脉冲信号检测中的窄带干扰抑制器设计

Design of Narrowband Interference Suppressor for Pulse Signal Detection

针对脉冲信号检测中的窄带信号干扰问题,从时域和频域角度分析了不同的干扰抑制措施,进一步基于数字调谐和一阶陷波方法,在FPGA上实现了简洁高效,可独立工作的干扰抑制电路,并推导了相应的干扰抑制条件.该方法通过频谱数据判定脉冲检测中的干扰信号频率和带宽,并经由数字下变频将干扰信号搬移至零频,利用简单的高通滤波器陷波后,再数字上变频恢复原始脉冲信号.实验结果表明:该干扰抑制器能够以较小的代价滤除一定频率间隔的窄带干扰,脉冲参数估计在容许均方差范围之内.

This paper analyzes narrowband interference suppression using temporal and frequency processing techniques for pulse signal detection.We implement a stand-alone interference suppressor on field programmable gate array（FPGA） based on digital tuning and 1st-order notch filtering.When a pulse signal along with narrowband interference is detected through spectral measurements,the interference signal is translated to zero frequency using down-converter and filtered out by a simple high-pass infinite impulse response（IIR）.The original pulse signal is translated to its previous frequency using corresponding up-converter after alleviating the effects of interference.Furthermore,we deduce the frequency interval between pulse signal and narrowband interference to satisfy interference suppression performance.Experimental results show that the proposed interference suppressor can reduce narrowband interference effect and detect pulse signal under acceptable root mean square（RMS） value.