通信信号的调制信息包含在信号的瞬时幅度、相位、频率的变化之中，不同的信号其频谱也呈现不同的特征，通过提取瞬时幅度、相位、频率以及频谱的参数统计特征，可以识别不同的通信信号。通常是利用对瞬时幅度、瞬时相位，瞬时频率和信号功率谱进行某种变换而得到可以明显区分各种信号的特征参数。-Communication signal modulation information is contained in the signal instantaneous amplitude, phase, frequency changes, the spectrum of different signals also show different characteristics, by extracting the instantaneous amplitude, phase, frequency and statistical characteristics of the parameters of the spectrum, you can identify different communication signals. Usually by the use of instantaneous amplitude, instantaneous phase, instantaneous frequency and signal power spectrum a transformation which can be clearly distinguished by the characteristic parameters of various signals.