Research On Ultrasound Doppler Sensing System And The Method Of Signal Processing

Ultrasound technology is widely used in clinical medicine for the reason of painless, harmless, non-ionizing radiation and so on. Doppler ultrasound diagnosis that based on Doppler Effect detects the flow of blood in organs to obtain the direction, velocity and other information of the blood. So it is widely used to evaluate the clinical peripheral arterial and venous diagnosis kinetics.Medical Doppler ultrasonic endoscope based on the ultrasonic endoscope system combines the advantage of ultrasound in diagnosis and the sensitivity of Doppler to the moving objects together. In order to capture the weak signal scattered from tissue, all-digital signal processing method is proposed in this paper. The quadrate demodulation and spectrum analysis were realized by using FPGA. Also, the experiment platform based on the Doppler physical model was set up to verify the performance of the system.The main work is listed below.(1) The Doppler Model based on the pump was set to get the signal from the flowing blood.(2) All-digital signal processing method is proposed based on FPGA according to the character of the echo signal by studying the method of extract the Doppler frequency shift information.(3) The Verilog program was write in Quartus II environment to realize the signal processing timing control and model design, and realized the function of demodulation, filtering, and spectrum analysis.(4) The experiment platform based on the Doppler physical model was set up to verify the performance of the system. The processing results were sending to the PC, and by comparing the sonogram under different situations, the system and signal processing method are proved reasonable and correct.