无延时校正滤波器数字正交解调性能分析

Performance Analysis of Digital Quadrature Architecture Without Delay Calibration Filter

提出了一种无延时校正滤波器的数字正交解调结构,并对其性能进行分析,重点分析了频率偏移对相位和相位差测量的影响。仿真结果表明,在频率偏移较小的情况下,采用此结构进行数字正交变换可获得较高的镜像抑制比;频率偏移较大时,可通过对多点相位求平均来减小相位差测量误差。本文所提结构具有结构简单、处理速度快、便于硬件实现等优点。将其应用于多通道数字接收机的设计,可在一定程度上减小硬件资源的占用,同时,便于满足信号的实时性处理要求。

A digital quadrature architecture without delay calibration filter is proposed and its performance is analyzed. And the impact of frequency offset on the phase and phase difference is emphatically analyzed. Simulation results show that high image rejection ratio （IRR） can be acquired when the frequency offset is small. Otherwise, the phase difference error can be reduced by accumulating the multi-point phase differences. The proposed architecture has such advantages as simple, faster processing speed and easy hardware realization. Applying this structure to the design of multi-channel digital receiver may decrease the occupation of the hardware resource to some extent and satisfy the real-time signal processing at the same time.