一种抑制数字接收机镜像干扰的方法

A New Method for Image Interference Rejection in Digital Receiver

现代脉冲多普勒体制雷达常规数字中频接收机大多采用带通采样方式。由于雷达信号一般采用脉冲波形,数字接收机在对射频回波下变频数字化后,对A/D数据进行时频谱分析时往往在脉冲边沿处会产生较大的镜像干扰。本文分析了脉冲多普勒雷达常规数字中频接收机在处理脉冲信号时脉冲边沿镜像干扰产生的机理,指出了中频带通滤波器在数字中频接收机链路中的主要作用,着重对中频带通滤波器的指标体系设计需求提出了新的关注点,以此达到抑制数字接收机脉冲边沿镜像干扰的目的。

The digital IF(intermediate frequency)receiver of PD radar adopts bandpass signal sampling.Because radar signals usually use pulse waveforms,at the time⁃spectrum analysis of the A/D data,image interference appears at the edge of the pulse after the digital receiver digitized the RF echo.In this paper,the mechanism of the pulse edge im⁃age interference in the pulse signal processing by conventional digital IF receiver of PD radar is analyzed,and the main function of IF bandpass filter in digital IF receiver link is pointed out.The focuses are paid on the design requirements of the index system of the IF bandpass filter,so as to achieve the purpose of suppressing the pulse edge image interfer⁃ence of the digital receiver.