Through the cooperation between the fast peak detector and the delay unit,the receiver is realized with lower BER, bettter receiver sensitivity and receiver dynamic range.

The peak delay time of S-wave,which is defined as the time lag from the direct S-wave onset to the maximum amplitude arrival of its envelope,is accepted to quantify the phenomenon of S-wave envelope broadening.

A comb-filter and envelope-demodulation method based on combined Morlet wavelets;

Inspired by these characters, we present the method of filter and envelope-demodulation based on combined morlet wavelets.

According to the analysis of vibration sign , using the envelope demodulation and FFT methods, improved the calculation precision for the rolling bear.

According to the analysis of vibration sign,using the envelope demodulation and FFT methods,improved the calculation precision for the rolling bearing diagnosis.

The ultrasonic carrier is modulated by the pseudo-random sequence adopting ASK modulation mode,and the pseudo-random sequence is recovered from the ultrasonic echo through envelope demodulation.