【摘要】 针对现有的包络解调方法对噪声宽容性差的不足,论文利用窄带调制类型信号相关函数的一个基本特性,建立了基于相移小波的信号包络提取方法。该方法采用Morlet小波为基小波,根据信号的中心频率和采样率等已知信息,能够有效地提取信号的包络,并且对低信噪比信号也具有良好的宽容性,仿真结果证明了该方法的有效性,并且证明了该方法的性能优于现有的其他解调方法。最后,采用该方法对一个实测的水声数据进行了分析处理,也取得了令人满意的结果。更多还原

【Abstract】 Current methods for envelope demodulation are always sensitive to noise.A demodulation method based on so-called “phase-shift wavelet transform” is proposed to solve this problem.This method is based on the property of cross-correlation function between two narrow band signals,which is that the envelope of their correlation(convolution)is half of the correlation(convolution)of their envelopes.The method adopts Morlet wavelet as basic wavelet,and the signal envelope can be extracted effectively from the signal center frequency and the sampling rate that are known,which shows good performance for signals with low S/N ratio.Simulation results show the efficiency of the method,and prove that the performance of this method is better than that of other demodulation methods currently used.Finally,the proposed method was successfully applied to a real underwater acoustic signal for envelope demodulation.更多还原