Applying the Difference Term Approach for Low Frequency Biomedical Filter
Yaqub Mahnashi* and Hussain Alzaher
Electrical Engineering Department King Fahd University of Petroleum and Minerals , Dhahran, Saudi Arabia
- *Corresponding Author:
- Yaqub Mahnashi
Electrical Engineering Department
King Fahd University of Petroleum and Minerals
Dhahran, 31261, Saudi Arabia
E-mail: [email protected]
Received Date: June 14, 2012; Accepted Date: June 25, 2012; Published Date: June 30, 2012
Citation: Mahnashi Y, Alzaher H (2012) Applying the Difference Term Approach for Low Frequency Biomedical Filter. J Biosens Bioelectron S11:004. doi:10.4172/2155-6210.S11-004
Copyright: © 2012 Mahnashi Y, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Low frequency continuous time filters are essential analog blocks for biomedical applications. Integrating such filters having large time constants is difficult as it requires large component values. A novel approach to scale down the pole frequency is presented. A 5-bit reduction in the cut off frequency is achieved. This is made possible through adding a passive resistor in the forward path of the op-amp based integrator introducing a difference term of the pole frequency. Also, the filter topology is modified to avoid changing the quality factor. As an example, a 2nd order low pass filter is designed and simulated. Simulation results show that the pole frequency is scaled down from 1.43 MHz to 4.97 kHz while maintaining tuning of 30% around the nominal value by controlling only one resistor.