Designing Low Frequency I.c Filter Using Pseudo Resistor for Biopotential Measurments

Standard medical diagnosis requires attaching sensors or electrodes to the patient and then connecting these electrodes to bulky equipment powered by mains supply. This is usually an acceptable procedure for short term patient monitoring. However, for long term monitoring, this approach is neither comfortable nor durable. Therefore considering fully implantable electronic systems which have many useful applications including monitoring cardiac irregularities in pacemaker systems, are the preferred. This thesis intends to show the design of low frequency IC filters. Given that large time constants are required in low cutoff frequency filter designs, various approaches can be utilized to provide large values of resistors or capacitors. To demonstrate the proposed method, third order low-pass and high-pass filters for ECG signals with cutoff frequencies in range of 0.1-100 Hz are implemented. Butterworth topology is used in both filter designs to preserve the morphological information of the ECG signals.