ccECG可穿戴式心电图测量系统.ppt

医疗保健中的通信 （二） ECG Electrocardiography (ECG 心电描记法) is one of the most widely used vital sign sensing and health monitoring methods and provides useful diagnostic information about the cardiovascular system. Conventional clinical ECG system （wet ECG） Two interfaces 1、Patient-sensor interface Dry-electrode Capacitively-coupled ECG (CC-ECG) 2、Sensor-cardiologist interface An efficient wireless protocol 1、Nernst path——consists of a resistor and an interface potential and is used in resistive ECG (wet method) 2、Capacitive path——a capacitor couples the signal onto the electrode. Advantages and Shortcomings System Description 1、three identical-sized PCBs as electrodes for signal acquisition and common mode attenuation 2、one main board for signal conditioning and transmission. Two of these electrodes are attached to the chest for signal acquisition from the body One of them is attached far from the chest on the right hip as a reference electrode Capacitive Electrodes 棉布作为绝缘层，介电常数为1.6，厚度为0.35mm 电极：~33mm*~33mm圆角 5Hz时，电容可以到115pF； Buffer：高输入阻抗，低输出阻抗，选用电路为LMC6001 ECG Signal Processing Circuits ECG signals are approximately in the range of 0.1~100 Hz。 LPF：a low-pass Butterworth active filter with a corner frequency of 85 Hz HPF：a passive HPF with corner frequency of 0.5 Hz Notch filter：60Hz ADC：PIC24FJ64GA(28-pin/QFN/6 mm × 6 mm) with 10-bit ADC Other Parts Battery： 3V/256mA/h lithium battery DC/DC voltage converter：TPS61040 SOT23-5 packages Wireless Data Transmission Zebra module：15 mA and measures 16 mm × 33 mm. Zigbee module(CC2420 RF)：19 mA in receive mode and 17 mA in transmit mode Bluetooth module(BluesenseAD from Corscience)： ~30 mW and measures 37 mm × 21 mm ANT system ANT无线网络是加拿大Dynastream Innovations 公司发起并推动的超低功耗无线网络标准。是一种同步自组织无线网络，操作频段为2.4G，通信距离30m，采用GFSK调制，支持星型和端对端等多种组网形式。 The isochronous feature Low-data-rate transmission of ANT Future improvements Making the capacitive electrodes even more convenient by employing flexible electrode PCBs R