System Design Of Track FSK Signal Based On Time-Frequency Distribution

Time–frequency Analysis has been proven to be a powerful tool in time–varying and nonstationary signals'analysis.This method shows clearly how the signal changes in frequency domain and in time domain at the same time.The phase of FSK signal transmitted in Frequency-shiftt rack circuitis continuous.Its carrier-frequency and low-frequency can be demodulated easily by Fourier Transform. However , by studying the characteristics of FSK signal,it is very difficult to realize the demodulation of FSK signal'supper and down side frequencies only through the analysis of FSK signal's Fourier transform spectrum.This paperm ainly studys the method of the demodulation of FSK signal based on Time-Frequency Analysis.It analyzes the common methods of Time-Frequency Analysis.w hich includes Short Time Fourier Transform,W igner-Ville Distribution and In stantaneous Frequency.Based on the producing method of FSK signal and its characteristic of FSK signal's spectrum.the arithmetic of ZOOM FFT is put forward.By the theoretical an alysis and computers imulation,it can be provent hat ZOOM FFT can realize the high precise detection of carrier-frequency and modulated frequency of FSK signal. To the problem of the demodulation of FSK signal's upper and down side frequencies.this paper expounds some kinds of algorithm that demodulate FSK signal using Time-Frequency Analysis which have been mentioned above,presents the demodulation performance of those algorithm by the simulation results, and acquires the result that SPWVD can realize the reliable and high precise demodulation of FSK signal's upper and down side frequencies.So it can become the theoretical basis to develop the new demodulating instrument.This paper also introduces the software and the hardware solution to the demodulation system of FSK signal using DSP The results of the experimentation prove that the method of the paper is feasible.So the method provides the foundation for the future research.