Siga este link para ver outros tipos de publicações sobre o tema: Amplifiers.
Artigos de revistas sobre o tema "Amplifiers"
Crie uma referência precisa em APA, MLA, Chicago, Harvard, e outros estilos
Veja os 50 melhores artigos de revistas para estudos sobre o assunto "Amplifiers".
Ao lado de cada fonte na lista de referências, há um botão "Adicionar à bibliografia". Clique e geraremos automaticamente a citação bibliográfica do trabalho escolhido no estilo de citação de que você precisa: APA, MLA, Harvard, Chicago, Vancouver, etc.
Você também pode baixar o texto completo da publicação científica em formato .pdf e ler o resumo do trabalho online se estiver presente nos metadados.
Veja os artigos de revistas das mais diversas áreas científicas e compile uma bibliografia correta.
1
Zygarlicki, Jarosław, e Janusz Mroczka. "Method of testing and correcting signal amplifiers’ transfer function using prony analysis". Metrology and Measurement Systems 19, n.º 3 (1 de outubro de 2012): 489–98. http://dx.doi.org/10.2478/v10178-012-0042-7.
Texto completo da fonteResumo:
Abstract This article presents a way of analyzing the transfer function of electronic signal amplifiers. It also describes the possibility of using signal precorrection which improves the parasitic harmonics in the THD (Total Harmonic Distortion) of the amplified signal by correcting linearity of the tested amplifier’s transfer function. The proposed method of analyzing and presenting the transfer function allows to diagnose the causes of generating parasitic harmonics, what makes it a useful tool when designing low distortion amplifier systems, such as e.g. amplifiers in measurement systems. The presented THD correction can be used in e.g. amplifier systems that cooperate with arbitrary generators.
2
Wang, Haishuo, Tiancheng Yu e Zhe Yang. "Design and output spectral peak power optimization of E-band fiber-amplified spontaneous emission spectra". Highlights in Science, Engineering and Technology 72 (15 de dezembro de 2023): 624–31. http://dx.doi.org/10.54097/4w1mdt53.
Texto completo da fonteResumo:
Fiber optic amplifiers will improve the power of signals propagating in optical fibers, usually using doped ions as amplifiers. The bismuth-doped fiber amplifier can amplify the current E-band signal light, which is less used, and provide a solution to enhance the communication transmission capacity.In this essay, Matlab is used as a research tool, and the bismuth-doped fiber amplifier is selected, and the energy level system is a three-energy levelThe 830 nm-wavelength pumping source amplifies the signal light at 1390 nm. The bismuth-ion velocity and power amplification propagation equations are established, and the amplified spontaneous radiated optical power is calculated. Amplified spontaneous radiation optical power, and through the calculation and simulated annealing algorithm to derive the amplified spontaneous radiation optical power amplification with the doping concentration and fiber length spectrum, in the fiber length of 3.3m and the number of doped particles of 9.1 * 10^25 to obtain the maximum optical power of 7.95*10^-9W.
3
Kumar, Sunil, e Arun Kr Chatterjee. "Comparative study of different Sense Amplifiers in 0.18um technology". INTERNATIONAL JOURNAL OF COMPUTERS & TECHNOLOGY 7, n.º 3 (10 de junho de 2013): 615–19. http://dx.doi.org/10.24297/ijct.v7i3.3440.
Texto completo da fonteResumo:
A comparative study of different types of sense amplifiers [1] using 0.18um technology is presented. The sense amplifiers under considerations are used in SRAM and DRAM cells.The sensing delay of different types of sense amplifiers are evaluated with respect to variation of bitline capacitance. Comparative results are also provided for the variation in delay with respect to power supply. Extensive results based on 0.18um CMOS technology using CADENCE Spectre simulation tools are presented for different architectures of sense amplifiers. From these results it has been proven that if the output of sense amplifier is isolated from the bitline parasitic capacitance then the sensing delay of sense amplifier reduces.
4
Sadegh Kazempourfard, Mohammad, Hamid Nadgaran e Seyed Mahdi Mousavi. "The effects of pump pulse fluence on the output energy and amplified spontaneous emission of a femtosecond regenerative amplifier". Laser Physics 32, n.º 1 (14 de dezembro de 2021): 015002. http://dx.doi.org/10.1088/1555-6611/ac3ee8.
Texto completo da fonteResumo:
Abstract In this paper, the effects of pump pulse fluence on the output energy and amplified spontaneous emission (ASE) of a femtosecond regenerative amplifier are investigated. One can easily enhance the output energy of laser amplifiers by increasing their pump fluence. This in turn can increase the ASE and reduce the performance of amplifiers in terms of output beam quality, beam stability, etc. This effect would eventually lead to what is called ‘temporal intensity contrast deterioration’. In this work, it is shown that an optimum state of the pump pulse fluence can indeed optimize the amount of the output energy from a regenerative amplifier without much reducing the performance of the amplifier due to the higher ASE. Temporal gain characteristics were employed to achieve this optimum value for a better design, performance, and maintenance of femtosecond laser amplifiers. The results of the current study can be effectively used in designing a wide range of regenerative amplifiers for femtosecond pulses.
5
Borel, Andžej. "DEVELOPMENT AND INVESTIGATION OF INPUT AMPLIFIER FOR THE OSCILOSCOPE". Mokslas - Lietuvos ateitis 12 (20 de janeiro de 2020): 1–5. http://dx.doi.org/10.3846/mla.2020.11420.
Texto completo da fonteResumo:
Digital oscilloscope’s structure has analog signal acquisition circuit, which transforms signal’s amplitude to fit ADC dynamic range. This circuit is commonly called oscilloscope’s vertical or front-end amplifier. Difficulty in designing front-end amplifiers in GHz range largely affects higher frequency range oscilloscope’s price. This work is focused on designing a front-end amplifier using discrete and openly sold components. We propose a design for attenuator, buffer, variable gain circuits. Amplifier’s prototype is designed. Main characteristics of the amplifier were measured. Measured bandwidth is 3 GHz. Amplifier’s gain and attenuation can support vertical scale sensitivity range from 10 mV/div to 1 V/div. Step response distortion is under 10 %. SMD and PTH relay model attenuators were evaluated. In this paper we review oscilloscope’s front-end purpose and structure. We review amplifiers design and provide the results of experimental measurements.
6
Kitsios, E. E., e R. F. Boucher. "The Dynamics of Vortex Amplifiers. Part 1: Analytical Model". Journal of Dynamic Systems, Measurement, and Control 107, n.º 3 (1 de setembro de 1985): 176–81. http://dx.doi.org/10.1115/1.3140717.
Texto completo da fonteResumo:
A semi-empirical technique for the dynamic modeling of vortex amplifiers is demonstrated with reference to one particular vortex amplifier geometry. The model parameters are determined explicitly from the amplifier static characteristics and geometry except for two which are estimated from measurements of the amplifier’s dynamic response. The two are time constants associated with the chamber time delay and the vortex rotational inertia. The model is linearized about a working point and is presented in terms of an admittance matrix. The paper is continued in Part 2 where two of the amplifier’s transfer admittances are measured experimentally and compared with the model predictions.
7
SUDO, SHOICHI. "PROGRESS IN OPTICAL FIBER AMPLIFIERS". International Journal of High Speed Electronics and Systems 07, n.º 01 (março de 1996): 1–35. http://dx.doi.org/10.1142/s0129156496000025.
Texto completo da fonteResumo:
Recent progress in fiber amplifier technology is reviewed. Broad band and high power are currently the key goals in the field of fiber amplifiers in conjunction with amplified system development. Broad-band EDFAs using fluoride-based hosts and high-power EDFAs with powerful pump lasers are described in detail. Recent progress and other requirements for optical amplifiers i.e. high gain, low noise, and high reliability, are all reviewed. The limitations in relation to achievable gain are described as well as the highest gain ever achieved. A method for its reduction are described. In relation to reliability, this paper mainly focuses on fluoride fiber. Recent progress on the main characteristics of 1.3 µm PDFA is reviewed and transmission experiment are described. Several attempts to construct fiber amplifiers operating at 0.8 µm, 1.4 µm, and 1.65 µm are also reviewed. In the field of amplified systems, WDM and remote pumping TDM techniques are a high priority. In particular, various WDM experiments such as long-distance WDM transmission, WDM soliton transmission, and WDM networks are all described in detail.
8
Ismail, Khadijah, P. S. Menon, Sahbudin Shaari, Abang Annuar Ehsan, Norhana Arsad e A. Ashrif A. Bakar. "Link Power Level Improvements in an Amplified 8-Channel CWDM System with Hybrid EDFA-SOA Pre-Amplifier". Applied Mechanics and Materials 799-800 (outubro de 2015): 1361–65. http://dx.doi.org/10.4028/www.scientific.net/amm.799-800.1361.
Texto completo da fonteResumo:
The link power improvement in a coarse wavelength division multiplexing (CWDM) system which is transmitted using a hybrid erbium-doped fiber amplifier (EDFA) and semiconductor optical amplifier (SOA) scheme as a pre-amplifier, is discussed. The network is designed for amplifying 8 CWDM channels ranging from 1471 nm to 1611 nm. The hybrid amplifiers’ gain measurement is obtained from experimental work with gain peak at 22 dB which is observed at 1531 nm. The amplifiers also caused power increment of 5.06 dB in the transmission link before the signal is split individually at the receiving end. Based on the higher gain peaks and power spectrum at 1531 nm and 1551 nm wavelengths, the proposed amplified link would be useful for the transmission of video applications.
9
Mei, Shangming, Yihua Hu, Hui Xu e Huiqing Wen. "The Class D Audio Power Amplifier: A Review". Electronics 11, n.º 19 (9 de outubro de 2022): 3244. http://dx.doi.org/10.3390/electronics11193244.
Texto completo da fonteResumo:
Class D power amplifiers, one of the most critical devices for application in sound systems, face severe challenges due to the increasing requirement of smartphones, digital television, digital sound, and other terminals. The audio power amplifier has developed from a transistor amplifier to a field-effect tube amplifier, and digital amplifiers have made significant progress in circuit technology, components, and ideological understanding. The stumbling blocks for a successful power amplifier are low power efficiency and a high distortion rate. Therefore, Class D audio amplifiers are becoming necessary for smartphones and terminals due to their power efficiency. However, the switching nature and intrinsic worst linearity of Class D amplifiers compared to linear amplifiers make it hard to dominate the market for high-quality speakers. The breakthrough arrived with the GaN device, which is appropriate for fast-switching and high-power-density power electronics switching elements compared with traditional Si devices, thus, reducing power electronic systems’ weight, power consumption, and cost. GaN devices allow Class D audio amplifiers to have high fidelity and efficiency. This paper analyzes and discusses the topological structure and characteristics and makes a judgment that Class D amplifiers based on GaN amplifiers are the future development direction of audio amplifiers.
10
Sullivan, J. A. "Simplified model for designing large KrF amplifiers". Laser and Particle Beams 11, n.º 1 (março de 1993): 241–56. http://dx.doi.org/10.1017/s0263034600007084.
Texto completo da fonteResumo:
A simplified model for determining the performance of large krypton-fluoride laser amplifiers is presented. The model includes a straightforward treatment of the controlling kinetics, an exact solution for energy extraction, and an approximation to amplified spontaneous emission losses; it can be easily programmed to run on personal computers. The inclusion of the controlling basic physics for KrF lasers makes the model ideally suited for the many calculations that are necessary to optimize the design of a specific amplifier. The basic parameters determined in the model are compared to experimental data wherever possible, and the large amplifier performance predictions are compared to the results from the most sophisticated kinetics and a 3-D extraction model that includes a full treatment of losses due to amplified spontaneous emission.
11
Sullivan, J. A., G. R. Allen, R. R. Berggren, S. J. Czuchlewski, D. B. Harris, M. E. Jones, B. J. Krohn et al. "KrF amplifier design issues and application to inertial confinement fusion system design". Laser and Particle Beams 11, n.º 2 (junho de 1993): 359–83. http://dx.doi.org/10.1017/s0263034600004961.
Texto completo da fonteResumo:
Los Alamos National Laboratory has assembled an array of experimental and theoretical tools to optimize amplifier design for future single-pulse KrF lasers. The next opportunity to exercise these tools is with the design of the second-generation NIKE system under construction at the Naval Research Laboratory with the collaboration of Los Alamos National Laboratory. Major issues include laser physics (energy extraction in large modules with amplified spontaneous emission) and diode performance and efficiency. Low cost is increasingly important for larger future KrF single-pulse systems (low cost and high efficiency is important for larger repetitively pulsed applications such as electric power production). In this article, we present our approach to amplifier scaling and discuss the more important design considerations for large single-pulse KrF amplifiers. We point out where improvements in the fundamental database for KrF amplifiers could lead to increased confidence in performance predictions for large amplifiers and address the currently unresolved issues of anomalous absorption near line center and the possibility of diode instabilities for lowimpedance designs. Los Alamos has applied these amplifier design tools to the conceptual design of a 100-kJ Laser Target Test Facility and a 3-MJ Laboratory Microfusion Facility.
12
Kharis, Muhamad, Dhidik Prastiyanto e Suryono Suryono. "Perbandingan Efisiensi Daya Penguat Audio Kelas AB dengan Penguat Audio Kelas D untuk Keperluan Sound System Lapangan". Jurnal Teknik Elektro 10, n.º 2 (19 de dezembro de 2018): 54–58. http://dx.doi.org/10.15294/jte.v10i2.11183.
Texto completo da fonteResumo:
Class AB audio amplifiers are commonly used but the efficiency is 50%. While the efficiency of class D audio amplifiers is 90% but are rarely used. The purpose of this research is to know how much the power efficiency of field sound system between 1000 watts class AB amplifier and 900 watts class D amplifier. This study is a comparative study that compares different variables with the same sample. The results of power efficiency are obtained from the percentage comparison between the output power and the input power of each audio amplifier. The power efficiency of class D audio amplifiers with IRS D900 type larger than class AB audio amplifiers with Apex B500 type. The efficiency value of class D audio amplifiers at the highest output power reaches 87% while class AB audio amplifiers are only 73%.
13
Li, Yin, Yijun Wang, Yun Mao, Weishao Peng, Di Jin e Ying Guo. "Continuous-Variable Quantum Key Distribution Based on Heralded Hybrid Linear Amplifier with a Local Local Oscillator". Entropy 23, n.º 11 (24 de outubro de 2021): 1395. http://dx.doi.org/10.3390/e23111395.
Texto completo da fonteResumo:
An improved continuous variable quantum key distribution (CVQKD) approach based on a heralded hybrid linear amplifier (HLA) is proposed in this study, which includes an ideal deterministic linear amplifier and a probabilistic noiseless linear amplifier. The CVQKD, which is based on an amplifier, enhances the signal-to-noise ratio and provides for fine control between high gain and strong noise reduction. We focus on the impact of two types of optical amplifiers on system performance: phase sensitive amplifiers (PSA) and phase insensitive amplifiers (PIA). The results indicate that employing amplifiers, local local oscillation-based CVQKD systems can enhance key rates and communication distances. In addition, the PIA-based CVQKD system has a broader application than the PSA-based system.
14
Zhou, Yiping, Xudong Li, Chaojie Wei, Xiaojie Chen, Haobo Xu, Rongwei Fan, Deying Chen, Yugang Jiang e Renpeng Yan. "5 kHz, 4.2mJ, 900 ps end-pumped Nd:YVO4 MOPA laser system". Optics Express 30, n.º 16 (29 de julho de 2022): 29833. http://dx.doi.org/10.1364/oe.468386.
Texto completo da fonteResumo:
A 5 kHz sub-nanosecond master oscillator power amplifier (MOPA) laser system was reported in this paper. The master oscillator was an electro-optically Q-switched Nd:YVO4 laser directly pumped at 879 nm, yielding a pulse energy of 520 µJ and a pulse width of 900 ps at 5 kHz. With two Nd:YVO4 amplifiers directly pumped at 914 nm, the pulse energy was further scaled up. Under the absorbed pump energy of 11.0 mJ, the pulse energy was amplified to 4.2 mJ, corresponding to a peak power of 4.7 MW. The optical-to-optical efficiency of the amplifiers reached 33.5%.
15
Lee, Dongho. "Second Harmonic Frequency Adjustment Strategy for Class-E Amplifier Design". International Journal of Electrical and Electronics Research 11, n.º 3 (10 de julho de 2023): 658–61. http://dx.doi.org/10.37391/ijeer.110303.
Texto completo da fonteResumo:
Class-E amplifiers are a type of switching amplifiers with an efficiency that approaches 100%. The harmonic frequency is very important in the design of Class-E amplifiers. In this study, the second harmonic frequency is considered in the design of a Class-E amplifier. The Class-E amplifier has been fabricated on FR4 and has demonstrated a power-added efficiency (PAE) of 74.5% at 1.01 GHz. This result shows that the termination of the second-harmonic output is essential for switching amplifiers.
16
Choi, Hojong. "Development of a Class-C Power Amplifier with Diode Expander Architecture for Point-of-Care Ultrasound Systems". Micromachines 10, n.º 10 (14 de outubro de 2019): 697. http://dx.doi.org/10.3390/mi10100697.
Texto completo da fonteResumo:
Point-of-care ultrasound systems are widely used in ambulances and emergency rooms. However, the excessive heat generated from ultrasound transmitters has an impact on the implementation of piezoelectric transducer elements and on battery consumption, thereby affecting the system’s sensitivity and resolution. Non-linear power amplifiers, such as class-C amplifiers, could substitute linear power amplifiers, such as class-A amplifiers, which are currently used in point-of-care ultrasound systems. However, class-C power amplifiers generate less output power, resulting in a reduction of system sensitivity. To overcome this issue, we propose a new diode expander architecture dedicated to power amplifiers to reduce the effects of sinusoidal pulses toward the power supply. Thus, the proposed architecture could increase the input pulse amplitudes applied to the main transistors in the power amplifiers, hence increasing the output voltage of such amplifiers. To verify the proposed concept, pulse-echo responses from an ultrasonic transducer were tested with the developed class-C power amplifier using a resistor divider and the designed diode expander architecture. The peak-to-peak amplitude of the echo signals of the ultrasonic transducers when using a class-C power amplifier with a diode expander architecture (2.98 Vp–p) was higher than that for the class-C power amplifier with a resistor divider architecture (2.51 Vp–p). Therefore, the proposed class-C power amplifier with diode expander architecture is a potential candidate for improving the sensitivity performance of piezoelectric transducers for point-of-care ultrasound systems.
17
Alybin, Vyacheslav, Aleksey Syomochkin, Vladimir Rozhkov e Sergey Avramenko. "Major Items of Construction Amplifiers of UNF Power for the Auxiliary Systems of Spacecrafts". Infocommunications and Radio Technologies 5, n.º 1 (25 de março de 2022): 70–78. http://dx.doi.org/10.29039/2587-9936.2022.05.1.05.
Texto completo da fonteResumo:
Prospective designs of microwave power amplifiers for on-board equipment of service systems are considered, in which the problem of minimizing the area occupied by them on a thermally stabilized plate of a spacecraft is solved. Microwave power amplifiers provide good heat dissipation and require a degree of redundancy. Each of the amplifiers included in the redundant microwave power amplifier is made on boards located perpendicular to the heat-stabilized plate and fixed on the plate on one or both sides. The area occupied by a duplicated or triple redundant microwave power amplifier does not exceed the area on a thermally stabilized plate required to remove heat from one microwave power amplifier included in its composition. And for a triple redundant microwave power amplifier – the area required for heat removal from two such amplifiers.
18
Murtianta, Budihardja, e Erlina Sari. "Penguat Jembatan dengan Untai Pembalik Fase". Elektrika 14, n.º 2 (22 de outubro de 2022): 58. http://dx.doi.org/10.26623/elektrika.v14i2.5329.
Texto completo da fonteResumo:
The maximum output voltage of the audio amplifier is limited to the magnitude of the power supply voltage of the power transistor or the operational amplifier on the final amplifier. This limits the maximum power of the audio amplifier output. The way to enlarge the output power of the audio amplifier without increasing the voltage is the bridge method or bridged modes. With this method a bridge amplifier will be generated. This Bridge Amplifier is also known as Bridge-Tied Load (BTL) or Bridged Transformerless. The principle of Bridge Amplifiers is to use a pair of final amplifiers whose outputs have opposite phase each other. There are 3 ways to make a pair of power amplifiers have opposing phases: with internal modification, with an audio transformer (phase splitting audio input transformer) and with a simple active phase reversal splitter circuit). This paper will discuss Bridge Amplifiers with simple phase inverting circuits. A pair of audio power amplifiers using two TDA2050 chips which are operated at ± 19 Volt supply voltage. The phase inverting circuit using IC TL072. Sinusoidal signal with an amplitude of 200 mVp and a frequency of 1 KHz is used as an input signal. The results to be observed and measured are gain, input, output and bandwidth of the bridged amplifier compared to the usual amplifier
19
Jurnal, Redaksi Tim. "PERANCANGAN RANGKAIAN PENGUAT DAYA DENGAN TRANSISTOR". Sutet 7, n.º 2 (27 de novembro de 2018): 88–92. http://dx.doi.org/10.33322/sutet.v7i2.81.
Texto completo da fonteResumo:
The power amplifier circuit is a circuit used to amplify or magnify input signals. The use of a transistor as an amplifier is that the current on the base is used to control the larger current given to the collector through the transistor. The small current change on the controlling base is what is called a large change in the current flowing from the collector to the emitter. The advantages of the amplifier transistors can not only amplify the signal, but these transistors can also be used as current amplifiers, voltage amplifiers and power amplifiers.
20
Sajedin, Maryam, I. T. E. Elfergani, Jonathan Rodriguez, Raed Abd-Alhameed e Monica Fernandez Barciela. "A Survey on RF and Microwave Doherty Power Amplifier for Mobile Handset Applications". Electronics 8, n.º 6 (25 de junho de 2019): 717. http://dx.doi.org/10.3390/electronics8060717.
Texto completo da fonteResumo:
This survey addresses the cutting-edge load modulation microwave and radio frequency power amplifiers for next-generation wireless communication standards. The basic operational principle of the Doherty amplifier and its defective behavior that has been originated by transistor characteristics will be presented. Moreover, advance design architectures for enhancing the Doherty power amplifier’s performance in terms of higher efficiency and wider bandwidth characteristics, as well as the compact design techniques of Doherty amplifier that meets the requirements of legacy 5G handset applications, will be discussed.
21
Tiwari, Nitendra kumar. "Low Power Reduction Techniques Implementation and Analysis in Sense Amplifier Circuit Configurations". Journal of Futuristic Sciences and Applications 5, n.º 2 (2022): 31–37. http://dx.doi.org/10.51976/jfsa.522205.
Texto completo da fonteResumo:
MTCMOS (Multi-Threshold CMOS), sleepy stack, sleepy keeper, and footer stack are examples of low power saving techniques incorporated into the core gpdk 90nm technology papers used in the proposed study using Cadence. The main focus of these tests is the power consumption of various sense amplifier circuits. The simulation results show that the charge-transfer sense amplifier uses much less energy than voltage and current sense amplifiers. The present mode detecting amplifier’s power consumption can be decreased by up to 98 percent by using MTCMOS technology.
22
Huang, Xiangyuan. "Design and Optimization of E-Band Fluor tellurate Fiber Amplifier Doped with Praseodymium". Highlights in Science, Engineering and Technology 72 (15 de dezembro de 2023): 198–204. http://dx.doi.org/10.54097/yyjefj52.
Texto completo da fonteResumo:
This study focuses on investigating and selecting an appropriate optical fiber material, specifically emphasizing the utilization of fluorotellurate as the base material. The objective is to enhance the performance of the optical fiber material by incorporating praseodymium ions, which possess unique properties advantageous for optical amplification.To gain an accurate understanding of the working principle of the fiber optic amplifier, a mathematical model is developed. This model acts as a valuable tool for simulating and optimizing the amplifier's performance. By conducting rigorous simulations and optimization processes using this model, critical parameters can be identified and fine-tuned to achieve optimal gain characteristics.To verify the efficacy of the designed fiber amplifier, comprehensive experimental tests are conducted. The results from these experiments convincingly demonstrate the amplifier's remarkable gain characteristics, particularly within the E-band frequency range. This research breakthrough not only highlights the amplification capabilities of the designed fiber amplifier but also presents a promising design scheme for future E-band communication systems. By selecting fluorotellurate as the base material and incorporating praseodymium ions, this study introduces an innovative approach to enhance the performance of optical fiber amplifiers. The development of a robust mathematical model enables efficient simulation and optimization, thus acting as a valuable tool for the future design and development of amplifiers. The successful experimental validation further emphasizes the potential of the designed fiber amplifier as a pivotal component for advanced E-band communication systems.
23
Chen, Ding. "Innovative Design and Application Analysis of Integrated Operational Amplifiers". Highlights in Science, Engineering and Technology 72 (15 de dezembro de 2023): 341–51. http://dx.doi.org/10.54097/xtqm8x55.
Texto completo da fonteResumo:
Operational amplifiers in integrated circuits come in many varieties and numbers and are an essential part of electronic systems. Its performance directly affects the accuracy and effectiveness of the whole system. As the market demand for operational amplifiers in different fields is growing day by day, according to different kinds of demand, people have designed a variety of operational amplifier structure. This paper describes the basic characteristics of operational amplifiers and analyzes three basic structures that are extremely relevant for modification circuits. The common-source, common-gate circuit structure op-amp has the advantages of high gain, high input common-mode range, high output swing, and high overall gain bandwidth, so it has been adopted as the most commonly used architecture today and in the future. The current improvements in operational amplifier design are mainly focused on two-stage operational amplifiers, and less on multi-stage operational amplifiers. The folded common source and common gate operational amplifier circuits are characterized by good frequency characteristics, comparatively low power consumption and high bandwidth per unit gain. The demands on the performance of operational amplifiers will become higher and more varied, and more excellent improved circuits are needed.
24
Xu, Lisong, Hongwen Li, Pengzhi Li e Chuan Ge. "The Application of Classical Control in the Design and Analysis of Power Amplifiers for Driving Piezoelectric Stack Actuators". Electronics 10, n.º 6 (18 de março de 2021): 720. http://dx.doi.org/10.3390/electronics10060720.
Texto completo da fonteResumo:
This study proposes a new method to design an analog circuit based on the control model of the circuit, and the method is applied in the design of the power amplifiers for driving piezoelectric stack actuators. Focusing on the stability of the circuit, two power amplifiers for driving piezoelectric stack actuators are analyzed deeply. The power amplifier using high-voltage operational amplifiers has a simple circuit structure, and the bandwidth and the ripple of the power amplifier are about 43 kHz and 16 mV, respectively. As for the power amplifier using general operational amplifiers, it possesses the qualities of low cost and simple circuit structure, and the bandwidth and the ripple are 53 kHz and less than 2 mV, respectively. Moreover, the proposed power amplifiers can well drive the mechanism stage during the moving range of the piezoelectric stack actuator, and the travelling ranges are both about 13 μm. Viewing the circuit design as control system design, applying control system design method in circuit design and working with PSpice simulation of the circuit: these are the main contents of the proposed method, and the method offers an answer to designing a power amplifier systematically.
25
Eimerl, David. "Amplified spontaneous emission in Cassegrainian amplifiers". Applied Optics 26, n.º 9 (1 de maio de 1987): 1594. http://dx.doi.org/10.1364/ao.26.001594.
Texto completo da fonte
26
Goren, Chana, Yitzhak Tzuk, Gilad Marcus e Shaul Pearl. "Amplified Spontaneous Emission in Slab Amplifiers". IEEE Journal of Quantum Electronics 42, n.º 12 (dezembro de 2006): 1239–47. http://dx.doi.org/10.1109/jqe.2006.884580.
Texto completo da fonte
27
Hu, Yipeng. "Improving noise levels based on amplifier structure analysis". Theoretical and Natural Science 14, n.º 1 (30 de novembro de 2023): 117–26. http://dx.doi.org/10.54254/2753-8818/14/20240912.
Texto completo da fonteResumo:
As the core component of electronic circuits, amplifiers play a pivotal role in fields such as communications, medical care, audio processing, instrumentation, scientific research and military technology. However, the noise problem of the amplifier has a direct impact on the reliability and accuracy of the system, how to reduce the impact of noise is crucial. This paper aims to study and solve noise problems in amplifier design. The first part focuses on the design of operational amplifiers. By adjusting the circuit structure and introducing current mirrors, the noise of the input and output stages is successfully reduced and the amplifier performance is improved. The second part focuses on the design of instrumentation amplifiers, introducing kT/C noise elimination technology, chopper modulation structure solves the noise and aliasing problems in switched capacitor instrumentation amplifiers and improve performance.
28
Mbonane, Sandile H., e Viranjay M. Srivastava. "Comparative Parametric Analysis of Class-B Power Amplifier Using BJT, Single-Gate MOSFET, and Double-Gate MOSFET". Materials Science Forum 1053 (17 de fevereiro de 2022): 137–42. http://dx.doi.org/10.4028/p-57edxh.
Texto completo da fonteResumo:
This paper presents system performance indices for a class-B power amplifier using Double-Gate (DG) Metal Oxide Semiconductor Field Effect Transistor (MOSFET). It also presents a comparative analysis of three power amplifiers using different switching devices, i.e. Bipolar Junction Transistor (BJT), MOSFET, and DG MOSFET. The MOSFET used in this research work is based on Silicon for n-MOSFET and SiO2 has been used as oxide layer. These power amplifiers are also being designed and simulated to test the speed and time (taken for each of these power amplifiers) to get the output signal when an input signal is applied. A comparison of these three power amplifier circuits is taken in the tabular form to conclude which power amplifier circuit performs better regarding its switching speed and the time. Switching speed relates with the time taken to amplify the signal, which is the same as its time to amplify the signal to a specific gain. Settling time for these three types of power amplifiers have also been tested and presented for the performance of these power amplifiers.
29
Cuntan, Corina, Caius Panoiu, Manuela Panoiu, Ioan Baciu e Sergiu Mezinescu. "Using the LabVIEW Simulation Program to Design and Determine the Characteristics of Amplifiers". Chips 3, n.º 2 (1 de abril de 2024): 69–97. http://dx.doi.org/10.3390/chips3020004.
Texto completo da fonteResumo:
Because of the large number of parameters that interact in amplifier functions, determining dynamic regime parameters as well as the mode of function of amplifier stages is an extremely complex problem. This paper describes a LabVIEW application for studying the functioning of an amplifier in various connections. The user selects the generator’s parameters, the type of connection and its parameters, as well as the load circuit characteristics. The application can determine both the stage characteristics and the Bode characteristics. The amplifier’s stability zone, as well as its gain and phase, are determined based on these characteristics. An important advantage of this application is that the design of the amplifier stage can be created starting from some parameters that the amplifier can establish, from which the values of components can be determined. In order to validate the simulation results from the LabVIEW application, the specialized program Multisim was used, as well as experimental measurements using the Electronics Explorer Board. Both Multisim and Electronics Explorer Board can determine Bode characteristics. In both simulations and experimental amplifiers, the same schemes with the same transistor were used. The application can be used for educational purposes as well as to design an amplifier’s stage to achieve specific parameters.
30
Li, Feng, Jiali Xiang, Tao Li, Danni Shen e Tian Li. "Active Indoor Soundscape Design: A Case Study of Ceramic Passive Amplifiers". International Journal of Environmental Research and Public Health 19, n.º 18 (7 de setembro de 2022): 11251. http://dx.doi.org/10.3390/ijerph191811251.
Texto completo da fonteResumo:
Indoor soundscape research has developed rapidly in recent years, with the aim of improving the single indoor noise reduction method and people’s acoustic comfort. However, practical solutions to promote the generation of positive indoor soundscapes are still insufficient. The purpose of this study was to explore the improvement effect of ceramic passive amplifiers on the indoor soundscape and the relationship between the improvement effect and different amplifier shapes. Objective sound pressure level (SPL) values and subjective soundscape perception were measured for 10 ceramic passive amplifiers based on the soundscape, mainly using a comparative method. Ten sample amplifiers were compared with the acoustic data of the original open-plan studio environment, and then with an electronic sound amplifier. The results show that ceramic passive amplifiers can improve the quality of the indoor soundscape by creating sound scenes with appropriate loudness. Regarding non-acoustic aspects, the shape and materials of ceramic passive amplifiers play a positive role in emotional guidance.
31
Park, Min-Sang, Gwon-Seok Sun e Jin-Young Kim. "A Study on the Automatic Calibration Function of RF Amplifiers Using Artificial Neural Networks". Korea Industrial Technology Convergence Society 28, n.º 2 (30 de junho de 2023): 41–49. http://dx.doi.org/10.29279/jitr.2023.28.2.41.
Texto completo da fonteResumo:
In this study, power amplifiers are designed and manufactured based on the frequency specifications by customers. After learning appropriate compensation values according to the function and performance degradation factors of the manufactured power amplifier using an artificial neural network, the power amplifier itself can maintain an optimal performance when its function and performance degrade. The artificial neural networks are applied to power amplifiers using the STM32F series of microcontrollers, which are being widely used for industrial purposes in recent years. Hence, after manufacturing the power amplifiers, the optimal state is maintained without additional tuning by workers, as well as changes in the external environment and aging of electronics parts. When the performance of the power amplifier is degraded owing to other factors, the performance of the power amplifier can be improved by itself.
32
Woestenburg, E. E. M. "Noise properties of balanced amplifier configurations". International Journal of Microwave and Wireless Technologies 3, n.º 1 (fevereiro de 2011): 67–75. http://dx.doi.org/10.1017/s1759078711000018.
Texto completo da fonteResumo:
This paper analyzes the noise properties of balanced amplifier configurations in terms of noise waves and discusses the effect of various amplifier configurations on the noise and signal parameters. It shows how the noise generated in the load on the input coupler of a balanced amplifier deteriorates the amplifiers noise resistance parameter with respect to that of its component amplifiers. The properties of two new balanced amplifier configurations will be discussed, which enable the reduction or elimination of this deterioration.
33
Kwak, Joon Young, e Sung-Yun Park. "Compact Continuous Time Common-Mode Feedback Circuit for Low-Power, Area-Constrained Neural Recording Amplifiers". Electronics 10, n.º 2 (11 de janeiro de 2021): 145. http://dx.doi.org/10.3390/electronics10020145.
Texto completo da fonteResumo:
A continuous-time common-mode feedback (CMFB) circuit for low-power, area-constrained neural recording amplifiers is proposed. The proposed CMFB circuit is compact; it can be realized by simply replacing passive components with transistors in a low-noise folded cascode operational transconductance amplifier (FC-OTA) that is one of the most widely adopted OTAs for neural recording amplifiers. The proposed CMFB also consumes no additional power, i.e., no separate CMFB amplifier is required, thus, it fits well to low-power, area-constrained multichannel neural recording amplifiers. The proposed CMFB is analyzed in the implementation of a fully differential AC-coupled neural recording amplifier and compared with that of an identical neural recording amplifier using a conventional differential difference amplifier-based CMFB in 0.18 μm CMOS technology post-layout simulations. The AC-coupled neural recording amplifier with the proposed CMFB occupies ~37% less area and consumes ~11% smaller power, providing 2.67× larger output common mode (CM) range without CM bandwidth sacrifice in the comparison.
34
Kwak, Joon Young, e Sung-Yun Park. "Compact Continuous Time Common-Mode Feedback Circuit for Low-Power, Area-Constrained Neural Recording Amplifiers". Electronics 10, n.º 2 (11 de janeiro de 2021): 145. http://dx.doi.org/10.3390/electronics10020145.
Texto completo da fonteResumo:
A continuous-time common-mode feedback (CMFB) circuit for low-power, area-constrained neural recording amplifiers is proposed. The proposed CMFB circuit is compact; it can be realized by simply replacing passive components with transistors in a low-noise folded cascode operational transconductance amplifier (FC-OTA) that is one of the most widely adopted OTAs for neural recording amplifiers. The proposed CMFB also consumes no additional power, i.e., no separate CMFB amplifier is required, thus, it fits well to low-power, area-constrained multichannel neural recording amplifiers. The proposed CMFB is analyzed in the implementation of a fully differential AC-coupled neural recording amplifier and compared with that of an identical neural recording amplifier using a conventional differential difference amplifier-based CMFB in 0.18 μm CMOS technology post-layout simulations. The AC-coupled neural recording amplifier with the proposed CMFB occupies ~37% less area and consumes ~11% smaller power, providing 2.67× larger output common mode (CM) range without CM bandwidth sacrifice in the comparison.
35
Singh, Kulwinder, Karan Goel, Kamaljit Singh Bhatia e Hardeep Singh Ryait. "Investigations of Different Amplifiers in 16 × 40 Gb/S WDM System". Journal of Optical Communications 40, n.º 4 (25 de outubro de 2019): 341–46. http://dx.doi.org/10.1515/joc-2017-0092.
Texto completo da fonteResumo:
Abstract Different fiber amplifiers such as semiconductor optical amplifier, erbium-doped fiber amplifier and erbium ytterbium-co-doped fiber amplifier (EYCDFA) are investigated for 16×40 GB/s wavelength division multiplexing system. Various performance parameters including Q-factor, bit error rate, jitter, eye opening and eye closure are observed and analyzed. It is reported that EYCDFA is a better choice among the tested amplifiers. The proposed system is also investigated in terms of transmission distance.
36
Huang, H., e G. J. Tallents. "The output of a laser amplifier with simultaneous amplified spontaneous emission and an injected seed". Laser and Particle Beams 27, n.º 3 (19 de junho de 2009): 393–98. http://dx.doi.org/10.1017/s0263034609000500.
Texto completo da fonteResumo:
AbstractThe minimum irradiance needed to overcome amplified spontaneous emission (ASE) of a seed beam injected into a laser amplifier is evaluated. The treatment is particularly applicable to extreme ultraviolet (EUV) and X-ray laser schemes to inject laser harmonic radiation as a seed into (1) plasma laser amplifiers and (2) free-electron lasers. Simple expressions and calculations are given for the minimum injected irradiance required for amplification of the injected seed beam to exceed ASE from the amplifier, including the effects of gain saturation, assuming one dimensional radiative transfer.
37
Sokol, Miroslav, Pavol Galajda e Patrik Jurik. "Design and Realization of Ultra-Wideband Differential Amplifiers for M-Sequence Radar Applications". Sensors 24, n.º 7 (27 de março de 2024): 2143. http://dx.doi.org/10.3390/s24072143.
Texto completo da fonteResumo:
Amplification of wideband high-frequency and microwave signals is a fundamental element within every high-frequency circuit and device. Ultra-wideband (UWB) sensor applications use circuits designed for their specific application. The article presents the analysis, design, and implementation of ultra-wideband differential amplifiers for M-sequence-based UWB applications. The designed differential amplifiers are based on the Cherry–Hooper structure and are implemented in a low-cost 0.35 µm SiGe BiCMOS semiconductor process. The article presents an analysis and realization of several designs focused on different modifications of the Cherry–Hooper amplifier structure. The proposed amplifier modifications are focused on achieving the best result in one main parameter’s performance. Amplifier designs modified by capacitive peaking to achieve the largest bandwidth, amplifiers with the lowest possible noise figure, and designs focused on achieving the highest common mode rejection ratio (CMRR) are described. The layout of the differential amplifiers was created and the chip was manufactured and wire-bonded to the QFN package. For evaluation purposes, a high-frequency PCB board was designed. Schematic simulations, post-layout simulations, and measurements of the individual parameters of the designed amplifiers were performed. The designed and fabricated ultra-wideband differential amplifiers have the following parameters: a supply current of 100–160 mA at −3.3 V or 3.3 V, bandwidth from 6 to 12 GHz, gain (at 1 GHz) from 12 to 16 dB, noise figure from 7 to 13 dB, and a common mode rejection ratio of up to 70 dB.
38
Zhu, Ziren, Yu Liu, Jinghan Ye, Juntao Tian, Tianjian Wan, Jinzhou Bai, Yijun Zheng, Rongqing Tan, Zhiyong Li e Xinjun Su. "Gain Measurement of ZnGeP2 Optical Parametric Oscillator Pulses in a High-Pressure CO2 Amplifier". Photonics 11, n.º 2 (5 de fevereiro de 2024): 154. http://dx.doi.org/10.3390/photonics11020154.
Texto completo da fonteResumo:
Laser pulse amplification by a high-pressure CO2 amplifier in the long-wave infrared (LWIR) spectral range is a feasible technology for strong-field physics research. Crystals such as ZnGeP2 (ZGP) have high nonlinear coefficients and transmittance in the LWIR region, with spectral widths of generated pulses closely matching the gain spectrum of high-pressure CO2 amplifiers. Therefore, ZGP optical parametric oscillation (OPO) may allow higher-efficiency energy extraction in amplifiers, improving the output characteristics of LWIR amplification systems. In this study, the gain measurement of ZGP OPO pulses amplified by a high-pressure CO2 amplifier was carried out for the first time. Single-detector acquisition was utilized to achieve a unified sensor responsivity, and a laser signal-triggered function generator was used to synchronize the seed pulse and amplifier. Six-pass amplification was performed successively, yielding an amplification factor of 4.5 for the peak power and a maximum coefficient of 0.42% cm−1 for the small-signal gain. The gain and loss effect during small-signal amplification were discussed. The potential capability of acquiring ultra-short pulses with ZGP OPO pulses was also explored with the FFT function of MATLAB software.
39
Sahota, Jasjot Kaur, e Divya Dhawan. "Performance Analysis of Homodyne-Based FSO System Using Various Optical Amplifiers". Journal of Optical Communications 41, n.º 4 (28 de abril de 2020): 339–46. http://dx.doi.org/10.1515/joc-2018-0005.
Texto completo da fonteResumo:
AbstractA detailed performance analysis of homodyne-based coherent detection in Free-space optics (FSO) with various optical amplifiers is presented in this paper. Using homodyne detection in FSO system, the effect of scintillation is mitigated. To further enhance the performance of FSO system, various optical amplifiers such as erbium-doped fibre amplifier, semiconductor optical amplifier, gain-controlled amplifier and black box model of amplifier can be employed in the system. Improvement in the system can be validated in terms of BER, Q-factor and eye diagram.
40
Jang, Jejin, Jaehyuk Choi, Donghun Lee e Hyungsoo Mok. "Design Procedure of Cascaded Multilevel Inverter for High-Power Amplifier in SONAR System". Energies 17, n.º 7 (26 de março de 2024): 1581. http://dx.doi.org/10.3390/en17071581.
Texto completo da fonteResumo:
In recent years, there has been a trend toward expanding the operating frequency range and increasing the output power of Sound Navigation and Ranging (SONAR) systems to enhance their acoustic detection capabilities. However, due to this increase in operational power, the electrical capacity of amplifiers for SONAR system operation also increases, necessitating High-Power Amplifiers. When configured with a single amplifier, as in conventional methods, the volume of amplifiers increases due to volumetric increases in heat dissipation, components, and windings. These issues are detrimental to SONAR amplifier installation, mobility, maintenance, and equipment lifespan due to stress on individual components. Additionally, amplifiers for SONAR systems are comprised of power conversion devices, transformers for LC filters and matching, necessitating consideration of LC filters and matching transformers for enhancing voltage quality and efficiency to improve amplifier performance transmitted to SONAR transducers. However, previous research has focused on single-amplifier design methods, neglecting such considerations. Therefore, this paper proposes a design technique that overcomes the drawbacks of using the conventional design method by configuring multiple H-bridge inverters in a cascade format and utilizes one of the optimization algorithms, Particle Swarm Optimization (PSO), to derive amplifier design techniques that optimize component parameters for enhancing high-capacity amplifier performance. Subsequently, theoretical analysis, simulations, and experimental results comparing the proposed high-power amplifier design method with conventional single-amplifier design methods demonstrate similar error rates in operational frequency bands.
41
Feldkord, Sven, Marco Reit e Wolfgang Mathis. "Implementation of a digital evaluation platform to analyze bifurcation based nonlinear amplifiers". Advances in Radio Science 14 (28 de setembro de 2016): 47–50. http://dx.doi.org/10.5194/ars-14-47-2016.
Texto completo da fonteResumo:
Abstract. Recently, nonlinear amplifiers based on the supercritical Andronov–Hopf bifurcation have become a focus of attention, especially in the modeling of the mammalian hearing organ. In general, to gain deeper insights in the input-output behavior, the analysis of bifurcation based amplifiers requires a flexible framework to exchange equations and adjust certain parameters. A DSP implementation is presented which is capable to analyze various amplifier systems. Amplifiers based on the Andronov–Hopf and Neimark–Sacker bifurcations are implemented and compared exemplarily. It is shown that the Neimark–Sacker system remarkably outperforms the Andronov–Hopf amplifier regarding the CPU usage. Nevertheless, both show a similar input-output behavior over a wide parameter range. Combined with an USB-based control interface connected to a PC, the digital framework provides a powerful instrument to analyze bifurcation based amplifiers.
42
Hiti, M. "Validation of combinatorial evaluation of strain-gauge amplifier linearity". ACTA IMEKO 9, n.º 5 (31 de dezembro de 2020): 205. http://dx.doi.org/10.21014/acta_imeko.v9i5.970.
Texto completo da fonteResumo:
This paper describes a validation of a combinatorial calibration technique based calibration procedure for strain-gauge amplifier calibration. The deviation between two strain-gauge amplifiers at calibration using the combinatorial technique is compared to the deviation between the same two amplifiers at calibration on a force calibration machine as a transducer-amplifier chain under unchanged conditions, serving as an amplifier linearity comparator. This enables the validation to be confirmed with a suitable expanded measurement uncertainty of 3 nV/V.
43
You, Kiheum, e Hojong Choi. "Wide Bandwidth Class-S Power Amplifiers for Ultrasonic Devices". Sensors 20, n.º 1 (4 de janeiro de 2020): 290. http://dx.doi.org/10.3390/s20010290.
Texto completo da fonteResumo:
Wide bandwidth ultrasonic devices are a necessity in high-resolution ultrasonic systems. Therefore, constant output voltages need to be produced across the wide bandwidths of a power amplifier. We present the first design of a wide bandwidth class-S power amplifier for ultrasonic devices. The −6 dB bandwidth of the developed class-S power amplifier was measured at 125.07% at 20 MHz, thus, offering a wide bandwidth for ultrasonic devices. Pulse-echo measurement is a performance measurement method used to evaluate the performance of ultrasonic transducers, components, or systems. The pulse-echo signals were obtained using an ultrasonic transducer with designed power amplifiers. In the pulse-echo measurements, time and frequency analyses were conducted to evaluate the bandwidth flatness of the power amplifiers. The frequency range of the ultrasonic transducer was measured and compared when using the developed class-S and commercial class-A power amplifiers with the same output voltages. The class-S power amplifiers had a relatively flat bandwidth (109.7 mV at 17 MHz, 112.0 mV at 20 MHz, and 109.5 mV at 23 MHz). When the commercial class-A power amplifier was evaluated under the same conditions, an uneven bandwidth was recorded (110.6 mV at 17 MHz, 111.5 mV at 20 MHz, and 85.0 mV at 23 MHz). Thus, we demonstrated that the designed class-S power amplifiers could prove useful for ultrasonic devices with a wide frequency range.
44
Lopez-Martin, Antonio, Maria Pilar Garde, Jose M. Algueta-Miguel, Javier Beloso-Legarra, Ramon G. Carvajal e Jaime Ramirez-Angulo. "Energy-Efficient Amplifiers Based on Quasi-Floating Gate Techniques". Applied Sciences 11, n.º 7 (6 de abril de 2021): 3271. http://dx.doi.org/10.3390/app11073271.
Texto completo da fonteResumo:
Energy efficiency is a key requirement in the design of amplifiers for modern wireless applications. The use of quasi-floating gate (QFG) transistors is a very convenient approach to achieve such energy efficiency. We illustrate different QFG circuit design techniques aimed to implement low-voltage, energy-efficient class AB amplifiers. A new super class AB QFG amplifier is presented as a design example, including some of the techniques described. The amplifier has been fabricated in a 130 nm CMOS test chip prototype. Measurement results confirm that low-voltage, ultra-low-power amplifiers can be designed, preserving, at the same time, excellent small-signal and large-signal performance.
45
Gajare, Milind, e Shedge D.K. "CMOS Trans Conductance based Instrumentation Amplifier for Various Biomedical Signal Analysis". NeuroQuantology 20, n.º 5 (30 de abril de 2022): 53–60. http://dx.doi.org/10.14704/nq.2022.20.5.nq22148.
Texto completo da fonteResumo:
Feed forward design techniques for the Trans-conductance operational amplifier removes the barriers of operating frequencies. It is now possible to design amplifiers with large the Trans-conductance that operates at Giga hertz frequency range. There are several Trans-conductance amplifiers used to design a medical and Industrial application that helps in processing various bio medical signals such as Electrocardiographs, Electroencephalographs, Electromyograms and several others. The proposed paper shows the implementation of an instrumentation amplifier using CMOS based the Trans-conductance operational amplifiers also the processing of biomedical ECG, EEG and EMG signals. The CMOS process technology helps to integrate complex circuits on minimal surface area. The Trans-conductance instrumentation operational amplifiers has features includes noise reduction, low DC offset, High output impedance and Common Mode rejection Ratio values. The circuit implementation and simulations has been done on Electronic Design and Automation tool with 0.13μm CMOS process technology.
46
Choi, Hojong. "Class-C Linearized Amplifier for Portable Ultrasound Instruments". Sensors 19, n.º 4 (21 de fevereiro de 2019): 898. http://dx.doi.org/10.3390/s19040898.
Texto completo da fonteResumo:
Transistor linearizer networks are proposed to increase the transmitted output voltage amplitudes of class-C amplifiers, thus, increasing the sensitivity of the echo signals of piezoelectric transducers, which are the main components in portable ultrasound instruments. For such instruments, class-C amplifiers could be among the most efficient amplifier schemes because, compared with a linear amplifier such as a class-A amplifier, they could critically reduce direct current (DC) power consumption, thus, increasing the battery life of the instruments. However, the reduced output voltage amplitudes of class-C amplifiers could deteriorate the sensitivity of the echo signals, thereby affecting the instrument performance. Therefore, a class-C linearized amplifier was developed. To verify the capability of the class-C linearized amplifier, typical pulse-echo responses using the focused piezoelectric transducers were tested. The echo signal amplitude generated by the piezoelectric transducers when using the class-C linearized amplifier was improved (1.29 Vp-p) compared with that when using the class-C amplifier alone (0.56 Vp-p). Therefore, the class-C linearized amplifier could be a potential candidate to increase the sensitivity of echo signals while reducing the DC power consumption for portable ultrasound instruments.
47
Shukla, Sachchida Nand, Syed Shamroz Arshad e Geetika Srivastava. "NPN Sziklai pair small-signal amplifier for high gain low noise submicron voltage recorder". International Journal of Power Electronics and Drive Systems (IJPEDS) 13, n.º 1 (1 de março de 2022): 11. http://dx.doi.org/10.11591/ijpeds.v13.i1.pp11-22.
Texto completo da fonteResumo:
Small signal-to-noise ratio (SNR) and multiple noise sources, coupled with very weak signal amplitudes of bio signals make brain-computer interface (BCI) application studies a challenging task. The front-end recorder amplifiers receive very-weak signal (few μV) from high impedance electrodes and for efficient processing of such weak and low frequency (<1 kHz) signals a high gain amplifier with very low operating voltage and low total harmonic distortion (THD) is required. Existing amplifiers suffer from problem of high non-linearity and low common mode rejection. A good sense amplifier at predeceasing stage can solve this problem. Utilizing very high amplification factor of Sziklai Pair, this paper proposes two circuit topologies of common-emitter and common-collector negative-positive-negative (NPN) Sziklai Pair small signal amplifiers suitable for use in preamplifier stages of such signal acquisition circuit. Present study provides broad-spectrum of analysis of these amplifiers covering effect of additional biasing resistance RA, variation of ‘ideal forward maximum beta’ β, temperature dependency, noise sensitivity and phase variation. The tunable capability of first topology makes it a suitable candidate in wide variety of other applications. The first amplifier operates on very low input voltage range (0.1μV-6mV) whereas the second amplifier works on 100 μV-11 mV range of input voltage.
48
Aminzadeh, Hamed. "A reliable model for the compensation loop of multistage amplifiers at high frequency". Circuit World 45, n.º 4 (4 de novembro de 2019): 268–78. http://dx.doi.org/10.1108/cw-03-2019-0021.
Texto completo da fonteResumo:
Purpose Multistage amplifiers require a reliable frequency compensation solution to remain stable in a closed-loop configuration. A frequency compensation scheme creates an inner negative feedback loop amongst different amplifying stages and shapes the frequency response such that an unconditionally stable single-pole amplifier results for closed-loop operation. The frequency compensation loop is thus responsible for the placement of the poles and zeros and the final stability of multistage amplifiers. An amplifier incorporating a sophisticated frequency compensation network cannot be, however, analyzed in the presence of a complex ac feedback loop. The purpose of this study is to provide a reliable model for the compensation loop of multistage amplifiers at the higher frequencies. Design/methodology/approach In this paper, the major part of the amplifier, including a two-port network comprising the compensation network, is characterized using a reliable feedback model. Findings The model integrates all the frequency-dependent components of the frequency compensation network, and it can evaluate the nondominant real or complex poles of an amplifier. Originality/value The reliability of the proposed model is verified through analysis of the frequency response of the amplifiers and by comparing the analytic results with the simulation results in standard CMOS process.
49
Chen, Yuening, Kecheng Wang e Yan Zhuang. "Current state and challenges of ECG amplifiers". Highlights in Science, Engineering and Technology 32 (12 de fevereiro de 2023): 177–85. http://dx.doi.org/10.54097/hset.v32i.4988.
Texto completo da fonteResumo:
This paper describes and compares three amplifiers for ECG recording, namely a four-transistor stage band-pass amplifier, a DDA-based fully differential CMOS instrumentation amplifier and an OTA amplifier using current reuse. The performance metrics of the three amplifiers are listed, their respective advantages are compared, what factors limit their disadvantages are analyzed, the current state of the art and the direction of development of the ECG amplifier are indicated, and suggestions are given for further enhancement of the ECG amp. These amplifier circuits are designed in 0.35 µm CMOS and are verified by layout followed by simulation simulations. The results show that running at 2V dc supply, the quad-transistor stage amplifier and the DDA fully differential amplifier consume 672nW, obtain at least 2uVrms of input reference noise, and obtain greater common mode rejection ratios of 86dB and 83dB, while the OTA amplifier consumes less 320nW, obtains the most 2.05uVrms of input reference noise, and obtains a smaller common-mode rejection ratio of 65dB.
50
Wang, Peiyuan. "Optimal Design of Fiber Amplifier based on Thulium, YttErbium and Bismuth." Highlights in Science, Engineering and Technology 46 (25 de abril de 2023): 134–41. http://dx.doi.org/10.54097/hset.v46i.7694.
Texto completo da fonteResumo:
Although Erbium-doped fiber amplifier is still the mainstream of optical fiber communication nowadays, it has some limitations. The operation of EDFA is limited to 1530-1610nm, so it is an important research direction to explore different elements. This paper introduces three kinds of fiber amplifiers doped with different rare earth elements: Thulium-doped, YttErbium-doped, and Bismuth-doped fiber amplifiers. The optimal optimization performance is obtained through comparison logic by adjusting various parameters. The maximum gains of three rare-earth-doped fiber amplifiers in different wavelength ranges are obtained: The maximum gain of a Thulium-doped fiber amplifier is 51dB in the wavelength range of 1900nm to 2050nm. The maximum gain of a YttErbium-doped fiber amplifier is 62. 5dB in the wavelength range of 1020nm to 1080nm. The maximum gain of a Bismuth-doped fiber amplifier is 23dB in the wavelength range of 1640nm to 1770nm. These works pave the way for future research.