two-stage power amplifiers

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Power Scaling of Laser Oscillators and Amplifiers Based on Nd:YVO4

Power Scaling of Laser Oscillators and Amplifiers Based on Nd:YVO4

In order to formulate an appropriate amplifier design strategy, the theory of laser amplification in end-pumped solid-state amplifiers is reviewed. Chapter 4 builds on the basic principles of amplification, initially in the small-signal limit and then extends this to account for saturation of the amplifier gain. An analytical approach is used to predict the effect of energy-transfer-upconversion on the small signal gain in an amplifier where the population inversion varies longitudinally, as in an end-pumped gain medium with a constant absorp- tion coefficient. An analysis of the saturated gain for a local area of the gain medium is reviewed, initially for a cw and then for a pulsed signal. This satu- rated gain formula for a pulsed signal is then used in a numerical integration to give the total gain for a Gaussian signal beam passing through an end-pumped gain medium where two simple approximations for the pump beam profile are compared. The effect of varying the ratio of the signal beam size to the pump beam size is explored and the optimisation of this overlap ratio with regard to maximising the gain is discussed. A simplified analysis of the degradation in beam quality, caused by aberrated thermal lensing, follows which is then used to extend the numerical model to make predictions of the brightness scaling potential of an amplifier. Finally the chapter discusses the use of multiple am- plifier stages and multiple pass amplifiers as a route for further power scaling In Chapter 5, many of the principles from Chapter 4 are brought together to form a multi-stage Nd:YVO 4 amplifier design where the seed laser is the
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Efficient Power Amplifiers for Millimeter-Wave Beamformers.

Efficient Power Amplifiers for Millimeter-Wave Beamformers.

After demonstrating high peak PAE single-path PAs, we investigate architectures that can improve output power and back-off PAE of millimeter-wave PAs. We investigate techniques for Doherty PAs that are key to improve the output power and back-off efficiency at millimeter-wave. These include multi-stage architecture choice, benefits and limitations of harmonic tuning, peaking PA trade-offs and output combiner choice. Two-stage carrier and peaking amplifiers were used for sufficient gain along each path which enabled the possibility of independent amplitude and phase adjustment of the two amplifiers using preceding phase shifter stage. Simple fundamental output match was preferred over harmonic tuning due to broadband performance. Design methodology of the peaking PA presented the impact of bias current density on power consumption and linearity of the Doherty PA. A high-impedance output match was preferred over optimum power match for the peaking PA to minimize leakage from the carrier PA. Efficacy of these techniques / design considerations are demonstrated with the implementation of a 60-GHz Doherty PA which demonstrates 3-dB higher oP 1dB and 5% points higher 6-dB-back-off PAE than the harmonic-tuned continuous class-AB mode
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Design Simulation of Low Power Two Stage CMOS Operational Amplifier

Design Simulation of Low Power Two Stage CMOS Operational Amplifier

An Operational amplifier is a high gain electronic voltage amplifier with a differential input and usually a single ended output. An Op-amp produces an output voltage that is typically larger than voltage difference between its input terminals [1]. Operational Amplifiers represents one of the most useful and one of the most used building blocks for analog and integrated circuit such as A/D,D/A circuits, switched capacitor filters Instrumentation amplifier, signal generator, voltage regulators and non-linear analog operators[1][3][4].

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High Power Two  Stage Class AB/J Power Amplifier with High Gain and Efficiency

High Power Two Stage Class AB/J Power Amplifier with High Gain and Efficiency

power, has led to the development of these technologies. In 1998, the first CMOS RF power amplifier was made with 1W power delivery at the 2GHz frequency range, with PAE = 41% and 2V power supply [1]. Simultaneously with the developments in the wireless communication industry, tremendous improvements in semiconductor technology emerged. Among them, the most significant progress was the development of CMOS technology. CMOS transistors' remarkable feature is that the speed will increase, while it consumes less power per function than digital and analog circuits which results in reducing the circuit cost and size. Therefore, the ultimate goal of engineers and researchers in the process is putting the power amplifier, IC transmitter and receiver, power management module and digital bandwidth on a piece of Si, GaAs or GaN. Wireless communication systems require high linear power amplifier to send a signal with minimum phase and amplitude distortion. Bandwidth, efficiency, linearity system and desirable output power are four basic and determinant factors for RF microwave power amplifier in the modern communication systems. Improving efficiency and achieving a high output power simultaneously, has proposed a useful design method which is a promising solution, using various classes of power amplifier (Single or Mix). Usually, power amplifiers are based on their configuration and their performance conditions, and are classified in various classes (eg, Class A, B, C, AB, D, F, F -1 , S, G, J, etc). Classes A, B, C, AB, depending on the
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TWO-STAGE FULLY-DIFFERENTIAL OTA FOR A 10-BIT 40-MSAMPLES/S CMOS ANALOG-TO-DIGITAL CONVERTER

TWO-STAGE FULLY-DIFFERENTIAL OTA FOR A 10-BIT 40-MSAMPLES/S CMOS ANALOG-TO-DIGITAL CONVERTER

A two-stage fully-differential Operational Transconductance Amplifier (OTA) for a 10-bit 40-Msamples/s Nyquist rate Analog-to-Digital Converter (ADC) using 0.35µm Complementary Metal-Oxide Semiconductor (CMOS) process is presented. A telescopic cascode topology is employed as main stage, with common source amplifiers as output stage for the differential outputs. The open loop amplifier achieved a gain of 108dB. The closed loop OTA has gain of 4 with settling time less than 11ns for an accuracy of 0.5%. Total output noise achieved is 63.4uVrms. Loop unity gain bandwidth is 205MHz with phase margin of 77.6degrees. The design has a dynamic range of 88.3dB. On the average, the amplifier dissipates 26.6mW of power from a 3V supply.
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Design And Construction Of 300W Audio Power Amplifier For Classroom

Design And Construction Of 300W Audio Power Amplifier For Classroom

O.P.T system is used to appear the sound from the output transformer to the output speaker. To get the good quality sound, push-pull system can be used in the output system. O.P.T system is constructed input, driver and output. In O.P.T system, low frequency response cannot easily get. And then, the size of the amplifier is big. O.T.L system is the sounds amplify system without output transformer. In this system, output capacitor is used instead of using output transformer. O.C.L system is used without output capacitor. Why O.T.L system cannot produce the good sound quality is because of using output condenser and the change of sound quality depending on the output condenser. B.C.L system is the system that two O.C.L combine with transistor or IC at the input stage. The output power of the B.C.L system is four times of the output power of O.C.L. Many types of amplifier classes are(i) Class A (ii) Class B (iii) Class C (iv) Class D (v) Class E (vi) Class F(vii) Class G(viii) Class H(ix) Class AB and so on. Class A Amplifier has low efficiency of less than 50% but good signal reproduction and linearity. Class B Amplifier is twice as efficient as Class A Amplifier with a maximum theoretical efficiency of about 70% because the amplifying device only conducts for half of the input signal. Class AB amplifier has an efficiency rating between that of Class A and Class B but poorer signal reproduction than Class A amplifiers. Class C Amplifier is most inefficient amplifier class as only a very small portion of the input signal is amplified therefore the output signal bears very little resemblance to the input signal. Class C Amplifiers have the worth reproduction. Class D operation makes the output circuit extremely efficient (around 90%) allowing high power output without the need for such high power transistors and elaborate heat sinks. Class D amplifier is very efficient class of amplifier suited to both high power audio and RF amplifiers and low power portable amplifiers. Class E and F amplifier is a highly efficient switching power amplifier. Class G amplifier aims that it reduces the amplifier power dissipation. Class G amplifier is very useful in large PA amplifiers.
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Multi Objective Optimization Of Two Stage Operational Amplifiers Using Antlion Optimization

Multi Objective Optimization Of Two Stage Operational Amplifiers Using Antlion Optimization

WITH respect to the assorted circuits, the formulation of circuit that functions in analog manner could involve many proboles such as takes a lot of time in formulation. Devoid of adequate tools that performs the process of formulation automatically involved in the design of analog circuits. Development of tools which performs the formulation of particular circuits was took place for the past two decades[1].On the other hand,majority, the developed tools lack in accuracy along with approximate prototyping. Involuntary formulation with respect to integrated circuits that might function in the analog manner will be the toughest due to the requirement with respect to least power dissipation formulation along with minimization of duration involved in production [2]. Currently, majority of the analog circuit formulation will be carried out physically besides the utilization of certain modelling tools which performs with equations. Excellence of formulated circuit will be relied upon the skill set of the engineer. Duration of formulation must be completed within short duration by utilizing the sophisticated formulation tools. Transistors with diverse dimension will be contained in the integrated circuit in analog form [3]. Involuntary computations that falls back in accuracy besides prototypes dependent with prototypes, formulations performed with numerous steps involved in modelling utilizing spice along with compressive traditional production of outline.
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A Hysteretic Two-phase Supply Modulator for Envelope Tracking RF Power Amplifiers

A Hysteretic Two-phase Supply Modulator for Envelope Tracking RF Power Amplifiers

In this paper, a two-phase supply modulator suitable for envelope tracking power amplifiers is proposed. The modulator has fewer numbers of external R and C elements and simpler architecture in comparison with PWM two-phase modulators. The output voltage ripples and consequently the linearity of the output voltage of the architecture has been improved compared to the single-phase architecture. Although the complexity of the two- phase modulator is more than that of the single- phase architecture, the efficiency is improved up to about 4 percent. These stems from the lower output voltage ripples, and consequently lower linear amplifier power consumption. The inductor size of the proposed modulator is lower than that of previously reported modulators. The lower inductance although increases the switching frequency, it improves the large signal transition response of the modulator, resulting in a better linearity performance. The class AB PA designed in this paper has a two-stage folded cascode architecture which has the ability to allow the switching ripples to be as low as 7.2mVrms at the switching frequency of 80 MHz.
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Optimization, Analysis and Comparison of Two Stage and Three Stage Operational Amplifiers using 0.3µM Process Technology for SCMOS

Optimization, Analysis and Comparison of Two Stage and Three Stage Operational Amplifiers using 0.3µM Process Technology for SCMOS

Operational Amplifiers are one of the most widely used building blocks for analog and mixed-signal systems. They are employed from dc bias applications to high speed amplifiers and filters. General purpose op amps can be used as buffers, summers, integrators, differentiators, comparators, negative impedance converters, and many other applications. With the quick improvements of computer aided design (CAD) tools, advancements of semiconductor modeling, steady miniaturization of transistor scaling, and the progress of fabrication processes, the integrated circuit market is growing rapidly. Nowadays, complementary metal-oxide semiconductor SCMOS technology has become dominant over bipolar technology for analog circuit design in a mixed-signal system due to the industry trend of applying standard process technologies to implement both analog circuits and digital circuits on the same chip. While many digital circuits can be adapted to a smaller device level with a smaller power supply, most existing analog circuitry requires considerable change or even a redesign to accomplish the same feat. With transistor length being scaled down to a few tens of nanometers, analog circuits are becoming increasingly more difficult to improve upon.. In particular, it has proved difficult to match the open loop gain of bipolar op amps with CMOS technology [3, 4]. This is due to the inherently lower transconductance of CMOS devices as well as the gain reduction due to short channel effects that come into play for submicron CMOS processes.
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Performance Improvement of Power Amplifiers with Volterra Model

Performance Improvement of Power Amplifiers with Volterra Model

Fig.1 shows an amplifier with negative feedback. the amplifier configuration can be divided into a linear and nonlinear part as represented by block diagram in Fig.2 [2]. The aim of our research is to design a linearization technique without changing the internal configuration of the main amplifier [5]. However, in Fig.2 the amplifier has been split into two stage: the first stage is linear and its gain is A V1 (s)and the nonlinear part of the circuit is represented by the operator G. Then the Kernel transform of the

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HIGH POWER FACTOR AC-DC CONVERTER WITHOUT PFC PREREGULATOR

HIGH POWER FACTOR AC-DC CONVERTER WITHOUT PFC PREREGULATOR

Two-stage ac–dc converters consist of two power-processing stages with their respective control circuits. However, two-stage ac–dc converters raise power losses and the manufacturing cost, eventually reducing the system efficiency and the price competitiveness. In efforts to reduce the component count, the size, and the cost, a number of single-stage ac–dc converters have been proposed and developed. The main idea is that a PFC input stage and a high frequency dc–dc converter are simplified by sharing common switches so that the PFC controller, the PFC switch, and its gate driver can be eliminated. Most single-stage ac–dc converters in low-power application employ single-switch dc–dc converters such as flyback or forward converters [5].
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2.4 GHz Class F Power Amplifier for Healthcare Application

2.4 GHz Class F Power Amplifier for Healthcare Application

Fig.2 shows that the basic sensing node can collect the physiological signals (e.g.: such as EEG, ECG, body temperature, blood pressure, heart beat etc.), when attached to a human body [3] [4] [5] [6]. The processing unit processes all the sensed signals, then sends out the data based on communication protocols. All the processed data will be transmitted through a wireless link to a portable, personal base-station. Doctors can then obtain all the patients’ data through the network. Two major requirements for a WSN are the need for a compact form factor and low cost. As seen in the figure 3, the power amplifier is the major consumer of power in a sensor node. A power amplifier design for a WSN would ideally be low cost while providing high gain, high linearity and low power consumption. This is a challenging design requirement. For instance, while silicon designs are low cost, amplifiers built in silicon do not typically provide high gain or linearity.
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Optimized Current-Mode Class-D RF Power Amplifier for Software Defined Radio

Optimized Current-Mode Class-D RF Power Amplifier for Software Defined Radio

For sake of comparison with the published results of class-D CMOS power amplifiers, Table 2 summarizes the performance parameters of the most recent publications. Recently, Broadband CMCD amplifier was demonstrated to attain an efficiency of 45% at RF frequency of 1.8 GHz with an output power of 26.8 dBm using 130 nm CMOS process and encapsulated in QFN package [6]. In [4], a CMCD power amplifier has been designed in 90-nm technology, achieving 76% maximum drain efficiency, with 16-dBm of output power at 2.45-GHz, using solely on-chip components. In [7] a VMCD RF PA operating at frequency of 1.85GHz, and supply voltage of 5.5V delivers +32 dBm in a standard 130nm CMOS technology this voltage mode PA utilizes four on-chip transformers to combine the outputs of eight Class-D stages. Our PA presented in this work operates at 2.4GHz and gives a best trade-off between PAE and output power with respect to the other published class-D PAs, The proposed power amplifier has largest1dB bandwidth among the tabulated amplifiers.
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10B-LR 10B-STD 10B-SUB OWNER S MANUAL

10B-LR 10B-STD 10B-SUB OWNER S MANUAL

In the event of a defect or malfunction, contact Bryston’s repair centers for return authorization. Products must be returned using original packaging material only. Packing material may be purchased from Bryston if necessary. This warranty is considered void if the defect, malfunction or failure of the product or any component part was caused by damage (not resulting from a defect or malfunction) or abuse while in the possession of the customer. Tampering by persons other than factory authorized service personnel or failure to fully comply with Bryston operating instructions voids the warranty. This warranty gives you specific legal rights and you may also have other rights which may vary from province to province and country to country. As of 2006-02-22 Bryston will only warranty Bryston products purchased through authorized Bryston dealers. Bryston products with a date code of 0608 or higher (date code format is “yyww”, where “yy” is the two least significant digits of the year and “ww” is the week of the year) must be accompanied by a copy of the bill-of-sale from a Bryston authorized dealer to qualify for warranty service. The warranty is transferable from the original owner to a subsequent owner as long as a copy of the bill-of-sale from the original authorized Bryston dealer accompanies the re-sale. The copy of the bill of sale to any subsequent owner need ONLY include the Name of the Bryston Authorized Dealer and the Model and Serial number of the Bryston product The warranty will only be honored in the country of the original purchase unless otherwise pre-authorized by Bryston.
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On the Minimization of Power Consumption in Base Stations using on/off Power Amplifiers

On the Minimization of Power Consumption in Base Stations using on/off Power Amplifiers

60% in energy consumption and up to 35% in CAPEX [14]. Noticeably, similarly to our work, a few number of MAC protocols have been proposed for wireless sensor networks (WSN). In particular, there are three MAC protocols, namely B-MAC [15], S-MAC [16] and T-MAC [17], where the unused sensors sleep periodically to save energy. The difficulty in adopting the philosophy of these sensor MAC protocols to the case of cellular networks, lays in the delay introduced by these MACs in the packet delivery, which is not a fundamental issue for sensor communications, while it is of paramount importance for cellular networks. Even though various energy saving solutions have been pressented in the past, we are the first to give a full representation, with a mathematical model, of a BS power consumption based on all of its components.
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First results from the microwave air yield beam experiment (MAYBE): Measurement of GHz radiation for ultra-high energy cosmic ray detection

First results from the microwave air yield beam experiment (MAYBE): Measurement of GHz radiation for ultra-high energy cosmic ray detection

A scan in deposited energy was made by varying the beam current of the Van de Graaff. This changes the instantaneous number of electrons in the beam which in turn changes the energy deposit in the chamber. This scan makes it possible measure the emission scaling with energy deposit. Data was taken with all three of the low noise amplifiers in different frequency bands and in both cross polarized and co-polarized configurations. The beam intensity was monitored with the pick-up coil at the beam exit and a power analysis like that performed for the power spectrum measurements was performed.
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Enhancement Gain of CMOS PA using Micro strip line for Millimeter wave applications

Enhancement Gain of CMOS PA using Micro strip line for Millimeter wave applications

Fig.1 shows the basic schematic PA circuit, it includes bias circuit, input matching network, and output matching network and inter-stage matching network. A two-stage amplifier bias circuit is composed of DC power VGG1 and VGG2. The gate values of VGG1 and VGG2 are chosen as 0.6V. A suitable quiescent point is provided, so the amplifier works at the mode of Class AB. As shown in the figure, input and output ports have 50Ω impedance. The desired impedances are obtained with the help of matching circuits. The power amplifier takes a small-amplitude signal at the output RF frequency as its input and drives a high power representation of the input into a lower impedance load. Generally, the load is an antenna having a resistance of 50 ohm. The purpose of the power amplifier is therefore to amplify the high frequency signal to be sent by the transceiver. The PA should be able to amplify the signal to transmit signals at powers high enough for the receiver to
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A Design Implementation of Single Stage Amplifiers  using  HEMT Technology

A Design Implementation of Single Stage Amplifiers  using  HEMT Technology

The HEMT is a heterostructure field effective device. This device gains an advantage of the larger transport properties of electrons i.e. high mobility and high carrier velocity [5].The Fig-2 exposed is a cross sectional view of HEMT structure. The variance in conduction band energies of two materials produces a quantum well on one side of the heterojunction. Due to which the electrons concentrate and form a two dimensional electron gas (2DEG). Similar to MESFET, the three terminals namely, source, gate and drain are arranged on the surface of the semiconductor structure to have the connection.
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CRYSTAL SETS TO SIDEBAND A Guide to Building an Amateur Radio Station

CRYSTAL SETS TO SIDEBAND A Guide to Building an Amateur Radio Station

High voltage power supply safety The old-tech QRP transmitter. Vacuum tube amplifiers[r]

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Design of a Low Power Class AB Two-Stage Op-Amp with Symmetrical Slew Rate

Design of a Low Power Class AB Two-Stage Op-Amp with Symmetrical Slew Rate

ABSTRACT: The operational amplifier is perhaps the most useful integrated device in existence today. It is widely used in analogue computers, simulation systems and in a variety of electronic applications such as filtering, buffering and comparison of signal levels. In this paper, the different schemes of power-efficient class AB two-stage op-amps using a current replication branch and adaptive loads were analysed. A CMOS class AB two-stage op-amp is proposed by modifying the existing power efficient class AB two-stage op-amps for low-power, optimum gain and symmetrical slew rate operation. In the proposed class AB two-stage op-amp power is significantly reduced. The circuits presented in this work are designed in 130nm technology by using mentor graphics backend tools with a supply voltage of 3.3V. Proposed class AB two-stage op-amp is compared with existing power efficient class AB two-stage op-amps and the results are discussed in detail.
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