Based on of analyzing the principle of QPSK modulation and demodulation,the BERs of three jamming modes used for QPSK are theoretically derived,and these three modes include the continuous noise jamming,single frequency modulation jamming and pointed single frequency modulation jamming.

Performance analysis of delay lock loop in coherent spread-spectrum system with single tone interference;

The new algorithm can not only suppress the single tone interference but also depress the system noise,so it can provide the DSSS system with higher performance gain than the linear prediction algorithm.

The current analysis focuses on the performance of BPSK modulation on 2-dimensional spread spectrum system with single-tone jamming.

A novel scheme for accurate estimation of single tone jammingparameters in a multi-carrier spread spectrum system;

A novel single tone jamming elimination scheme for multi-carrier spread spectrum system;

A new space-time Rake MMSE receiver based on antenna diversity is proposed and its performance for rejecting single-tone jamming analyzed in this paper.

Techniques of the strong single-frequency-interfere in extremely Low SNR short-wave can offer special anti-single wave interfere technique in condition of bad electromagnetism, finite frequency band and incapable of spread-spectrum technique, to make sure the short-wave can transmit an emergency communication.