Md. Jahid Hasan*, Nurul Bashar, Susmita Sarker, Sumiya Alam Lopa, and Tofayel Ahmed
Abstract: In contemporary times, the ubiquity of filters is undeniable. Active filters are frequently discussed and utilized among the various types of filters. This literature seeks to compare two types of second-order low pass filters, the second-order Butterworth Sallen & Key (VCVS) low pass filter and the Multiple Feedback (MFB) low pass filter, to shed light on the characteristics and performance of each filter. Upon analysis of the results, it was determined that the VCVS filter operates in a non-inverting mode, while the MFB filter operates in an inverting mode. Notably, when subject to an open loop noise-added signal, the VCVS filter output was observed to be 50-80% closer to the desired signal. Conversely, the MFB filter produced a severely distorted output under the same conditions. In a closed-loop PID-controlled method, both filters exhibited an output that was 90-95% closer to the desired output. However, the MFB low pass filter output in the closed-loop setting was considerably superior to that of the closed-loop VCVS filter. In light of these findings, it is evident that the selection of an appropriate filter must be made with consideration of a host of factors such as the cost of the filter, the desired signal quality, and the application’s specific requirements. Ultimately, the appropriate filter selection could play a vital role in the successful execution of a given application or system.
Keywords: Low pass filter, sallen & key, butterworth, multiple feedback filter, closed-loop
References
2nd Order Active Filters, Band-Pass—K7MEM. (n. d.). Retrieved February 26, 2023, from https://k7mem.com/Fil_2nd_Active_BP.html
Badajos, J. C. T., Ochoa, K. M. P., Tejadilla, R. A. P., & Peñas, R. T. L. (2019). Reduction of Audio Noise with Lowpass Chebyshev Type II Filter Simulated using GNU Octave. 2019 IEEE 11th International Conference on Humanoid, Nanotechnology, Information Technology, Communication and Control, Environment, and Management (HNICEM), 1–6.
Category: Electronic filter topology. (2022). In Wikipedia. https://en.wikipedia.org/w/index.php?title=Category:Electronic_filter_topology&oldid=1122765651
Efficient Inverse Filters based on Second-Generation Voltage Conveyor (VCII) | SpringerLink. (n.d.). Retrieved February 26, 2023, from https://link.springer.com/article/10.1007/s13369-021-05775-5
Harry, J. R., Blinch, J., Barker, L. A., Krzyszkowski, J., & Chowning, L. (2022). Low-Pass Filter Effects on Metrics of Countermovement Vertical Jump Performance. Journal of Strength and Conditioning Research, 36(5), 1459–1467.
Nanopower multiple-input DTMOS OTA and its applications to high-order filters for biomedical systems—ScienceDirect. (n.d.). Retrieved February 26, 2023, from https://www.sciencedirect.com/science/article/abs/pii/S1434841120327801
Smith, S. W. (1997). The scientist and engineer’s guide to digital signal processing. California Technical Pub. San Diego.
Sudhakar, M. V., Charan, M. P., G. N., P., Harika, L., & Yamini, P. (2021). Audio signal noise cancellation with adaptive filter techniques. Mater. Today Proc.