水声接收机前置放大电路噪声分析与改进

Noise Analysis and Improvement of Preamplifier Circuit in Underwater Acoustic Receiver

水声信号经换能器转换为电学信号之后,其强度通常较弱,在应用之前需通过前置放大电路进行放大处理,提高其信噪比。为改善现有水声接收机前置放大电路的低噪声性能,基于通用的噪声模型,结合噪声叠加原理,对现有的水声接收机前置放大电路的噪声源进行分析,并对输出端的总电压密度和均方根噪声进行计算。在此基础上,提出2种降低前置放大电路噪声的方法,并通过仿真验证其降噪性能。此外,综合考虑降噪性能和实际应用要求,从这2种方法中选出更优方法,供后续前置放大电路降噪项目的开展参考。

Underwater acoustic signals are converted into electrical signals by transducers,but the electrical signals are very weak,so preamplification circuit is required to enhance them and to improve the signal-to-noise ratio for signal preprocessing.In order to further improve the low noise performance of the preamplifier circuit in the existing underwater acoustic receiver,based on the general noise model and noise superposition principle,this paper analyzes the noise source of the existing circuit,and theoretically calculates the total voltage density and root mean square noise at the output.On this basis,two improved schemes are devised.Simulation results show that they both can reduce noise effectively.The two schemes are compared and,for the particular application,the suitable improvment"scheme 1"is selected.