Abstract
A pulse oximeter is a noninvasive oxyhemoglobin saturation monitoring instrument with optical components. When developing miniaturization and wireless communication technologies, small sized portable health care system are demanded. Therefore, continuous health care monitoring and precaution device for emergency are required for the patient. To develop the device on these demands, the sensing interface circuit is requested to minimize for protable reason and the photoplethysmographic to be reduce noise. The major source of noise is body motion, for this reason, motion artifact reduction is the key technique to develop. In this paper, a portable sensing interface circuit and a motion artifact reduction method was proposed. The device had a shape of the finger band, which measured the photoplethysmographic on the finger. For the purpose of a portable device, components of the transimpedance ampligier, LED driver, analog multiplexer, and filters, were integrated into a printed circuit board. Moreover, the transconductance-C filter of low-pass filter, band-pass filter, and notch filter, were integrated into a chip using TSMC 0.18μm technology. Finally, this research presents a motion artifact reduction method with correction of optical calculation and active noise cancellation method with a reference signal to reduce signal distortion by body motion.