Inductor-less FO Low-pass Notch Filter with High Q and High Attenuation for ECG Signal Processing

This paper presents a design of an inductor-less fractional order (FO) low-pass notch filter (LPNF) for processing ECG signal. The filter is designed with a D element and a fractor which are realized in hardware using a grounded GIC and an RC ladder, respectively. The filter is tunable in a small range (35-80 Hz) by varying a series resistor, as well as, in a wide range (35-20000 Hz) by varying a GIC resistor. With the proposed filter an attenuation of 105.8 dB has been achieved in 50 Hz by adjusting the fractance value. The order a is set between 0.2 to 0.3 to ensure the low-pass notch action. The quality factor of the proposed FO LPNF is 97-112 in the frequency range 40-60 Hz (experimental). Spice simulations for different test cases, design examples, and experimental results are presented. A comparison with reported integer order and other FO notch filters are also given.