基于全通分相网络的数字正交采样技术

Digital Quadrature Sampling Based on All-pass Phase-splitting Networks

数字正交变换是雷达和通信等系统中为数字信号处理提供高质量的正交信号的关键技术之一。本文基于全通数字分相网络,设计并分析了一种新的数字正交采样方案。该方案的优点就是把数字滤波器设计成一对90°的分相网络,利用分相网络的一些对称特性可以简化数字滤波器的结构,从而使计算量大为减少,且无需考虑两个正交分量之间的匹配问题。更为重要的是,这种数字滤波器的设计比较简单,易于工程实现。代价是需要一个具有更高采样率的A/D转换器。

The digital quadrature transformation is one of the key technologies to provide high quality quadrature signals for digital signal processing in radar, communication and other systems. A new digital quadrature sampiing scheme is given and discussed, which is based on all - pass digital phase-splitting networks. The advantage of the scheme is that the digital filter is designed as a pair of 90° phase-splitting networks and the matching of two quadrature components is avoided. The symmetrical features of the phase-splitting networks are exploited to simplify the structure of the digital filter, and therefore, the computation task is reduced. Furthermore, the digital filter design is simple and easy to be implemented; however the cost is that the A/D converter with higher sampling rate is needed.