The Design Of An Improved Matched Filter In Dsss-Gmsk System

This paper introduces the principle of DSSS-GMSK system, analyses the superiority of GMSK modulation over MSK modulation. Accord that the method of de-spread before demodulation can effectively improve the capability of the system with spread spectrum gain, this paper researches an improved method with matched filter to de-spread and demodulate the DSSS signals. The local PN code is modulated with GMSK modulation before being correlated with received signal, then we can get the synchronous PN code, de-spread and demodulate the signal. MATLAB simulation shows that this method is more efficient than the method of demodulation before de-spread in low SNR environment.