Detect And Reserch Of Ophthalmic Blood Flow Doppler Singnals

Ultrasound Doppler imaging is used to measure the parameter of blood flowaccording to Doppler phenomenon. It has many merits, such as convenient, visual, noninvasive, repetitive and can be observed continuously and dynamically. In recentyears, Ultrasound Doppler imaging is developed rapidly in the diagnose field ofophthalmology, and its field of application is broadened step by step. It can makestudys of eyeball's tissue, the characteristics of blood flow kinetics and pathologicalstate by examining the position, the direction and velocity of blood flow ofophthalmic artery, central retinal artery and posterior ciliary artery as well as theblood vessels in the back of eyeball. Ultrasound Doppler imaging providesconvenience for diagnose various ophthalmic diseases, broadens the field of visionand offset the limitation of other several kinds of medical imaging. It has importantvalue for diagnose and distinguish various ophthalmic diseases, such as orbital bloodvessel disease, the tumour in entoptic and orbital cavity, eyeground disease andglaucoma.This project detects Doppler signals of eye blood flow, which is based onophthalmic ultrasound diagnose instrument. This paper will give an introduction ofUltrasound Doppler imaging and discourse on the hardware circuit of entire system.Furthermore, this paper will describe the whole process of how to transmit, receive, magnify at high frequency, demodulation and distance gating. Moreover, it's transmitstimulation of pulse, dual-channel quadrature signals and sampling volume arecontrolled by CPLD. Eventually, by inputing these sampling data into computer, usingthe software MATLAB to accomplish digital filter and then draw time-frequencyanalysis chart, we have obtained good detecting effect.