A Design On Program-Controlled Power Amplifier With Super Power And Low Frequency

Underwater acoustic signal transmitter, an important part of active sonar, includes signal source, power amplifier, matching network and transducer. With the development of modern electronic technology, some battery-powered underwater acoustic equipment, such as sonobuoy, portable underwater acoustic communications equipment, portable underwater detection equipment, have increasingly required transmitter with higher efficiency, bandwidth, and intelligence. To meet these requirements, starting from basic theories, this thesis makes an in-depth analysis of the principles of the transmitter circuit, and has a circuit design for the major parts. What’s more, the thesis researches methods of expanding the bandwidth of the transmitter system, increasing the power amplifier, improving the system efficiency and making the system more intelligent. And the proposed methods have been proven feasible in circuit design and circuit debugging.This thesis analyzes the principles and structures of several widely used functional unit-circuits of power amplifier. In the analysis of how to improve the efficiency of the power amplifier, the thesis proposes to use two different amplification circuits of which the amplifier is consisted of semiconductor devices. Due to the high equivalent resistance of the transducer which needs to adopt high-voltage output, the amplifier is composed of multistage amplification structure so as to realize the function of amplifying voltage and current.In order to make the power amplifier more intelligent, the thesis also designs a control circuit which can control the power amplifier through an upper monitor. With the intention of making the transmitter into an ideal state, and taking the impedance of underwater acoustic transducer in the broadband into consideration, it is necessary to put the broadband matching between the transmitter and the transducer. From the perspective of scattering matrix and power transmission gain of two-port network, the thesis discusses the commonly used single and double resonance point matching technology and the original real frequency method and provides the verification of the original real frequency method the matters should be concerned in the design. In the end, through a experimental testing, it shows that the whole system works well and achieves anticipated technical requirements.