基于时频分布的MPSK信号识别解调

通信信号的自动识别解调技术受到日益广泛的重视。针对衰落信道中广泛存在的多普勒频移现象,本文提出了一种MPSK信号数字化识别解调的方法。该方法基于信号的时频分布,在时频二维平面上对MPSK信号进行分析,用双线性变换提取基带相位信息,并且实时估计和跟踪载波频率,从而实现MPSK信号识别解调。文中还给出了对一个QPSK信号进行数字化识别解调的仿真结果,并讨论了信噪比、窗函数对解调性能的影响。最后以QPSK信号为例,给出了解调器性能的仿真曲线。

Time-Frequency Analysis Applies to the Recognition and Demodulation for MPSK Signals

Identification and demodulation techniques for digital communication signals are growing more and more important. A new method for digital identification and demodulation of MPSK signals is presented under the condition of the Doppler frequency shift of channel attenuation. Based on the WVD, this method analyzes MPSK signals on the time-frequency (two-dimension) surface to estimate and trace carrier frequency instantaneously and abstract base-band signals via bilinear transformation analysis. Then MPSK signals are identified and demodulated. The effect of SNR and window functions on demodulation properties is discussed in this paper. Finally, a simulation of QPSK signals is given as an example.