Fh Signal Detection And Receiver System Design And Fpga Implementation

The spread spectrum communication system, which is applied in communication region, has many advantages, such as keeping secret and anti-jamming excellently.Going with the development of computer hardware, micro-electronics and software technology, more and more communication systems construct on the spread spectrum communication system.In practice, direct sequence spread spectrum (DS) and frequency hopping (FH) are widely used, both of them belong to the spread spectrum communication system. But they are different in the way of anti-jamming: DS keeps out of the jamming, but FH evades it.In the 1950s, the west countries had started to research on the frequency-hopping system. In some local wars during the 1990s, the frequency -hopping equipments are widely equipped.Development is interactional between the frequency-hopping technology and the anti-frequency-hopping technology.In the future, achieving victory in warfare lies on the advanced technology, so it is necessary to develop the anti-frequency-hopping system.The main purpose of this paper is how to detect and get the information of communication which used frequency-hopping.On this purpose, it is designed as FPGA realization of the frequency-hopping detecting system, which is based on time-frequency analysis method, and its availability and practicability is proved by the experiment results.The main results are as follows:1. Summarized developments of the frequency-hopping detecting system and principles of the Spread Spectrum Communication system and Short Time Fourier Transform (STFT)2. Analyzed the feasibility and practicality of the method in paper, with which the frequency-hopping communication can be detected3. Accomplished FPGA realization of the frequency-hopping detecting system, including the FIR filter realization, FFT realization and digital down converter (DDC) etc.In implement of FIR, two methods based on the multiplier and DA are analyzed and DA is choosed.In implement of FFT, two arithmetic: DIT-2FFT and DIT-4FFT are analyzed and implemented.In implement of DDC, a set of filters are used to make signal satisfied request.