A new method for polyphase pulse compression codes modulation recognision based on IQPF and FRFT

For the problem of typical polyphase codes recognition, an algorithm based on integrated quadratic phase function (IQPF) and fractional Fourier transform (FRFT) is proposed. Firstly, IQPF is used to estimate the chirp rate of the signals for pre classification. Then accurate identification is realized according to the spectral characteristics of the signals' FRFT. The simulation results show that the probability of correct recognition is higher than 90% when signal to noise ratio (SNR) is above −7dB.