Portable Multi-Function Monitor Based On ARM

The electrocardiogram (ECG), blood pressure (BP), sphygmus and blood oxygen saturation (SO2) are the most fundamental bio-indicators of human beings, which can be monitored by multi-function monitor for long time. Because of the use of these monitors, patients are better treated and the death rate of severe patients decreases a lot.The portable multi-function monitor as described in this paper features small size, low power consumption and strong performance. The processor with the ARM920T core embedded is used as the central processing unit. It integrates various digital sources and features fast speed and low power consumption, which meets the needs of the portable system. The ECG module is implemented based on two techniques:Σ-ΔADC and oversampling. The analog circuit of the module contains a direct current (DC) amplifying stage which replaces the traditional alternating current (AC) amplifying. The new circuit has high integration and robust, and can avoid amplifier blocking. The passive linear net is used to suppress the electrosurgical interference.We choose the embedded Linux as the operation system (OS) based on ARM. The graphic user interface (GUI) is developed using the software Qt/E. All of the bio-indicators can be show on the screen, as data or wave. This paper also introduces several algorithms for the noise removal of ECG base on the plain processor. The improved algorithm of adaptive coherent model is detailed for its advantages: high performance, simple and being easy to use, without reference channels, high speed and real-time implementing.Designed on modularization technique, the system is divided into several modules with specific function and clear frame, facilitating its further modification, optimization and maintenance. It can be widely used in sickroom, operating theatre, community medical room and on the ambulance.