解调分析中差频现象的理论分析及细化解调／频谱分析集成算法

应用泰勒级数展开方法研究了解调分析中的差频现象,指出信号解调前必须滤除与调制信息无关的加性频率成分。为方便实际应用,提出了细化解调／频谱分析集成算法,算法中两种信号分析方法均由带通滤波、Hibert变换和重抽样三个步骤组成,算法实现时将这三个步骤集成在一个复解析带通滤波过程之中,具有很高的计算效率,算法的有效性得到了仿真的验证。

Difference Frequency Effect in Demodulation and an Integrative Algorithm for Zoom Demodulation/Spectrum Analysis

Demodulation is a widely used signal processing method for machine fault diagnosis. By using Taylor series expansion, the difference frequency effect in demodulation is theoretically analyzed. It is suggested that the technique of demodulation should be combined with that of band pass filtering, then an integrative algorithm for zoom demodulation and spectrum analysis is proposed, which is of great benefit to software realization and engineering application. The flows of the two signal processing methods, in the integrative algorithm, are both composed of three steps, i.e., band pass filtering, hilbert transform and resampling. The three operations are integrated into a single analytical band pass filtering procedure. Therefore the presented algorithm has high computational efficiency, and its effectiveness is verified by the treatment of synthetic signal.