Six Order Cascaded Power Line Notch Filter for ECG Detection Systems with Noise Shaping

This paper presents the design of an operational transconductance amplifier-C (OTA-C) notch filter for a portable Electrocardiogram (ECG) detection system. A six order cascaded filter is utilized to reduce the effect of the power line interference at (50/60 Hz). The proposed filter is based on a programmable balanced OTA circuit. Based on this, PSPICE post layout simulation results for the extracted filter using 0.25 μ m technology and operating under ± 0.8 V voltage supply are also given. The six order notch filter provides a notch depth of 65 dB (43 dB for 4th order), input referred noise spectral density with noise shaping of 9 μ Vrms/ √ Hz at the pass band frequencies and 9 mVrms/ √ Hz at the notch (zero) frequency which provide noise shaping for the ECG signal. These results demonstrate the ability of the filter to be used for ECG signal filtering which is located within 150 Hz.