摘　要: 经过限带滤波后的QDPSK 信号的码元波形可分为稳定区与过渡区, 根据这一特点可以利用DFT 方法来实现信

号的解调和位同步。 在这种数字化解调器中需要设计一个合适的带通滤波器, 以便尽可能地消除信号的旁瓣分量而不影响信号

码元稳定区内的波形。本文介绍了上述带通滤波器的方案选择和基于M at lab 的滤波器参数设计方法, 以及仿真效果。-Abs tra c t: A f ter a band pass f ilter, QDPSK signal′ s symbo l can be divided into steady sect i on and t ransit i on sect i on, so the

demodulat i on and synch ronizat i on fo r th is signal can be realized w ith DFT 1 In such a digital demodulato r, it is i mpo r tant to design a

p roper band pass f ilter to get r id of side beam pow er effect ively and don′ t change the w avefo rm in steady sect i on1 Th is paper

int roduces the scheme select i on, parameter design method and si mulate effect fo r th is f ilter based onM at lab1