The Simulation Study Of Ultrasound Doppler Signal Processing Based On Wavelet Transform

Ultrasonic Doppler flowmeter without breaking into fluid was worshiped. Butaccurate frequency disturbing by the direction of the ultrasonic transducer, the signalsabsorbed and attenuated in the sound field,the number of particles of a certainvelocity and the noise in the process of transmission.This paper intoduced waveletspectrum method to process the ultrasonic doppler signals, this method not onlyimprove the accuracy and get the velocity of the fluid,but also get the direction of thefluid,therefor this reseach is very significative.This paper also introduced the method of dual-frequency ultrasonic dopplerflowmeter, comparing two methods, the superiority of the wavelet spectrum method isincarnated in the designing of the hardware and software.In the paper, firstly,we built a academic model of the doppler signal,thensimulated the doppler echo signal on computer. Secondly, infering the principle of themethod of dual-frequency ultrasonic doppler flowmeter in detail, and using it toprocess the imitating doppler signal. At last,this paper mainly discussed the waveletspectrum method. We defined the wavelet spectrum by wavelet transform andconversation of energy, and infered the quality of the wavelet spectrum by combiningfourier spectrum and wavelet transform'excellences.Then using this quality and thecharacteristic of the doppler echo signal, import the benchmark signal and distill thevalue of the frequecy shift of the doppler echo signal, then define the method of thewavelet spectrum. The benchmark signal don't resolve the problem of the fourierspectrum peak and wavelet spectrum peak,but also determinant the direction offluid,which is a techno-breakthrough.This paper used MATLAB software to simulate in the process of imitating anddistilling doppler echo signal. Comparing the imitated results, we confirmed that thewavelet spectrum method has superiority and practicability to process the dopplerecho signal.