asymmetric coupled lines and transforms a low output impedance of the amplifier to a standard 50 Ω...

Development and energization of IOT based RF amplifier

International Nuclear Information System (INIS)

Mandal, A.; Som, S.; Raj, P.R.; Manna, S.K.; Ghosh, S.; Seth, S.; Thakurta, S.; Thakur, S.K.; Saha, S.; Panda, U.S.

2013-01-01

A 704 MHz IOT based CW RF amplifier has been developed in VECC. It can also be used with proper tuning to power cavity modules operating at 650 MHz in high energy high intensity proton linear accelerator proposed to be built for ADSS/SNS programme in India and Project-X at Fermilab, USA. This IOT based amplifier provides up to 60 kW continuous wave RF power at 700 MHz. It required various power supplies, LCW cooling and forced air cooling for its operation. The auxiliary power supplies like Grid, Filament and Ion-pump, are floated and mounted on an isolated frame, i.e., HV deck. The mains inputs are electrically isolated by means of isolation transformer. Also, a Programmable Logic Controller (PLC) based interlocks along with high voltage collector power supply has been designed and developed for the safe operation of the RF amplifier. This paper discusses about various developments and energization of the IOT based RF amplifier with high power dummy load. (author)

Amplifiers dedicated for large area SiC photodiodes

Science.gov (United States)

Doroz, P.; Duk, M.; Korwin-Pawlowski, M. L.; Borecki, M.

2016-09-01

Large area SiC photodiodes find applications in optoelectronic sensors working at special conditions. These conditions include detection of UV radiation in harsh environment. Moreover, the mentioned sensors have to be selective and resistant to unwanted signals. For this purpose, the modulation of light at source unit and the rejection of constant current and low frequency component of signal at detector unit are used. The popular frequency used for modulation in such sensor is 1kHz. The large area photodiodes are characterized by a large capacitance and low shunt resistance that varies with polarization of the photodiode and can significantly modify the conditions of signal pre-amplification. In this paper two pre-amplifiers topology are analyzed: the transimpedance amplifier and the non-inverting voltage to voltage amplifier with negative feedback. The feedback loops of both pre-amplifiers are equipped with elements used for initial constant current and low frequency signals rejections. Both circuits are analyzed and compared using simulation and experimental approaches.

Spatial chirp in Ti:sapphire multipass amplifier

International Nuclear Information System (INIS)

Li Wenkai; Lu Jun; Li Yanyan; Guo Xiaoyang; Wu Fenxiang; Yu Linpeng; Wang Pengfei; Xu Yi; Leng Yuxin

2017-01-01

The spatial chirp generated in the Ti:sapphire multipass amplifier is numerically investigated based on the one-dimensional (1D) and two-dimensional (2D) Frantz–Nodvik equations. The simulation indicates that the spatial chirp is induced by the spatially inhomogeneous gain, and it can be almost eliminated by utilization of proper beam profiles and spot sizes of the signal and pump pulses, for example, the pump pulse has a top-hatted beam profile and the signal pulse has a super-Gaussian beam profile with a relatively larger spot size. In this way, a clear understanding of spatial chirp mechanisms in the Ti:sapphire multipass amplifier is proposed, therefore we can effectively almost eliminate the spatial chirp and improve the beam quality of a high-power Ti:sapphire chirped pulse amplifier system. (paper)

An automated test facility for neutronic amplifiers

International Nuclear Information System (INIS)

Beattie, W.J.

1997-01-01

Neutronic amplifiers are used at the Chalk River Laboratory in applications such as neutron flux monitoring and reactor control systems. Routine preventive maintenance of control and safety systems included annual calibration and characterization of the neutronic amplifiers. An investigation into the traditional methods of annual routine maintenance of amplifiers concluded that frequency and phase response measurements in particular were labour intensive and subject to non-repeatable errors. A decision was made to upgrade testing methods and facilities by using programmable test equipment under the control of a computer. In order to verify the results of the routine measurements, expressions for the transfer functions were derived from the circuit diagrams. Frequency and phase responses were then calculated and plotted thus providing a bench-mark to which the test results can be compared. (author)

Smoothing by spectral dispersion using random phase modulation for inertial confinement fusion

International Nuclear Information System (INIS)

Rothenberg, J.E.

1995-01-01

Numerical simulations of beam smoothing using random phase modulation and grating dispersion are presented. Spatial spectra of the target illumination show that significantly improved smoothing at low spatial frequency is achieved while maintaining uniform intensity in the laser amplifier

Dynamic range meter for radiofrequency amplifiers

Directory of Open Access Journals (Sweden)

Drozd S. S.

2009-04-01

Full Text Available The new measurement setup having increased on 20…30 dB the own dynamic range in comparison with the standard circuit of the dynamic range meter is offered and the rated value of an error bringing by setup in the worst case does not exceed ± 2,8 dB. The measurement setup can be applied also to determinate levels of intermodulation components average power amplifiers and powerful amplifiers of a low-frequency at replacement of the quartz filter on meeting low-frequency the LC-filter and the spectrum analyzer.

Cavity enhanced rephased amplified spontaneous emission

International Nuclear Information System (INIS)

A Williamson, Lewis; J Longdell, Jevon

2014-01-01

Amplified spontaneous emission is usually treated as an incoherent noise process. Recent theoretical and experimental work using rephasing optical pulses has shown that rephased amplified spontaneous emission (RASE) is a potential source of wide bandwidth time-delayed entanglement. Due to poor echo efficiency the plain RASE protocol does not in theory achieve perfect entanglement. Experiments done to date show a very small amount of entanglement at best. Here we show that RASE can, in principle, produce perfect multimode time-delayed two mode squeezing when the active medium is placed inside a Q-switched cavity. (paper)

Pulse GaAs field transistor amplifier with subnanosecond time transient

International Nuclear Information System (INIS)

Sidnev, A.N.

1987-01-01

Pulse amplifier on fast field effect GaAs transistors with Schottky barrier is described. The amplifier contains four cascades, the first three of which are made on combined transistors on the common-drain circuit. The last cascade is made on high-power field effect GaAs transistor for coordination with 50 ohm load. The amplifier operates within the range of input signals from 0.5 up to 100 mV with repetition frequency up to 16 Hz, The gain of the amplifier is ≅ 20 dB. The setting time at output pulses amplitude up to 1 V constitutes ∼ 0.2 ns

TARC: Carlo Rubbia's Energy Amplifier

CERN Multimedia

Laurent Guiraud

1997-01-01

Transmutation by Adiabatic Resonance Crossing (TARC) is Carlo Rubbia's energy amplifier. This CERN experiment demonstrated that long-lived fission fragments, such as 99-TC, can be efficiently destroyed.

Designing and development of a synchronous analogic amplifier

International Nuclear Information System (INIS)

De la Hoz, E.; Ortiz, A.

1989-01-01

A large number of electronic systems used in the measurement and analysis of weak signals involve a ''lock-in'' amplifier, because it provides an effective method for the recovery of signals buried below a considerable high level of noise. The use of the ''lock-in'' amplifier in our institutions is very limited due to the high expense and the lack of warranties for its maintenance. The purpose of the present work is to design and build a low cost ''lock-in'' amplifier using components available in the local market. Its optimization has allowed us to increase the sensitivity and linearity of the systems, making it very versatile for dedicated applications

On the unlimited gain of a nonlinear parametric amplifier

DEFF Research Database (Denmark)

Sorokin, Vladislav

2014-01-01

The present paper is concerned with analysis of the response of a nonlinear parametric amplifier in abroad range of system parameters, particularly beyond resonance. Such analysis is of particular interestfor micro- and nanosystems, since many small-scale parametric amplifiers exhibit a distinctly...... nonlinearbehavior when amplitude of their response is sufficiently large. The modified method of direct separa-tion of motions is employed to study the considered system. As the result it is obtained that steady-stateamplitude of the nonlinear parametric amplifier response can reach large values in the case...... of arbitrarilysmall amplitude of external excitation, so that the amplifier gain tends to infinity. Very large amplifiergain can be achieved in a broad range of system parameters, in particular when the amplitude of para-metric excitation is comparatively small. The obtained results clearly demonstrate that very...

Rare-Earth Doped Photonic Crystal Fibre Lasers and Amplifiers

DEFF Research Database (Denmark)

Hougaard, Kristian G.

2005-01-01

In this thesis, a theoretical and numerical study of the use of rare-earthdoped photonic crystal fibres as optical amplifiers and lasers, has been performed. Photonic crystal fibres or microstructured optical fibres is a new kind of optical fibre in which the cladding region typically consist....... Their novel properties allow for design of optical fibre amplifiers and fibre lasers with superior performance, compared to solutions based on conventional fibres. The primary applications considered are high efficiency fibre amplifiers based on index guiding photonic crystal fibres, and cladding pumped....... The thesis also presents the basic properties of optical amplification, and describes the numerical model developed to model the behaviour of lasers and amplifiers based on photonic crystal fibres. The developed numerical tools are then used to investigate specific applications of photonic crystal fibres...

BET bromodomain inhibition of MYC-amplified medulloblastoma.

Science.gov (United States)

Bandopadhayay, Pratiti; Bergthold, Guillaume; Nguyen, Brian; Schubert, Simone; Gholamin, Sharareh; Tang, Yujie; Bolin, Sara; Schumacher, Steven E; Zeid, Rhamy; Masoud, Sabran; Yu, Furong; Vue, Nujsaubnusi; Gibson, William J; Paolella, Brenton R; Mitra, Siddhartha S; Cheshier, Samuel H; Qi, Jun; Liu, Kun-Wei; Wechsler-Reya, Robert; Weiss, William A; Swartling, Fredrik J; Kieran, Mark W; Bradner, James E; Beroukhim, Rameen; Cho, Yoon-Jae

2014-02-15

MYC-amplified medulloblastomas are highly lethal tumors. Bromodomain and extraterminal (BET) bromodomain inhibition has recently been shown to suppress MYC-associated transcriptional activity in other cancers. The compound JQ1 inhibits BET bromodomain-containing proteins, including BRD4. Here, we investigate BET bromodomain targeting for the treatment of MYC-amplified medulloblastoma. We evaluated the effects of genetic and pharmacologic inhibition of BET bromodomains on proliferation, cell cycle, and apoptosis in established and newly generated patient- and genetically engineered mouse model (GEMM)-derived medulloblastoma cell lines and xenografts that harbored amplifications of MYC or MYCN. We also assessed the effect of JQ1 on MYC expression and global MYC-associated transcriptional activity. We assessed the in vivo efficacy of JQ1 in orthotopic xenografts established in immunocompromised mice. Treatment of MYC-amplified medulloblastoma cells with JQ1 decreased cell viability associated with arrest at G1 and apoptosis. We observed downregulation of MYC expression and confirmed the inhibition of MYC-associated transcriptional targets. The exogenous expression of MYC from a retroviral promoter reduced the effect of JQ1 on cell viability, suggesting that attenuated levels of MYC contribute to the functional effects of JQ1. JQ1 significantly prolonged the survival of orthotopic xenograft models of MYC-amplified medulloblastoma (P < 0.001). Xenografts harvested from mice after five doses of JQ1 had reduced the expression of MYC mRNA and a reduced proliferative index. JQ1 suppresses MYC expression and MYC-associated transcriptional activity in medulloblastomas, resulting in an overall decrease in medulloblastoma cell viability. These preclinical findings highlight the promise of BET bromodomain inhibitors as novel agents for MYC-amplified medulloblastoma. ©2013 AACR

Investigation of switching frequency variations in self-oscillating class D amplifiers

OpenAIRE

Nielsen, Dennis; Knott, Arnold; Pfaffinger, Gerhard; Andersen, Michael A. E.

2009-01-01

Class D audio amplifiers have gained significant influence in sound reproduction due to their high efficiency. One of the most commonly used control methods in class D amplifiers is known as self-oscillation. An parameter of key interest in self-oscillating class D amplifiers is the switching frequency, which can be directly related to the performance of the amplifier. This paper will clearify the myth of the switching frequency through investigation of its dependency on modulation index and ...

Model of pulse extraction from a copper laser amplifier

International Nuclear Information System (INIS)

Boley, C.D.; Warner, B.E.

1997-03-01

A computational model of pulse propagation through a copper laser amplifier has been developed. The model contains a system of 1-D (in the axial direction), time-dependent equations for the laser intensity and amplified spontaneous emission (ASE), coupled to rate equations for the atomic levels. Detailed calculations are presented for a high-power amplifier at Lawrence Livermore National Laboratory. The extracted power agrees with experiment near saturation. At lower input power the calculation overestimates experiment, probably because of increased ASE effects. 6 refs., 6 figs

Efficient performance simulation of class D amplifier output stages

DEFF Research Database (Denmark)

Nyboe, Flemming; Risbo, Lars; Andreani, Pietro

2005-01-01

Straightforward simulation of amplifier distortion involves transient simulation of operation on a sine wave input signal, and a subsequent FFT of the output voltage. This approach is very slow on class D amplifiers, since the switching behavior forces simulation time steps that are many orders...... of magnitude smaller than the duration of one period of an audio sine wave. This work presents a method of simulating the amplifier transfer characteristic using a minimum amount of simulation time, and then deriving THD from the results....

Ripple compensation for a class-D amplifier

OpenAIRE

Cox, Stephen M.; du Toit Mouton, Hendrik

2015-01-01

This paper presents the first detailed mathematical analysis of the ripple compensation technique for reducing audio distortion in a class-D amplifier with negative feedback. The amplifier converts a relatively low-frequency audio signal to a high-frequency train of rectangular pulses whose widths are slowly modulated according to the audio signal (pulse-width modulation, PWM). Distortion manifests itself through unwanted audio-frequency harmonics that arise in the output due to nonlinearitie...

Progress on the gyrocon deflection-modulated amplifier

International Nuclear Information System (INIS)

Tallerico, P.J.

1982-01-01

The gyrocon is a high-power deflection-modulated amplifier that can have excellent spatial bunching and, hence, high dc-to-rf conversion efficiency. A program to design and build a prototype amplifier at 450 MHz is discussed. Peak powers of 150 kW and conversion efficiencies of 23% have been measured; the testing program is being pursued to improve this performance. Some possible mechanisms for the difference between the experimental and calculated performance are discussed

A high-power compact regenerative amplifier FEL

International Nuclear Information System (INIS)

Nguyen, D.C.; Sheffield, R.L.; Fortgang, C.M.; Kinross-Wright, J.M.; Ebrahim, N.A.; Goldstein, J.C.

1997-01-01

The Regenerative Amplifier FEL (RAFEL) is a new FEL approach aimed at achieving the highest optical power from a compact rf-linac FEL. The key idea is to feed back a small fraction ( 5 in single pass) wiggler to enable the FEL to reach saturation in a few passes. This paper summarizes the design of a high-power compact regenerative amplifier FEL and describes the first experimental demonstration of the RAFEL concept

Radiation hardening techniques for rare-earth based optical fibers and amplifiers

International Nuclear Information System (INIS)

Girard, Sylvain; Marcandella, Claude; Vivona, Marilena; Prudenzano, Luciano Mescia F.; Laurent, Arnaud; Robin, Thierry; Cadier, Benoit; Pinsard, Emmanuel; Ouerdane, Youcef; Boukenter, Aziz; Cannas, Marco; Boscaino, Roberto

2012-01-01

Er/Yb doped fibers and amplifiers have been shown to be very radiation sensitive, limiting their integration in space. We present an approach including successive hardening techniques to enhance their radiation tolerance. The efficiency of our approach is demonstrated by comparing the radiation responses of optical amplifiers made with same lengths of different rare-earth doped fibers and exposed to gamma-rays. Previous studies indicated that such amplifiers suffered significant degradation for doses exceeding 10 krad. Applying our techniques significantly enhances the amplifier radiation resistance, resulting in a very limited degradation up to 50 krad. Our optimization techniques concern the fiber composition, some possible pre-treatments and the interest of simulation tools used to harden by design the amplifiers. We showed that adding cerium inside the fiber phospho-silicate-based core strongly decreases the fiber radiation sensitivity compared to the standard fiber. For both fibers, a pre-treatment with hydrogen permits to enhance again the fiber resistance. Furthermore, simulations tools can also be used to improve the tolerance of the fiber amplifier by helping identifying the best amplifier configuration for operation in the radiative environment. (authors)

Effects of gamma radiation on commercial operational amplifiers

International Nuclear Information System (INIS)

Claro, Luiz H.; Santos, Jose A. dos

2009-01-01

The operational amplifiers are widely used in nuclear instrumentation. Their applications span the signal conditioning circuits, analog instrumentation, amplifiers, converters, oscillators and others. If an operational amplifier is used to work in a radiation environment, the device suffers degradation in its performance leading to the bad work in the systems. Some of these devices are designed as rad-hard components and therefore the effects of radiation damage are minimized, however its main disadvantage is the high cost and difficult to find in the market. As an alternative one can use the conventional electronic components available in the market and named COTS (Commercially Available Off-The-Shelf) but they must be tested under a radiation environment. In this work the effect of the radiation damage is studied in two typical operational amplifiers. Some electric parameters of these devices were measured for different gamma radiation doses and they were working at different input signal frequencies. A 60 Co isotopic radiation source was used and the results show that there is a certain degradation of the device depending on the radiation absorbed dose. (author)

Bandwidth limitations in current mode and voltage mode integrated feedback amplifiers

DEFF Research Database (Denmark)

Bruun, Erik

1995-01-01

loop bandwidth remains constant for a feedback amplifier. The constant-bandwidth relations of such amplifier designs are reviewed in this paper and they are combined with the constraints imposed by technology when the feedback amplifier is to be designed in an integrated technology. From this analysis...

Using MEMS Capacitive Switches in Tunable RF Amplifiers

Directory of Open Access Journals (Sweden)

Danson John

2006-01-01

Full Text Available A MEMS capacitive switch suitable for use in tunable RF amplifiers is described. A MEMS switch is designed, fabricated, and characterized with physical and RF measurements for inclusion in simulations. Using the MEMS switch models, a dual-band low-noise amplifier (LNA operating at GHz and GHz, and a tunable power amplifier (PA at GHz are simulated in m CMOS. MEMS switches allow the LNA to operate with 11 dB of isolation between the two bands while maintaining dB of gain and sub- dB noise figure. MEMS switches are used to implement a variable matching network that allows the PA to realize up to 37% PAE improvement at low input powers.

Electronically Tunable Transimpedance Instrumentation Amplifier Based on OTRA

Directory of Open Access Journals (Sweden)

Rajeshwari Pandey

2013-01-01

Full Text Available Operational transresistance amplifier (OTRA is the most suitable analog building block (ABB for transimpedance type signal processing due to its very nature of current input and voltage output. In this paper, OTRA-based transimpedance instrumentation amplifier (TIA is presented. It provides high differential gain and bandwidth, which is independent of gain. It also offers high common-mode rejection ratio (CMRR. The amplifier gain can be controlled electronically by implementing resistors using MOS transistors operating in linear region. The circuit can be made fully integrated. The proposed circuit is insensitive to parasitic input capacitances and input resistances due to the internally grounded input terminals of OTRA. Theoretical analysis is verified through PSPICE simulations and experimentation.

Bias-Voltage Stabilizer for HVHF Amplifiers in VHF Pulse-Echo Measurement Systems.

Science.gov (United States)

Choi, Hojong; Park, Chulwoo; Kim, Jungsuk; Jung, Hayong

2017-10-23

The impact of high-voltage-high-frequency (HVHF) amplifiers on echo-signal quality is greater with very-high-frequency (VHF, ≥100 MHz) ultrasound transducers than with low-frequency (LF, ≤15 MHz) ultrasound transducers. Hence, the bias voltage of an HVHF amplifier must be stabilized to ensure stable echo-signal amplitudes. We propose a bias-voltage stabilizer circuit to maintain stable DC voltages over a wide input range, thus reducing the harmonic-distortion components of the echo signals in VHF pulse-echo measurement systems. To confirm the feasibility of the bias-voltage stabilizer, we measured and compared the deviations in the gain of the HVHF amplifier with and without a bias-voltage stabilizer. Between -13 and 26 dBm, the measured gain deviations of a HVHF amplifier with a bias-voltage stabilizer are less than that of an amplifier without a bias-voltage stabilizer. In order to confirm the feasibility of the bias-voltage stabilizer, we compared the pulse-echo responses of the amplifiers, which are typically used for the evaluation of transducers or electronic components used in pulse-echo measurement systems. From the responses, we observed that the amplitudes of the echo signals of a VHF transducer triggered by the HVHF amplifier with a bias-voltage stabilizer were higher than those of the transducer triggered by the HVHF amplifier alone. The second, third, and fourth harmonic-distortion components of the HVHF amplifier with the bias-voltage stabilizer were also lower than those of the HVHF amplifier alone. Hence, the proposed scheme is a promising method for stabilizing the bias voltage of an HVHF amplifier, and improving the echo-signal quality of VHF transducers.

Preparation of Phi29 DNA polymerase free of amplifiable DNA using ethidium monoazide, an ultraviolet-free light-emitting diode lamp and trehalose.

Directory of Open Access Journals (Sweden)

Hirokazu Takahashi

Full Text Available We previously reported that multiply-primed rolling circle amplification (MRPCA using modified random RNA primers can amplify tiny amounts of circular DNA without producing any byproducts. However, contaminating DNA in recombinant Phi29 DNA polymerase adversely affects the outcome of MPRCA, especially for negative controls such as non-template controls. The amplified DNA in negative control casts doubt on the result of DNA amplification. Since Phi29 DNA polymerase has high affinity for both single-strand and double-stranded DNA, some amount of host DNA will always remain in the recombinant polymerase. Here we describe a procedure for preparing Phi29 DNA polymerase which is essentially free of amplifiable DNA. This procedure is realized by a combination of host DNA removal using appropriate salt concentrations, inactivation of amplifiable DNA using ethidium monoazide, and irradiation with visible light from a light-emitting diode lamp. Any remaining DNA, which likely exists as oligonucleotides captured by the Phi29 DNA polymerase, is degraded by the 3'-5' exonuclease activity of the polymerase itself in the presence of trehalose, used as an anti-aggregation reagent. Phi29 DNA polymerase purified by this procedure has little amplifiable DNA, resulting in reproducible amplification of at least ten copies of plasmid DNA without any byproducts and reducing reaction volume. This procedure could aid the amplification of tiny amounts DNA, thereby providing clear evidence of contamination from laboratory environments, tools and reagents.

Microwave amplifier and active circuit design using the real frequency technique

CERN Document Server

Jarry, Pierre

2016-01-01

This book focuses on the authors' Real Frequency Technique (RFT) and its application to a wide variety of multi-stage microwave amplifiers and active filters, and passive equalizers for radar pulse shaping and antenna return loss applications. The first two chapters review the fundamentals of microwave amplifier design and provide a description of the RFT. Each subsequent chapter introduces a new type of amplifier or circuit design, reviews its design problems, and explains how the RFT can be adapted to solve these problems. The authors take a practical approach by summarizing the design steps and giving numerous examples of amplifier realizations and measured responses. Provides a complete description of the RFT as it is first used to design multistage lumped amplifiers using a progressive optimization of the equalizers, leading to a small umber of parameters to optimize simultaneously Presents modifications to the RFT to design trans-impedance microwave amplifiers that are used for photodiodes acti...

Investigation of switching frequency variations in self-oscillating class D amplifiers

DEFF Research Database (Denmark)

Nielsen, Dennis; Knott, Arnold; Pfaffinger, Gerhard

2009-01-01

Class D audio amplifiers have gained significant influence in sound reproduction due to their high efficiency. One of the most commonly used control methods in class D amplifiers is known as self-oscillation. An parameter of key interest in self-oscillating class D amplifiers is the switching fre...

Empirical multichannel power consumption model for erbium-doped fiber amplifiers

DEFF Research Database (Denmark)

Saldaña Cercos, Silvia; de Paiva, Getulio E. R.; Argentato, Marcio Colazza

2015-01-01

In this paper we report on the first experimental power consumption analysis and model of single and multi-stage booster erbium-doped fiber amplifiers (EDFAs) with automatic gain control (AGC), accounting for channel number dependency. Results show that the amount of channels being amplified simu......-users, it is relevant to study channel number dependent power consumption for devising EDFA power efficient control and design.......In this paper we report on the first experimental power consumption analysis and model of single and multi-stage booster erbium-doped fiber amplifiers (EDFAs) with automatic gain control (AGC), accounting for channel number dependency. Results show that the amount of channels being amplified...... simultaneously contributes significantly, up to 48%, to the total power consumption due to the circuitry used for controlling the EDFA. As the number of simultaneous amplified WDM channels in high capacity long and medium reach transmission links reflects closely traffic patterns generated by end...

Analysis and evaluation of the power amplifier device

Energy Technology Data Exchange (ETDEWEB)

Kim, Y. K.; Ryu, J. W. [Kongju National University, Gongju (Korea, Republic of)

2011-11-15

We developed a master oscillator power amplifier (MOPA) type fiber amplifier for the separation of the Ca-48 isotope by using a fiber laser. The ytterbium (Yb)-doped end-capped rod-type photonic crystal fiber (PCF) was used as a gain medium of MOPA amplifier. The PCFs used in our experiments were a 56-cm and an 81-cm rod-type end-capped Yb-doped double-clad PM fibers 'DC-285/100-PM-Yb-Rod', with a 100-{mu}m core (NA 0.02) and a 285-{mu}m cladding (NA 0.6) fabricated by NKT Photonics. The mode field diameter (MFD) of the rod-type PCF was 75-{mu}m, and an absorption efficiency of 30 dB/m at 976 nm and a low NA 0.02 helped to sustain the excellent lasing beam quality. We obtained an output power of 112 W at a pump power of 380 W with a repetition rate of 150 kHz. The measured pulse width was 13 ns at 150 kHz, 1056 nm. The laser beam quality shows a single mode amplification characteristics with a beam quality factor values of M2 are 2 -3. The PCF launching efficiency reached a maximum value of 86.7% with an average efficiencies of above 80%. At a pump power of 250 W and seed power input of 4 W, the CW PCF amplifier was found to generate average output powers of 138 W, 110 W, and 82 W at 1056-nm, 1070-nm, and 1089-nm wavelengths, respectively. The amplified PCF output beam had a line width of 70 MHz full width at half maximum (FWHM). These PCF amplified beams had good beam qualities with M2values of less than 1.8 at all three wavelengths. The gain saturation seed input power in the 81-cm PCF was found to be {approx}6 W at 1056 nm. The temperature of the PCF core reached over 230 .deg. C at the pumping section of the PCF. The temperatures of the end-cap heads on both the pumping and the output end-cap sides were 81.4 .deg. C and 35.7 .deg. C, respectively. The PCF amplifier maintained good polarization mode characteristics with an average DOP of over 87%. The slight decrease in the DOP oat output powers over 170 W output power may have been caused by a

Development of microwave amplifier based on gallium nitride semiconductor structures

International Nuclear Information System (INIS)

Pavlov, D.Yi.; Prokopenko, O.V.; Tsvyirko, Yu.A.; Pavlov, Yi.L.

2014-01-01

Microwave properties of microwave amplifier based on gallium nitride (GN) semiconductor structures has been calculated numerically. We proposed the method of numerical calculation of device. This method is accurately sets the value of its characteristics depending on the elements that are used in design of amplifier. It is shown that the device based on GN HEMT-transistors could have amplification factor about 50 dB, while its sizes are 27x18x5.5 mm 3 . Also was provided the absolute stability an amplifier in the whole operating frequency range. It is quite important when using this type of amplifiers in different conditions of exploitation and various fields of use the radioelectronic equipment

New Packaging for Amplifier Slabs

Energy Technology Data Exchange (ETDEWEB)

Riley, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Thorsness, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Suratwala, T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Steele, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Rogowski, G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2015-03-18

The following memo provides a discussion and detailed procedure for a new finished amplifier slab shipping and storage container. The new package is designed to maintain an environment of <5% RH to minimize weathering.

Directional amplifier in an optomechanical system with optical gain

Science.gov (United States)

Jiang, Cheng; Song, L. N.; Li, Yong

2018-05-01

Directional amplifiers are crucial nonreciprocal devices in both classical and quantum information processing. Here we propose a scheme for realizing a directional amplifier between optical and microwave fields based on an optomechanical system with optical gain, where an active optical cavity and two passive microwave cavities are coupled to a common mechanical resonator via radiation pressure. The two passive cavities are coupled via hopping interaction to facilitate the directional amplification between the active and passive cavities. We obtain the condition of achieving optical directional amplification and find that the direction of amplification can be controlled by the phase differences between the effective optomechanical couplings. The effects of the gain rate of the active cavity and the effective coupling strengths on the maximum gain of the amplifier are discussed. We show that the noise added to this amplifier can be greatly suppressed in the large cooperativity limit.

Deep UV light generation by a fiber/bulk hybrid amplifier at 199 nm

International Nuclear Information System (INIS)

Urata, Yoshiharu; Shinozaki, Tatsuya; Wada, Yoshio; Kaneda, Yushi; Wada, Satoshi; Imai, Shinichi

2009-01-01

A high-pulse-repetition-frequency (PRF) pulsed light source in the deep ultraviolet region has been realized by a multiple wavelength conversion technique using a hybrid fiber/bulk amplifier system. Output of 199 nm with a power of 50 mW was achieved at 2.4 MHz PRF. The 1 μm amplifier consisted of a Yb-doped fiber amplifier and a Nd-doped YVO4 amplifier. A 1.5 μm fiber master-oscillator power amplifier was employed as the other fundamental source. The amplifiers exhibited good amplification properties in pulse energy, polarization extinction ratio, and spectrum for nonlinear wavelength conversion

A high performance electrometer amplifier of hybrid design

International Nuclear Information System (INIS)

Rao, N.V.; Nazare, C.K.

1979-01-01

A high performance, reliable, electrometer amplifier of hybrid design for low current measurements in mass spectrometers has been developed. The short term instability with a 5 x 10 11 ohms input resistor is less than 1 x 10sup(-15) Amp. The drift is better than 1 mV/hour. The design steps are illustrated with a typical amplifier performance details. (auth.)

Embedded control system for high power RF amplifiers

International Nuclear Information System (INIS)

Sharma, Deepak Kumar; Gupta, Alok Kumar; Jain, Akhilesh; Hannurkar, P.R.

2011-01-01

RF power devices are usually very sensitive to overheat and reflected RF power; hence a protective interlock system is required to be embedded with high power solid state RF amplifiers. The solid state RF amplifiers have salient features of graceful degradation and very low mean time to repair (MTTR). In order to exploit these features in favour of lowest system downtime, a real-time control system is embedded with high power RF amplifiers. The control system is developed with the features of monitoring, measurement and network publishing of various parameters, historical data logging, alarm generation, displaying data to the operator and tripping the system in case of any interlock failure. This paper discusses the design philosophy, features, functions and implementation details of the embedded control system. (author)

A second-order class-D audio amplifier

OpenAIRE

Cox, Stephen M.; Tan, M.T.; Yu, J.

2011-01-01

Class-D audio amplifiers are particularly efficient, and this efficiency has led to their ubiquity in a wide range of modern electronic appliances. Their output takes the form of a high-frequency square wave whose duty cycle (ratio of on-time to off-time) is modulated at low frequency according to the audio signal. A mathematical model is developed here for a second-order class-D amplifier design (i.e., containing one second-order integrator) with negative feedback. We derive exact expression...

Modeling Distortion Effects in Class-D Amplifier Filter Inductors

DEFF Research Database (Denmark)

Knott, Arnold; Stegenborg-Andersen, Tore; Thomsen, Ole Cornelius

2010-01-01

Distortion is generally accepted as a quantifier to judge the quality of audio power amplifiers. In switchmode power amplifiers various mechanisms influence this performance measure. After giving an overview of those, this paper focuses on the particular effect of the nonlinearity of the output f...

Switching-mode Audio Power Amplifiers with Direct Energy Conversion

DEFF Research Database (Denmark)

Ljusev, Petar; Andersen, Michael Andreas E.

2005-01-01

has been replaced with a high frequency AC link. When compared to the conventional Class D amplifiers with a separate DC power supply, the proposed single conversion stage amplifier provides simple and compact solution with better efficiency and higher level of integration, leading to reduced...

Amplifying mirrors with saturated gain without and with a resonator

DEFF Research Database (Denmark)

Skettrup, Torben

2007-01-01

An investigation of amplifying mirrors with a view to their use in resonator structures has been performed. Both non-saturated and saturated amplifying mirrors are demonstrated. It was found that relatively high values of gain (typical 5-10 times) can be obtained even when saturation is taken...... into account. Several resonator structures containing from two up to four mirrors, some including beamsplitters, are investigated. It was found that the gain to a first approximation depends only on the ratio between the pumping power and the input power on the amplifying mirror. It was also found...... that the configuration with four mirrors is well suited as an amplifier device working as an optical transistor since high values of gain up to 40 times could be obtained....

Development of high sensitivity transimpedance amplifier module for self powered neutron detectors

International Nuclear Information System (INIS)

Khan, T.K.; Tamboli, P.K.; Antony, J.; Balasubramanian, R.; Agilandaeswari, K.; Pramanik, M.

2010-01-01

This paper describes design and development of a Transimpedance Amplifier for amplification of very low current from in core Self Powered Neutron Detectors (SPND). Measurement of neutron flux is very important for operation, control and protection of Nuclear Power Plant (NPP). SPND is used to measure Reactor incore flux/power. Based on sensitivity of emitter material used in SPND, pitch length and neutron flux (power level); the current output from SPND varies from few pA to few μA. The described amplifier is suitable to use for this current range. The amplifier provides a very high gain using a resistive T network feedback topology. The amplifier is designed in two stages using ultra low bias current FET OPAMPs. Design of Transimpedance amplifier is carefully done to include ultra low input bias current, low offset voltage and noise. The amplifier has in built test facility for calibration and on line test facility for measurement of insulation resistance (IR). The amplifier module has on board isolated DC-DC converter circuit complying MIL/STD/461C/D which generate isolated +/-15V and +12V supply to provide parameter to parameter ground isolation and independence among each module/signal.The output from the amplifier is 0V to 6V for 0 to 150%FP. The design is simulated in computer and amplifier used at TAPS-3 was modified as per new design and has been tested at TAPS-3 site. The amplifier performed satisfactorily. The results showed that the IR measurement technique adopted in the design can tolerate lower IR of SPND in existing design. (author)

Transimpedance Amplifier for MEMS SAW Oscillator in 1.4GHz

Science.gov (United States)

Kamarudin, N.; Karim, J.; Hussin, H.

2018-03-01

This work is to design a transimpedance amplifier for MEMS SAW resonator to achieve low power consumption at desired frequency. A transimpedance amplifier is designed and characterized for MEMS SAW resonator in 0.18μm CMOS process. The transimpedance amplifier achieves gain is 31 dBΩ at 176°. The power consume by oscillator is 0.6mW at VDD 1.8V while phase noise at -133.97dBc/Hz at 10kHz.

C.A.D for broad-band multistage microwave transimpedance amplifier.

OpenAIRE

Olomo Ngongo, A.; Perennec, A.; Soares, R.; Jarry, P.

1992-01-01

In high data rate optical-fiber, it is necessary to employ an ultra broad-band transimpedance amplifier. In this paper, we present a technique for the design of a transimpedance amplifiers. It can be applied as well to the design of interstage equalizers for microwave transimpedance amplifiers. In the version described in this paper, the optimisation process is applied to the transimpedance gain and noise which is adjusted. Based on the load charge matching technique, a sequential procedure t...

Linear Distributed GaN MMIC Power Amplifier with Improved Power-added Efficiency

Science.gov (United States)

2017-03-01

QPSK LTE waveform, the ACPR1improved by ~10 dBc at average output power of 23 dBm, without digital pre-distortion. Keywords: GaN, linear amplifiers...wideband amplifier, OIP3, LTE Introduction RF communications with spectral efficiency utilizes complex modulation schemes that require amplifier...wideband amplifiers remain. In this paper, we report on the measured CW performance of a multi-octave (100 MHz ‒ 8 GHz) GaN MMIC NDPA fabricated with

Nuclear magnetic resonance experiments with dc SQUID amplifiers

International Nuclear Information System (INIS)

Heaney, M.B.

1990-11-01

The development and fabrication of dc SQUIDs (Superconducting QUantum Interference Devices) with Nb/Al 2 O 3 /Nb Josephson junctions is described. A theory of the dc SQUID as a radio-frequency amplifier is presented, with an optimization strategy that accounts for the loading and noise contributions of the postamplifier and maximizes the signal-to-noise ratio of the total system. The high sensitivity of the dc SQUID is extended to high field NMR. A dc SQUID is used as a tuned radio-frequency amplifier to detect pulsed nuclear magnetic resonance at 32 MHz from a metal film in a 3.5 Tesla static field. A total system noise temperature of 11 K has been achieved, at a bath temperature of 4.2 K. The minimum number of nuclear Bohr magnetons observable from a free precession signal after a single pulse is about 2 x 10 17 in a bandwidth of 25 kHz. In a separate experiment, a dc SQUID is used as a rf amplifier in a NQR experiment to observe a new resonance response mechanism. The net electric polarization of a NaClO 3 crystal due to the precessing electric quadrupole moments of the Cl nuclei is detected at 30 MHz. The sensitivity of NMR and NQR spectrometers using dc SQUID amplifiers is compared to the sensitivity of spectrometers using conventional rf amplifiers. A SQUID-based spectrometer has a voltage sensitivity which is comparable to the best achieved by a FET-based spectrometer, at these temperatures and operating frequencies

Design of a transimpedance amplifier for a bio-optical fiber sensor

International Nuclear Information System (INIS)

Pola, L.; Camasa, J.; Gomez B, J.

2012-01-01

In this work we present a fairly detailed model for a photodiode coupled to an operational amplifier in the trans impedance circuit configuration, for the applications in Biotechnology. An optical signal of the fiber optic biosensor is detected by a photodiode and its photocurrent generated is introduced in the trans impedance amplifier. The proposed design uses a photodiode in photovoltaic mode, and its photocurrent is coupled to an amplifier with positive output. Finally, the trans impedance amplifier presents reliable design characteristics such as accuracy, stability, low noise, and the ability to measure photocurrent from 1nA to 100μA. (Author)

Current-Driven Switch-Mode Audio Power Amplifiers

DEFF Research Database (Denmark)

Knott, Arnold; Buhl, Niels Christian; Andersen, Michael A. E.

2012-01-01

The conversion of electrical energy into sound waves by electromechanical transducers is proportional to the current through the coil of the transducer. However virtually all audio power amplifiers provide a controlled voltage through the interface to the transducer. This paper is presenting...... a switch-mode audio power amplifier not only providing controlled current but also being supplied by current. This results in an output filter size reduction by a factor of 6. The implemented prototype shows decent audio performance with THD + N below 0.1 %....

Reflection amplifiers in self-regulated learning

NARCIS (Netherlands)

Verpoorten, Dominique

2012-01-01

Verpoorten, D. (2012). Reflection amplifiers in self-regulated learning. Doctoral thesis. November, 9, 2012, Heerlen, The Netherlands: Open Universiteit (CELSTEC). Datawyse / Universitaire Pers Maastricht.

A digitally assisted, signal folding neural recording amplifier.

Science.gov (United States)

Chen, Yi; Basu, Arindam; Liu, Lei; Zou, Xiaodan; Rajkumar, Ramamoorthy; Dawe, Gavin Stewart; Je, Minkyu

2014-08-01

A novel signal folding and reconstruction scheme for neural recording applications that exploits the 1/f(n) characteristics of neural signals is described in this paper. The amplified output is 'folded' into a predefined range of voltages by using comparison and reset circuits along with the core amplifier. After this output signal is digitized and transmitted, a reconstruction algorithm can be applied in the digital domain to recover the amplified signal from the folded waveform. This scheme enables the use of an analog-to-digital convertor with less number of bits for the same effective dynamic range. It also reduces the transmission data rate of the recording chip. Both of these features allow power and area savings at the system level. Other advantages of the proposed topology are increased reliability due to the removal of pseudo-resistors, lower harmonic distortion and low-voltage operation. An analysis of the reconstruction error introduced by this scheme is presented along with a behavioral model to provide a quick estimate of the post reconstruction dynamic range. Measurement results from two different core amplifier designs in 65 nm and 180 nm CMOS processes are presented to prove the generality of the proposed scheme in the neural recording applications. Operating from a 1 V power supply, the amplifier in 180 nm CMOS has a gain of 54.2 dB, bandwidth of 5.7 kHz, input referred noise of 3.8 μVrms and power dissipation of 2.52 μW leading to a NEF of 3.1 in spike band. It exhibits a dynamic range of 66 dB and maximum SNDR of 43 dB in LFP band. It also reduces system level power (by reducing the number of bits in the ADC by 2) as well as data rate to 80% of a conventional design. In vivo measurements validate the ability of this amplifier to simultaneously record spike and LFP signals.

Subjective test of class D amplifiers without output filter

DEFF Research Database (Denmark)

Agerkvist, Finn T.; Fenger, Lars M.

2004-01-01

This paper presents the results of subjective listening tests designed to determine whether the output filter on class D amplifiers used in active loudspeakers can be omitted without audible errors occurring. The frequency range of the amplifiers was limited to 0-3 kHz corresponding to a woofer...

47 CFR 2.815 - External radio frequency power amplifiers.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 1 2010-10-01 2010-10-01 false External radio frequency power amplifiers. 2... AND RADIO TREATY MATTERS; GENERAL RULES AND REGULATIONS Marketing of Radio-frequency Devices § 2.815 External radio frequency power amplifiers. (a) As used in this part, an external radio frequency power...

Gain characteristics of a saturated fiber optic parametric amplifier

DEFF Research Database (Denmark)

Rottwitt, Karsten; Lorenzen, Michael Rodas; Noordegraaf, Danny

2008-01-01

In this work we discuss saturation performance of a fiber optic parametric amplifier. A simple numerical model is described and applied to specific cases. A system experiment using a saturated amplifier illustrates a 4 dB improvement in required signal to noise ratio for a fixed bit error ratio....

Design and performance of the main amplifier system for the National Ignition Facility

International Nuclear Information System (INIS)

Beullier, J; Erlandson, A; Grebot, E; Guenet, J; Guenet, M; Horvath, J; Jancaitis, K; Larson, D; Lawson, J; LeTouze, G; Maille, X; Manes, K; Marshall, C; Mengue, T; Moor, E; Payne, S; Pedrotti, L; Rotter, M; Seznec, S; Sutton, S; Zapata, L.

1999-01-01

This paper describes the design and performance of flashlamp-pumped, Nd:glass. Brewster-angle slab amplifiers intended to be deployed in the National Ignition Facility (NIF). To verify performance, we tested a full-size, three-slab-long, NIF prototype amplifier, which we believe to be the largest flashlamp-pumped Nd:glass amplifier ever assembled. Like the NIF amplifier design, this prototype amplifier had eight 40-cm-square apertures combined in a four-aperture-high by two-aperture-wide matrix. Specially-shaped reflectors, anti-reflective coatings on the blastshields, and preionized flashlamps were used to increase storage efficiency. Cooling gas was flowed over the flashlamps to remove waste pump heat and to accelerate thermal wavefront recovery. The prototype gain results are consistent with model predictions and provide high confidence in the final engineering design of the NIF amplifiers. Although the dimensions, internal positions, and shapes of the components in the NIF amplifiers will be slightly different from the prototype, these differences are small and should produce only slight differences in amplifier performance

Detection of weak optical signals with a laser amplifier

International Nuclear Information System (INIS)

Kozlovskii, A. V.

2006-01-01

Detection of weak and extremely weak light signals amplified by linear and four-wave mixing laser amplifiers is analyzed. Photoelectron distributions are found for different input photon statistics over a wide range of gain. Signal-to-noise ratios are calculated and analyzed for preamplification schemes using linear and four-wave mixing amplifiers. Calculations show that the high signal-to-noise ratio (much higher than unity), ensuring reliable detection of weak input signals, can be attained only with a four-wave mixing preamplification scheme. Qualitative dependence of the signal-to-noise ratio on the quantum statistical properties of both signal and idler waves is demonstrated

Cryogenic transimpedance amplifier for micromechanical capacitive sensors.

Science.gov (United States)

Antonio, D; Pastoriza, H; Julián, P; Mandolesi, P

2008-08-01

We developed a cryogenic transimpedance amplifier that works at a broad range of temperatures, from room temperature down to 4 K. The device was realized with a standard complementary metal oxide semiconductor 1.5 mum process. Measurements of current-voltage characteristics, open-loop gain, input referred noise current, and power consumption are presented as a function of temperature. The transimpedance amplifier has been successfully applied to sense the motion of a polysilicon micromechanical oscillator at low temperatures. The whole device is intended to serve as a magnetometer for microscopic superconducting samples.

Low Loss Nanostructured Polymers for Chip-scale Waveguide Amplifiers.

Science.gov (United States)

Chen, George F R; Zhao, Xinyu; Sun, Yang; He, Chaobin; Tan, Mei Chee; Tan, Dawn T H

2017-06-13

On-chip waveguide amplifiers offer higher gain in small device sizes and better integration with photonic devices than the commonly available fiber amplifiers. However, on-chip amplifiers have yet to make its way into the mainstream due to the limited availability of materials with ideal light guiding and amplification properties. A low-loss nanostructured on-chip channel polymeric waveguide amplifier was designed, characterized, fabricated and its gain experimentally measured at telecommunication wavelength. The active polymeric waveguide core comprises of NaYF 4 :Yb,Er,Ce core-shell nanocrystals dispersed within a SU8 polymer, where the nanoparticle interfacial characteristics were tailored using hydrolyzed polyhedral oligomeric silsesquioxane-graft-poly(methyl methacrylate) to improve particle dispersion. Both the enhanced IR emission intensity from our nanocrystals using a tri-dopant scheme and the reduced scattering losses from our excellent particle dispersion at a high solid loading of 6.0 vol% contributed to the outstanding optical performance of our polymeric waveguide. We achieved one of the highest reported gain of 6.6 dB/cm using a relatively low coupled pump power of 80 mW. These polymeric waveguide amplifiers offer greater promise for integrated optical circuits due to their processability and integration advantages which will play a key role in the emerging areas of flexible communication and optoelectronic devices.

Multiformity of inherent randomicity and visitation density in n symbolic dynamics

International Nuclear Information System (INIS)

Zhang Yagang; Wang Changjiang

2007-01-01

The multiformity of inherent randomicity and visitation density in n symbolic dynamics will be clarified in this paper. These stochastic symbolic sequences bear three features. The distribution of frequency, inter-occurrence times and the alignment of two random sequences are amplified in detail. The features of visitation density in surjective maps presents catholicity and the catholicity in n letters randomicity has the same measure foundation. We hope to offer a symbolic platform that satisfies these stochastic properties and to attempt to study certain properties of DNA base sequences, 20 amino acids symbolic sequences of proteid structure, and the time series that can be symbolic in finance market et al

Two-section semiconductor optical amplifier used as an efficient channel dropping node

DEFF Research Database (Denmark)

Jørgensen, Carsten; Storkfelt, Niels; Durhuus, T.

1992-01-01

High responsivity in a two-section semiconductor optical amplifier/detector, serving as a channel dropping mode is described. A simple receiver constructed using a 50 Ω amplifier with a sensitivity of -30.2 dBm at 140 Mb/s is demonstrated......High responsivity in a two-section semiconductor optical amplifier/detector, serving as a channel dropping mode is described. A simple receiver constructed using a 50 Ω amplifier with a sensitivity of -30.2 dBm at 140 Mb/s is demonstrated...

Diode-pumped laser amplifiers: application to 0.946 {mu}m Nd:YAG

Energy Technology Data Exchange (ETDEWEB)

Barnes, Norman P [NASA Langley Research Center, Hampton, VA 23681 (United States); Axenson, Theresa J [Science and Technology Corporation, 10 Basil Sawyer Drive, Hampton, VA 23666 (United States); Jr, Donald J Reichle [NASA Langley Research Center, Hampton, VA 23681 (United States); Walsh, Brian M [NASA Langley Research Center, Hampton, VA 23681 (United States)

2003-03-14

A diode-pumped laser amplifier model is derived from first principles and applied to a Nd:YAG amplifier operating on the {sup 4}F{sub 3/2} to {sup 4}I{sub 9/2} transition at 0.946 {mu}m. The effects of amplified spontaneous emission are included in the model and the addition of this effect is shown to produce better agreement with the data. The amplifier model includes effects of the transverse and longitudinal variation of the pump beam, transverse and longitudinal variation of the probe beam, and multiple passes of the probe beam. Experimental results obtained with a quasi four-level Nd:YAG amplifier operating at 0.946 {mu}m are used to validate the model. The amplifier was evaluated as a function of the pump energy, the probe energy, the probe beam radius, the pulse repetition frequency and the temperature. For all of the experimental conditions, the experimental results and the model agree.

High efficiency class-I audio power amplifier using a single adaptive supply

International Nuclear Information System (INIS)

Peng Zhenfei; Yang Shanshand; Feng Yong; Hong Zhiliang; Liu Yang

2012-01-01

A high efficiency class-I linear audio power amplifier (PA) with an adaptive supply is presented. Its efficiency is improved by a dynamic supply to reduce the power transistors' voltage drop. A gain compression technique is adopted to make the amplifier accommodate a single positive supply. Circuit complicity and chip area are reduced because no charge pump is necessary for the negative supply. A common shared mode voltage and a symmetric layout pattern are used to minimize the non-linearity. A peak efficiency of 80% is reached at peak output power. The measured THD+N before and after the supply switching point are 0.01% and 0.05%, respectively. The maximum output power is 410 mW for an 8 Ω speaker load. Unlike switching amplifiers, the class-I amplifier operates as a linear amplifier and hence has a low EMI. The advantage of a high efficiency and low EMI makes the class-I amplifier suitable for portable and RF sensitive applications. (semiconductor integrated circuits)

Multi-kW coherent combining of fiber lasers seeded with pseudo random phase modulated light

Science.gov (United States)

Flores, Angel; Ehrehreich, Thomas; Holten, Roger; Anderson, Brian; Dajani, Iyad

2016-03-01

We report efficient coherent beam combining of five kilowatt-class fiber amplifiers with a diffractive optical element (DOE). Based on a master oscillator power amplifier (MOPA) configuration, the amplifiers were seeded with pseudo random phase modulated light. Each non-polarization maintaining fiber amplifier was optically path length matched and provides approximately 1.2 kW of near diffraction-limited output power (measured M2polarization control. A low power sample of the combined beam after the DOE provided an error signal for active phase locking which was performed via Locking of Optical Coherence by Single-Detector Electronic-Frequency Tagging (LOCSET). After phase stabilization, the beams were coherently combined via the 1x5 DOE. A total combined output power of 4.9 kW was achieved with 82% combining efficiency and excellent beam quality (M2splitter loss was 5%. Similarly, losses due in part to non-ideal polarization, ASE content, uncorrelated wavefront errors, and misalignment errors contributed to the efficiency reduction.

Asymmetric gain-saturated spectrum in fiber optical parametric amplifiers

DEFF Research Database (Denmark)

Lali-Dastjerdi, Zohreh; Rottwitt, Karsten; Galili, Michael

2012-01-01

We demonstrate experimentally and numerically an unexpected spectral asymmetry in the saturated-gain spectrum of single-pump fiber optical parametric amplifiers. The interaction between higher-order four-wave mixing products and dispersive waves radiated as an effect of third-order dispersion inf...... characteristics of the amplifier and shows local maxima for specific dispersion values....

KrF laser amplifier with phase-conjugate Brillouin retroreflectors.

Science.gov (United States)

Gower, M C

1982-09-01

We have demonstrated the use of phase-conjugate stimulated Brillouin scattering mirrors to produce high-quality, short-pulse KrF laser beams from angular multiplexed and regenerative amplifiers. The mirror was also shown to isolate systems optically from amplifier spontaneous emission. Automatic alignment of targets using this mirror as a retroreflector was also demonstrated.

Prototype disc amplifier for Iskra-6 facility

International Nuclear Information System (INIS)

Grigorovich, S.V.; Eroshenko, V.F.; Krotov, V.A.; Demidov, V.L.; Kalinin, N.V.; Kurunov, R.F.; Smirnov, V.G.; Fomin, V.M.

2006-01-01

Eight-channel disk amplifiers of the ISKRA-6 facility are made up of sections. An amplifier section consists of eight active elements (2*4) made of KGSS-0180/35-grade neodymium phosphate glass 400*690*40 mm in size located in frames at the Brewster angle. Twenty flash-lamps are arranged in one amplifier module. The flash-lamps have an inter electrode distance of 1600 mm, the tube is 40 mm in inner diameter. The results of numerical investigations into the dynamics of high-current pulse radiation discharge are presented. The investigations were carried out by the 1-dimensional RMHD-model. This model takes into account the transient processes in the electric circuit and the physical processes in the discharge plasma: ionization, Joule heating, thermal conductivity, radiation transfer and plasma motion caused by the non-uniformity of energy introduction into the discharge in case of a non-uniform initial ionization of gas in the pumping lamp. The experimental results of spectral measurements and light efficiency of the flash-lamps depending on specific power and value of energy contribution are presented

Influence of mode competition on beam quality of fiber amplifier

International Nuclear Information System (INIS)

Xiao Qi-Rong; Yan Ping; Sun Jun-Yi; Chen Xiao; Ren Hai-Cui; Gong Ma-Li

2014-01-01

Theoretical and experimental studies of the influence of the mode competition on the output beam quality of fiber amplifiers are presented. Rate equations and modal decomposition method are used in the theoretical model. In the experiment, the output beam-quality factor of a fiber amplifier, which is based on a Yb-doped double-clad large mode area fiber as a function of the seed beam quality and the pump power of the amplifier, is measured. The experimental results are consistent with the theoretical analysis. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

Minimizing Crosstalk in Self Oscillating Switch Mode Audio Power Amplifiers

DEFF Research Database (Denmark)

Knott, Arnold; Ploug, Rasmus Overgaard

2012-01-01

a method to minimize this phenomenon by improving the integrity of the various power distribution systems of the amplifier. The method is then applied to an amplifier built for this investigation. The results show that the crosstalk is suppressed with 30 dB, but is not entirely eliminated......The varying switching frequencies of self oscillating switch mode audio amplifiers have been known to cause interchannel intermodulation disturbances in multi channel configurations. This crosstalk phenomenon has a negative impact on the audio performance. The goal of this paper is to present...

Research on disk amplifiers as polarizer of electro-optical switch

CERN Document Server

Zheng Kui Xing; Feng Bin; Zheng Jian; Dong Yun; Peng Zhi Tao; Lu Jing Ping; Jing Feng; Wei Xiao Feng

2002-01-01

It benefits to decrease the engineering cost and to debase the technical crisis by the polarizer composed of amplifier Nd sup 3 sup + : glass slabs located with the Brewster angle in large scale multi-passes laser facility. The relationships of the isolation efficiency with the numbers of slab, the growth of the amplifier and the switch efficiency of Pockels cell are calculated theoretically. The experimental results indicated that the output energy ratio of this Pockels cell-amplifier isolation system is 1 : 8 while Pockels cell is on and off

Random distributed feedback fibre lasers

Energy Technology Data Exchange (ETDEWEB)

Turitsyn, Sergei K., E-mail: s.k.turitsyn@aston.ac.uk [Aston Institute of Photonic Technologies, Aston University, Birmingham B4 7ET (United Kingdom); Novosibirsk State University, 2 Pirogova str., 630090, Novosibirsk (Russian Federation); Babin, Sergey A. [Novosibirsk State University, 2 Pirogova str., 630090, Novosibirsk (Russian Federation); Institute of Automation and Electrometry SB RAS, 1 Ac. Koptug. ave., 630090, Novosibirsk (Russian Federation); Churkin, Dmitry V. [Aston Institute of Photonic Technologies, Aston University, Birmingham B4 7ET (United Kingdom); Novosibirsk State University, 2 Pirogova str., 630090, Novosibirsk (Russian Federation); Institute of Automation and Electrometry SB RAS, 1 Ac. Koptug. ave., 630090, Novosibirsk (Russian Federation); Vatnik, Ilya D.; Nikulin, Maxim [Institute of Automation and Electrometry SB RAS, 1 Ac. Koptug. ave., 630090, Novosibirsk (Russian Federation); Podivilov, Evgenii V. [Novosibirsk State University, 2 Pirogova str., 630090, Novosibirsk (Russian Federation); Institute of Automation and Electrometry SB RAS, 1 Ac. Koptug. ave., 630090, Novosibirsk (Russian Federation)

2014-09-10

The concept of random lasers exploiting multiple scattering of photons in an amplifying disordered medium in order to generate coherent light without a traditional laser resonator has attracted a great deal of attention in recent years. This research area lies at the interface of the fundamental theory of disordered systems and laser science. The idea was originally proposed in the context of astrophysics in the 1960s by V.S. Letokhov, who studied scattering with “negative absorption” of the interstellar molecular clouds. Research on random lasers has since developed into a mature experimental and theoretical field. A simple design of such lasers would be promising for potential applications. However, in traditional random lasers the properties of the output radiation are typically characterized by complex features in the spatial, spectral and time domains, making them less attractive than standard laser systems in terms of practical applications. Recently, an interesting and novel type of one-dimensional random laser that operates in a conventional telecommunication fibre without any pre-designed resonator mirrors–random distributed feedback fibre laser–was demonstrated. The positive feedback required for laser generation in random fibre lasers is provided by the Rayleigh scattering from the inhomogeneities of the refractive index that are naturally present in silica glass. In the proposed laser concept, the randomly backscattered light is amplified through the Raman effect, providing distributed gain over distances up to 100 km. Although an effective reflection due to the Rayleigh scattering is extremely small (∼0.1%), the lasing threshold may be exceeded when a sufficiently large distributed Raman gain is provided. Such a random distributed feedback fibre laser has a number of interesting and attractive features. The fibre waveguide geometry provides transverse confinement, and effectively one-dimensional random distributed feedback leads to the

Random distributed feedback fibre lasers

International Nuclear Information System (INIS)

Turitsyn, Sergei K.; Babin, Sergey A.; Churkin, Dmitry V.; Vatnik, Ilya D.; Nikulin, Maxim; Podivilov, Evgenii V.

2014-01-01

The concept of random lasers exploiting multiple scattering of photons in an amplifying disordered medium in order to generate coherent light without a traditional laser resonator has attracted a great deal of attention in recent years. This research area lies at the interface of the fundamental theory of disordered systems and laser science. The idea was originally proposed in the context of astrophysics in the 1960s by V.S. Letokhov, who studied scattering with “negative absorption” of the interstellar molecular clouds. Research on random lasers has since developed into a mature experimental and theoretical field. A simple design of such lasers would be promising for potential applications. However, in traditional random lasers the properties of the output radiation are typically characterized by complex features in the spatial, spectral and time domains, making them less attractive than standard laser systems in terms of practical applications. Recently, an interesting and novel type of one-dimensional random laser that operates in a conventional telecommunication fibre without any pre-designed resonator mirrors–random distributed feedback fibre laser–was demonstrated. The positive feedback required for laser generation in random fibre lasers is provided by the Rayleigh scattering from the inhomogeneities of the refractive index that are naturally present in silica glass. In the proposed laser concept, the randomly backscattered light is amplified through the Raman effect, providing distributed gain over distances up to 100 km. Although an effective reflection due to the Rayleigh scattering is extremely small (∼0.1%), the lasing threshold may be exceeded when a sufficiently large distributed Raman gain is provided. Such a random distributed feedback fibre laser has a number of interesting and attractive features. The fibre waveguide geometry provides transverse confinement, and effectively one-dimensional random distributed feedback leads to the

Complementary DNA-amplified fragment length polymorphism ...

African Journals Online (AJOL)

Complementary DNA-amplified fragment length polymorphism (AFLP-cDNA) analysis of differential gene expression from the xerophyte Ammopiptanthus mongolicus in response to cold, drought and cold together with drought.

A Review of High Voltage Drive Amplifiers for Capacitive Actuators

DEFF Research Database (Denmark)

Huang, Lina; Zhang, Zhe; Andersen, Michael A. E.

2012-01-01

This paper gives an overview of the high voltage amplifiers, which are used to drive capacitive actuators. The amplifiers for both piezoelectric and DEAP (dielectric electroactive polymer) actuator are discussed. The suitable topologies for driving capacitive actuators are illustrated in detail...

Design optimization of single-main-amplifier KrF laser-fusion systems

International Nuclear Information System (INIS)

Harris, D.B.; Pendergrass, J.H.

1985-01-01

KrF lasers appear to be a very promising laser fusion driver for commercial applications. The Large Amplifier Module for the Aurora Laser System at Los Alamos is the largest KrF laser in the world and is currently operating at 5 kJ with 10 to 15 kJ eventually expected. The next generation system is anticipated to be a single-main-amplifier system that generates approximately 100 kJ. This paper examines the cost and efficiency tradeoffs for a complete single-main-amplifier KrF laser fusion experimental facility. It has been found that a 7% efficient $310/joule complete laser-fusion system is possible by using large amplifier modules and high optical fluences

A numerical design approach for single amplifier, Active-RC Butterworth filter of order 5

DEFF Research Database (Denmark)

Gaunholt, Hans

2007-01-01

filter applying just one operational amplifier coupled as a unity gain amplifier. It is shown that the influence from the real operational amplifier may be reduced by trimming just one resistor in the circuit. The unity gain amplifiers have the advantage of providing low power consumption, yielding...

A Transimpedance Amplifier for Remotely Located Quartz Tuning Forks

OpenAIRE

Kleinbaum, Ethan; Csathy, Gabor

2012-01-01

The cable capacitance in cryogenic and high vacuum applications of quartz tuning forks imposes severe constraints on the bandwidth and noise performance of the measurement. We present a single stage low noise transimpedance amplifier with a bandwidth exceeding 1 MHz and provide an in-depth analysis of the dependence of the amplifier parameters on the cable capacitance.

High peak power picosecond hybrid fiber and solid-state amplifier system

International Nuclear Information System (INIS)

Wushouer, X; Yan, P; Yu, H; Liu, Q; Fu, X; Yan, X; Gong, M

2010-01-01

We report the high peak power picosecond hybrid fiber and solid-state laser amplifier system. The passively mode-locked solid-state seed source produced an average power of 1.8 W with pulse width of 14 ps and repetition rate of 86 MHz. It was directly coupled into the first Yb-doped polarized photonic crystal fiber amplifier stage. To avoid the nonlinear effects in fiber, the output power from the first stage was merely amplified to 24 W with the narrow spectra broadening of 0.21 nm. For the improvement of the peak power, the dual-end pumped composite Nd:YVO 4 amplifier system has been chosen at the second stage. To reduce the serious thermal effect, the thermally bonded composite YVO 4 – Nd:YVO 4 – YVO 4 rod crystal was used as the gain medium. The 53 W TEM 00 mode with the peak power of 40 kW, beam quality of M 2 < 1.15, corresponding to the optical-optical efficiency of 42.4% was obtained at the hybrid amplifier laser system. The system allows using a low power seed source and demonstrates an increase in the peak power beyond a fiber master oscillator power amplifier's (MOPA's) limit

Development of an efficient fungal DNA extraction method to be used in random amplified polymorphic DNA-PCR analysis to differentiate cyclopiazonic acid mold producers.

Science.gov (United States)

Sánchez, Beatriz; Rodríguez, Mar; Casado, Eva M; Martín, Alberto; Córdoba, Juan J

2008-12-01

A variety of previously established mechanical and chemical treatments to achieve fungal cell lysis combined with a semiautomatic system operated by a vacuum pump were tested to obtain DNA extract to be directly used in randomly amplified polymorphic DNA (RAPD)-PCR to differentiate cyclopiazonic acid-producing and -nonproducing mold strains. A DNA extraction method that includes digestion with proteinase K and lyticase prior to using a mortar and pestle grinding and a semiautomatic vacuum system yielded DNA of high quality in all the fungal strains and species tested, at concentrations ranging from 17 to 89 ng/microl in 150 microl of the final DNA extract. Two microliters of DNA extracted with this method was directly used for RAPD-PCR using primer (GACA)4. Reproducible RAPD fingerprints showing high differences between producer and nonproducer strains were observed. These differences in the RAPD patterns did not differentiate all the strains tested in clusters by cyclopiazonic acid production but may be very useful to distinguish cyclopiazonic acid producer strains from nonproducer strains by a simple RAPD analysis. Thus, the DNA extracts obtained could be used directly without previous purification and quantification for RAPD analysis to differentiate cyclopiazonic acid producer from nonproducer mold strains. This combined analysis could be adaptable to other toxigenic fungal species to enable differentiation of toxigenic and non-toxigenic molds, a procedure of great interest in food safety.

Predistortion of a Bidirectional Cuk Audio Amplifier

DEFF Research Database (Denmark)

Birch, Thomas Hagen; Nielsen, Dennis; Knott, Arnold

2014-01-01

Some non-linear amplifier topologies are capable of providing a larger voltage gain than one from a DC source, which could make them suitable for various applications. However, the non-linearities introduce a significant amount of harmonic distortion (THD). Some of this distortion could be reduced...... using predistortion. This paper suggests linearizing a nonlinear bidirectional Cuk audio amplifier using an analog predistortion approach. A prototype power stage was built and results show that a voltage gain of up to 9 dB and reduction in THD from 6% down to 3% was obtainable using this approach....

Optimization of a high efficiency FEL amplifier

International Nuclear Information System (INIS)

Schneidmiller, E.A.; Yurkov, M.V.

2014-10-01

The problem of an efficiency increase of an FEL amplifier is now of great practical importance. Technique of undulator tapering in the post-saturation regime is used at the existing X-ray FELs LCLS and SACLA, and is planned for use at the European XFEL, Swiss FEL, and PAL XFEL. There are also discussions on the future of high peak and average power FELs for scientific and industrial applications. In this paper we perform detailed analysis of the tapering strategies for high power seeded FEL amplifiers. Application of similarity techniques allows us to derive universal law of the undulator tapering.

Tapered amplifier laser with frequency-shifted feedback

Directory of Open Access Journals (Sweden)

A. Bayerle, S. Tzanova, P. Vlaar, B. Pasquiou, F. Schreck

2016-10-01

Full Text Available We present a frequency-shifted feedback (FSF laser based on a tapered amplifier. The laser operates as a coherent broadband source with up to 370GHz spectral width and 2.3us coherence time. If the FSF laser is seeded by a continuous-wave laser a frequency comb spanning the output spectrum appears in addition to the broadband emission. The laser has an output power of 280mW and a center wavelength of 780nm. The ease and flexibility of use of tapered amplifiers makes our FSF laser attractive for a wide range of applications, especially in metrology.

A high efficiency PWM CMOS class-D audio power amplifier

Energy Technology Data Exchange (ETDEWEB)

Zhu Zhangming; Liu Lianxi; Yang Yintang [Institute of Microelectronics, Xidian University, Xi' an 710071 (China); Lei Han, E-mail: zmyh@263.ne [Xi' an Power-Rail Micro Co., Ltd, Xi' an 710075 (China)

2009-02-15

Based on the difference close-loop feedback technique and the difference pre-amp, a high efficiency PWM CMOS class-D audio power amplifier is proposed. A rail-to-rail PWM comparator with window function has been embedded in the class-D audio power amplifier. Design results based on the CSMC 0.5 mum CMOS process show that the max efficiency is 90%, the PSRR is -75 dB, the power supply voltage range is 2.5-5.5 V, the THD+N in 1 kHz input frequency is less than 0.20%, the quiescent current in no load is 2.8 mA, and the shutdown current is 0.5 muA. The active area of the class-D audio power amplifier is about 1.47 x 1.52 mm{sup 2}. With the good performance, the class-D audio power amplifier can be applied to several audio power systems.

A high efficiency PWM CMOS class-D audio power amplifier

International Nuclear Information System (INIS)

Zhu Zhangming; Liu Lianxi; Yang Yintang; Lei Han

2009-01-01

Based on the difference close-loop feedback technique and the difference pre-amp, a high efficiency PWM CMOS class-D audio power amplifier is proposed. A rail-to-rail PWM comparator with window function has been embedded in the class-D audio power amplifier. Design results based on the CSMC 0.5 μm CMOS process show that the max efficiency is 90%, the PSRR is -75 dB, the power supply voltage range is 2.5-5.5 V, the THD+N in 1 kHz input frequency is less than 0.20%, the quiescent current in no load is 2.8 mA, and the shutdown current is 0.5 μA. The active area of the class-D audio power amplifier is about 1.47 x 1.52 mm 2 . With the good performance, the class-D audio power amplifier can be applied to several audio power systems.

A high efficiency PWM CMOS class-D audio power amplifier

Science.gov (United States)

Zhangming, Zhu; Lianxi, Liu; Yintang, Yang; Han, Lei

2009-02-01

Based on the difference close-loop feedback technique and the difference pre-amp, a high efficiency PWM CMOS class-D audio power amplifier is proposed. A rail-to-rail PWM comparator with window function has been embedded in the class-D audio power amplifier. Design results based on the CSMC 0.5 μm CMOS process show that the max efficiency is 90%, the PSRR is -75 dB, the power supply voltage range is 2.5-5.5 V, the THD+N in 1 kHz input frequency is less than 0.20%, the quiescent current in no load is 2.8 mA, and the shutdown current is 0.5 μA. The active area of the class-D audio power amplifier is about 1.47 × 1.52 mm2. With the good performance, the class-D audio power amplifier can be applied to several audio power systems.

Development of 650 MHz solid state RF amplifier for proton accelerator

International Nuclear Information System (INIS)

Jain, Akhilesh; Sharma, Deepak; Gupta, Alok; Tiwari, Ashish; Rao, Nageswar; Sekar, Vasanthi; Lad, M.; Hannurkar, P.R.; Gupta, P.D.

2011-01-01

Design and development of 30 kW high powers RF source at 650 MHz, using solid RF state technology, has been initiated at RRCAT. The indigenous technology development efforts will be useful for the proposed high power proton accelerators for SNS/ADS applications. In this 650 MHz amplifier scheme, 30 kW CW RF power will be generated using modular combination of 8 kW amplifier units. Necessary studies were carried out for device selection, choice of amplifier architecture and design of high power combiners and dividers. Presently RF amplifier delivering 250 W at 650 MHz has been fabricated and tested. Towards development of high power RF components, design and engineering prototyping of 16-port power combiner, directional coupler and RF dummy loads has been completed. The basic 8 kW amplifier unit is designed to provide power gain of 50 dB, bandwidth of 20 MHz and spurious response below 30 dB from fundamental signal. Based on the results of circuit simulation studies and engineering prototyping of amplifier module, two RF transistor viz. MRF3450 and MRF 61K were selected as solid state active devices. Impedance matching network in amplifier module is designed using balanced push pull configuration with transmission line BALUN. Due to high circulating current near drain side, metal clad RF capacitors were selected which helps in avoiding hot spot from output transmission path, ensuring continuous operation at rated RF power without damage to RF board. 350 W circulator is used to protect the RF devices from reflected power. Based on the prototype design and measured performance, one of these RF transistors will be selected to be used as workhorse for all amplifier modules. Two amplifier modules are mounted on water cooled copper heat-sink ensuring proper operating temperature for reliable and safe operation of amplifier. Also real time control system and data logger has been developed to provide DAQ and controls in each rack. For power combining and power measurement

Detection of genetic variability in Basmati and non-Basmati rice varieties and their radiation induced mutants through random amplified polymorphic DNA (RAPD)

Energy Technology Data Exchange (ETDEWEB)

Farooq, S; Iqbal, N; Arif, M [Nuclear Institute for Agriculture and Biology (NIAB), Faisalabad (Pakistan)

1998-03-01

Random Amplified Polymorphic DNA (RAPDs) markers were utilized to detect polymorphism between pure lines and commercially available Basmati rice varieties to assess variation which may be helpful in quality control and varietal identification (Basmati-370 and derived radiation induced mutants), differentiation of mutants and parents, and identification of RAPD markers co-segregating with important agronomic traits including plant height, days to flower and grain quality. Basmati varieties were distinguished from non-Basmati varieties with the help of five diagnostic markers which will be useful for detecting mixing of non-Basmati and Basmati rices, currently a serious marketing problem. Different Basmati cultivars were identified with the help of diagnostic RAPD markers which can be used in quality control as well as for ``fingerprinting`` of cultivars. Different radiation induced mutants were also successfully distinguished from the parents on the basis of variety specific and mutant specific markers which will be useful for varietal identification. In addition to this, other markers were also identified which can differentiate mutants from each other and are being, used for the fingerprinting of different mutants, particularly the dwarf mutants having similar appearance but different parentage. For identification of RAPD markers co-segregating with plant height and days to flower, 50 F{sub 2} plants and four F{sub 3} families were studied from a reciprocal cross made between Kashmir Basmati (tall and early) and Basmati-198 (dwarf and late). Segregating bands were observed within these populations, and indicating the possible use of RAPD markers for tagging gene(s) of agronomic importance in rice. (author). 38 refs, 6 figs, 3 tabs.

Detection of genetic variability in Basmati and non-Basmati rice varieties and their radiation induced mutants through random amplified polymorphic DNA (RAPD)

International Nuclear Information System (INIS)

Farooq, S.; Iqbal, N.; Arif, M.

1998-01-01

Random Amplified Polymorphic DNA (RAPDs) markers were utilized to detect polymorphism between pure lines and commercially available Basmati rice varieties to assess variation which may be helpful in quality control and varietal identification (Basmati-370 and derived radiation induced mutants), differentiation of mutants and parents, and identification of RAPD markers co-segregating with important agronomic traits including plant height, days to flower and grain quality. Basmati varieties were distinguished from non-Basmati varieties with the help of five diagnostic markers which will be useful for detecting mixing of non-Basmati and Basmati rices, currently a serious marketing problem. Different Basmati cultivars were identified with the help of diagnostic RAPD markers which can be used in quality control as well as for ''fingerprinting'' of cultivars. Different radiation induced mutants were also successfully distinguished from the parents on the basis of variety specific and mutant specific markers which will be useful for varietal identification. In addition to this, other markers were also identified which can differentiate mutants from each other and are being, used for the fingerprinting of different mutants, particularly the dwarf mutants having similar appearance but different parentage. For identification of RAPD markers co-segregating with plant height and days to flower, 50 F 2 plants and four F 3 families were studied from a reciprocal cross made between Kashmir Basmati (tall and early) and Basmati-198 (dwarf and late). Segregating bands were observed within these populations, and indicating the possible use of RAPD markers for tagging gene(s) of agronomic importance in rice. (author)

A low noise charge sensitive amplifier for use in vacuum photo diode readout

International Nuclear Information System (INIS)

Stephenson, R.

1982-08-01

The amplifier described consists of a charge sensitive pre-amplifier optimised for low noise with low values of input shunt capacitance, and a shaping amplifier providing both differentiation and integration. Amplifier gain is adjustable up to a maximum of approximately 100 μV/electron with a rise time of 2 μS to the peak of the output voltage, and with an open circuit input noise level of 150 electrons RMS. (author)

A numerical design approach for single amplifier, Active-RC Butterworth filter of order 5

OpenAIRE

Gaunholt, Hans

2007-01-01

A design method is presented for the design of all pole lowpass active-RC filters applying operational amplifiers. The operational amplifier model used is the integrator model: omegat/s where omegat is the unity gain frequency. The design method is used for the design of a fifth order Butterworth filter applying just one operational amplifier coupled as a unity gain amplifier. It is shown that the influence from the real operational amplifier may be reduced by trimming just one resistor in th...

Self-oscillating modulators for direct energy conversion audio power amplifiers

DEFF Research Database (Denmark)

Ljusev, Petar; Andersen, Michael Andreas E.

2005-01-01

Direct energy conversion audio power amplifier represents total integration of switching-mode power supply and Class D audio power amplifier into one compact stage, achieving high efficiency, high level of integration, low component count and eventually low cost. This paper presents how self-oscillating...

A Power Efficient Audio Amplifier Combining Switching and Linear Techniques

NARCIS (Netherlands)

van der Zee, Ronan A.R.; van Tuijl, Adrianus Johannes Maria

1998-01-01

Integrated Class D audio amplifiers are very power efficient, but require an external filter which prevents further integration. Also due to this filter, large feedback factors are hard to realise, so that the load influences the distortion- and transfer characteristics. The amplifier presented in

Low-power, enhanced-gain adaptive-biasing-based Operational Transconductance Amplifiers

DEFF Research Database (Denmark)

Moradi, Farshad

A symmetrical PMOS OTA (Operational Transconductance Amplifier) is used to build an advanced rail-to-rail amplifier with improved DC-gain and reduced power consumption. By using the adaptive biasing circuit for two differential inputs, a low stand-by current can be achieved, reducing power...

A real-time control system architecture for industrial power amplifiers

NARCIS (Netherlands)

Qureshi, F.; Spinu, V.; Wijnands, C.G.E.; Lazar, M.

2013-01-01

Power amplifiers are a highly important component in a range of industrial applications, such as, servo-drives, magnetic resonance imaging, energy systems, and audio. The control system for power amplifiers should satisfy a range of requirements, e.g., offset free tracking, stability margins, and

Combined Yb/Nd driver for optical parametric chirped pulse amplifiers.

Science.gov (United States)

Michailovas, Kirilas; Baltuska, Andrius; Pugzlys, Audrius; Smilgevicius, Valerijus; Michailovas, Andrejus; Zaukevicius, Audrius; Danilevicius, Rokas; Frankinas, Saulius; Rusteika, Nerijus

2016-09-19

We report on the developed front-end/pump system for optical parametric chirped pulse amplifiers. The system is based on a dual output fiber oscillator/power amplifier which seeds and assures all-optical synchronization of femtosecond Yb and picosecond Nd laser amplifiers operating at a central wavelength of 1030 nm and 1064 nm, respectively. At the central wavelength of 1030 nm, the fiber oscillator generates partially stretched 4 ps pulses with the spectrum supporting a scaling currently is prevented by limited dimensions of the diffraction gratings, which, because of the fast progress in MLD grating manufacturing technologies is only a temporary obstacle.

Design and Fabrication of a 1 THz Backward Wave Amplifier

DEFF Research Database (Denmark)

Paoloni, Claudio; Di Carlo, Aldo; Brunetti, Francesca

2011-01-01

, to get a level of output power to enable applications at these frequencies. The OPTHER (Optically driven THz amplifier) project, funded by the European Community, is on the road to realize the first 1 THz vacuum tube amplifier. Technology at the state of the art has been used for the realization...... of the parts with dimensions supporting THz frequencies. A backward wave amplifier configuration is chosen to make the parts realizable. A carbon nanotube cold cathode has been considered for electron generation. A thermionic micro electron gun is designed to test the tube. A novel slow-wave structure (SWS...

1-MHz high power femtosecond Yb-doped fiber chirped-pulse amplifier

Science.gov (United States)

Hu, Zhong-Qi; Yang, Pei-Long; Teng, Hao; Zhu, Jiang-Feng; Wei, Zhi-Yi

2018-01-01

A practical femtosecond polarization-maintaining Yb-doped fiber amplifier enabling 153 fs transform-limited pulse duration with 32 μJ pulse energy at 1 MHz repetition rate corresponding to a peak power of 0.21 GW is demonstrated. The laser system based on chirped-pulse amplification (CPA) technique is seeded by a dispersion managed, nonlinear polarization evolution (NPE) mode-locked oscillator with spectrum bandwidth of 31 nm at 1040 nm and amplified by three fiber pre-amplifying stages and a rod type fiber main amplifying stage. The laser works with beam quality of M2 of 1.3 and power stability of 0.63% (root mean square, RMS) over 24 hours will be stable sources for industrial micromachining, medical therapy and scientific research.

Static thermo-optic instability in double-pass fiber amplifiers

DEFF Research Database (Denmark)

Lægsgaard, Jesper

2016-01-01

A coupled-mode formalism, earlier used to describe transverse mode instabilities in single-pass optical fiber amplifiers, is extended to the case of double-pass amplifiers. Contrary to the single-pass case, it is shown that the thermo-optic nonlinearity can couple light at the same frequency...... between the LP01 and LP11 modes, leading to a static deformation of the output beam profile. This novel phenomenon is caused by the interaction of light propagating in either direction with thermo-optic index perturbations caused by light propagating in the opposite direction. The threshold power...... for the static deformation is found to be several times lower than what is typically found for the dynamic modal instabilities observed in single-pass amplifiers. (C) 2016 Optical Society of America...

Class H power amplifier for power saving in fluxgate current transducers

OpenAIRE

Velasco Quesada, Guillermo; Román Lumbreras, Manuel; Pérez Delgado, Raul; Conesa Roca, Alfons

2016-01-01

This paper presents a new improvement in the design of a fluxgate-based current transducer in order to reduce the power consumption of control electronics. The proposed improvement involves the replacement of the output linear amplifier of the transducer by a class H amplifier. The output amplifier is devoted to the magnetic flux compensation and generates the transducer output current, which is proportional to the current to be measured. In this way, it is possible to reduce significantly th...

Amplifying Islam : Pluralism, Secularism, and Religious Sounds in The Netherlands

NARCIS (Netherlands)

Tamimi Arab, P.

2015-01-01

This dissertation is an ethnographic study of the amplified azan, the Islamic call to prayer, in the Netherlands, adding a sonic dimension to analyses of the politics of Islamic aesthetics in the western world. Often rejected by opponents as noise pollution, facilitating the amplified azan is an

Detailed dynamic model for semiconductor optical amplifiers and their crosstalk and intermodulation distortion

DEFF Research Database (Denmark)

Durhuus, Terji; Mikkelsen, Benny; Stubkjær, Kristian

1992-01-01

. The model is used to assess intermodulation distortion and crosstalk. Cascaded amplifiers are considered, and the crosstalk and intermodulation distortion due to cascaded amplifiers are found to accumulate by adding together in amplitude; this may limit the number or cascaded amplifiers in multichannel...

A Reduced Switch Voltage Stress Class E Power Amplifier Using Harmonic Control Network

OpenAIRE

Ali Reza Zirak; Sobhan Roshani

2016-01-01

In this paper, a harmonic control network (HCN) is presented to reduce the voltage stress (maximum MOSFET voltage) of the class E power amplifier (PA). Effects of the HCN on the amplifier specifications are investigated. The results show that the proposed HCN affects several specifications of the amplifier, such as drain voltage, switch current, output power capability (Cp factor), and drain impedance. The output power capability of the presented amplifier is also improved, compared with the ...

Dielectric waveguide amplifiers and lasers

NARCIS (Netherlands)

Pollnau, Markus

The performance of semiconductor amplifiers and lasers has made them the preferred choice for optical gain on a micro-chip. In the past few years, we have demonstrated that also rare-earth-ion-doped dielectric waveguides show remarkable performance, ranging from a small-signal gain per unit length

Large area electron beam pumped krypton fluoride laser amplifier

International Nuclear Information System (INIS)

Sethian, J.D.; Obenschain, S.P.; Gerber, K.A.; Pawley, C.J.; Serlin, V.; Sullivan, C.A.; Webster, W.; Deniz, A.V.; Lehecka, T.; McGeoch, M.W.; Altes, R.A.; Corcoran, P.A.; Smith, I.D.; Barr, O.C.

1997-01-01

Nike is a recently completed multi-kilojoule krypton fluoride (KrF) laser that has been built to study the physics of direct drive inertial confinement fusion. This paper describes in detail both the pulsed power and optical performance of the largest amplifier in the Nike laser, the 60 cm amplifier. This is a double pass, double sided, electron beam-pumped system that amplifies the laser beam from an input of 50 J to an output of up to 5 kJ. It has an optical aperture of 60 cm x 60 cm and a gain length of 200 cm. The two electron beams are 60 cm high x 200 cm wide, have a voltage of 640 kV, a current of 540 kA, and a flat top power pulse duration of 250 ns. A 2 kG magnetic field is used to guide the beams and prevent self-pinching. Each electron beam is produced by its own Marx/pulse forming line system. The amplifier has been fully integrated into the Nike system and is used on a daily basis for laser-target experiments. copyright 1997 American Institute of Physics

Charge sensitive amplifies. The state of arts

Energy Technology Data Exchange (ETDEWEB)

Mori, Kunishiro [Clear Pulse Co., Tokyo (Japan)

1996-07-01

In the radiation detectors, signals are essentially brought with charges produced by radiation, then it is naturally the best way to use a charge sensitive amplifier (CSA) system to extract those signals. The CSA is thought to be the best amplifier suitable to almost all the radiation detectors, if neglecting economical points of view. The CSA has been only applied to special fields like radiation detection because the concept of `charges` is not so universal against the concepts of `voltage` and `current`. The CSA, however, is low in noise and a high speed amplifier and may be applicable not only to radiation measurement but also piezoelectric devices and also bolometers. In this article, noise in the CSA, basic circuit on the CSA, concepts of `equivalent noise charge` (ENC), a method for the ENC, and importance of the `open-loop gain` in the CSA to achieve better performance of it and how to realize in a practical CSA were described. And, characteristics on a counting rate of the CSA, various circuit used in the CSA, and CSAs which are commercially available at present and special purpose CSAs were also introduced. (G.K.)

Wideband amplifier design

CERN Document Server

Hollister, Allen L

2007-01-01

In this book, the theory needed to understand wideband amplifier design using the simplest models possible will be developed. This theory will be used to develop algebraic equations that describe particular circuits used in high frequency design so that the reader develops a ""gut level"" understanding of the process and circuit. SPICE and Genesys simulations will be performed to show the accuracy of the algebraic models. By looking at differences between the algebraic equations and the simulations, new algebraic models will be developed that include parameters originally left out of the model

Building valve amplifiers

CERN Document Server

Jones, Morgan

2013-01-01

Building Valve Amplifiers is a unique hands-on guide for anyone working with tube audio equipment--as an electronics hobbyist, audiophile or audio engineer. This 2nd Edition builds on the success of the first with technology and technique revisions throughout and, significantly, a major new self-build project, worked through step-by-step, which puts into practice the principles and techniques introduced throughout the book. Particular attention has been paid to answering questions commonly asked by newcomers to the world of the valve, whether audio enthusiasts tackling their first build or

Analysis and simulation of nonlinearity and effects of spontaneous emission in Schottky-junction-based plasmonic amplifiers.

Science.gov (United States)

Livani, Abdolber Mallah; Kaatuzian, Hassan

2015-07-01

An amplifier that operates on surface plasmon polaritons has been analyzed and simulated. Nonlinearity behavior and the spontaneous emission effects of the plasmonic amplifier are investigated in this paper. A rate equations approach has been used in which parameters are derived from simulation results of the plasmonic amplifier (Silvaco/ATLAS). Details on the method of this derivation are included, which were not previously reported. Rate equations are solved numerically by MATLAB codes. These codes verify the Silvaco results. The plasmonic amplifier operates on surface plasmons with a free-space wavelength of 1550 nm. Results show that, even without the effect of spontaneous emission, gain of the plasmonic amplifier saturates in high input levels. Saturation power, which can be used for comparing nonlinearity of different amplifiers, is 2.1 dBm for this amplifier. Amplified spontaneous emission reduces the gain of the amplifiers, which is long. There is an optimum value for the length of the amplifier. For the amplifier of this work, the optimum length for the small signal condition is 265 μm.

Ultrafast optical signal processing using semiconductor quantum dot amplifiers

DEFF Research Database (Denmark)

Berg, Tommy Winther; Mørk, Jesper

2002-01-01

The linear and nonlinear properties of quantum dot amplifiers are discussed on the basis of an extensive theoretical model. These devices show great potential for linear amplification as well as ultrafast signal processing.......The linear and nonlinear properties of quantum dot amplifiers are discussed on the basis of an extensive theoretical model. These devices show great potential for linear amplification as well as ultrafast signal processing....

Noise figure of amplified dispersive Fourier transformation

International Nuclear Information System (INIS)

Goda, Keisuke; Jalali, Bahram

2010-01-01

Amplified dispersive Fourier transformation (ADFT) is a powerful tool for fast real-time spectroscopy as it overcomes the limitations of traditional optical spectrometers. ADFT maps the spectrum of an optical pulse into a temporal waveform using group-velocity dispersion and simultaneously amplifies it in the optical domain. It greatly simplifies spectroscopy by replacing the diffraction grating and detector array in the conventional spectrometer with a dispersive fiber and single-pixel photodetector, enabling ultrafast real-time spectroscopic measurements. Following our earlier work on the theory of ADFT, here we study the effect of noise on ADFT. We derive the noise figure of ADFT and discuss its dependence on various parameters.

A unified framework for the statistical characterization of the SNR of amplify-and-forward multihop channels

KAUST Repository

Yilmaz, Ferkan

2010-01-01

In this paper, we present a unified approach to analyze the exact statistical characteristics of the harmonic mean of N ≥ 2 statistically independent and non-identically distributed random variables (RVs), which we term the N-normalized harmonic distribution (i.e., NHD distribution), for the purpose of modeling the amplify-and-forward multihop relay channels. We present exact statistical metrics for the moments-generating function (MGF), moments (Mellin moments-generating function), probability density function (PDF) and cumulative distribution function (CDF) of the NHD distribution. Aside from unifying past results based on the geometric-mean approximation of the harmonic-mean, our approach relies on the algebraic combination of Mellin and Laplace transforms to obtain exact single integral expressions which can be easily computed using the Gauss-Laguerre quadrature rule or can be readily expressed in terms of the multivariable Meijer\\'s G of Fox\\'s H functions. Numerical and simulation results, performed to verify the correctness of the proposed formulation, are in perfect agreement. The proposed formulation can be used to analyze the performance measures of the amplify-and-forward multihop relay channels such as outage probability, outage capacity, average capacity and average bit error probabilities. © 2009 IEEE.

M.V.A. amplifier for plasma position control by vertical magnetic field

International Nuclear Information System (INIS)

Schenk, G.

1978-01-01

The radial plasma position in the WEGA torus is controlled by a power amplifier, acting on the vertical magnetic field. Up to now the feedback loop contains, as amplifying elements, two 90 kW DC-transistor amplifiers, acting in push-pull operation. As increased plasma stability and lifetime is desirable, we have to increase the power amplifier to about 1 Megawatt. Industry offered a thyristor rectifier, operating at 50 or 300 Hz, and alternatively a thyristor chopper amplifier at a few kHz frequency response. Theses offers did not correspond to our demand, as far as response time, price and primary power requirements are concerned. We have implemented a bipolar switching-type amplifier (also called H-bridge converter) with the characteristics: time response < 0,05 ms., pulsed power = 1 MW (400 V, 2500 A), primary power = 2,5 kW. As power switch, a network of parallel high voltage transistors, driven by three transistor stages, has been chosen, to control a vertical magnetic field or +/- 180 G, with a precision of about one per cent. Precautions for transistor switches concerning mainly critical voltage, current, instantaneous power and selfoscillating behaviour have been taken. This systems corresponds to our demands

Dispersion-Engineered Traveling Wave Kinetic Inductance Parametric Amplifier

Science.gov (United States)

Zmuidzinas, Jonas (Inventor); Day, Peter K. (Inventor)

2014-01-01

A traveling wave kinetic inductance parametric amplifier comprises a superconducting transmission line and a dispersion control element. The transmission line can include periodic variations of its dimension along its length. The superconducting material can include a high normal state resistivity material. In some instances the high normal state resistivity material includes nitrogen and a metal selected from the group consisting of titanium, niobium and vanadium. The traveling wave kinetic inductance parametric amplifier is expected to exhibit a noise temperature below 100 mK/GHz.

Power amplifiers for the S-, C-, X- and Ku-bands an EDA perspective

CERN Document Server

Božanić, Mladen

2016-01-01

This book provides a detailed review of power amplifiers, including classes and topologies rarely covered in books, and supplies sufficient information to allow the reader to design an entire amplifier system, and not just the power amplification stage. A central aim is to furnish readers with ideas on how to simplify the design process for a preferred power amplifier stage by introducing software-based routines in a programming language of their choice. The book is in two parts, the first focusing on power amplifier theory and the second on EDA concepts. Readers will gain enough knowledge of RF and microwave transmission theory, principles of active and passive device design and manufacturing, and power amplifier design concepts to allow them to quickly create their own programs, which will help to accelerate the transceiver design process. All circuit designers facing the challenge of designing an RF or microwave power amplifier for frequencies from 2 to 18 GHz will find this book to be a valuable asset.

Gain measurements on a prototype NIF/LMJ amplifier pump cavity

International Nuclear Information System (INIS)

Rotter, M.D.; McCracken, R.; Erlandson, A.; Guenet, M.

1996-12-01

We are currently developing large-aperture amplifiers for the National Ignition Facility (NIF) and Laser Megajoules (LMJ) lasers. These multisegment amplifiers are of the flashlamp-pumped, Nd:Glass qW and are designed to propagate a nominally 36 cm square beam. The apertures within a particular amplifier bundle are arranged in a four-high by two-wide configuration and utilize two side lamp arrays and a central flashlamp array for pumping. The configuration is very similar to that used in the Beamlet laser, a single-beam prototype for the NIF/LMJ lasers, which has four apertures arranged in a two- high by two-wide configuration

Radiofrequency amplifier based on a DC superconducting quantum interference device

International Nuclear Information System (INIS)

Martinis, J.M.; Hilbert, C.; Clarke, J.

1986-01-01

A method is described of amplifying a radiofrequency signal consisting of: disposing a single symmetrically biased dc SQUID and an input coil within a superconducting shield, the dc SQUID having a superconducting ring interrupted by two shunted Josephson junctions, and the input coil being inductively coupled solely to the ring of the single SQUID, establishing a constant magnetic flux threading the SQUID ring, applying the radiofrequency signal to the input coil from outside of the superconducting shield, obtaining an amplified radiofrequency signal solely from across the ring of the single SQUID, transmitting the amplified radiofrequency signal from across the SQUID ring to the outside of the superconducting shield

High-performace cladding-pumped erbium-doped fibre laser and amplifier

International Nuclear Information System (INIS)

Kotov, L V; Likhachev, M E; Bubnov, M M; Medvedkov, O I; Lipatov, D S; Vechkanov, N N; Guryanov, Aleksei N

2012-01-01

We report cladding-pumped erbium-doped fibre laser and amplifier configurations. Through fibre design optimisation, we have achieved a record-high laser slope efficiency, 40 % with respect to absorbed pump power (λ = 976 nm), and an output power of 7.5 W. The erbium-doped fibre amplifier efficiency reaches 32 %.

Amplified spontaneous emission measurements on the Aurora large aperture module

International Nuclear Information System (INIS)

Oertel, J.A.; Czuchlewski, S.J.; Leland, W.T.; Turner, T.P.

1990-01-01

The large aperture module (LAM) of the Aurora KrF laser can be used to address a number of issues that relate to the scaling of KrF amplifiers to larger ICF systems. Perhaps foremost among these are the possible effects of amplified spontaneous emission (ASE) on laser performance. To assess this problem a 3-D computer code has been developed to model these ASE effects. The code uses an iterative procedure to arrive at a self-consistent steady state solution to the 3-D distribution of coherent and incoherent fluxes within the amplifier. Two-pass energy extraction, wall reflectivity, and nonuniform excitation are included in the model. The authors previously reported the effects of ASE on the small signal gains measured in the 1- x 1- x 2-m 3 LAM. The code also makes quantitative predictions of the ASE that should be generated in the amplifier. This paper indicates the radiance expected for a medium of uniform gain in terms of the (g - ν)L product and the parameter g/a. The quantity (g - ν)L is the product of the net gain and the path length along the direction of observation. The present experiments compare values of ASE measured at various locations around the LAM with the code predictions. The impact of ASE on amplifier output, is also discussed

Design of low noise transimpedance amplifier for intravascular ultrasound

KAUST Repository

Reda, Dina

2009-11-01

In this paper, we study transimpedance amplifiers for capacitive sensing applications with a focus on Intravascular Ultra Sound (IVUS). We employ RF noise cancellation technique on capacitive feedback based transimpedance amplifiers. This technique eliminates the input-referred noise of TIAs completely and enhances the dynamic range of front-end electronics. Simulation results verify the proposed technique used in two different TIA topologies employing shunt-shunt feedback. ©2009 IEEE.

Nonclassical photon streams using rephased amplified spontaneous emission

International Nuclear Information System (INIS)

Ledingham, Patrick M.; Naylor, William R.; Longdell, Jevon J.; Beavan, Sarah E.; Sellars, Matthew J.

2010-01-01

We present a fully quantum mechanical treatment of optically rephased photon echoes. These echoes exhibit noise due to amplified spontaneous emission; however, this noise can be seen as a consequence of the entanglement between the atoms and the output light. With a rephasing pulse one can get an 'echo' of the amplified spontaneous emission, leading to light with nonclassical correlations at points separated in time, which is of interest in the context of building wide bandwith quantum repeaters. We also suggest a wideband version of DLCZ protocol based on the same ideas.

1000 kW ICRH amplifiers for MFTF-B

International Nuclear Information System (INIS)

Boksberger, U.

1986-01-01

For the startup of the MFTF-B ICRH heating will be applied. Two commercial amplifiers derived from standard broadcast transmitters provide 1000 kW RF power each into a matching system for any VSWR as high as 1.5. Emphasis is put on the specific environment of magnetic fields and seismic loads as well as to the particular RF power control requirements and remote operation. Also addressed is the amplifier's performance into a typical load. The load variations due to the MFTF-B plasma coupling were calculated by TRW

Power scaling of supercontinuum seeded megahertz-repetition rate optical parametric chirped pulse amplifiers.

Science.gov (United States)

Riedel, R; Stephanides, A; Prandolini, M J; Gronloh, B; Jungbluth, B; Mans, T; Tavella, F

2014-03-15

Optical parametric chirped-pulse amplifiers with high average power are possible with novel high-power Yb:YAG amplifiers with kW-level output powers. We demonstrate a compact wavelength-tunable sub-30-fs amplifier with 11.4 W average power with 20.7% pump-to-signal conversion efficiency. For parametric amplification, a beta-barium borate crystal is pumped by a 140 W, 1 ps Yb:YAG InnoSlab amplifier at 3.25 MHz repetition rate. The broadband seed is generated via supercontinuum generation in a YAG crystal.

Theoretical analysis of quantum dot amplifiers with high saturation power and low noise figure

DEFF Research Database (Denmark)

Berg, Tommy Winther; Mørk, Jesper

2002-01-01

Semiconductor quantum dot amplifiers are predicted to exhibit superior characteristics such as high gain, and output power and low noise. The analysis provides criteria and design guidelines for the realization of high quality amplifiers.......Semiconductor quantum dot amplifiers are predicted to exhibit superior characteristics such as high gain, and output power and low noise. The analysis provides criteria and design guidelines for the realization of high quality amplifiers....

Stability of a 500 km erbium-doped fiber amplifier cascade

DEFF Research Database (Denmark)

Lumholt, Ole; Bjarklev, Anders Overgaard; Povlsen, Jørn Hedegaard

1992-01-01

The stability of a cascade system of erbium-doped fiber amplifiers, due to pump and signal power variations, has been examined by use of a very accurate model. Even with an automatic gain control loop included, a fallout of a pump laser in the first inline amplifier is shown to produce a more than...

Tunable Balun Low-Noise Amplifier in 65nm CMOS Technology

Directory of Open Access Journals (Sweden)

J. Sturm

2014-04-01

Full Text Available The presented paper includes the design and implementation of a 65 nm CMOS low-noise amplifier (LNA based on inductive source degeneration. The amplifier is realized with an active balun enabling a single-ended input which is an important requirement for low-cost system on chip implementations. The LNA has a tunable bandpass characteristics from 4.7 GHz up to 5.6 GHz and a continuously tunable gain from 22 dB down to 0 dB, which enables the required flexibility for multi-standard, multi-band receiver architectures. The gain and band tuning is realized with an optimized tunable active resistor in parallel to a tunable L-C tank amplifier load. The amplifier achieves an IIP3 linearity of -8dBm and a noise figure of 2.7 dB at the highest gain and frequency setting with a low power consumption of 10 mW. The high flexibility of the proposed LNA structure together with the overall good performance makes it well suited for future multi-standard low-cost receiver front-ends.

Multi-path interferometric Josephson directional amplifier for qubit readout

Science.gov (United States)

Abdo, Baleegh; Bronn, Nicholas T.; Jinka, Oblesh; Olivadese, Salvatore; Brink, Markus; Chow, Jerry M.

2018-04-01

We realize and characterize a quantum-limited, directional Josephson amplifier suitable for qubit readout. The device consists of two nondegenerate, three-wave-mixing amplifiers that are coupled together in an interferometric scheme, embedded in a printed circuit board. Nonreciprocity is generated by applying a phase gradient between the same-frequency pumps feeding the device, which plays the role of the magnetic field in a Faraday medium. Directional amplification and reflection-gain elimination are induced via wave interference between multiple paths in the system. We measure and discuss the main figures of merit of the device and show that the experimental results are in good agreement with theory. An improved version of this directional amplifier is expected to eliminate the need for bulky, off-chip isolation stages that generally separate quantum systems and preamplifiers in high-fidelity, quantum-nondemolition measurement setups.

Optimal control of a high-frequency class-D amplifier

DEFF Research Database (Denmark)

Dahl, Nicolai J.; Iversen, Niels Elkjær; Knott, Arnold

2018-01-01

Control loops have been used with switch-mode audio amplifiers to improve the sound quality of the amplifier. Because these amplifiers use a high-frequency modulation, precautions in the controller design must be taken. Further, the quality factor of the output filter can have a great impact...... on the controller's capabilities to suppress noise and track the audio signal. In this paper design methods for modern control are presented. The control method proves to easily overcome the challenge of designing a good performing controller when the output filter has a high quality factor. The results show...... that the controller is able to produce a clear improvement in the Total Harmonic Distortion with up to a 30 times improvement compared to open-loop with a clear reduction in the noise. This places the audio quality on pair with current solutions....

Design of a power amplifier for the LAMPF proton storage ring transverse damper system

International Nuclear Information System (INIS)

Lunsford, J.S.

1981-01-01

A power amplifier has been designed to drive the 50-Ω stripline deflection structures in the transverse active damper of the Los Alamos 800-MeV Proton Storage Ring (PSR). The unit will provide 600-V peak-to-peak with a dc-to-100-MHz bandwidth. Other important characteristics include < 40-ns delay time, 50-dB voltage gain, and 4-ns risetime with < 5% overshoot and ringing. Because of the current-drive properties of the amplifier, two amplifiers could be combined to provide over 1000-V peak-to-peak into 50 Ω, with very little bandwidth degradation. Components in the power amplifier that represent new designs are a 20-tube distributed-amplifier output stage; a driver stage, using VMOS FET and bipolar transistors; a high-voltage probe, with good dc stability and 150-MHz bandwidth; a transient suppressor circuit, using PIN diodes to protect the transistorized drivers from tube arcing; a nonlinear amplifier to compensate for the nonlinear characteristics of the distributed amplifier; and a first-fail indicator circuit to aid in locating the prime causes of equipment failures

Ferrite bead effect on Class-D amplifier audio quality

OpenAIRE

Haddad , Kevin El; Mrad , Roberto; Morel , Florent; Pillonnet , Gael; Vollaire , Christian; Nagari , Angelo

2014-01-01

International audience; This paper studies the effect of ferrite beads on the audio quality of Class-D audio amplifiers. This latter is a switch-ing circuit which creates high frequency harmonics. Generally, a filter is used at the amplifier output for the sake of electro-magnetic compatibility (EMC). So often, in integrated solutions, this filter contains ferrite beads which are magnetic components and present nonlinear behavior. Time domain measurements and their equivalence in frequency do...

An analog integrated front-end amplifier for neural applications

OpenAIRE

Zhou, Zhijun; Warr, Paul

2017-01-01

The front-end amplifier forms the critical element for signal detection and pre-processing within neural monitoring systems. It determines not only the fidelity of the biosignal, but also impacts power consumption and detector size. In this paper, a combined feedback loop-controlled approach is proposed to neutralize for the input leakage currents generated by low noise amplifiers when in integrated circuit form, alongside signal leakage into the input bias network. Significantly, this loop t...

Remote optically-tunable transimpedance amplifiers for quantum well diodes

Energy Technology Data Exchange (ETDEWEB)

Carraresi, L.; Landi, G.; Rocchi, S.; Vignoli, V

1999-08-01

In a previous paper we discussed the advantages in using linear optical transmission systems based on quantum well diodes in modern high energy physics experiments. In this paper, after a short summary of the quantum well theory, the electronics section of the above optical transmission system is presented. In particular the basic configuration of a transimpedance amplifier and the arrangement of an optical remote control system for the amplifier gain and bandwidth tuning are discussed.

Remote optically-tunable transimpedance amplifiers for quantum well diodes

International Nuclear Information System (INIS)

Carraresi, L.; Landi, G.; Rocchi, S.; Vignoli, V.

1999-01-01

In a previous paper we discussed the advantages in using linear optical transmission systems based on quantum well diodes in modern high energy physics experiments. In this paper, after a short summary of the quantum well theory, the electronics section of the above optical transmission system is presented. In particular the basic configuration of a transimpedance amplifier and the arrangement of an optical remote control system for the amplifier gain and bandwidth tuning are discussed

Self-amplifying autocrine actions of BDNF in axon development

OpenAIRE

Cheng, Pei-Lin; Song, Ai-Hong; Wong, Yu-Hui; Wang, Sheng; Zhang, Xiang; Poo, Mu-Ming

2011-01-01

A critical step in neuronal development is the formation of axon/dendrite polarity, a process involving symmetry breaking in the newborn neuron. Local self-amplifying processes could enhance and stabilize the initial asymmetry in the distribution of axon/dendrite determinants, but the identity of these processes remains elusive. We here report that BDNF, a secreted neurotrophin essential for the survival and differentiation of many neuronal populations, serves as a self-amplifying autocrine f...

Enhanced timing channel for spectroscopy amplifiers

Energy Technology Data Exchange (ETDEWEB)

Ianakiev, K; Grigorov, N [Inst. for Nuclear Research and Nuclear Energy, Sofia (Bulgaria)

1996-12-31

Purpose of this paper is to analyze noise and timing performance of some methods of filtering in the fast channel. Implementation of RLC-filter into a semi-Gaussian amplifier allows to obtain the time resolution of 420 ns. 5 refs.

Note: a transimpedance amplifier for remotely located quartz tuning forks.

Science.gov (United States)

Kleinbaum, Ethan; Csáthy, Gábor A

2012-12-01

The cable capacitance in cryogenic and high vacuum applications of quartz tuning forks imposes severe constraints on the bandwidth and noise performance of the measurement. We present a single stage low noise transimpedance amplifier with a bandwidth exceeding 1 MHz and provide an in-depth analysis of the dependence of the amplifier parameters on the cable capacitance.

High efficiency RF amplifier development over wide dynamic range for accelerator application

Science.gov (United States)

Mishra, Jitendra Kumar; Ramarao, B. V.; Pande, Manjiri M.; Joshi, Gopal; Sharma, Archana; Singh, Pitamber

2017-10-01

Superconducting (SC) cavities in an accelerating section are designed to have the same geometrical velocity factor (βg). For these cavities, Radio Frequency (RF) power needed to accelerate charged particles varies with the particle velocity factor (β). RF power requirement from one cavity to other can vary by 2-5 dB within the accelerating section depending on the energy gain in the cavity and beam current. In this paper, we have presented an idea to improve operating efficiency of the SC RF accelerators using envelope tracking technique. A study on envelope tracking technique without feedback is carried out on a 1 kW, 325 MHz, class B (conduction angle of 180 degrees) tuned load power amplifier (PA). We have derived expressions for the efficiency and power output for tuned load amplifier operating on the envelope tracking technique. From the derived expressions, it is observed that under constant load resistance to the device (MOSFET), optimum amplifier efficiency is invariant whereas output power varies with the square of drain bias voltage. Experimental results on 1 kW PA module show that its optimum efficiency is always greater than 62% with variation less than 5% from mean value over 7 dB dynamic range. Low power amplifier modules are the basic building block for the high power amplifiers. Therefore, results for 1 kW PA modules remain valid for the high power solid state amplifiers built using these PA modules. The SC RF accelerators using these constant efficiency power amplifiers can improve overall accelerator efficiency.

On cuff imbalance and tripolar ENG amplifier configurations.

Science.gov (United States)

Triantis, Iasonas F; Demosthenous, Andreas; Donaldson, Nick

2005-02-01

Electroneurogram (ENG) recording techniques benefit from the use of tripolar cuffs because they assist in reducing interference from sources outside the cuff. However, in practice the performance of ENG amplifier configurations, such as the quasi-tripole and the true-tripole, has been widely reported to be degraded due to the departure of the tripolar cuff from ideal behavior. This paper establishes the presence of cuff imbalance and investigates its relationship to cuff asymmetry, cuff end-effects and interference source proximity. The paper also presents a comparison of the aforementioned amplifier configurations with a new alternative, termed the adaptive-tripole, developed to automatically compensate for cuff imbalance. The output signal-to-interference ratio of the three amplifier configurations were compared in vivo for two interference signals (stimulus artifact and M-wave) superimposed on compound action potentials. The experiments showed (for the first time) that the two interference signals result in different cuff imbalance values. Nevertheless, even with two distinct cuff imbalances present, the adaptive-tripole performed better than the other two systems in 61.9% of the trials.

Fiber optical parametric amplifiers in optical communication systems

Science.gov (United States)

Marhic (†), Michel E; Andrekson, Peter A; Petropoulos, Periklis; Radic, Stojan; Peucheret, Christophe; Jazayerifar, Mahmoud

2015-01-01

The prospects for using fiber optical parametric amplifiers (OPAs) in optical communication systems are reviewed. Phase-insensitive amplifiers (PIAs) and phase-sensitive amplifiers (PSAs) are considered. Low-penalty amplification at/or near 1 Tb/s has been achieved, for both wavelength- and time-division multiplexed formats. High-quality mid-span spectral inversion has been demonstrated at 0.64 Tb/s, avoiding electronic dispersion compensation. All-optical amplitude regeneration of amplitude-modulated signals has been performed, while PSAs have been used to demonstrate phase regeneration of phase-modulated signals. A PSA with 1.1-dB noise figure has been demonstrated, and preliminary wavelength-division multiplexing experiments have been performed with PSAs. 512 Gb/s have been transmitted over 6,000 km by periodic phase conjugation. Simulations indicate that PIAs could reach data rate x reach products in excess of 14,000 Tb/s × km in realistic wavelength-division multiplexed long-haul networks. Technical challenges remaining to be addressed in order for fiber OPAs to become useful for long-haul communication networks are discussed. PMID:25866588

SHIVA Nd: glass disk-amplifier-assembly facility and special purpose fixtures

International Nuclear Information System (INIS)

Jones, W.A.; Patton, H.G.; Stowers, I.F.; Wentworth, D.E.

1977-09-01

The facility built to assemble and maintain the laser amplifiers in the SHIVA Laser System is described. The facility is a Class-100 clean room which includes a high pressure solvent spray box, optical inspection equipment, and several unique amplifier-assembly fixtures

Pulse distortion, energy extraction, and ASE in an HF amplifier with angular multiplexing

International Nuclear Information System (INIS)

McGuire, E.J.

1976-09-01

It has been proposed that 1 ns pulses can be efficiently extracted from the e-beam initiated HF laser by angular multiplexing, i.e., filling the amplifier with the 1 ns pulses, 1 ns apart in time, each pulse at a slightly different angle; each pulse has an input intensity of 1 W/cm 2 per line and almost fills the amplifier. We have treated this in a one dimensional model, neglecting transverse amplified spontaneous emission. We conclude that the scheme is efficient, and that most of the pulses are amplified but not distorted. The first few pulses are distorted by transient effects and the last pulse has an enhanced tail. The ratio of peak pulse intensity to forward ASE at the output is 10 4 . We then include transverse ASE and find a drastically different situation. ASE saturates the inversion after a short time depending on pulse intensity (4 ns at I/sub o/ = 1 W/cm 2 , 7 ns at I/sub o/ = 100 W/cm 2 ). The saturation time is only weakly dependent on the transverse reflection coefficient. Calculations were done on an amplifier system designed for 10 KJ output. At an incident peak pulse intensity of 10 4 W/cm 2 -line (.77 MW/cm 2 for 77 lines) 2.5 KJ was obtained in amplified pulse energy, i.e., only 6 pulses of the 24 pulse train were fully amplified. The calculations indicate that double passing the pulse train through the amplifier would enhance the energy extracted

Coherent combining of high brightness tapered lasers in master oscillator power amplifier configuration

Science.gov (United States)

Albrodt, P.; Hanna, M.; Moron, F.; Decker, J.; Winterfeldt, M.; Blume, G.; Erbert, G.; Crump, P.; Georges, P.; Lucas-Leclin, G.

2018-02-01

Improved diode laser beam combining techniques are in strong demand for applications in material processing. Coherent beam combining (CBC) is the only combining approach that has the potential to maintain or even improve all laser properties, and thus has high potential for future systems. As part of our ongoing studies into CBC of diode lasers, we present recent progress in the coherent superposition of high-power single-pass tapered laser amplifiers. The amplifiers are seeded by a DFB laser at λ = 976 nm, where the seed is injected into a laterally single-mode ridge-waveguide input section. The phase pistons on each beam are actively controlled by varying the current in the ridge section of each amplifier, using a sequential hill-climbing algorithm, resulting in a combined beam with power fluctuations of below 1%. The currents into the tapered sections of the amplifiers are separately controlled, and remain constant. In contrast to our previous studies, we favour a limited number of individual high-power amplifiers, in order to preserve a high extracted power per emitter in a simple, low-loss coupling arrangement. Specifically, a multi-arm interferometer architecture with only three devices is used, constructed using 6 mm-long tapered amplifiers, mounted junction up on C-mounts, to allow separate contact to single mode and amplifier sections. A maximum coherently combined power of 12.9 W is demonstrated in a nearly diffraction-limited beam, corresponding to a 65% combining efficiency, with power mainly limited by the intrinsic beam quality of the amplifiers. Further increased combined power is currently sought.

Ways to suppress click and pop for class D amplifiers

International Nuclear Information System (INIS)

Wang Haishi; Zhang Bo; Sun Jiang

2012-01-01

Undesirable audio click and pop may be generated in a speaker or headphone. Compared to linear (class A/B/AB) amplifiers, class D amplifiers that comprise of an input stage and a modulation stage are more prone to producing click and pop. This article analyzes sources that generate click and pop in class D amplifiers, and corresponding ways to suppress them. For a class D amplifier with a single-ended input, click and pop is likely to be due to two factors. One is from a voltage difference (V DIF ) between the voltage of an input capacitance (V CIN ) and a reference voltage (V REF ) of the input stage, and the other one is from the non-linear switching during the setting up of the bias and feedback voltages/currents (BFVC) of the modulation stage. In this article, a fast charging loop is introduced into the input stage to charge V CIN to roughly near V REF . Then a correction loop further charges or discharges V CIN , substantially equalizing it with V REF . Dummy switches are introduced into the modulation stage to provide switching signals for setting up BFVC, and the power switches are disabled until the BFVC are set up successfully. A two channel single-ended class D amplifier with the above features is fabricated with 0.5 μm Bi-CMOS process. Road test and fast Fourier transform analysis indicate that there is no noticeable click and pop. (semiconductor integrated circuits)

Op-amp based low noise amplifier for magnetic particle spectroscopy

Directory of Open Access Journals (Sweden)

Malhotra Ankit

2017-09-01

Full Text Available Magnetic particle spectrometry (MPS is a novel technique used to measure the magnetization response of superparamagnetic iron oxide nanoparticles (SPIONs. Therefore, it is one of the most important tools for the characterization of the SPIONs for imaging modalities such as magnetic particle imaging (MPI and Magnetic Resonance Imaging (MRI. In MPS, change in the particle magnetization induces a voltage in a dedicated receive coil. The amplitude of the signal can be very low (ranging from a few nV to 100 μV depending upon the concentration of the nanoparticles. Hence, the received signal needs to be amplified with a low noise amplifier (LNA. LNA’s paramount task is to amplify the received signal while keeping the noise induced by its own circuitry minimum. In the current research, we purpose modeling, design, and development of a prototyped LNA for MPS. The designed prototype LNA is based on the parallelization technique of Op-amps. The prototyped LNA consists of 16 Op-amps in parallel and is manufactured on a printed circuit board (PCB, with a size of 110.38 mm × 59.46 mm and 234 components. The input noise of the amplifier is approx. 546 pV/√Hz with a noise figure (NF of approx. 1.4 dB with a receive coil termination. Furthermore, a comparison between the prototyped LNA and a commercially available amplifier is shown.

Spectroscopic amplifier for pin diode; Amplificador espectroscopico para diodo Pin

Energy Technology Data Exchange (ETDEWEB)

Alonso M, M. S.; Hernandez D, V. M.; Vega C, H. R., E-mail: bebe.luna_s@hotmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico)

2014-10-15

The photodiode remains the basic choice for the photo-detection and is widely used in optical communications, medical diagnostics and field of corpuscular radiation. In detecting radiation it has been used for monitoring radon and its progeny and inexpensive spectrometric systems. The development of a spectroscopic amplifier for Pin diode is presented which has the following characteristics: canceler Pole-Zero (P/Z) with a time constant of 8 μs; constant gain of 57, suitable for the acquisition system; 4th integrator Gaussian order to waveform change of exponential input to semi-Gaussian output and finally a stage of baseline restorer which prevents Dc signal contribution to the next stage. The operational amplifier used is the TLE2074 of BiFET technology of Texas Instruments with 10 MHz bandwidth, 25 V/μs of slew rate and a noise floor of 17 nv/(Hz)1/2. The integrated circuit has 4 operational amplifiers and in is contained the total of spectroscopic amplifier that is the goal of electronic design. The results show like the exponential input signal is converted to semi-Gaussian, modifying only the amplitude according to the specifications in the design. The total system is formed by the detector, which is the Pin diode, a sensitive preamplifier to the load, the spectroscopic amplifier that is what is presented and finally a pulse height analyzer (Mca) which is where the spectrum is shown. (Author)

Ways to suppress click and pop for class D amplifiers

Science.gov (United States)

Haishi, Wang; Bo, Zhang; Jiang, Sun

2012-08-01

Undesirable audio click and pop may be generated in a speaker or headphone. Compared to linear (class A/B/AB) amplifiers, class D amplifiers that comprise of an input stage and a modulation stage are more prone to producing click and pop. This article analyzes sources that generate click and pop in class D amplifiers, and corresponding ways to suppress them. For a class D amplifier with a single-ended input, click and pop is likely to be due to two factors. One is from a voltage difference (VDIF) between the voltage of an input capacitance (VCIN) and a reference voltage (VREF) of the input stage, and the other one is from the non-linear switching during the setting up of the bias and feedback voltages/currents (BFVC) of the modulation stage. In this article, a fast charging loop is introduced into the input stage to charge VCIN to roughly near VREF. Then a correction loop further charges or discharges VCIN, substantially equalizing it with VREF. Dummy switches are introduced into the modulation stage to provide switching signals for setting up BFVC, and the power switches are disabled until the BFVC are set up successfully. A two channel single-ended class D amplifier with the above features is fabricated with 0.5 μm Bi-CMOS process. Road test and fast Fourier transform analysis indicate that there is no noticeable click and pop.

The design of a 4’th order Bandpass Butterworth filter with one operational amplifier.

OpenAIRE

Gaunholt, Hans

2008-01-01

A numerical design method is presented for the design of all pole band pass active-RC filters applying just one operational amplifier. The operational amplifier model used is the integrator model: ωt/s where ωt is the unity gain fre-quency. The design method is used for the design of a fourth order band pass filter with Butterworth poles applying just one operational amplifier coupled as a unity gain amplifier. The unity gain amplifiers have the advantage of providing low power consumption, y...

Repeated Evolution of Power-Amplified Predatory Strikes in Trap-Jaw Spiders.

Science.gov (United States)

Wood, Hannah M; Parkinson, Dilworth Y; Griswold, Charles E; Gillespie, Rosemary G; Elias, Damian O

2016-04-25

Small animals possess intriguing morphological and behavioral traits that allow them to capture prey, including innovative structural mechanisms that produce ballistic movements by amplifying power [1-6]. Power amplification occurs when an organism produces a relatively high power output by releasing slowly stored energy almost instantaneously, resulting in movements that surpass the maximal power output of muscles [7]. For example, trap-jaw, power-amplified mechanisms have been described for several ant genera [5, 8], which have evolved some of the fastest known movements in the animal kingdom [6]. However, power-amplified predatory strikes were not previously known in one of the largest animal classes, the arachnids. Mecysmaucheniidae spiders, which occur only in New Zealand and southern South America, are tiny, cryptic, ground-dwelling spiders that rely on hunting rather than web-building to capture prey [9]. Analysis of high-speed video revealed that power-amplified mechanisms occur in some mecysmaucheniid species, with the fastest species being two orders of magnitude faster than the slowest species. Molecular phylogenetic analysis revealed that power-amplified cheliceral strikes have evolved four times independently within the family. Furthermore, we identified morphological innovations that directly relate to cheliceral function: a highly modified carapace in which the cheliceral muscles are oriented horizontally; modification of a cheliceral sclerite to have muscle attachments; and, in the power-amplified species, a thicker clypeus and clypeal apodemes. These structural innovations may have set the stage for the parallel evolution of ballistic predatory strikes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Portable Amplifier Design for a Novel EEG Monitor in Point-of-Care Applications.

Science.gov (United States)

Luan, Bo; Sun, Mingui; Jia, Wenyan

2012-01-01

The Electroencephalography (EEG) is a common diagnostic tool for neurological diseases and dysfunctions, such as epilepsy and insomnia. However, the current EEG technology cannot be utilized quickly and conveniently at the point of care due to the complex skin preparation procedures required and the inconvenient EEG data acquisition systems. This work presents a portable amplifier design that integrates a set of skin screw electrodes and a wireless data link. The battery-operated amplifier contains an instrumentation amplifier, two noninverting amplifiers, two high-pass filters, and a low-pass filter. It is able to magnify the EEG signals over 10,000 times and has a high impedance, low noise, small size and low weight. Our electrode and amplifier are ideal for point-of-care applications, especially during transportation of patients suffering from traumatic brain injury or stroke.

Cathode-follower power amplifier

International Nuclear Information System (INIS)

Giordano, S.; Puglisi, M.

1983-01-01

In circular accelerators and particularly in storage rings it is essential that the total impedance, as seen by the beam, be kept below some critical value. A model of the accelerating system was built using a single-ended cathode-follower amplifier driving a ferrite-loaded cavity. The system operated at 234.5 kHz with a peak output voltage of +-10 kV on the gap. The dynamic output impedance, as measured on the gap, was < 15 ohms

High-Performance Operational and Instrumentation Amplifiers

NARCIS (Netherlands)

Shahi, B.

2015-01-01

This thesis describes techniques to reduce the offset error in precision instrumentation and operational amplifiers. The offset error which is considered a major error source associated with gain blocks, together with other errors are reviewed. Conventional and newer approaches to remove offset and

A High-Voltage Class D Audio Amplifier for Dielectric Elastomer Transducers

DEFF Research Database (Denmark)

Nielsen, Dennis; Knott, Arnold; Andersen, Michael A. E.

2014-01-01

Dielectric Elastomer (DE) transducers have emerged as a very interesting alternative to the traditional electrodynamic transducer. Lightweight, small size and high maneuverability are some of the key features of the DE transducer. An amplifier for the DE transducer suitable for audio applications...... is proposed and analyzed. The amplifier addresses the issue of a high impedance load, ensuring a linear response over the midrange region of the audio bandwidth (100 Hz – 3.5 kHz). THD+N below 0.1% are reported for the ± 300 V prototype amplifier producing a maximum of 125 Var at a peak efficiency of 95 %....

An amplifier for VUV photomultiplier operating in cryogenic environment

International Nuclear Information System (INIS)

Arneodo, F.; Benabderrahmane, M.L.; Dahal, S.; Di Giovanni, A.; D'Inzeo, M.; Franchi, G.; Pazos Clemens, L.

2016-01-01

We present the characterisation of an amplifier potentially interesting for noble liquid detectors. The design has been conceived considering the requirements of low power consumption (less than 30 mW), low noise, amplification factor of 10 at 100 MHz and use of commercial components. The amplifier has been integrated onto an electronic board with a voltage divider to operate an Hamamatsu R11410 photomultiplier tube (used in XENON1T, Aprile et al. (2014) [1] dark matter experiment).

An amplifier for VUV photomultiplier operating in cryogenic environment

Energy Technology Data Exchange (ETDEWEB)

Arneodo, F.; Benabderrahmane, M.L.; Dahal, S. [New York University Abu Dhabi, Abu Dhabi (United Arab Emirates); Di Giovanni, A., E-mail: adriano.digiovanni@nyu.edu [New York University Abu Dhabi, Abu Dhabi (United Arab Emirates); D' Inzeo, M.; Franchi, G. [Age Scientific srl – Capezzano Pianore (Italy); Pazos Clemens, L. [New York University Abu Dhabi, Abu Dhabi (United Arab Emirates)

2016-07-11

We present the characterisation of an amplifier potentially interesting for noble liquid detectors. The design has been conceived considering the requirements of low power consumption (less than 30 mW), low noise, amplification factor of 10 at 100 MHz and use of commercial components. The amplifier has been integrated onto an electronic board with a voltage divider to operate an Hamamatsu R11410 photomultiplier tube (used in XENON1T, Aprile et al. (2014) [1] dark matter experiment).

Size-amplified acoustofluidic separation of circulating tumor cells with removable microbeads

Science.gov (United States)

Liu, Huiqin; Ao, Zheng; Cai, Bo; Shu, Xi; Chen, Keke; Rao, Lang; Luo, Changliang; Wang, Fu-Bin; Liu, Wei; Bondesson, Maria; Guo, Shishang; Guo, Feng

2018-06-01

Isolation and analysis of rare circulating tumor cells (CTCs) is of great interest in cancer diagnosis, prognosis, and treatment efficacy evaluation. Acoustofluidic cell separation becomes an attractive method due to its contactless, noninvasive, simple, and versatile features. However, the indistinctive physical difference between CTCs and normal blood cells limits the purity of CTCs using current acoustic methods. Herein, we demonstrate a size-amplified acoustic separation and release of CTCs with removable microbeads. CTCs selectively bound to size-amplifiers (40 μm-diameter anti-EpCAM/gelatin-coated SiO2 microbeads) have significant physical differences (size and mechanics) compared to normal blood cells, resulting in an amplification of acoustic radiation force approximately a hundredfold over that of bare CTCs or normal blood cells. Therefore, CTCs can be efficiently sorted out with size-amplifiers in a traveling surface acoustic wave microfluidic device and released from size-amplifiers by enzymatic degradation for further purification or downstream analysis. We demonstrate a cell separation from blood samples with a total efficiency (E total) of ∼ 77%, purity (P) of ∼ 96%, and viability (V) of ∼83% after releasing cells from size-amplifiers. Our method substantially improves the emerging application of rare cell purification for translational medicine.

FDML swept source at 1060 nm using a tapered amplifier

DEFF Research Database (Denmark)

Marschall, Sebastian; Klein, Thomas; Wieser, Wolfgang

2010-01-01

We present a novel frequency-swept light source working at 1060nm that utilizes a tapered amplifier as gain medium. These devices feature significantly higher saturation power than conventional semiconductor optical amplifiers and can thus improve the limited output power of swept sources in this...... an axial resolution of 15 µm in air (~11µm in tissue) for OCT applications can be achieved....

Slow Light at High Frequencies in an Amplifying Semiconductor Waveguide

DEFF Research Database (Denmark)

Öhman, Filip; Yvind, Kresten; Mørk, Jesper

2006-01-01

We demonstrate slow-down of a modulated light signal in a semiconductor waveguide. Concatenated amplifying and absorbing sections simultaneously achieve both amplification and a controllable time delay at 15 GHz.......We demonstrate slow-down of a modulated light signal in a semiconductor waveguide. Concatenated amplifying and absorbing sections simultaneously achieve both amplification and a controllable time delay at 15 GHz....

Active rc filter permits easy trade-off of amplifier gain and sensitivity to gain

Science.gov (United States)

Kerwin, W. J.; Shaffer, C. V.

1968-01-01

Passive RC network was designed with zeros of transmission in the right half of the complex frequency plane in the feedback loop of a simple negative-gain amplifier. The proper positioning provides any desired trade-off between amplifier gain and sensitivity to amplifier gain.

Low-noise wide-band amplifiers for stochastic beam cooling experiments

International Nuclear Information System (INIS)

Leskovar, B.; Lo, C.C.

1982-01-01

Noise characteristics of the continuous-wave wide-band amplifier systems for stochastic beam cooling experiments are presented. Also, the noise performance, bandwidth capability and gain stability of components used in these amplifiers are summarized and compared in the 100 MHz to 40 GHz frequency range. This includes bipolar and field-effect transistors, parametric amplifier, Schottky diode mixer and maser. Measurements of the noise characteristics and scattering parameters of variety GaAs FETs as a function of ambient temperature are also given. Performance data and design information are presented on a broadband 150-500 MHz preamplifier having noise temperature of approximately 35 0 K at ambient temperature of 20 0 K. An analysis of preamplifier stability based on scattering parameters concept is included

High sensitivity amplifier/discriminator for PWC's

International Nuclear Information System (INIS)

Hansen, S.

1983-01-01

The facility support group at Fermilab is designing and building a general purpose beam chamber for use in several locations at the laboratory. This pwc has 128 wires per plane spaced 1 mm apart. An initial production of 25 signal planes is anticipated. In proportional chambers, the size of the signal depends exponentially on the charge stored per unit of length along the anode wire. As the wire spacing decreases, the capacitance per unit length decreases, thereby requiring increased applied voltage to restore the necessary charge per unit length. In practical terms, this phenomenon is responsible for difficulties in constructing chambers with less than 2 mm wire spacing. 1 mm chambers, therefore, are frequently operated very near to their breakdown point and/or a high gain gas containing organic compounds such as magic gas is used. This argon/iso-butane mixture has three drawbacks: it is explosive when exposed to the air, it leaves a residue on the wires after extended use and is costly. An amplifier with higher sensitivity would reduce the problems associated with operating chambers with small wire spacings and allow them to be run a safe margin below their breakdown voltage even with an inorganic gas mixture such as argon/CO2, this eliminating the need to use magic gas. Described here is a low cost amplifier with a usable threshold of less than 0.5 μA. Data on the performance of this amplifier/discriminator in operation on a prototype beam chamber are given. This data shows the advantages of the high sensitivity of this design

First operation of a wiggler-focused, sheet beam free electron laser amplifier

International Nuclear Information System (INIS)

Destler, W.W.; Cheng, S.; Zhang, Z.X.; Antonsen, T.M. Jr.; Granatstein, V.L.; Levush, B.; Rodgers, J.

1994-01-01

A wiggler-focused, sheet beam free electron laser (FEL) amplifier utilizing a short-period wiggler magnet has been proposed as a millimeter-wave source for current profile modification and/or electron cyclotron resonance heating of tokamak plasmas. As proposed, such an amplifier would operate at a frequency of approximately 100--200 GHz with an output power of 1--10 MW CW. Electron beam energy would be in the range 500--1000 keV. To test important aspects of this concept, an initial sheet beam FEL amplifier experiment has been performed using a 1 mmx2 cm sheet beam produced by a pulse line accelerator with a pulse duration of 100 ns. The 500--570 keV, 4--18 A sheet beam is propagated through a 56 period uniform wiggler (λ w =9.6 mm) with a peak wiggler amplitude of 2--5 kG. Linear amplification of a 5--10 W, 94 GHz signal injected in the TE 01 rectangular mode is observed. All features of the amplified signal, including pulse shape and duration, are in accordance with the predictions of numerical simulation. Amplified signal gain has been measured as a function of injected beam energy, current, and wiggler field amplitude and is also in good agreement with simulation results. Continuation of this experiment will involve studying nonlinear amplifier operation and adding a section of tapered wiggler

Modeling of Yb3+-sensitized Er3+-doped silica waveguide amplifiers

DEFF Research Database (Denmark)

Lester, Christian; Bjarklev, Anders Overgaard; Rasmussen, Thomas

1995-01-01

A model for Yb3+-sensitized Er3+-doped silica waveguide amplifiers is described and numerically investigated in the small-signal regime. The amplified spontaneous emission in the ytterbium-band and the quenching process between excited erbium ions are included in the model. For pump wavelengths...

Colorimetric Detection of Specific DNA Segments Amplified by Polymerase Chain Reactions

Science.gov (United States)

Kemp, David J.; Smith, Donald B.; Foote, Simon J.; Samaras, N.; Peterson, M. Gregory

1989-04-01

The polymerase chain reaction (PCR) procedure has many potential applications in mass screening. We describe here a general assay for colorimetric detection of amplified DNA. The target DNA is first amplified by PCR, and then a second set of oligonucleotides, nested between the first two, is incorporated by three or more PCR cycles. These oligonucleotides bear ligands: for example, one can be biotinylated and the other can contain a site for a double-stranded DNA-binding protein. After linkage to an immobilized affinity reagent (such as a cloned DNA-binding protein, which we describe here) and labeling with a second affinity reagent (for example, avidin) linked to horseradish peroxidase, reaction with a chromogenic substrate allows detection of the amplified DNA. This amplified DNA assay (ADA) is rapid, is readily applicable to mass screening, and uses routine equipment. We show here that it can be used to detect human immunodeficiency virus sequences specifically against a background of human DNA.

A simplified digital lock-in amplifier for the scanning grating spectrometer.

Science.gov (United States)

Wang, Jingru; Wang, Zhihong; Ji, Xufei; Liu, Jie; Liu, Guangda

2017-02-01

For the common measurement and control system of a scanning grating spectrometer, the use of an analog lock-in amplifier requires complex circuitry and sophisticated debugging, whereas the use of a digital lock-in amplifier places a high demand on the calculation capability and storage space. In this paper, a simplified digital lock-in amplifier based on averaging the absolute values within a complete period is presented and applied to a scanning grating spectrometer. The simplified digital lock-in amplifier was implemented on a low-cost microcontroller without multipliers, and got rid of the reference signal and specific configuration of the sampling frequency. Two positive zero-crossing detections were used to lock the phase of the measured signal. However, measurement method errors were introduced by the following factors: frequency fluctuation, sampling interval, and integer restriction of the sampling number. The theoretical calculation and experimental results of the signal-to-noise ratio of the proposed measurement method were 2055 and 2403, respectively.

Randomized Controlled Trial: Multimodal Anxiety and Social Skill Intervention for Adolescents with Autism Spectrum Disorder

Science.gov (United States)

White, Susan W.; Ollendick, Thomas; Albano, Anne Marie; Oswald, Donald; Johnson, Cynthia; Southam-Gerow, Michael A.; Kim, Inyoung; Scahill, Lawrence

2013-01-01

Anxiety is common among adolescents with autism spectrum disorders (ASD) and may amplify the core social disability, thus necessitating combined treatment approaches. This pilot, randomized controlled trial evaluated the feasibility and preliminary outcomes of the Multimodal Anxiety and Social Skills Intervention (MASSI) program in a sample of 30…

The spectacular human nose: an amplifier of individual quality?

Directory of Open Access Journals (Sweden)

Åse Kristine Rognmo Mikalsen

2014-04-01

Full Text Available Amplifiers are signals that improve the perception of underlying differences in quality. They are cost free and advantageous to high quality individuals, but disadvantageous to low quality individuals, as poor quality is easier perceived because of the amplifier. For an amplifier to evolve, the average fitness benefit to the high quality individuals should be higher than the average cost for the low quality individuals. The human nose is, compared to the nose of most other primates, extraordinary large, fragile and easily broken—especially in male–male interactions. May it have evolved as an amplifier among high quality individuals, allowing easy assessment of individual quality and influencing the perception of attractiveness? We tested the latter by manipulating the position of the nose tip or, as a control, the mouth in facial pictures and had the pictures rated for attractiveness. Our results show that facial attractiveness failed to be influenced by mouth manipulations. Yet, facial attractiveness increased when the nose tip was artificially centered according to other facial features. Conversely, attractiveness decreased when the nose tip was displaced away from its central position. Our results suggest that our evaluation of attractiveness is clearly sensitive to the centering of the nose tip, possibly because it affects our perception of the face’s symmetry and/or averageness. However, whether such centering is related to individual quality remains unclear.

Investigation of switching frequency variations and EMI properties in self-oscillating class D amplifiers

DEFF Research Database (Denmark)

Nielsen, Dennis; Knott, Arnold; Pfaffinger, Gerhard

2009-01-01

Class D audio amplifiers have gained significant influence in sound reproduction due to their high efficiency. One of the most commonly used control methods in these amplifiers is self-oscillation. A parameter of key interest in self-oscillating amplifiers is the switching frequency, which is kno...

Reducing Switching Artifacts in Chopper Amplifiers

NARCIS (Netherlands)

Kusuda, Y.

2018-01-01

This thesis describes the theory, design, and implementation of chopper operational amplifiers (op-amps) in CMOS integrated circuits (ICs). The chopping technique periodically corrects DC errors of such op-amps, so that low 1/f noise and stable, microvolt-level offset can be achieved. However,

Direct-conversion switching-mode audio power amplifier with active capacitive voltage clamp

Energy Technology Data Exchange (ETDEWEB)

Ljusev, P.; Andersen, Michael A.E.

2005-07-01

This paper discusses the advantages and problems when implementing direct energy conversion switching-mode audio power amplifiers. It is shown that the total integration of the power supply and Class D audio power amplifier into one compact direct converter can simplify design, increase efficiency and integration level, reduce product volume and lower its cost. As an example, the principle of operation and the measurements made on a direct-conversion switching-mode audio power amplifier with active capacitive voltage clamp are presented. (au)

Direct-conversion switching-mode audio power amplifier with active capacitive voltage clamp

DEFF Research Database (Denmark)

Ljusev, Petar; Andersen, Michael Andreas E.

2005-01-01

This paper discusses the advantages and problems when implementing direct energy conversion switching-mode audio power amplifiers. It is shown that the total integration of the power supply and Class D audio power amplifier into one compact direct converter can simplify the design, increase...... efficiency, reduce the product volume and lower its cost. As an example, the principle of operation and the measurements made on a direct-conversion switching-mode audio power amplifier with active capacitive voltage clamp are presented....

Design, construction and test of RF solid state power amplifier for IRANCYC-10

Science.gov (United States)

Azizi, H.; Dehghan, M.; Abbasi Davani, F.; Ghasemi, F.

2018-03-01

In this paper, design, simulation and construction of a high power amplifier to provide the required power of a cyclotron accelerator (IRANCYC-10) is presented step-by-step. The Push-Pull designed amplifier can generate 750 W at the operating frequency of 71 MHz continous wave (CW). In this study, achieving the best efficiency of the amplifier, as well as reducing overall volume using baluns, were two important goals. The new offered water-cooled heat sink was used for cooling the amplifier which increases the operating life of the transistor. The gain and PAE of the SSPA were obtained 20 dB and 77.7%, respectively. The simulated and measured RF results are in good agreement with each other. The results show that, using an RF transformer in matching impedance of matching networks, it causes a smaller size and also a better amplifier performance.

Antimicrobial susceptibility, virulence genes, and randomly amplified polymorphic DNA analysis of Staphylococcus aureus recovered from bovine mastitis in Ningxia, China.

Science.gov (United States)

Wang, Dong; Zhang, Limei; Zhou, Xuezhang; He, Yulong; Yong, Changfu; Shen, Mingliang; Szenci, Otto; Han, Bo

2016-12-01

Staphylococcus aureusis the leading pathogen involved inbovine mastitis, but knowledgeabout antimicrobial resistance, virulence factors, and genotypes of Staphylococcus aureus resulting in bovine mastitis in Ningxia, China, is limited. Therefore, antimicrobial susceptibility, virulence gene, and randomly amplified polymorphic DNA (RAPD) analyses of Staph. aureus were carried out. A total of 327 milk samples from cows with clinical and subclinical mastitis in 4 regions of Ningxia were used for the isolation and identification of pathogens according to phenotypic and molecular characteristics. Antimicrobial susceptibility against 22 antimicrobial agents was determined by disk diffusion. The presence of 8 virulence genes in Staph. aureus isolates was tested by PCR. Genotypes of isolates were investigated based on RAPD. Results showed that 35 isolates obtained from mastitis milk samples were identified as Staph. aureus. The isolates were resistant to sulfamethoxazole (100%), penicillin G (94.3%), ampicillin (94.3%), erythromycin (68.6%), azithromycin (68.6%), clindamycin (25.7%), amoxicillin (11.4%), and tetracycline (5.7%). All of the isolates contained one or more virulence genes with average (standard deviation) of 6.6±1.6. The most prevalent virulence genes were hlb (97.1%), followed by fnbpA, hla, coa (94.3% each), nuc (85.7%), fnbpB (80%), clfA (77.1%), and tsst-1 (40%). Nine different gene patterns were found and 3 of them were the dominant gene combinations (77.1%). Staphylococcus aureus isolates (n=35) were divided into 6 genotypes by RAPD tying, the genotypes III and VI were the most prevalent genotypes. There was greatvariation in genotypes of Staph. aureus isolates, not only among different farms, but also within the same herd in Ningxia province. The study showed a high incidence of Staph. aureus with genomic variation of resistance genes, which is matter of great concern in public and animal health in Ningxia province of China. Copyright © 2016 American

Pulse propagation in a two-pass optical amplifier with arbitrary laser beams overlap

Directory of Open Access Journals (Sweden)

AH Farahbod

2011-09-01

Full Text Available An analytical model for two-pass optical amplifier with arbitrary beams overlap has been developed which generalized the classical theory of Frantz-Nodvik for single pass amplifier. The effect of counterpropagating beams on gain and output energy fluence included in the model. Moreover, the appropriate limiting relations for two special cases of weak input signal and saturation state of the amplifier gain have been derived. The results indicate that for complete beams overlap, the gain and output energy have the least values. The model predictions are consistent with experimental observations and exact analytical model for two-pass amplifier when beam propagation paths are coincided.

Loss of heterozygosity on the X chromosome in human breast cancer.

Science.gov (United States)

Loupart, M L; Adams, S; Armour, J A; Walker, R; Brammar, W; Varley, J

1995-08-01

The analysis of loss of heterozygosity (LOH) in tumours can be a powerful tool for mapping the sites of tumour suppressor genes in the human genome. A panel of breast cancer patients was assembled as pairs of tumour and lymphocyte DNA samples and LOH studies carried out by Southern hybridisation with polymorphic loci mapping to the X chromosome with appropriate controls. Deletion mapping revealed a high frequency of small regionalised deletions, defining at least three independent regions, one of which is particularly well mapped to a 500 kb stretch of DNA in the distal portion of the pseudoautosomal region of Xp. A second region has been identified within the pseudoautosomal region close to the pseudoautosomal boundary, and there is a third discrete site of loss on distal Xq. Perturbations of sequences at these regions represent independent events in a number of patients. This study represents the first detailed analysis of LOH on the X chromosome in human breast tumours, the results of which indicate that at least three regions of this chromosome are involved in the disease.

Constant Switching Frequency Self-Oscillating Controlled Class-D Amplifiers

OpenAIRE

Nguyen-Duy, Khiem; Knott, Arnold; Andersen, Michael A. E.

2014-01-01

The self-oscillating control approach has been used extensively in class-D amplifiers. It has several advantages such as high bandwidth and high audio performance. However, one of the primary disadvantages in a self-oscillating controlled system is that the switching frequency of the amplifier varies with the ratio of the output voltage to the input rail voltage. In other words, the switching frequency varies with the duty cycle of the output. The drop in the frequency results in lower contro...

100J-level nanosecond pulsed Yb:YAG cryo-cooled DPSSL amplifier

Science.gov (United States)

Smith, J. M.; Butcher, T. J.; Mason, P. D.; Ertel, K.; Phillips, P. J.; Banerjee, S.; De Vido, M.; Chekhlov, O.; Divoky, M.; Pilar, J.; Shaikh, W.; Hooker, C.; Lucianetti, A.; Hernandez Gomez, C.; Mocek, T.; Edwards, C.; Collier, J. L.

2018-02-01

We report on the successful demonstration of the world's first kW average power, 100 Joule-class, high-energy, nanosecond pulsed diode-pumped solid-state laser (DPSSL), DiPOLE100. Results from the first long-term test for amplification will be presented; the system was operated for 1 hour with 10 ns duration pulses at 10 Hz pulse repetition rate and an average output energy of 105 J and RMS energy stability of approximately 1%. The laser system is based on scalable cryogenic gas-cooled multi-slab ceramic Yb:YAG amplifier technology. The DiPOLE100 system comprises three major sub-systems, a spatially and temporally shaped front end, a 10 J cryo-amplifier and a 100 J cryo-amplifier. The 10 J cryo-amplifier contain four Yb:YAG ceramic gain media slabs, which are diode pumped from both sides, while a multi-pass architecture configured for seven passes enables 10 J of energy to be extracted at 10 Hz. This seeds the 100 J cryo-amplifier, which contains six Yb:YAG ceramic gain media slabs with the multi-pass configured for four passes. Our future development plans for this architecture will be introduced including closed-loop pulse shaping, increased energy, higher repetition rates and picosecond operation. This laser architecture unlocks the potential for practical applications including new sources for industrial materials processing and high intensity laser matter studies as envisioned for ELI [1], HiLASE [2], and the European XFEL [3]. Alternatively, it can be used as a pump source for higher repetition rate PW-class amplifiers, which can themselves generate high-brightness secondary radiation and ion sources leading to new remote imaging and medical applications.

Digital lock-in amplifier based on soundcard interface for physics laboratory

Science.gov (United States)

Sinlapanuntakul, J.; Kijamnajsuk, P.; Jetjamnong, C.; Chotikaprakhan, S.

2017-09-01

The purpose of this paper is to develop a digital lock-in amplifier based on soundcard interface for undergraduate physics laboratory. Both series and parallel RLC circuit laboratory are tested because of its well-known, easy to understand and simple confirm. The sinusoidal signal at the frequency of 10 Hz - 15 kHz is generated to the circuits. The amplitude and phase of the voltage drop across the resistor, R are measured in 10 step decade. The signals from soundcard interface and lock-in amplifier are compared. The results give a good correlation. It indicates that the design digital lock-in amplifier is promising for undergraduate physic laboratory.

Solid state high power amplifier for driving the SLC injector klystron

International Nuclear Information System (INIS)

Judkins, J.G.; Clendenin, J.E.; Schwarz, H.D.

1985-03-01

The SLC injector klystron rf drive is now provided by a recently developed solid-state amplifier. The high gain of the amplifier permits the use of a fast low-power electronic phase shifter. Thus the SLC computer control system can be used to shift the phase of the high-power rf rapidly during the fill time of the injector accelerator section. These rapid phase shifts are used to introduce a phase-energy relationship in the accelerated electron pulse in conjunction with the operation of the injector bunch compressor. The amplifier, the method of controlling the rf phase, and the operational characteristics of the system are described. 5 refs., 4 figs

Entanglement-based linear-optical qubit amplifier

Czech Academy of Sciences Publication Activity Database

Meyer-Scott, E.; Bula, M.; Bartkiewicz, K.; Černoch, Antonín; Soubusta, Jan; Jennewein, T.; Lemr, Karel

2013-01-01

Roč. 87, č. 1 (2013), "012327-1"-"012327-7" ISSN 1050-2947 R&D Projects: GA ČR GAP205/12/0382 Institutional support: RVO:68378271 Keywords : quantum physics * photonics qubits * qubit amplifier Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.991, year: 2013

Amplifiers with ground-isolated inputs and outputs

International Nuclear Information System (INIS)

Da Costa Vieira, David; Merite, Bernard; Tattegrain, Alain

1969-06-01

The amplifiers described in this note aim at ensuring a connection between different apparatuses with grounds being at a different potential. They will be inserted in the measurement channels of the Cabri reactor

High Efficiency S-Band 20 Watt Amplifier

Data.gov (United States)

National Aeronautics and Space Administration — This project includes the design and build of a prototype 20 W, high efficiency, S-Band amplifier.   The design will incorporate the latest semiconductor technology,...

Trial manufacture of an insulated amplifier

International Nuclear Information System (INIS)

Okuno, Shigeo; Matsuura, Kiyokata.

1978-10-01

Trial manufacture of an insulated amplifier was carried out. The input signals are divided by filters Th and Tl into high frequency component and low frequency component. The high frequency component drives a transformer T 1 , and secondary signals are induced. The low frequency component drives a transformer T 2 through a buffer and a modulator. The secondary signals from both transformers are recombined to make the output signals. Compensation for the frequency characteristics of the high frequency transformer and that for the effect of a filter in the demodulation circuit for low frequency component are considered. The time constant of output signals for rectangular input signals was 30 microsec, when only the low frequency part is operated. The drift of the direct current level is within 5 mV. The characteristic features of the high frequency part was also investigated. The overall characteristic features of this amplifier were good for the frequency range of 0 to 500 kHz. (Kato, T.)

Stability investigation for InP DHBT mm‐wave power amplifier

DEFF Research Database (Denmark)

Yan, Lei; Johansen, Tom Keinicke; Kammersgaard, Jacob

2013-01-01

microwave integrated circuit power amplifier. Experimental results from a redesigned power amplifier with improved stability are presented to confirm that the previously detected oscillation loop is removed using odd‐mode stabilization resistors with the correct choice of values and locations. © 2012 Wiley......In this article, we discuss stability issues for mm‐wave monolithic integrated power amplifiers using InP double heterojunction bipolar transistor (DHBT) technology targeting E‐band applications at 71–76 GHz and 81–86 GHz. Different stability detection methods based on the classical two‐port K......‐Δs pair, linear three‐port graphical analysis, system identifications, circuit modal analysis, and normalized determinant function are all reviewed. The corresponding techniques are employed to predict the occurrence of instability at 15 GHz observed during measurements on a fabricated monolithic...

CMOS 60-GHz and E-band power amplifiers and transmitters

CERN Document Server

Zhao, Dixian

2015-01-01

This book focuses on the development of design techniques and methodologies for 60-GHz and E-band power amplifiers and transmitters at device, circuit and layout levels. The authors show the recent development of millimeter-wave design techniques, especially of power amplifiers and transmitters, and presents novel design concepts, such as “power transistor layout” and “4-way parallel-series power combiner”, that can enhance the output power and efficiency of power amplifiers in a compact silicon area. Five state-of-the-art 60-GHz and E-band designs with measured results are demonstrated to prove the effectiveness of the design concepts and hands-on methodologies presented. This book serves as a valuable reference for circuit designers to develop millimeter-wave building blocks for future 5G applications.

Amplifier channel for a fission fragment semiconductor detector

International Nuclear Information System (INIS)

Tyurin, G.P.

1981-01-01

To compensate the decrease of the transformation coefficient of fission fragment semiconductor detector (SCD) developed is a special amplification channel with controlled transfer coefficient. The block diagram of the channel is presented, the main functional units of which are as follows: preamplifying head with charge-sensitive and timing preamplifiers, linear amplifier and the circuit of spectrum position stabilization, which includes a differential discriminator, integrator and reference signal generator. The amplification channel is made in the CAMAC standard and has the following specifications: dinamical input capacitance of charge-sensitive amplifier c=10000 n PHI, signal amplitude at output of the linear amplifier at energy of fission fragments of 120 MeV has negative polarity and is equal to 5 V. Pulse amplitude change at SCD sensitivity decrease to 50% constitutes not more than 1%. Timing preamplifier has the gain factor at voltage of K=80 at front duration of 3.5 nc. Time resolution of the amplification channel is not worse than 1 nc. Dimensions of preamplifying head are 40x40x15 mm. The amplification channel permitted to use SCD for long-term measurements of fission fragment spectra [ru

A Kinetics Model for KrF Laser Amplifiers

Science.gov (United States)

Giuliani, J. L.; Kepple, P.; Lehmberg, R.; Obenschain, S. P.; Petrov, G.

1999-11-01

A computer kinetics code has been developed to model the temporal and spatial behavior of an e-beam pumped KrF laser amplifier. The deposition of the primary beam electrons is assumed to be spatially uniform and the energy distribution function of the nascent electron population is calculated to be near Maxwellian below 10 eV. For an initial Kr/Ar/F2 composition, the code calculates the densities of 24 species subject to over 100 reactions with 1-D spatial resolution (typically 16 zones) along the longitudinal lasing axis. Enthalpy accounting for each process is performed to partition the energy into internal, thermal, and radiative components. The electron as well as the heavy particle temperatures are followed for energy conservation and excitation rates. Transport of the lasing photons is performed along the axis on a dense subgrid using the method of characteristics. Amplified spontaneous emission is calculated using a discrete ordinates approach and includes contributions to the local intensity from the whole amplifier volume. Specular reflection off side walls and the rear mirror are included. Results of the model will be compared with data from the NRL NIKE laser and other published results.

A megajoule class krypton fluoride amplifier for single shot, high gain ICF application

International Nuclear Information System (INIS)

Rose, E.; Hanson, D.; Krohn, B.; McLeod, J.; Kang, M.

1988-01-01

A design study is underway to define the optimal architecture for a KrF laser system which will deliver 10 MJ of 248-nm light to an ICF target. We present one approach which incorporates final power amplifiers in the megajoule class, achieving 10 MJ with four final amplifiers. Each double-pass laser amplifier employs two-sided electron-beam pumping of the laser gas medium. Details of the design are based on a Monte-Carlo electron-beam deposition code, a one-dimensional, time-dependent kinetics code, and pulsed power circuit modeling. Linear dimensions of the amplifier's extracted gain volume are 6.25 m in height and length and 5.12 m in width. Each amplifier handles 160 angularly multiplexed laser channels. The one-amagat, krypton-rich laser medium is e-beam pumped at 60-kW cm/sup /minus/3/ (4-MA at3.3-MV) over the 2-microsecond duration of the laser beam pulse train. 5 refs., 4 figs

High brightness photonic lantern kW-class amplifier

Science.gov (United States)

Montoya, Juan; Hwang, Chris; Aleshire, Chris; Reed, Patricia; Martz, Dale; Riley, Mike; Trainor, Michael; Belley, Catherine; Shaw, Scot; Fan, T. Y.; Ripin, Dan

2018-02-01

Pump-limited kW-class operation in a multimode fiber amplifier using adaptive mode control was achieved. A photonic lantern front end was used to inject an arbitrary superposition of modes on the input to a kW-class fiber amplifier to achieve a nearly diffraction-limited output. We report on the adaptive spatial mode control architecture which allows for compensating transverse-mode disturbances at high power. We also describe the advantages of adaptive spatial mode control for optical phased array systems. In particular, we show that the additional degrees of freedom allow for broader steering and improved atmospheric turbulence compensation relative to piston-only optical phased arrays.

Low Genetic Diversity Among Garlic (Allium sativum L. Accessions Detected Using Random Amplified Polymorphic DNA (RAPD Escasa Diversidad Genética entre Accesiones de Ajo (Allium sativum L. Detectada Mediante ADN Polimórfico Amplificado al Azar (RAPD

Directory of Open Access Journals (Sweden)

Mario Paredes C

2008-03-01

Full Text Available Garlic (Allium sativum L. is a species of vegetative propagation, showing high morphological diversity. Besides, its clones have specific adaptations to different agroclimatic regions. The objective of this study was to determine the genetic diversity of 65 garlic clones collected in Chile and introduced from different countries, by using RAPD (Random Amplified Polymorphic DNA. Fourty random primers of 10 mers generated a total of 398 bands with an 87% of polymorphism. Each primer amplified between two and 20 bands. The size of the fragments obtained fluctuated between 3200 and 369 bp. The results showed that the clones analyzed had a genetic similarity rate of 94%. In addition, 70% of them were clustered in one major group. However, in spite of that situation several clones have different agronomic characteristicsEl ajo (Allium sativum L. es una especie de propagación vegetativa, que presenta una amplia variabilidad morfológica. Los clones de esta especie tienen una adaptación específica a diferentes regiones agroclimáticas. El objetivo de este estudio fue determinar la diversidad genética existente en 65 clones de ajos colectados en Chile e introducidos desde diferentes países, utilizando RAPD (ADN Polimórfico Amplificado al Azar. Para esta evaluación se utilizaron 40 partidores de 10-mers. Los partidores generaron entre dos y 20 bandas, observándose un alto número de patrones con bandas múltiples. Los fragmentos generados difieren en su tamaño entre 3.200 y 369 pb. Los partidores generaron 398 bandas, de las cuales un 87% fueron polimórficas. El análisis estadístico realizado detectó una similitud genética alta, de un 94% entre las accesiones evaluadas, donde aproximadamente un 70% de los clones formaron un grupo homogéneo. Sin embargo, este grupo incluye clones que presentan diferentes características agronómicas

X-ray image amplifying tube

International Nuclear Information System (INIS)

1977-01-01

The photo electrons from the picture on the fluorescent input screen are amplified by an electron optical system and produce an intensified image on the output screen. This can be photographed and shown on a TV screen. The effects of stray magnetic fields are reduced by covering the input screen with a grating made of strips of ferromagnetic material such as μ metal. (T.S.E.T.)

Amplified music exposure carries risks to hearing.

Science.gov (United States)

da Silva, Valéria Gomes; de Oliveira, Carlos Augusto Costa Pires; Tauil, Pedro Luíz; de Castro Silva, Isabella Monteiro; Sampaio, André Luiz Lopes

2017-02-01

To investigate the association between changes in the outer hair cells and exposure to amplified music in a group of high-school students. In this retrospective, case-control study, 86 subjects underwent audiometry, immittance audiometry, and distortion-product otoacoustic emission tests. The subjects were questioned about their listening habits and divided into 2 groups: exposed and unexposed. Most of the subjects had reduced function in their outer hair cells, mainly beginning at 8 kHz. Among 60 subjects-30 cases and 30 controls-75% were considered exposed and 25% unexposed. The exposed subjects were 9.33 times more likely to have altered outer hair cells than the unexposed subjects were. Exposure to amplified music is associated with reduced function in the hair cells. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

State-dependent linear-optical qubit amplifier

Czech Academy of Sciences Publication Activity Database

Bartkiewicz, K.; Černoch, Antonín; Lemr, K.

2013-01-01

Roč. 88, č. 6 (2013), "062304-1"-"062304-7" ISSN 1050-2947 R&D Projects: GA ČR GAP205/12/0382 Institutional support: RVO:68378271 Keywords : linear-optical qubit amplifier * quantum cloning * quantum cryptography Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.991, year: 2013

Very fast, high peak-power, planar triode amplifiers for driving optical gates

International Nuclear Information System (INIS)

Howland, M.M.; Davis, S.J.; Gagnon, W.L.

1979-01-01

Recent extensions of the peak power capabilities of planar triodes have made possible the latter's use as very fast pulse amplifiers, to drive optical gates within high-power Nd:glass laser chains. These pulse amplifiers switch voltages in the 20 kV range with rise times of a few nanoseconds, into crystal optical gates that are essentially capacitive loads. This paper describes a simplified procedure for designing these pulse amplifiers. It further outlines the use of bridged-T constant resistance networks to transform load capacitance into pure resistance, independent of frequency

Development and detection efficiency of sequence characterized amplified region markers for authentication of medicinal plant Ruta graveolens and its adulterant Euphorbia dracunculoides

Directory of Open Access Journals (Sweden)

Irum Gul

2016-01-01

Full Text Available Background: With the increase in demand of herbal medicines, adulteration in these drugs is also gaining momentum and remains an indispensable problem in domestic and export markets. Correct identification is the first step toward assuring quality, safety, and efficacy of indigenous herbal medicines. Materials and Methods: In this study, sequence characterized amplified region (SCAR markers were developed to discriminate Ruta graveolens from its adulterant Euphorbia dracunculoides. Random amplified polymorphic DNA (RAPD was performed and subsequently converted into SCAR markers. Results: After performing RAPD, SCAR primers were designed from the selected unique RAPD amplicons of the genuine drug as well as its adulterant. These primers produced 670 bp and 750 bp SCAR markers with genomic DNA sample of R. graveolens and E. dracunculoides, respectively. Conclusion: Development of these markers will help in the quality control of herbal drugs and monitoring widespread adulteration of these drugs by pharmaceutical industries and government agencies.

Gallium nitride based transistors for high-efficiency microwave switch-mode amplifiers

Energy Technology Data Exchange (ETDEWEB)

Maroldt, Stephan

2012-07-01

Highly-efficient switch-mode power amplifiers form key elements in future fully-digital base stations for mobile communication. This novel digital base station concept reduces system energy consumption, complexity, size and costs, while the flexibility in terms of multi-band operation and signal modulation improves. In this work, innovative core circuits for digital high-efficiency class-D and class-S power amplifiers based on gallium nitride (GaN) technology were developed for the application in digital base stations. A combination of optimized GaN devices and improvements in circuit design allow a highly-efficient switch-mode operation at mobile communication frequencies between 0.45 GHz and 2 GHz. Transistor device modeling for switch-mode operation, the simulation environment, and a broadband measurement system were established for the design and evaluation of digital switchmode power amplifiers. The design of broadband core circuits for switch-mode amplifier concepts was analyzed for dual-stage amplifier circuits, using an initial GaN technology with a gate length of 0.25 {mu}m. A speed-enhanced driver stage improved the circuit switching speed sufficiently above 1 GHz. Speed and efficiency of the amplifier core circuits were studied related to transistor parameters like cut-off frequency or gate capacitance. A reduced gate length was found to improve the switching speed, while a lower on-resistance allows the reduction of the inherent static losses of the GaN-based switches. Apart from this, the restriction of a 50 Ohm environment was found to be a major output power and switching speed limitation, due to a poor switching drive capability of the input capacitance of the GaN circuit. Finally, the optimized transistor and circuit design with an output gate width of 1.2 mm were effectively implemented in the given environment for an operation up to 2 GHz with a high drain efficiency of >65% and a digital output power of 5 W. A maximum output power of 9.7 W and a

Suppression of Gain Ripples in Superconducting Traveling-Wave Kinetic Inductance Amplifiers

Science.gov (United States)

Bal, Mustafa; Erickson, Robert P.; Ku, Hsiang Sheng; Wu, Xian; Pappas, David P.

Superconducting traveling-wave kinetic inductance (KIT) amplifiers demonstrated gain over a wide bandwidth with high dynamic range and low noise. However, the gain curve exhibits ripples. Impedance mismatch at the input and output ports of the KIT amplifier as wells as split ground planes of the coplanar waveguide (CPW) geometry are potential contributors to the ripple in the gain curve. Here we study the origin of these ripples in KIT amplifiers configured in CPW geometry using approximately 20 nm thick NbTiN films grown by reactive co-sputtering of NbN and TiN. Our NbTiN films have non-linear kinetic inductance as a function of current, described by L =L0 (1 +(I /I*) 2) , where I* = 15 . 96 +/- 0 . 11 mA measured by time domain reflectometry. We report the results of implementing an impedance taper that takes into account a significantly reduced phase velocity as it narrows, adding Au onto the CPW split grounds, as well as employing different designs of dispersion engineering. Qubit Measurements using KIT amplifiers will also be reported.

Design techniques and measured performance for a uniformly-pumped 4-cm diameter rod amplifier

International Nuclear Information System (INIS)

Linford, G.J.; Yarema, S.M.

1976-01-01

A solid-state laser rod amplifier of moderate aperture achieving a high degree of spatial gain uniformity has been constructed and its performance evaluated. Digital and analogue techniques were used to optimize the amplifier design for performance in a laser fusion application. Results of simple 2-D computer simulations and experimental evaluations of amplifier performance are presented

Auto-locking waveguide amplifier system for lidar and magnetometric applications

Science.gov (United States)

Pouliot, A.; Beica, H. C.; Carew, A.; Vorozcovs, A.; Carlse, G.; Kumarakrishnan, A.

2018-02-01

We describe a compact waveguide amplifier system that is suitable for optically pumping rubidium magnetometers. The system consists of an auto-locking vacuum-sealed external cavity diode laser, a semiconductor tapered amplifier and a pulsing unit based on an acousto-optic modulator. The diode laser utilises optical feedback from an interference filter to narrow the linewidth of an inexpensive laser diode to 500 kHz. This output is scannable over an 8 GHz range (at 780 nm) and can be locked without human intervention to any spectral marker in an expandable library of reference spectra, using the autolocking controller. The tapered amplifier amplifies the output from 50 mW up to 2 W with negligible distortions in the spectral quality. The system can operate at visible and near infrared wavelengths with MHz repetition rates. We demonstrate optical pumping of rubidium vapour with this system for magnetometric applications. The magnetometer detects the differential absorption of two orthogonally polarized components of a linearly polarized probe laser following optical pumping by a circularly polarized pump laser. The differential absorption signal is studied for a range of pulse lengths, pulse amplitudes and DC magnetic fields. Our results suggest that this laser system is suitable for optically pumping spin-exchange free magnetometers.

A Method To ModifyCorrect The Performance Of Amplifiers

Directory of Open Access Journals (Sweden)

Rohith Krishnan R

2015-01-01

Full Text Available Abstract The actual response of the amplifier may vary with the replacement of some aged or damaged components and this method is to compensate that problem. Here we use op-amp Fixator as the design tool. The tool helps us to isolate the selected circuit component from rest of the circuit adjust its operating point to correct the performance deviations and to modify the circuit without changing other parts of the circuit. A method to modifycorrect the performance of amplifiers by properly redesign the circuit is presented in this paper.

Thermal-recovery of modal instability in rod fiber amplifiers

DEFF Research Database (Denmark)

Jørgensen, Mette Marie; Laurila, Marko; Noordegraaf, Danny

2013-01-01

We investigate the temporal dynamics of Modal instabilities (MI) in ROD fiber amplifiers using a 100 μm core rod fiber in a single-pass amplifier configuration, and we achieve ~200W of extracted output power before the onset of MI. Above the MI threshold, we investigate the temporal dynamics of b...... and thermally annealed between each test series. We find that the MI threshold degrades as it is reached multiple times, but is recovered by thermal annealing. We also find that the test history of the rods affects the temporal dynamics....

SINGLE CONVERSION ISOLATED IMPEDANCE TRANSFORMATION AMPLIFIER

DEFF Research Database (Denmark)

2003-01-01

The invention relates to a switch mode power amplifier. A first and a second change-over switch are inserted between a DC voltage supply and a primary side of an isolation transformer. Two secondary windings are connected to a power output terminal. A first and a second secondary side power switc...

Integrating amplifiers for PHENIX lead-glass and lead-scintillator calorimeters

International Nuclear Information System (INIS)

Wintenberg, A.L.; Simpson, M.L.; Britton, C.L. Jr.; Palmer, R.L.; Jackson, R.G.

1995-01-01

Two types of integrating amplifier systems have been developed for use with lead-glass and lead-scintillator calorimeters with photomultiplier tube readout. Requirements for the amplifier system include termination of the line from the photomultiplier, compact size and low power dissipation to allow multiple channels per chip, dual range outputs producing 10-bit accuracy over a 14-bit dynamic range, rms noise levels of one LSB or less, and compatibility with timing filter amplifiers, tower sum circuits for triggering and calibration circuits to be built on the same integrated circuit (IC). Advantages and disadvantages of an active integrator system are compared and contrasted to those of a passive integrator-based system. In addition, details of the designs and results from prototype devices including an 8-channel active integrator IC fabricated in 1.2 microm Orbit CMOS are presented

The design of programme-controlled gain and linear pulse amplifier

International Nuclear Information System (INIS)

Guan Xuemei; Chen Chunkai; Northeast Normal Univ., Changchun; Qiao Shuang; Zhou Chuansheng

2006-01-01

The authors have designed a kind of new-style programme-controlled gain and linear pulse amplifier with accurate gausses of CR-RC-CR shaping circuit structure. The use of non-volatile digital electric potential device and accurate operational amplifier makes the circuit structure simple greatly, makes the ability stronger that resists assault. It can realize multistage gain in succession and make the drift of temperature low and make the linearity of pulse well. (authors)

A 500-600 MHz GaN power amplifier with RC-LC stability network

Science.gov (United States)

Ma, Xinyu; Duan, Baoxing; Yang, Yintang

2017-08-01

A 500-600 MHz high-efficiency, high-power GaN power amplifier is designed and realized on the basis of the push-pull structure. The RC-LC stability network is proposed and applied to the power amplifier circuit for the first time. The RC-LC stability network can significantly reduce the high gain out the band, which eliminates the instability of the power amplifier circuit. The developed power amplifier exhibits 58.5 dBm (700 W) output power with a 17 dB gain and 85% PAE at 500-600 MHz, 300 μs, 20% duty cycle. It has the highest PAE in P-band among the products at home and abroad. Project supported by the National Key Basic Research Program of China (No. 2014CB339901).

Ultra-stable, diode-pumped Nd-doped glass regenerative amplifier for the National Ignition Facility (NIF)

International Nuclear Information System (INIS)

Crane, J.K.; Martinez, M.; Beach, R.J.; Mitchell, S.; Pratt, G.; Christensen, J.J.

1995-12-01

We describe a diode laser-pumped Nd:glass regenerative amplifier that amplifies temporally shaped pulses with low distortion, high pulse-to- pulse stability, and high gain. This laser amplifier is a prototype subsystem for the National Ignition Facility (NIF) laser system. 2 refs., 1 fig

Three-Stage InP Submillimeter-Wave MMIC Amplifier

Science.gov (United States)

Pukala, David; Samoska, Lorene; Man, King; Gaier, Todd; Deal, William; Lai, Richard; Mei, Gerry; Makishi, Stella

2008-01-01

A submillimeter-wave monolithic integrated- circuit (S-MMIC) amplifier has been designed and fabricated using an indium phosphide (InP) 35-nm gate-length high electron mobility transistor (HEMT) device, developed at Northrop Grumman Corporation. The HEMT device employs two fingers each 15 micrometers wide. The HEMT wafers are grown by molecular beam epitaxy (MBE) and make use of a pseudomorphic In0.75Ga0.25As channel, a silicon delta-doping layer as the electron supply, an In0.52Al0.48As buffer layer, and an InP substrate. The three-stage design uses coplanar waveguide topology with a very narrow ground-to-ground spacing of 14 micrometers. Quarter-wave matching transmission lines, on-chip metal-insulator-metal shunt capacitors, series thin-film resistors, and matching stubs were used in the design. Series resistors in the shunt branch arm provide the basic circuit stabilization. The S-MMIC amplifier was measured for S-parameters and found to be centered at 320 GHz with 13-15-dB gain from 300-345 GHz. This chip was developed as part of the DARPA Submillimeter Wave Imaging Focal Plane Technology (SWIFT) program (see figure). Submillimeter-wave amplifiers could enable more sensitive receivers for earth science, planetary remote sensing, and astrophysics telescopes, particularly in radio astronomy, both from the ground and in space. A small atmospheric window at 340 GHz exists and could enable ground-based observations. However, the submillimeter-wave regime (above 300 GHz) is best used for space telescopes as Earth s atmosphere attenuates most of the signal through water and oxygen absorption. Future radio telescopes could make use of S-MMIC amplifiers for wideband, low noise, instantaneous frequency coverage, particularly in the case of heterodyne array receivers.

Bottom-up driven involuntary auditory evoked field change: constant sound sequencing amplifies but does not sharpen neural activity.

Science.gov (United States)

Okamoto, Hidehiko; Stracke, Henning; Lagemann, Lothar; Pantev, Christo

2010-01-01

The capability of involuntarily tracking certain sound signals during the simultaneous presence of noise is essential in human daily life. Previous studies have demonstrated that top-down auditory focused attention can enhance excitatory and inhibitory neural activity, resulting in sharpening of frequency tuning of auditory neurons. In the present study, we investigated bottom-up driven involuntary neural processing of sound signals in noisy environments by means of magnetoencephalography. We contrasted two sound signal sequencing conditions: "constant sequencing" versus "random sequencing." Based on a pool of 16 different frequencies, either identical (constant sequencing) or pseudorandomly chosen (random sequencing) test frequencies were presented blockwise together with band-eliminated noises to nonattending subjects. The results demonstrated that the auditory evoked fields elicited in the constant sequencing condition were significantly enhanced compared with the random sequencing condition. However, the enhancement was not significantly different between different band-eliminated noise conditions. Thus the present study confirms that by constant sound signal sequencing under nonattentive listening the neural activity in human auditory cortex can be enhanced, but not sharpened. Our results indicate that bottom-up driven involuntary neural processing may mainly amplify excitatory neural networks, but may not effectively enhance inhibitory neural circuits.

Electrically Pumped Vertical-Cavity Amplifiers

DEFF Research Database (Denmark)

Greibe, Tine

2007-01-01

In this work, the design of electrically pumped vertical cavity semiconductor optical amplifiers (eVCAs) for use in a mode-locked external-cavity laser has been developed, investigated and analysed. Four different eVCAs, one top-emitting and three bottom emitting structures, have been designed...... and discussed. The thesis concludes with recommendations for further work towards the realisation of compact electrically pumped mode-locked vertical externalcavity surface emitting lasers....

A third-order class-D amplifier with and without ripple compensation

Science.gov (United States)

Cox, Stephen M.; du Toit Mouton, H.

2018-06-01

We analyse the nonlinear behaviour of a third-order class-D amplifier, and demonstrate the remarkable effectiveness of the recently introduced ripple compensation (RC) technique in reducing the audio distortion of the device. The amplifier converts an input audio signal to a high-frequency train of rectangular pulses, whose widths are modulated according to the input signal (pulse-width modulation) and employs negative feedback. After determining the steady-state operating point for constant input and calculating its stability, we derive a small-signal model (SSM), which yields in closed form the transfer function relating (infinitesimal) input and output disturbances. This SSM shows how the RC technique is able to linearise the small-signal response of the device. We extend this SSM through a fully nonlinear perturbation calculation of the dynamics of the amplifier, based on the disparity in time scales between the pulse train and the audio signal. We obtain the nonlinear response of the amplifier to a general audio signal, avoiding the linearisation inherent in the SSM; we thereby more precisely quantify the reduction in distortion achieved through RC. Finally, simulations corroborate our theoretical predictions and illustrate the dramatic deterioration in performance that occurs when the amplifier is operated in an unstable regime. The perturbation calculation is rather general, and may be adapted to quantify the way in which other nonlinear negative-feedback pulse-modulated devices track a time-varying input signal that slowly modulates the system parameters.

High Power Narrow Linewidth 1.26 Micron Ho-Doped Fiber Amplifier, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — This proposal is for the development of an innovative, high power, and extremely reliable 1.26-micron Ho-doped fluoride fiber amplifier. The proposed fiber amplifier...

High Power Narrow Linewidth 1.26 Micron Ho-Doped Fiber Amplifier, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — This proposal is for the development of an innovative, high power, and extremely reliable 1.26-micron Ho-doped fluoride fiber amplifier. The proposed fiber amplifier...

Cryogenic cooling for high power laser amplifiers

Directory of Open Access Journals (Sweden)

Perin J.P.

2013-11-01

Full Text Available Using DPSSL (Diode Pumped Solid State Lasers as pumping technology, PW-class lasers with enhanced repetition rates are developed. Each of the Yb YAG amplifiers will be diode-pumped at a wavelength of 940 nm. This is a prerequisite for achieving high repetition rates (light amplification duration 1 millisecond and repetition rate 10 Hz. The efficiency of DPSSL is inversely proportional to the temperature, for this reason the slab amplifier have to be cooled at a temperature in the range of 100 K–170 K with a heat flux of 1 MW*m−2. This paper describes the thermo-mechanical analysis for the design of the amplification laser head, presents a preliminary proposal for the required cryogenic cooling system and finally outlines the gain of cryogenic operation for the efficiency of high pulsed laser.

A CMOS-MEMS clamped–clamped beam displacement amplifier for resonant switch applications

Science.gov (United States)

Liu, Jia-Ren; Lu, Shih-Chuan; Tsai, Chun-Pu; Li, Wei-Chang

2018-06-01

This paper presents a micromechanical clamped–clamped beam (CC-beam) displacement amplifier based on a CMOS-MEMS fabrication process platform. In particular, a 2.0 MHz resonant displacement amplifier composed of two identical CC-beams coupled by a mechanical beam at locations where the two beams have mismatched velocities exhibits a larger displacement, up to 9.96×, on one beam than that of the other. The displacement amplification prevents unwanted input impacting—the structure switches only to the output but not the input—required by resonant switch-based mechanical circuits (Kim et al 2009 22nd IEEE Int. Conf. on Micro Electro Mechanical Systems; Lin et al 2009 15th Int. Conf. on Solid-State Sensors, Actuators, & Microsystems (TRANSDUCERS’09) Li et al 2013 17th Int. Conf. on Solid-State Sensors, Actuators, & Microsystems (TRANSDUCERS’13)). Compared to a single CC-beam displacement amplifier, theory predicts that the displacement amplifying CC-beam array yields a larger overall output displacement for displacement gain beyond 1.13 thanks to the preserved input driving force. A complete analytical model predicts the resultant stiffness and displacement gain of the coupled CC-beam displacement amplifier that match well with finite element analysis (FEA) prediction and measured results.

Novel Approach to Design Ultra Wideband Microwave Amplifiers: Normalized Gain Function Method

Directory of Open Access Journals (Sweden)

R. Kopru

2013-09-01

Full Text Available In this work, we propose a novel approach called as “Normalized Gain Function (NGF method” to design low/medium power single stage ultra wide band microwave amplifiers based on linear S parameters of the active device. Normalized Gain Function TNGF is defined as the ratio of T and |S21|^2, desired shape or frequency response of the gain function of the amplifier to be designed and the shape of the transistor forward gain function, respectively. Synthesis of input/output matching networks (IMN/OMN of the amplifier requires mathematically generated target gain functions to be tracked in two different nonlinear optimization processes. In this manner, NGF not only facilitates a mathematical base to share the amplifier gain function into such two distinct target gain functions, but also allows their precise computation in terms of TNGF=T/|S21|^2 at the very beginning of the design. The particular amplifier presented as the design example operates over 800-5200 MHz to target GSM, UMTS, Wi-Fi and WiMAX applications. An SRFT (Simplified Real Frequency Technique based design example supported by simulations in MWO (MicroWave Office from AWR Corporation is given using a 1400mW pHEMT transistor, TGF2021-01 from TriQuint Semiconductor.

High-resolution melt-curve analysis of random amplified polymorphic DNA (RAPD-HRM) for the characterisation of pathogenic leptospires: intra-serovar divergence, inter-serovar convergence, and evidence of attenuation in Leptospira reference collections.

Science.gov (United States)

Tulsiani, S M; Craig, S B; Graham, G C; Cobbold, R C; Dohnt, M F; Burns, M-A; Jansen, C C; Leung, L K-P; Field, H E; Smythe, L D

2010-07-01

High-resolution melt-curve analysis of random amplified polymorphic DNA (RAPD-HRM) is a novel technology that has emerged as a possible method to characterise leptospires to serovar level. RAPD-HRM has recently been used to measure intra-serovar convergence between strains of the same serovar as well as inter-serovar divergence between strains of different serovars. The results indicate that intra-serovar heterogeneity and inter-serovar homogeneity may limit the application of RAPD-HRM in routine diagnostics. They also indicate that genetic attenuation of aged, high-passage-number isolates could undermine the use of RAPD-HRM or any other molecular technology. Such genetic attenuation may account for a general decrease seen in titres of rabbit hyperimmune antibodies over time. Before RAPD-HRM can be further advanced as a routine diagnostic tool, strains more representative of the wild-type serovars of a given region need to be identified. Further, RAPD-HRM analysis of reference strains indicates that the routine renewal of reference collections, with new isolates, may be needed to maintain the genetic integrity of the collections.

Study on the ELDRS of bipolar linear operational amplifier

International Nuclear Information System (INIS)

Yang Hui; Liu Yanfang; Chen Yu; Bai Hua; Zhang Dong

2011-01-01

Bipolar linear devices laboratory irradiation testing results are significantly different from the actual in flight exposure to the radiation. In this paper the total dose irradiation of operational amplifiers, and analysis upon the total dose response of these bipolar circuits under the different test conditions were investigated in the same experiment. Total dose tests of bipolar linear operational amplifiers show susceptible to dose rate, bias and room temperature annealing during exposure. The critical sensitive parameters of operational amplifier are input bias current, input offset current, input offset voltage, and open loop gain, which exhibits both bias and dose rate dependence. With calculating the change of each electrical parameter (Δpara) for each sample at 300 Gy radiation level, it has been found that ratio of the Δpara at low dose rate to the Δpara at high dose rate exceeds 2.46 times for any of the parameters. So these parts are considered to be ELDRS susceptible. After room temperature annealing, the main parameters have time dependence effect at low dose rate and without time dependent effect at high dose rate. (authors)

An 8–18 GHz broadband high power amplifier

International Nuclear Information System (INIS)

Wang Lifa; Yang Ruixia; Li Yanlei; Wu Jingfeng

2011-01-01

An 8–18 GHz broadband high power amplifier (HPA) with a hybrid integrated circuit (HIC) is designed and fabricated. This HPA is achieved with the use of a 4-fingered micro-strip Lange coupler in a GaAs MMIC process. In order to decrease electromagnetic interference, a multilayer AlN material with good heat dissipation is adopted as the carrier of the power amplifier. When the input power is 25 dBm, the saturated power of the continuous wave (CW) outputted by the power amplifier is more than 39 dBm within the frequency range of 8–13 GHz, while it is more than 38.6 dBm within other frequency ranges. We obtain the peak power output, 39.4 dBm, at the frequency of 11.9 GHz. In the whole frequency band, the power-added efficiency is more than 18%. When the input power is 18 dBm, the small signal gain is 15.7 ± 0.7 dB. The dimensions of the HPA are 25 × 15 × 1.5 mm 3 . (semiconductor integrated circuits)

A Collaborative Project for the Development of Energy Amplifier

International Nuclear Information System (INIS)

Joo, H. K.; Kim, S. J.; Kim, Y. H.; Lee, Y. W.; Cho, C. H.; Song, T. Y.

2009-11-01

An energy amplifier can be an option for the future system for electricity generation and for management of spent fuel. An energy amplifier system is composed of a proton accelerator and a proton transportation system, a target system, a subcritical reactor, and a heat transfer system. A development plan for energy amplifier should be individually prepared for each sub-sytem. For the development of a subcritical reactor, a feasibility and conceptual studies is recommended to be carried out till the basic research phase which is performed with the development of the accelerator system. The feasibility study needs 1∼2 years of research period and 1.5 man-year of efforts. The conceptual design for the subcritical reactor will determine a reactor concept, the power of reactor and accelerator, the interface with a target system, fuel design, the performance and safety analysis of the core, and the fuel cycle option including thorium cycle, and it requires 2∼3 years of research period and 6 man-year of man power

Amplifier Module for 260-GHz Band Using Quartz Waveguide Transitions

Science.gov (United States)

Padmanabhan, Sharmila; Fung, King Man; Kangaslahti, Pekka P.; Peralta, Alejandro; Soria, Mary M.; Pukala, David M.; Sin, Seth; Samoska, Lorene A.; Sarkozy, Stephen; Lai, Richard

2012-01-01

Packaging of MMIC LNA (monolithic microwave integrated circuit low-noise amplifier) chips at frequencies over 200 GHz has always been problematic due to the high loss in the transition between the MMIC chip and the waveguide medium in which the chip will typically be used. In addition, above 200 GHz, wire-bond inductance between the LNA and the waveguide can severely limit the RF matching and bandwidth of the final waveguide amplifier module. This work resulted in the development of a low-loss quartz waveguide transition that includes a capacitive transmission line between the MMIC and the waveguide probe element. This capacitive transmission line tunes out the wirebond inductance (where the wire-bond is required to bond between the MMIC and the probe element). This inductance can severely limit the RF matching and bandwidth of the final waveguide amplifier module. The amplifier module consists of a quartz E-plane waveguide probe transition, a short capacitive tuning element, a short wire-bond to the MMIC, and the MMIC LNA. The output structure is similar, with a short wire-bond at the output of the MMIC, a quartz E-plane waveguide probe transition, and the output waveguide. The quartz probe element is made of 3-mil quartz, which is the thinnest commercially available material. The waveguide band used is WR4, from 170 to 260 GHz. This new transition and block design is an improvement over prior art because it provides for better RF matching, and will likely yield lower loss and better noise figure. The development of high-performance, low-noise amplifiers in the 180-to- 700-GHz range has applications for future earth science and planetary instruments with low power and volume, and astrophysics array instruments for molecular spectroscopy. This frequency band, while suitable for homeland security and commercial applications (such as millimeter-wave imaging, hidden weapons detection, crowd scanning, airport security, and communications), also has applications to

A High-Efficiency 100-W GaN Three-Way Doherty Amplifier for Base-Station Applications

NARCIS (Netherlands)

Pelk, M.J.; Neo, W.C.E.; Gajadharsing, J.R.; Pengelly, R.S.; De Vreede, L.C.N.

2008-01-01

A three-way Doherty 100-W GaN base-station power amplifier at 2.14 GHz is presented. Simple, but accurate design equations for the output power combiner of the amplifier are introduced. Mixed-signal techniques are utilized for uncompromised control of the amplifier stages to optimize efficiency, as

A compact 500 MHz 4 kW Solid-State Power Amplifier for accelerator applications

Energy Technology Data Exchange (ETDEWEB)

Gaspar, M., E-mail: marcos.gaspar@psi.c [Paul Scherrer Institute, CH 5232 Villigen PSI (Switzerland); Pedrozzi, M. [Paul Scherrer Institute, CH 5232 Villigen PSI (Switzerland); Ferreira, L.F.R. [Department of Physics, University of Coimbra, 3004-516 Coimbra (Portugal); Garvey, T. [Paul Scherrer Institute, CH 5232 Villigen PSI (Switzerland)

2011-05-01

We present the development of a compact narrow-band Solid-State Power Amplifier (SSPA). We foresee a promising application of solid-state amplifiers specifically in accelerators for new generation synchrotron light sources. Such a new technology has reached a competitive price/performance ratio and expected lifetime in comparison with klystron and IOT amplifiers. The increasing number of synchrotron light sources using 500 MHz as base frequency justifies the effort in the development of the proposed amplifier. Two different techniques are also proposed to improve the control and performance of these new distributed amplification systems which we call, respectively, complete distributed system and forced compression.

A compact 500 MHz 4 kW Solid-State Power Amplifier for accelerator applications

International Nuclear Information System (INIS)

Gaspar, M.; Pedrozzi, M.; Ferreira, L.F.R.; Garvey, T.

2011-01-01

We present the development of a compact narrow-band Solid-State Power Amplifier (SSPA). We foresee a promising application of solid-state amplifiers specifically in accelerators for new generation synchrotron light sources. Such a new technology has reached a competitive price/performance ratio and expected lifetime in comparison with klystron and IOT amplifiers. The increasing number of synchrotron light sources using 500 MHz as base frequency justifies the effort in the development of the proposed amplifier. Two different techniques are also proposed to improve the control and performance of these new distributed amplification systems which we call, respectively, complete distributed system and forced compression.

Analysis of a hysteresis-controlled self-oscillating class-D amplifier

OpenAIRE

Cox, Stephen M.; Yu, Jun; Goh, Wang Ling; Tan, Meng Tong

2016-01-01

This paper gives the first systematic perturbation analysis of the audio distortion and mean switching period for a self-oscillating class-D amplifier. Explicit expressions are given for all the principal components of audio distortion, for a general audio input signal; the specific example of a sinusoidal input is also discussed in some detail, yielding an explicit closed-form expression for the total harmonic distortion (THD). A class-D amplifier works by converting a low-frequency audio in...

Linearizing of Low Noise Power Amplifier Using 5.8GHz Double Loop Feedforward Linearization Technique

Directory of Open Access Journals (Sweden)

Abdulkareem Mokif Obais

2017-05-01

Full Text Available In this paper, a double loop feedforward linearization technique is analyzed and built with a MMIC low noise amplifier “HMC753” as main amplifier and a two-stage class-A power amplifier as error amplifier. The system is operated with 5V DC supply at a center frequency of 5.8GHz and a bandwidth of 500MHz. The proposed technique, increases the linearity of the MMIC amplifier from 18dBm at 1dB compression point to more than 26dBm. In addition, the proposed system is tested with OFDM signal and it reveals good response in maximizing the linearity region and eliminating distortions. The proposed system is designed and simulated onAdvanced Wave Research-Microwave Office (AWR-MWO.

Numerical simulation of cross field amplifiers

International Nuclear Information System (INIS)

Eppley, K.

1990-01-01

Cross field amplifiers (CFA) have been used in many applications where high power, high frequency microwaves are needed. Although these tubes have been manufactured for decades, theoretical analysis of their properties is not as highly developed as for other microwave devices such as klystrons. One feature distinguishing cross field amplifiers is that the operating current is produced by secondary emission from a cold cathode. This removes the need for a heater and enables the device to act as a switch tube, drawing no power until the rf drive is applied. However, this method of generating the current does complicate the simulation. We are developing a simulation model of cross field amplifiers using the PIC code CONDOR. We simulate an interaction region, one traveling wavelength long, with periodic boundary conditions. An electric field with the appropriate phase velocity is imposed on the upper boundary of the problem. Evaluation of the integral of E·J gives the power interchanged between the wave and the beam. Given the impedance of the structure, we then calculate the change in the traveling wave field. Thus we simulate the growth of the wave through the device. The main advance of our model over previous CFA simulations is the realistic tracking of absorption and secondary emission. The code uses experimental curves to calculate secondary production as a function of absorbed energy, with a theoretical expression for the angular dependence. We have used this code to model the 100 MW X-band CFA under construction at SLAC, as designed by Joseph Feinstein and Terry Lee. We are examining several questions of practical interest, such as the power and spectrum of absorbed electrons, the minimum traveling wave field needed to initiate spoke formation, and the variation of output power with dc voltage, anode-cathode gap, and magnetic field. 5 refs., 8 figs

A broadband high-efficiency Doherty power amplifier using symmetrical devices

Science.gov (United States)

Cheng, Zhiqun; Zhang, Ming; Li, Jiangzhou; Liu, Guohua

2018-04-01

This paper proposes a method for broadband and high-efficiency amplification of Doherty power amplifier (DPA) using symmetric devices. In order to achieve the perfect load modulation, the carrier amplifier output circuit total power length is designed to odd multiple of 90°, and the peak amplifier output total power length is designed to even multiple of 180°. The proposed method is demonstrated by designing a broadband high-efficiency DPA using identical 10-W packaged GaN HEMT devices. Measurement results show that over 51% drain efficiency is achieved at 6-dB back-off power, over the frequency band of 1.9–2.4 GHz. Project supported by the National Natural Science Foundation of China (No. 60123456), the Zhejiang Provincial Natural Science Foundation of China (No. LZ16F010001), and the Zhejiang Provincial Public Technology Research Project (No. 2016C31070).

K-Band Traveling-Wave Tube Amplifier

Science.gov (United States)

Force, Dale A.; Simons, Rainee N.; Peterson, Todd T.; Spitsen, Paul C.

2010-01-01

A new space-qualified, high-power, high-efficiency, K-band traveling-wave tube amplifier (TWTA) will provide high-rate, high-capacity, direct-to-Earth communications for science data and video gathered by the Lunar Reconnaissance Orbiter (LRO) during its mission. Several technological advances were responsible for the successful demonstration of the K-band TWTA.

Two-wave mixing in a broad-area semiconductor amplifier

DEFF Research Database (Denmark)

Chi, M.; Jensen, S.B.; Huignard, J.P.

2006-01-01

The two-wave mixing in the broad-area semiconductor amplifier was investigated, both theoretically and experimentally. In detail we investigated how the optical gain is affected by the presence of the two-wave mixing interference grating. In the experimental setup we are able to turn on and off...... the interference pattern in the semiconductor amplifier. This arrangement allows us to determine the two-wave mixing gain. The coupled-wave equations of two-wave mixing were derived based on the Maxwell’s wave equation and rate equation of the carrier density. The analytical solutions of the coupled-wave equations...

Compact fibre-laser-pumped Ho:YLF oscillator–amplifier system

CSIR Research Space (South Africa)

Koen, W

2010-04-01

Full Text Available of the amplifier crystal L and the pump spot radius wp ( Ω = 2pi · (1 − cosβ), with β = tan−1(wpL )). Calculating the local population in (3) and iterating (6) and (11) along the length of the amplifier crystal, we obtain the extracted photon densities...-pumped tunable Tm: silica- fibre laser. Appl. Phys. B 79, 559 (2004) 6. E. Lippert, S. Nicolas, G. Arisholm, K. Stenersen, G. Rustad, Mid- infrared laser source with high power and beam quality. Appl. Opt. 45, 3839 (2006) 7. S.A. Payne, L.L. Chase, L...

Gain dynamics and saturation in semiconductor quantum dot amplifiers

DEFF Research Database (Denmark)

Berg, Tommy Winther; Mørk, Jesper; Hvam, Jørn Märcher

2004-01-01

Quantum dot (QD)-based semiconductor optical amplifiers offer unique properties compared with conventional devices based on bulk or quantum well material. Due to the bandfilling properties of QDs and the existence of a nearby reservoir of carriers in the form of a wetting layer, QD semiconductor...... optical amplifiers may be operated in regimes of high linearity, i.e. with a high saturation power, but can also show strong and fast nonlinearities by breaking the equilibrium between discrete dot states and the continuum of wetting layer states. In this paper, we analyse the interplay of these two...

Updated design for a low-noise, wideband transimpedance photodiode amplifier

International Nuclear Information System (INIS)

Paul, S. F.; Marsala, R.

2006-01-01

The high-speed rotation diagnostic developed for Columbia's HBT-EP tokamak requires a high quantum efficiency, very low drift detector/amplifier combination. An updated version of the circuit developed originally for the beam emission spectroscopy experiment on TFTR is being used. A low dark current (2 nA at 15 V bias), low input source capacitance (2 pF) FFD-040 N-type Si photodiode is operated in photoconductive mode. It has a quantum efficiency of 40% at the 468.6 nm (He II line that is being observed). A low-noise field-effect transistor (InterFET IFN152 with e Na =1.2 nV/√Hz) is used to reduce the noise in the transimpedance preamplifier (A250 AMPTEK op-amp) and a very high speed (unity-gain bandwidth=200 MHz) voltage feedback amplifier (LM7171) is used to restore the frequency response up to 100 kHz. This type of detector/amplifier is photon-noise limited at this bandwidth for incident light with a power of >∼2 nW. The circuit has been optimized using SIMETRIX 4.0 SPICE software and a prototype circuit has been tested successfully. Though photomultipliers and avalanche photodiodes can detect much lower light levels, for light levels >2 nW and a 10 kHz bandwidth, this detector/amplifier combination is more sensitive because of the absence of excess (internally generated) noise

Statistical Analysis of Coherent Ultrashort Light Pulse CDMA With Multiple Optical Amplifiers Using Additive Noise Model

Science.gov (United States)

Jamshidi, Kambiz; Salehi, Jawad A.

2005-05-01

This paper describes a study of the performance of various configurations for placing multiple optical amplifiers in a typical coherent ultrashort light pulse code-division multiple access (CULP-CDMA) communication system using the additive noise model. For this study, a comprehensive performance analysis was developed that takes into account multiple-access noise, noise due to optical amplifiers, and thermal noise using the saddle-point approximation technique. Prior to obtaining the overall system performance, the input/output statistical models for different elements of the system such as encoders/decoders,star coupler, and optical amplifiers were obtained. Performance comparisons between an ideal and lossless quantum-limited case and a typical CULP-CDMA with various losses exhibit more than 30 dB more power requirement to obtain the same bit-error rate (BER). Considering the saturation effect of optical amplifiers, this paper discusses an algorithm for amplifiers' gain setting in various stages of the network in order to overcome the nonlinear effects on signal modulation in optical amplifiers. Finally, using this algorithm,various configurations of multiple optical amplifiers in CULP-CDMA are discussed and the rules for the required optimum number of amplifiers are shown with their corresponding optimum locations to be implemented along the CULP-CDMA system.