A blind demodulation method of short-time burst fm-mfsk composite modulation signal based on stft

Реферат: The invention discloses a blind demodulation method of short-time burst FM-MFSK composite modulation signal based on STFT. It mainly solves the problem of high bit error rate (BER) in the demodulation of FM-MFSK signals with short bursts and low signal-to-noise ratio (SNR), and it is very difficult to determine the data symbol. The method comprises the following steps: 1) extracting a data segment using a detection algorithm for short-time burst signal based on correlation sum s'(k); 2) extracting a time-frequency ridge sequence F(i) and an energy sequence E(i) based on STFT; 3) synchronizing and extracting a code element based on energy decision for acquiring a time-frequency ridge sequence F(i) and an energy sequence E(i); and 4) completing demodulation of a short-time burst composite modulation FM-MFSK signal. On the premise of low SNR and open-loop demodulation, the invention realizes the demodulation work of FM-MFSK type signal of short-time burst composite modulation, effectively reduces the error rate, provides a strong guarantee for the smooth development of the subsequent decoding and decoding work, and can be used in the integrated communication reconnaissance system.