Research Of Laser Doppler Flowmetry

The information of body microcirculation blood flow, has an important research valuein medicine, it is used to judge absorption of drug in human body, understand preventionand treatment about many cute or chronic disease, observe clinical nursing of patients withinjury and so on. The blood flow measurement in microcirculation has become animportant research work in the contemporary biomedical fields. The traditional methods ofmeasuring blood flow, such as infrared, ultrasonic, etc., have a complex structure, manydefects such as the complicated operation and invasive measurement, even cause damageto the body’s tissue. But the advanced laser doppler blood flow measurement, has theadvantages of no wound and wide adaptability and simple operation, can get blood flowinformation in real time, do not need to contact with the body’s tissues by usingnoninvasive, it is more widely used because of widespread clinical use value. So in thispaper, we study a kind of laser doppler flowmetry based on DSP chip TMS320VC5402.First, based on the analysis of the laser doppler measurement principle, this paperstudies the detection methods of doppler frequency shift, the double beam with doublescattering light path model with more simple structure more convenient adjustment isselected, based on the demand of harmless to human, the780nm semiconductor laser isselected, and select a photoelectric detector most appropriate for the band response,implement the design of laser optical path detection part.Then, design hardware circuit of signal processing, choose the DSP circuit systembased on cost-effective chip TMS320VC5402, set up including its peripheral circuit,amplifying circuit and AD conversion circuit based on12high-speed serial chipTLV2544. On the design of system software, by comparing the common doppler signalprocessing methods, choose the Fast Fourier Transform FFT method of data processing.The simulation design process of DSP system program using software CCStudio v3.3simulators XDS510are described in detail. The whole design of hardware circuit isrelatively simple, the software design using FFT algorithm for signal frequency makes theoperation more flexible, even the signal noise ratio (SNR) is low or the signal is bad, it can also be good to extract the signal frequency.Finally, summarize the all design work, put forward the idea to the next step researchwork.