Design Of Multi-Channel Transmitter And Receiver And Research Of Phase Testing Algorithm

The transmitter and receiver are two important parts of active sonar system. This paper completes the design of multi-channel sonar transmitter and receiver by taking the researches of the small-aperture image sonar and single-beam dual-frequency ultrasonic fish finder as background. In addition, the research and realization of an algorithm in phase coherence testing of Multi-Channel receiver is completed.First this paper introduces the composition and characteristic of sonar transmitter. And a single-beam dual-frequency ultrasonic fish finder transmitter is designed, It adopts D class power amplifier driven by MOSFET. According to the reliability problem that square wave stimulating reactance load when using push-pull amplifying, detailed description is given of the principle that go against the transmitter reliability, and various improvement measures are given. Then a 4-channel image sonar transmitter is designed according to the practical demand, it adopts AB class power amplifier and works under the mode of transformer coupling push-pull amplifying.The receiver designed in this paper is mainly composed of preamplifier and Band-Pass filter. Low noise design of preamplifier and phase coherence design among Multi-Channel of receiver are the key technologies. The electrical noise of preamplifier limits its ability that detecting weak signal, namely it has influence on the sensitivity and dynamic range of receiver. The phase coherence among Multi-Channel is very important because it has great influence on the subsequent signal processing. This paper makes detailed analysis to the low noise design of preamplifier and phase coherence design among Multi-Channel of receiver.It is low precision, easily subject to environment for traditional measurement method of phase difference. According to the practical application demand, this paper puts forward measurement of phase difference with digital signal processing and it is realized on the data acquisition platform. The paper emphasizes on two methods: the adaptive phase estimator and the measurement of phase difference based on Fourier Transform.