New portable ECG software and hardware design (1)

I. introduction

Cardiovascular disease is currently the largest human harm of a disease, and ECG is the inspection, diagnosis and prevention of such diseases and the principal means.

As a result of traditional PC-based platform of ECG monitor, expensive, bulky and not easy to move and mainly concentrated in large hospitals, and failed to real-time monitoring of patient's condition, to physicians and patients in great inconvenience. In recent years, with embedded and network communication technologies and the rapid development, we have developed a novel based on ARM7 processor embedded ECG monitor, it uses one of the Samsung company ARM7TDMI core 32-bit high-speed RISC processor S3C44B0X, cost, small volume, high reliability, the advantages of simple operation, suitable for individuals, small and medium-sized hospitals and community health units to family health care (HHC) and telemedicine (Telemedicine) and other emerging medical way provides good help and support.

Second, the system works

Figure a new embedded cardiac monitor system architecture diagram

ECG Electrode by dedicated people left and right arm collected after being fed into the signal processing circuit, first going to the preamplifier initial zoom, high-pass filter to filter out DC signal and low-frequency interference, the baseline after the class amplifier and filter further filtering out 50 Hz mains frequency interference, the low-pass filter to meet the requirements of the ECG, the analog signal input into the ADC for high-precision A/D conversion.

In order to better prevent interference signal and loose and falling off the lead, we in the circuit also introduces a right leg drive circuit and leads off detection circuit. System control core with Samsung's S3C44BOX, liquid crystal display (LCD) and establish a good human-computer interaction interface, the acquisition of the signal through the LCD display and playback in real time, data via the Internet based on TCP/IP (Transmission Control Protocol/Internet Protocol) in order to reliably transmit data to the ECG monitoring center, health care professionals to provide timely and accurate diagnosis. Embedded real-time operating system uses the now popular uClinx, manage and coordinate the work of the module system to guarantee reliable operation.

III. system hardware module design

3.1, signal conditioning circuit

Signal conditioning circuits include: amplifiers, bandpass filter, notch filter, etc.

Figure 2 ECG preamplifier