PCM/FM信号软件化解调算法研究

Research on the Software Demodulation Algorithm for PCM/FM Signal

根据PCM/FM信号的特点,提出一种新的基于STFT的软件化解调算法。首先,利用STFT计算PCM/FM信号中f0和f1频点的能量,然后,根据两个频点能量的变化规律,实现信号的码同步及解调。论述此种解调算法的基本原理及实现过程,分析其算法的复杂度,提出一种新的码同步提取和修正的方法。计算机仿真结果表明,该算法不但能够有效地抑制实际信号中的各种干扰对码同步精度的影响,具有较好的解调性能,而且其实现原理简单,运行效率较高,便于实现软件化的实时处理。该解调算法在实际的PCM/FM信号的处理中收到了较好的效果,具有一定的应用价值。

According to the characteristic of PCM/FM signal,this paper presents a new algorithm of software demodulation based on Short-Time Fourier Transform(STFT).Firstly,through STFT the energies of f0 and f1 of PCM/FM signal are computed.Then,by comparing the energy of f0 with the energy of f1,the bit synchronization and demodulation are realized. The paper discusses the basic theory and application course,analyses the complexity of this algorithm,and proposes a new method to get bit synchronization.The results of computer simulation show that the algorithm not only is good at anti-jamming and has better performance of demodulation,but also is effective and is convenient to realize real-time processing by software.This algorithm has a bright future for the application to demodulate PCM/FM signal.