Research Of Multi-Frequency-One-Time Exciting Measurement Circuit For Biological Electrical Impedance

Multi-Frequency-One-Time(MFOT) exciting bioelectrical impedance measurement technology by means of measuring the electrical impedance information of the biological tissue at different frequencies at one time, thereby the physiological and pathological state of biological tissue is judged. The technology can solve the problem of measurement error due to factor such as blood flow change at One-Frequency-One-Time(OFOT) exciting measurement, it is a hot research topic at home and abroad currently. Multi-Frequency-One-Time exciting measurement circuit is one of the core research questions of this technology. In order to acquire the impedance of biological tissue at the same time at different frequency, a design scheme of Multi-Frequency-One-Time exciting measurement circuit based-on Walsh function is presented and implemented.The main research tasks of the thesis which are base on the pervious research work are as follows:1. The key principle and future trends of bioelectrical impedance measurement system are analyzed. In the comparison of some of the classical bioelectrical impedance measurement systems, one design scheme of Walsh function Multi-Frequency-One-Time exciting measurement circuit based-on FPGA platform is presented.2. Main functional modules of the presented circuit include Multi-frequency excitation source module, A/D convert module, data storage module, communication module and so on are designed.3. Software architecture of the system is analyzed. The program flow diagrams and the core program codes are given. The main system software are designed on FPGA Quartus II10.0development platform.4. The performance of hardware and software of primary circuit modules are tested. The software and hardware of the circuit modules are integrated. The experimental results show that the presented measurement circuit is feasible.