Papers by Keyword: Power Amplifier

Abstract: Understanding heat transfer phenomena is crucial in high-power amplifiers to keep components within safe operating temperatures. This article investigates the GaN Power Amplifier (PA) thermal analysis for the optimum design of the heatsink. GaN PAs are roughly separated into junction, package, and heat sink layers to calculate the junction’s transient thermal response. It has been proven that allowing individual components to operate at temperatures over their maximum rated junction temperatures significantly reduces the system's operational reliability as a whole. This analysis investigates two different heat sinks for the optimum case temperature (T_case) for these different PAs. These PAs are operating S-band (2-3.4 GHz) and C-Ku-band (5-18 GHz) with drain efficiency of 60-65% and 9-22%, respectively. The design analysis of the heat sink for optimal performance is explored in this work.

Abstract: A revise system on frequency response based on power amplifier of shortwave transmitter is designed to solve the problem of nonlinear response at different frequencies on power amplifier. This system is able to guarantee the output of power amplifier to fluctuate slightly around the rated power though the two processes named pre-revise on frequency response of power amplifier and current revise on frequency response of power amplifier. A modified variable step and multi-rate updated LMS algorithm is put into use to reduce the calculated amount and boost the rate of the revise. It is demonstrated by experiment that the revise system of this paper is able to guarantee the output of power amplifier around the rated power with the deviation of dB at a high convergence rate.

Abstract: According to the requirements of smart substation metering system, a digital interface based on IEC 61850 specification is given, then the functional model of the merging unit is discussed. Meanwhile, according to the actual situation, the author proposes an analog output interface, in order to fit with traditional substation secondary equipment. Then the solution based on TMS320F28335 digital control platform is described, for which the voltage control module of the software and hardware circuits are discussed in detail. The experimental data shows that the proposed merging unit and analog voltage output interface can meet the accuracy standard of electronic transformer in the smart substation.

Abstract: In this paper, we present a high efficiency Doherty power amplifier (PA) employing dynamic power dividing network which automatically adjusts the input power division ratio in accordance with the level of input power to enhance efficiency. Doherty PA circuit parameters of each amplifier are determined by basic performance analysis according to the datasheet. Simulated circuits through Advanced Design System (ADS) exhibit an improvement of 4% at a 6 dB backoff point from its saturated output power (PSAT) than that of a conventional Doherty PA. Implemented Doherty PA using two Freescale MRF6S27015N laterally diffused metal oxide semiconductor (LDMOS) field-effect transistors (FETs) achieves excellent drain efficiency of 46.5% at a 6 dB backoff point from PSAT, which is 2% higher than conventional Doherty PA.

Abstract: In order to improve the nonlinear problems of power amplifier, this paper discussed about the nonlinear characteristic of power amplifier without memory and put forward a kind of new pre-distortion model. The MATLAB simulation process was being used to obtain the input and output amplitude curves, and calculated the normalized mean square error NMES and error vector magnitude EVM, the results show that the power amplifier linearization improved after pre-distortion processing.

Abstract: The modern demands for hearing level is getting higher and higher, so the authenticity of stereo sound quality demand is higher and higher, the stereo power amplifier is integrated circuit TDA2030A primarily composed of stereo power amplifier, it USES the typical power amplification circuit, with less distortion, peripheral components, high stability, wide frequency response range, high fidelity, the advantages of large power, at the same time adopt SiYun put GL324A of input audio signal processing and high, bass, and thus more output sound of quality guarantee. Articles of amplifiers made simple introduction, and give the detailed design and debug program.

Abstract: Presents a OFDM signal generation method which transforms general OFDM signal to constant envelope signal. Through out-of-band of original OFDM signal insertion synthetic noise signal, the composite signal in time domain is constant envelope, and in in-band can achieve a high signal-to-noise ratio. Simulations show that the method can be used in OFDM system to improve the efficiency of power amplifier. Simulations show that the method does not need too high sampling rate, at the same time there is no stability problems, compared to the high efficiency power amplifier based on time-domain Sigma-Delta modulation technology.

Abstract: Power amplifier is an important part of maglev control system and it may need lots of time and manpower at regulating PI parameters. To solve this problem, an equivalent model was proposed to simplify the parameter adjustment. In this paper, firstly, mathematical model of the power amplifier was proposed and the Simulink model was built in Matlab software. Then the experimental platform was established and dynamic properties of the power amplifier were studied by simulation and experiment. The results show that the overshoot and rise time of experiment and simulation results matches well and the error of cut-off frequency is less than 10%. Therefore, it has instructional significance for parameters design.

Abstract: The cyborg can control robotic arm by means of the brain implant. The design of implantable node is critical because the surgically implanted node should consume very low power. In this paper, an efficient CMOS Transmitter in terms of low power is presented for Implantable Medical Devices in the MICS band. The RF front-end transmitter consists of up-conversion mixer and a power amplifier. The designs have been done using Cadence RF Spectre tools with 180 nm technology and the transmitter front-end consumes 900μW for the MICS band.

Abstract: By analyzing the input and output data of memoryless power amplifier (PA), we construct the polynomial model and study the nonlinearities characteristics of it. Based on that the mathematic model of predistorter is gained, Least-square (LS) and adaptive LMS are used respectively to solve the question. Simulation results demonstrate predistortion can effectively correct the nonlinearities and both LS and LMS work well depending on different conditions.