Ultrasonic Doppler Bloodstream Spectrum Analysis System

The important reason for malignant cardiovascular disease (the "CCVD"), including Apoplexy and cardiocerebrovascular accidents, is long-term hyperlipidemia and high viscosity. They cling to the vessel wall, especially the neck vessel wall, and form blood fat sedimentation which caused angiosclerosis and blockages. As a result, the blood situation in neck vessels shall be controlled in time to avoid CCVD. However, the practicality is unavailable resulting from complex design, difficult debugging and expensive construction cost of traditional ultrasonic Doppler blood analyzer equipment, based on analog signal processing. Therefore, in this thesis, a portable continuous ultrasonic Doppler blood spectrum analyzer system with low cost has been studied and worked out. Meanwhile, the blood rate spectrogram has been set up by analyzing collected ultrasonic Doppler signal to achieve quantitative analysis of blood and vessel blockages.This paper briefly introduces the mathematical model of blood flow Doppler ultrasound technique, pointed out that the blood flow ultrasonic echo signal is a narrowband FM signal, and the modulation comes from the movement of blood flow. By demodulating the narrowband FM signal, we could get baseband signal which reflects the blood flow. Finally, we get the sound spectrum by STFT of the baseband signal.Then this paper design a set of hardware and software system, make a detail instruction of the structure,functions to every items in this system. At the end, this paper makes a complete test of the entire system functional modules, the result shows out this system works fine, and the spectrum is clear and exquisite.The system designed by this paper provides low-cost and effective technology solutions to detect blood flow of neck vessels, which will help remote villages, the primary level hospitals, family doctors and other user groups to defend the CCVD as earlier as possible. So, this system will have a strong practical value and market value.In addition, this study will also be useful to other Doppler ultrasound detection of human physiological data, such as the detection of cardiac wall motion, pregnant women, fetal cardiac cycle, providing a theoretical basis and effective implementation. There is a good reference.