A LabVIEW based measure system for pulse wave transit time

Pulse wave transit time (PWTT) is used as a non-invasive and cuffless method for blood pressure estimation. In this paper, we design a system that can measure PWTT by monitoring ECG and pulse wave continuously. The system includes analog signal sampling in PCB, signal display and data processing in computer. We measure pulse wave by the photo-plethysmograph (PPG) device in finger which includes an infrared LED transmitting light, photodiode in OPT101 as detector, amplifier and filters. We measure ECG by the sensor on limb. We design amplifier, 0.01 Hz high pass filter, 75 Hz low pass filter, and 50 Hz notch filter. After filtering and amplification, ECG and PPG are sampled by MCU and then the data are transmitted to computer. LabVIEW is used to receive, display and process these data, and finally figure out the PWTT. Based on PWTT value, we coarsely calculate the SBP.