Pain monitoring is essential during general anesthesia operations. Previous researchers have found relationship between pulse wave and painful stimulation and introduced parameters based on photoplethysmography (PPG). According to arterial windkessel model, pulse wave transfer function (PWTF) would represent the transmission of stimulation but there was little research on this. A synchronous dual channel PPG acquiring system with ECG circuit and external blood pressure module is built to push on the research. System works well with testers aged from 10 to 65, both male and female.

In this paper we designed a portable ECG monitoring system based on Cortex-M3. The system was composed of the microcontroller LPC1788 and the analog front-end ADS1298 which provided a low-noise, 8-channel, 24-bit delta-sigma analog-to-digital converter. The monitor used SD card for data storage and USB for data transmission, which was capable of monitoring both dynamic ECG and conventional ECG. The system could work up to 24 hours with a resolution of 24 bits and 1024Hz sampling rate. The designed system embodies several characteristics including portability, low power, large capacity, and high resolution, which are quite suitable for ECG monitoring.