In order to reduce calculation in the process of vertical scale identification of torpedo acoustic image,we present an improved decoherent multiple signal classification(MUSIC) method based on quadrature complex sampling which suits to estimating the vertical highlights of submarine with the characteristics of near distance and coherent signals.

Carrier recovery is the key technology for coherent demodulation receiver in RF communication,and carrier recovery algorithm directly determiner the performance of the receiver.

Taking the modulated signal,one of the typical narrow-band random processes,as an example,this paper simulates the whole process of speech communication in the white Gauss noise background,and compares the quality of speech signal taking coherent demodulation method with the one taking envelope demodulation method.

We programmed useful software to get three types of coherence algorithms: C1, C2 and C3.

In order to enhance the signal/noise ratio and resolution of the seismic section and to distinguish and pursue the seismic event more easily, the authors suggest in this paper the utilization of the LOG operator and the modified coherence algorithm.

In order to enhance the signal/noise ratio and resolution of seismic profile, LOG operator and the modified coherence algorithm are introduced and compared with other methods.