Automatic Recognizing Of The Communication Signal Modulation And Digital Demodulating Technology

This paper deals with the sampling, processing, characterristic extraction, automatic identification, clusster analysis of the communication signals including AM(DSB,SSB),ASK,FSK,PSK signals and demodulation of the BPSK signal. By the means of combining time- and frequency-domain, first we extract the instant amplitude and the instant phase by Hubert transfrom, and further draw the statistic diagram of the instant amplitude and instant phase. Integrating with spectrum analysis,we identify and classify the modulation method of communication signal comprehensively. As to the demodulation of the SPSK commuciation signal, eight correlative signals are used to approach the 8PSK signal, so as to realize the real time demodulation. Finally the hardware implement with high speed DSP is given. Hlbert transfrom, FFT transfrom, pattern identification and clusster analysis are used in the article. The results of simulation show that the methods for communication signal identification and classification and the demodulation of 8PSK signal are practical.