一种中频直接采样方案及其硬件实现

An Approach to Direct Digital Sampling of IF Bandpass Signal and Its Hardware Implementation

本文介绍了一种中频直接采样的硬件实现方案，即只用一片Ａ／Ｄ变换器直接对中频带限信号采样，经数字处理获得同相（Ｉ）和正交（Ｑ）两路数字信号。该方法避免了传统正交采样中的Ｉ／Ｑ通道幅相不平衡造成镜像频率虚假信号的缺陷。最后给出了计算机定点仿真结果和硬件框图及其测试结果。

A method is proposed to implement the direct digital sampling of iF bandpass signal. The method,creates In-phase(I)and quadrature(Q)digital signals from an IF band-limited real signal using a single A/ D converter,thus, avoiding the residual at the image frequency resulting from the amplitude-phase unbalance between I/Q channels in conventional approach to coherent detection. After fixed-point computer simulation, the hardware implementation is described by the flowchart of the procedure and its testing result.