基于小波包变换的自适应阈值抑制窄带干扰

为了进一步提高直接序列扩频通信系统的窄带干扰抑制能力，本文实现了基于小波包变换的自适应阈值抑制窄带干扰算法。通过分析直扩信号在小波包分解后的能量分布特点，来设定自适应阈值以定位和剔除窄带干扰。解决了干扰判决阈值难以确定的问题。自适应阈值能够迅速跟踪和准确定位窄带干扰所在的子带的，并对干扰的强度变化具有自适应的特点。仿真结果表明，该阈值抑制算法使直接序列扩频通信系统的抗干扰性能得到进一步提高。

Adaptive threshold in Suppression narrow band interference based on wavelet packet transforms

To further improve the ability that the Direct Sequence Spread Spectrum System restrains the narrowband interference, the paper realized adaptive threshold suppressing the narrowband interference basing on wavelet packet transformation. Through analyzing the power spread of the DS signal in wavelet packet transform, the thesis sets the adaptive threshold to orientate and reject the narrow-band interference. And the problem that the threshold is hard to settle is resolved. The adaptive threshold can quickly track and accurately locate the contaminate subsidiary-band, and be adaptive for the interference changing. Finally, the results of simulation demonstrate that the anti-jamming ability of the DSSS was further improved by the threshold algorithm.