Design Of Impedance Spectroscopy Plethysmograp H-Y Measurement System Based On FPGA

Impedance Plethysmography(IPG)is an important technique for detecting physiology and pathology of blood vessels using bioelectrical impedance methods.However,traditional IPG technology has lost a lot of valuable information due to its single-frequency,impedance-only measurement method.In order to solve this defect,Bioimpedance Spectroscopy(BIS)technology was introduced into IPG,and a new method based on BIS ultrafast measurement of Impedance spectroscopy plethysmography(ISPG)was proposed.A set of ISPG detection system based on FPGA was designed,the main contents are as follows:1.Explain the measurement principle of traditional IPG technology,analyze the significance of IPG parameters,introduce its development background and development history,and point out the key problems of IPG technology at this stage.2.The concept,background and basic theory of BIS technology are introduced.The principle and implementation method of BIS ultrafast measurement method used in this thesis are expounded.The concept of ISPG is proposed.3.The FPGA-based ISPG detection system is designed,and the system hardware and software design are introduced separately.The ISPG detection system includes a signal generation module,a signal acquisition module,a signal processing module and a data storage module.The ISPG detection system can complete the acquisition buffer of the excitation signal and the response signal,the FFT and Cordic algorithm processing,the impedance spectrum calculation fitting and the data storage function.The impedance amplitude and phase spectrum of 64 frequency points in the range of 16～1024kHz can be directly obtained in one measurement cycle(about 1ms).4.Two sets of three components and pure resistance were constructed.The ISPG detection system and the standard impedance meter WK6500B were used to measure them separately.The system calibration and error analysis were carried out to verify the accuracy of the ISPG detection system.5.The human body impedance measurement experiment was carried out using the ISPG detection system,,and the results of human body impedance fitting were given.Impedance spectroscopy plethysmography measurement experiment was performed using the ISPG detection system,and the measuring waveform of 5 frequency points in the range of 32～512kHz was given.The source of the noise in the measured waveform was analyzed and the solution was pointed out.