A robust MSK demodulator through DSP

Abstract

A minimum shift keying or fast frequency shift keying coherent demodulating algorithm is discussed. Both carrier synchronisation and optimal symbol correlation are done within two decision switched Costas loops, each operating at one of the reference signal frequencies. Simulation shows the demodulator to be robust against phase distortion and frequency drift in the received signal. The receiver is relatively simple and well suited to a DSP or digital implementation.<>