Research On The Responder Multi-frequency Interfere Overcoming Technique

Underwater acoustic communication technique is applied to the ocean exploitation. The communication quality of underwater responders, which respond to transmit instruction and data, become more and more important.Because of the application of spread spectrum communication technique in the underwater acoustic communication, the spectrum of the signal is spreaded and the duration of the code becomes narrow. As the narrow impulse contains abundant frequency components, large signals boundary frequency components will pass the vicinity frequency channel in the multi-frequency channel system, and turn into the sharp pulse interference of the vicinity frequency channel, that is so-called "channel interference",which make the signal is hard to distinct .The communication quality also will be abated.This paper is mainly about how to ovecome the multi-frequency interfere and achieve frequency estimation. It contains two partions. In the first portion, a circuit board of underwater signal receive system is designed to know the reception and judgement process for the underwater responders. In the second portion, a algorithm based on cascade N-order notch filter is presented to increase frequency resolution and restraining multi-frequency interfere. The algorithm is deduced in theory and applyed to computer simulation. The results of simulation and pool experiment prove that the algorithm is effective on increasing frequency resolution and restraining multi-frequency interfere.