新型低功率與高雜訊抑制電生理訊號量測系統之前端電路設計與分析

Abstract

在無線網路的蓬勃發展下，許多結合無線網路的應用也由此應運而生。居家醫療看戶及遠距醫療即為其中的一項應用，而建構『電生理訊號量測與監控系統之無線化與晶片化』即為實現居家看護與遠距醫療的第一步。當一個生醫量測系統能夠結合無線網路時，我們便能夠在任何地方和任何時間下，輕易的監控一個人的身體狀況。 本論文將設計一個應用於『電生理訊號量測與監控系統』晶片之前端電路，在此前端電路中，包括了兩個部份: 一個用以抑制人體雜訊之儀表放大器以及一個低頻的帶通濾波器。在本論文中，提出一個擁有高共模抑制比的儀表放大器，將有效抑制人體中大量的低頻雜訊，而後端的低頻帶通濾波器的設計將使用『跳蛙架構』 (Leapfrog Structure)來減低元件飄移對於電路表現的影響。

此電生理訊號量測之前端電路，使用台灣積體電路 0.35微米製程模擬，此電路第一級的儀表放大電路操作於3.3伏特，功率消耗為0.1毫瓦，頻寬為2至16千赫茲，有0至60dB之電壓增益，共模拒絕比率可達到200分貝至250分貝以抑制人體中之大量低頻雜訊。在此儀表放大器的後端，是一個可濾出不同所需人體訊號之低頻濾波器，而此操作於3.3伏特下之低頻濾波器，功率消耗為0.13毫瓦，濾波器頻寬為50赫茲至2千赫茲，並有可調整之介於0~60分貝的電壓增益。整體的前端電路消耗0.23毫瓦，有200至250分貝之共模拒絕比率，頻寬為2至16千赫茲。

With the growing development of wireless networks, many applications combined with wireless networks come into existence. Home nursing and remote medical care is one of the applications. And constructing the electrophysiological signals measurement and control system is the first step to realize the home nursing and remote medical care. While the measurement system is combined with wireless network, we can easily monitor the physical condition of people.

In this thesis, we will design the front-end circuit of the electrophysiological signals measurement and control system. The front-end circuit is composed of two parts, the instrumentation amplifier(INA) to compress the noise of human bodies and the low- frequency bandpass filter. In this thesis, we will announce a instrumentation amplifier with high common-mode rejection ratio (CMRR) which can effectively compress the noises in human bodies. The low-frequency bandpass filter behind the instrumentation amplifier uses leapfrog structure to decrease the influence on circuit performance due to devices variation. The front-end circuits of the electrophysiological signals measurement simulates with TSMC 0.35um technology. The first stage INA operates at 3.3V, consumes the power of 0.1mW. Its bandwidth is between 2~16 kHz, and its CMRR archives the magnitude 200~250 dB to suppress the enormous low-frequency noises in human bodies. Behind the INA is the low-frequency bandpass filter which filters different human-body signals. The low-frequency bandpass filter operates at 3.3V and consumes 0.13mW. Its bandwidth is from 50Hz to 2kHz and has the tunable gain between 0~60dB.