盲频移滤波器信号提取的改进算法

利用循环平稳特性可以进行信号提取,频移滤波器对循环频率误差较为敏感。分析了循环频率误差导致频移滤波器恶化的原因,针对存在循环频率误差时频移滤过波器性能急剧下降的缺点,采用遗忘因子法对频移滤波器进行改善。理论分析表明,引入遗忘因子可以消除采样有限时间窗谱函数的零点,从而大大降低了频移滤波器对循环频率误差的敏感性。该算法无需对循环频率进行估计,计算量小、易于实现,仿真实验证明了该算法是有效的和可行的。

Improved algorithm for blind signal extraction

Blind FRESH(frequency shift filter) can separate desired signals from spectrally over lapping interference by exploiting cyclostationarity.FRESH gets severe performance degradation,when there is a small mismatch in the cyclic frequency error of the desired signal.The behavior of the FRESH in the presence of cyclic frequency error is considered.A forgetting factor algorithm to alleviate the performance degradation is adopted.Based on the theoretical analysis,forgetting factor can eliminate the zero point of sinc function due to finite data samples.So this algorithm would largely depress the sensitivity of the FRESH to cyclic frequency error.It also has a low computational complexity and easy application without estimating cyclic frequency.