基于冲激谱线检测的调制识别

现代卫星通信系统为满足传输速率和加密等要求,采用了多种复杂或高阶复合调制信号。为实现各类调制信号的检测与识别,信号之间不同类型谱的谱线分布是重要特征之一。在介绍常见通信卫星调制信号在不同类型谱下的冲激谱线特征基础上,提出了一种基于线性调频Z变换的冲激谱线检测方法,消除了离散频谱“栅栏效应”对检测值的影响。通过高次方谱和分数低阶循环自相关谱的区域谱线检测方法,构建特征向量进行分类设计,实现对常见通信卫星调制信号的分类识别。该算法在低信噪比、未知码元速率等先验信息的情况下具有较好的识别效果。

Modulation Recognition Based on Spectral Line Detection

For meeting the requirements of transmission rate and encryption,modern satellite communication system adopts a variety of complex or high-order composite modulation signals.In order to detect and recognize all kinds of modulation signals,the spectral line of signal is one of the important characteristics.According to introduction to the characteristics of impulse spectral lines of common satellite signals in different types of spectrum,an impulse spectral line detection method based on Chirp-Z transform is proposed,which eliminates the influence of discrete spectrum"fence effect"on the detection.Then,the feature vector for classification is constructed through the method of regional spectral line detection in high order spectrum and fractional low-order cyclic autocorrelation function.This algorithm has high recognition performance in the condition that the signal-to-noise ratio is low and the symbol rate and other prior information is unknown.