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A Study on Intrinsic Noise of Capacitively Coupled Active Electrode  

Lim, Yong-Gyu (상지대학교)
Publication Information
Journal of the Institute of Convergence Signal Processing / v.13, no.1, 2012 , pp. 44-49 More about this Journal
Abstract
The indirect-contact ECG measurement is a newly developed method for unconstrained and nonconscious measurement in daily Life. This study is the first step to reducing the large background noise appearing in indirect-contact ECG. This study built the thermal noise model of capacitively coupled active electrode which is used in indirect-contact ECG. The results show that the level of thermal noise estimated by the thermal noise model is much the same as that of actual background noise for the capacitively coupled active electrode alone. By applying the actual electrical properties of a sample cotton cloth to the thermal noise model, the theoretical level of thermal noise in the indirect-contact ECG was estimated. The results also show that the level of op-amp's intrinsic noise is so small that it can be negligible in comparison with thermal noise of resistors. The relationship between the level of thermal noise and the resistance of the bias resistor was derived, and it is the base for the further study how to choice the optimal resistance for the bias resistor.
Keywords
Indirect-contact ECG; Capacitively coupled active electrode; Thermal noise; Background noise;
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