一种基于DFT的AM信号数字化解调算法

该文提出一种在软件无线电中基于离散傅立叶变换（DFT）算法的幅度调制信号（AM）数字化解调算法，方法是对采样后的数字化AM信号进行带通滤波后，按照每一个（或数个）载波周期内的采样值进行离散傅立叶变换（DFT），求出载波的幅值，再去掉直流量。与数字化正交解调结构相比，省去了本地载波恢复，两路低通滤波，简单而易于实现。该解调方案的仿真结果表明抗干扰性能也有所明显改善，可望在采用AM信号方式的数字化接收机的设计中得到应用。

A DFT-based Algorithm for AM Signal Demodulation

This paper presents a DFT-based digital demodulation algorithm for AM signals in software radio. The main idea is to filter the digitalized AM signal received with BPF, then do DFT on samples in every one (or several) carrier circle to get the amplitude of the AM signal and get rid of zero frequency current. Comparing with digital quadrature demodulation framework, it is simple and easier to be realized for it doesn't need to resume local carrier and filter with LPF in two branches. Simulation of this demodulation scheme indicates that noise-resisting property has been improved obviously. It is hopeful for this demodulation scheme to be applied to the design of AM signal digital receiver.