说明：  分析了在超宽带通信系统中的扩频干扰，并用两种通用的调制技术实现了对提出的抗干扰方法的仿真
(he ultra wideband (UWB) interference to direct sequence spread spectrum (DSSS) receiver is analyzed. Two popular UWB modulation schemes, the time hopping pulse position modulation (TH-PPM) and time hopping pulse amplitude modulation (TH-PAM), are considered. The pulse repetition rate (T’RR) of UWB signal and the freqnency hand of the DSSS play the primary roles in the BER performance of the DSSS receiver in the presence of UWB interference. The UWB signal parameters raising the interference to DSSS receiver are discussed. The characteristics of an aggregation of multiple UWB signals are somehow different from that of a single UWB device, especially for the TB-PPM scheme, where discrete spectral lines maybe exist in the band of DSSS receiver. The system parameters of TH-PPM such as the modulaiion index and maximum shift incurred hy the time hopping code determine the amplitude of the discret)