Browsing by Subject "Amplifiers (Electronics)"
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Item A high performance class-D amplifier with cascaded sigma-delta modulators(Texas Tech University, 2004-05) Trehan, ChintanThe focus of this thesis is on analysis, simulation and board level implementation of the proposed Class-D power amplifier architecture. The structural design consists of two Sigma-Delta Modulator (SDM) stages in cascade with an intermediate decimation-filter between them. Noise and high tone introduced at the first- stage is filter out through the decimation filter. The signal is converted to a 1-bit Pulse Duration Modulation (PDM) signal by the second stage SDM. The H-Bridge is made part of the SD loop, which enables not only the noise shaping of the quantization noise but also stabilizes the output power switching stage. Output of the H-Bridge is converted to a digital signal using a comparator and latch circuitry and is fed back. To further increase the linearity and performance, high frequency ripples introduced at the H-Bridge is quantized by using a 4-bit SD Analog-to-Digital Converter (ADC) in the feedback loop. Due to the intermediate digital stage and the feedback control at the output stage, the proposed structure has high efficiency and linearity and still is very compact making it possible for wide range of applications.Item Analysis of laser power amplifiers.(Texas Tech University, 1975-08) Shaw, Dihwa ShirleyThe design of laser systems based on the HF chemical reaction presents special problems resulting from the shape of the active region. In this study, a Rigrod-type approach is used to analyze a master oscillator power amplifier. By suitably arranging two flat mirrors beside the active media, a multipass amplifier is devised. The advantage of the multipass amplifier is that the active medium can be driven to saturation more easily and also the gain is enhanced. This analysis is interesting because a multipass amplifier has never been analyzed successfully. A general design procedure is offered and a number of cases are discussed. In particular, a five pass MORA is designed to fit a spatial gain distribution of interest,Item Design study of a spatial signal feedback amplifier(Texas Tech University, 1976-05) Bell, Steven VanceNot availableItem Harmonic distortion test development for class-D amplifier(Texas Tech University, 2004-05) Williams, Kirt TClass-D amplifiers are quickly replacing Class-AB amplifiers in various audio applications because Class-D amplifiers are more efficient than Class-AB amplifiers. This is a very competitive market. The total harmonic distortion plus noise (THD+N) of an amplifier, along with its' efficiency, determines the quality of the amplifier. It has been determined that Class-D amplifiers are the most efficient of all the current Classes. The manufacturer's goal is to achieve the lowest possible THD+N on their Class-D amplifiers. However, all measurements including THD+N measurements can be time consuming and expensive. Manufacturing companies moved from bench testing to Automatic Test Equipment (ATE) testing as a solution to reduce test time. As ATEs became popular a variety has appeared with different configurations and price tags. Manufacturing cost accelerated because of the need for expensive ATEs. Manufacturing companies are trying to reduce test cost by moving various devices over to cheaper ATEs that produce equivalent (or almost equivalent within reason) results. For this project, a method for testing the THD+N for a Class-D amplifier will be created on four platforms (bench testing, LabVIEW testing, ATS-2 testing, and ATE testing). The resulting THD+N of the three platforms will be compared along with the THD+N measured on an ATE (Teradyne A567). The comparison shows how each platform varies in cost, ease of testing, and the level of THD+N measured.