【摘要】 目的采用FPGA芯片实现NLMS算法,从而生成高性能的自适应滤波器来滤除通信信号中时变、未知的干扰信号,得到高质量的通信信号.方法通过对LMS及其改进算法的原理讨论及比较,确定适合于FPGA芯片上实现的NLMS算法,并对算法的具体实现方法进行论述.采用分段移位的方法实现除法运算,从而提高运算速度.结果通过对输出信号的频谱分析,当信号带宽为200 kHz,频率偏离中心频率0.087 5 MHz时,衰减达到了99.21 dB.结论本设计能高速度、高质量地滤除通信信道中的干扰信号,并很好地处理了FPGA的资源与速度的关系,能满足高速信号处理的要求.更多还原

【Abstract】 An adaptive filter was implemented in this paper,which was based on NLMS algorithm.High performance signals could be obtained by filtering the time-varying and unknown interferences in the communication channels.The NLMS algorithm was achieved by considering the principle of LMS algorithm and its improvements.It was concluded that NLMS algorithm could be implemented on FPGA chips.This paper described the method of the specific implementation as well.This method introduced bit-shift in terms of subsection instead of division compution,by which the operation speed of FPGA was greatly improved.The spectrogram of the output signals proved that the attenuation reached to 99.21 dB when the signal bandwidth was 200 KHz and the frequency was 0.087 5 MHz offset from the center frequency.The adaptive filter could effectively filter the interferences in the communication channels and split the differences between the resources and areas of the FPGA chips,meeting the requirements of high-speed signal processing.更多还原