成形QAM信号的小波特性和尺度选取问题研究

Study on Wavelet Characters and the Appropriate Scale of WT for Pulse Shaped QAM Signals

对经均方根升余弦脉冲成形的QAM信号的小波特性进行了推导,主要包括QAM信号的瞬时包络和瞬时相位,并通过仿真将得到的结果与传统的基于Hilbert变换的提取方法进行了比较。同时从改善信号信噪比的角度,对小波变换最佳尺度选择问题进行了详细的研究,得出了利用最佳尺度下小波变换提取QAM信号瞬时包络和瞬时相位的一种算法,并通过仿真验证了算法的可行性。

The wavelet characters and the appropriate scale of WT for QAM signals is studied after pulse shaping using the raise cosine roll-off filter.Firstly, the instantaneous envelope and the instantaneous phase of QAM is extracted as the coefficients of Haar wavelet transform,compared with the traditional method based on Hilbert transform approach.Then the selection of the appropriate scale from improving the signal-to-noise ratios is proposed,deducing the conclusion and verifying the feasibility with the help of simulation.