The Design Of Underwater Acoustic Power Amplifier And The Research Of Matching Technique

Underwater acoustic power amplifier is an indispensable part of sonar transmitter. Itsmain function is to improve the voltage gain and current gain of the audio signal, and improvethe power output. The signal power generated by the waveform generator is very small andcan not direct drive transducer. So the power amplifier is very important to signal poweramplification.The matching network between underwater acoustic power amplifier and transducer ismainly used to complete the impedance matching between power amplifier and transducer.The impedance matching include turning matching and variable resistance matching. Usuallyuse transformer to realize the variable resistance matching. The transducer resistance istransformed into a right value by the transformer, making the power output voltage andcurrent utilization supreme. In the broadband system, broadband transformer is used to realizethe variable resistance matching. But due to the resistance of the broadband transducer in thein-band is not a constant value, therefore the radiation power changes with frequency.Resonance method is most used in turning matching. It is divided into single frequency on thesingle tuned matching and two resonant point double-tuned matching. Resonance method iswidely used in narrow band system. It uses inductive or capacitive component to matchcapacitive reactance transducer and inductive reactance transducer. When resonance in thework frequency point, the virtual work is minimum and the power factor is the largest. In thatcase, transmitter and transducer are in the best working state. The turning matching ofbroadband system is more complex because reactance value is not linear. It is difficult to useanalytic expression. In wireless communication, we commonly use real frequency method tosolve the matching problem of broadband, this method can also be used in underwateracoustic area.This pater first discusses the basic principle of the power amplifier and some keyproblems in the design of underwater acoustic power amplifier. And then discusses theacoustic transducer impedance matching methods, including single frequency point matchingand broadband matching. Finally, in order to meet the actual needs, I design a class ABacoustic power amplifier, complete the principle diagram and PCB design, and then completethe matching between the power amplifier and the transducer. I also design two class D poweramplifier, complete the principle diagram and PCB design.