Analysis of signal error rate of time-varying channel effects on ASK band transmission of deep-sea abandoned profiler measuring instrument

摘要

Amplitude of digital signal attenuates seriously with the increase of probing depth, transmission rate and random noise, because channel impedance parameters of deep-sea abandoned profiler measuring instrument is time-varying in the process of transmission and it will seriously affect the stability of signal transmission in the ASK frequency band transmission. This paper first expounds the method of ASK amplitude demodulation and optimizes the transmission channel model. Secondly, this paper analyzes the variation of XCTD channel impedance parameters in the range of 2000m detection. And then, the method focuses on the effects of random noise, XCTD channel time-varying parameters and the transmission frequency on demodulation signal. It comes to conclusion that noise is the main factor affecting the stability of ASK transmission. Meanwhile, this paper analyzes in detail the size of error rate of demodulated signal in great depth measurement. In the process of ASK band transmission in the detection range of 2000m, the accuracy of signal transmission can be improved to some extent by selecting the band pass filter rightly. In the kind of transmission condition, the noise magnitude less than -50dB is most suitable for ASK band transmission mode.