CDMA2000数字中频的设计

Design for CDMA2000 Digital Intermediate Frequence

在CDMA2000系统中,信道是经过QPSK四相扩频正交调制传输的,数字中频与模拟中频相比能产生严格的幅相平衡正交信号,处理时能保证有严格的线性相位。为此介绍了CDMA2000系统数字中频调制解调实现的方案,对其中抗混叠滤波器、数字频率合成器的设计方法进行了详细的讨论,最后给出了用基于高密度逻辑门电路可编程集成片编辑器(FPGACompiler)实现的结果。

In CDMA system,the channels are transmi tted via to QPSK quadrature modulation.Comparing with analog IF,digital If can produces strict amplitude balance quadrature signal,which can guarantee strict linear phase while processing.This paper presents a pattern of digital IF for CDMA system and the method to design antialiasing filter and digital frequence s ynthesizer in detail.At last,the implementation results based on FPGA are giv en.