On the amplitude‐ and frequency‐modulation decomposition of signals
On the amplitude‐ and frequency‐modulation decomposition of signals
复制标题
DOI：
10.1121/1.416061
复制
发表时间：
1996-09
影响因子：
2.4
通讯作者：
P. Loughlin;B. Tacer
中科院分区：
文献类型：
--
作者：
P. Loughlin;B. Tacer
一般来说，确定信号的幅度和频率调制（调幅和调频）的问题是不恰当的，因为有无限数量的调幅和调频组合将产生给定的信号。虽然Gabor提出了一种唯一定义信号的调幅和调频的方法，即通过分析信号，但得到的结果有时在物理上是矛盾的。本文提出了计算信号的调幅和调频应满足的四个合理的物理条件。解析信号法一般不能满足这四个条件中的两个。给出了一种利用正（Cohen-Posch）时频分布和时变信号相干解调的方法，以获得满足上述四个条件的调幅和调频信号。与公认的定义相反，满足这些条件的瞬时频率（即调频）通常不是信号相位的导数。相反，这个阶段被分成两个部分，所以……
In general, the problem of determining the amplitude and frequency modulations (AM and FM) of a signal is ill posed because there is an unlimited number of combinations of AM and FM that will generate a given signal. Although Gabor proposed a method for uniquely defining the AM and FM of a signal, namely via the analytic signal, the results obtained are sometimes physically paradoxical. In this paper, four reasonable physical conditions that the calculated AM and FM of a signal should satisfy are proposed. The analytic signal method generally fails to satisfy two of the four conditions. A method utilizing the positive (Cohen–Posch) time‐frequency distribution and time‐varying coherent demodulation of the signal is given for obtaining an AM and FM that satisfy the four proposed conditions. Contrary to the accepted definition, the instantaneous frequency (i.e., the FM) that satisfies these conditions is generally not the derivative of the phase of the signal. Rather, the phase is separated into two parts, o...