Assessment of Driven-right-leg Circuit Performance in Dry-electrode EMG Data Acquisition System

The purpose of this study is to assess the performance of driven right leg (DRL) circuit within the proposed EMG data acquisition system that utilizes dry electrodes to investigate the effect of dry electrode on a DRL circuit and providing an estimated DRL attenuation equation to be used in line interference modelling of the measurement system. The assessment was done by measuring common-mode voltage on human body in different environments, and curve fitting method is applied to obtain the actual gain as a function of user-expected gain during operation. It was found that the polynomial equation is estimated which shows nonlinearity in driven right circuit in reducing common-mode voltage. The result implies that driven right leg performance is affected by the use of dry electrode, which nonlinearity would be contributed from high value of electrode-skin impedance of dry electrode. Hence, a future study on electrode-skin impedance effect on driven right leg circuit is suggested to preserve the circuit's linearity when utilizing dry electrodes.