A method for intercepting and demodulating slow frequency hopping DPSK signals

This paper presents a non-coherent wireless communication receiver design for intercepting and demodulating frequency hopping spread spectrum (FH-SS) signals. This interception receiver is based on phase modulation to amplitude modulation conversion (PM to AM), and is specifically designed for demodulating a slow frequency-hopped signal that has differentially encoded phase shift keying (DPSK) modulation. The intercept receiver uses a bank of bandpass filters at the front end. Matlab simulations show that if a signal has a signal to noise ratio (SNR) greater than approximately 30 dB (where the bandwidth (BW) of each of the intercept filters in the simulation is five times the message bit frequency), the intercept receiver can demodulate it by using an approach based on PM to AM conversion and adaptive pattern recognition. The performance of the receiver is characterized with simulations and analytical calculations.