QPSK-DS communication detecting method based on delay multiplication

The invention discloses a QPSK-DS communication detecting method based on delay multiplication. A system is initialized and begins to scan a target frequency band to amplify signals entering the system from the radio frequency front end, radio frequency signals are converted into fixed middle frequency to be amplified through a difference frequency method, digital signals can be achieved through analog-digital conversion, delay multiplication operation is carried out, digital lowpass filtering is carried out to obtain lowpass signals, and a frequency spectrum of the lowpass signals can be achieved through an FFT algorithm. The QPSK-DS communication detecting method has the advantages of adopting a linear and non-linear processing method to achieve full detection on QPSK-DS communication through simple comprehensive analysis and processing on time frequency domains and being simple to achieve, strong in operability and strong in capacity adapting to low signal to noise ratio. Meanwhile, the method adopts the middle frequency analysis instead of radio frequency or baseband processing to avoid high requirements for performance of processing capacity of a receiver as possible. Furthermore, the method can achieve real-time processing easily and is strong in practicability.