低信噪比码元瞬时特性数字调制信号识别研究

Research on Recognition of Digital Modulation Signals Based on Code Element Instantaneous Characteristics in Low SNR

数字调制信号具有瞬时特性以及易受噪声干扰的特点。在各瞬时特性的提取中,瞬时相位的提取一直被认为难度较大。本文提出一种瞬时相位提取方法,能更真实反映调制信号的相位特性。在此基础上得到5个基于码元瞬时特性的特征参数,并对6种数字调制信号进行了识别。仿真结果表明该识别算法在信噪比大于等于3dB时对信号的理论识别率可达100%,从而在一定程度上减小了噪声对数字调制信号识别的影响。

Digital modulation signals have instantaneous characteristics and are susceptible to noise interference. In extraction of instantaneous characteristics, instantaneous phase extraction is considered more difficult. In this paper an instantaneous phase extraction method was put formard,which could more truly reflect the phase characteristics of modulation signals. Five characteristic parameters based on the code element instantaneous characteristics were obtained and six kinds of digital modulation signals were recognized. The simulation results show that when the SNR is equal to or greater than 3 dB, the theoretical signal recognition rate of the recogni tion algorithm can reach 100%, thus reducing the influence of noises on digital modulation signal recognition to a certain extent.