Study And Development Of A USB-based Data Acquisition System For Impedance Cardiography Signals

Impedance Cardiography (ICG) is an important clinical means of detecting and diagnosing cardiovascular diseases. Accordingly, developments of advanced ICG detection systems are vital for biomedical research, industry and social healthcare.This thesis is an outcome of our work towards a portable and cost-effective ICG monitoring and diagnosing system. In this thesis, some important issues and key techniques concerning acquisition and processing of ICG signals such as collecting, adjusting, A/D transforming and transmitting, were investigate on the basis of studying relevant biomedical principles, and a portable data acquisition system with USB interface was designed and fabricated as a prototype.Experiments with testees show that the system developed is capable of acquiring ICG signals (including base impedance Z₀,impedanceâ–³Z and differential impedance dZ/dt) and ECG signals without noticeable distortion, and it can transmit the collected data to a host computer via a USB 2.0 interface for waveform display and further processing. Besides, it works without any external power source and boast of a feature of plug and play. Such results suggest that by mating it with a specially developed software package, an ICG-based medical monitoring and diagnosing system will come true with many expected merits such as portable, high performance and low cost. Moreover, it is somewhat universal by virtue of USB interface. That is, it might work well with other relevant software package, and some techniques demonstrated by it especially that of USB interface, are applicable or suggestive to other systems.