A Fractional Order Notch Filter to Compensate the Attenuation-Loss Due to Change in Order of the Circuit
Arpit Sourav Mohapatra, Karabi Biswas
Abstract
Analog integer order notch filters (IONF) are practically realised by using two or more capacitors. If the dissipation factor of capacitors (used in the IONF) increases then the overall order of the circuit reduces. Reduction in the order causes attenuation-loss at the notch frequency. Once the order reduces, the loss can only be compensated by reducing the quality factor of the IONF circuit, which is not desirable. This problem can be overcome by using a fractional order notch filter (FONF). The FONF circuit uses fractional order capacitors (Z = 1/Cs <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">β</sup> ), which provides an extra degree of design freedom to control the order of the circuit, thereby helping in compensating the attenuation-loss. In this work, a new fractional order notch filter (FONF) has been proposed in which the attenuation-loss, due to change in the order of the system, can be compensated by tuning resistor/s of the proposed circuit.