Wearable Blood Pressure Measurement Device Development Based On Electrical Characteristic

This thesis implements a wearable blood pressure measuring equipment based on pulse transmission delay method.After comparing different possible pulse waveforms combinations,we choose electrocardiosignal(ECG)and photoplethysmography signals(PPG)in this work to measure the blood pressure.We then develop a hardware prototype of the whole device.Specifically,the whole hardware system is implemented on printed circuit board(PCB).The size of the PCB is only 4 cm * 3 cm,which is suitable for wearable design.In the process of hardware circuit design,this paper reasonably implements ECG,PPG signal acquisition module.The ECG signal acquisition module is implemented using a chip which is previously designed by our group,and the integration of system with the ECG chip is greatly improved.For PPG acquisition circuit,we proposed a structure using 4 LED circuit.Through the practical measurement,we found that the circuit can save power consumption and reduce the interference due to the motion.This paper also designs the wearable mode of the system.In order to meet the need of wearable,we also develop an application on android smartphones as the software user interface of the device.This thesis also proposes to use an adaptive threshold for the peak detection algorithm.We use the MIT/BIH database to test the peak detection accuracy.The result shows that the algorithm can achieve high peak detection accuracy.At the same time this paper tests different transformation model of PTT and blood preasure,finally chose the better one.The whole system has been tested in lab.In summary,the precision of blood pressure measurement can achieve SBP:4.471±7.351 mmHg,DBP:3.513±3.703 mmHg.We have also compared the results with other related work in recent 10 years.The comparisons demonstrate the performance of our device.