Electronically Tunable Fully-Differential Fractional-Order Low-Pass Filter

Lukas Langhammer, Jan Dvorak, Roman Sotner, Jan Jerabek


The paper presents proposal of a fully-differential (1 + α)-order low-pass filter. The order of the filter and its cut-off frequency can be controlled electronically. The filter is proposed using operational transconductance amplifiers (OTAs), adjustable current amplifiers (ACAs) and fully-differential current follower (FD-CF). The circuit structure is based on well-known Inverse Follow-the-Leader Feedback (IFLF) topology. Design correctness of the proposed filter is supported by PSpice simulations with transistor-level simulation models. The ability of the electronic control of the order has been tested for five individual values of parameter α. Furthermore, the ability of the electronic control of the cut-off frequency of the filter has been also tested for five different values. Additionally, the simulation results of the proposed fully-differential (F-D) filter are compared with the results of the single-ended (S-E) equivalent of the presented filter.

DOI: http://dx.doi.org/10.5755/j01.eie.23.3.18332


Active filter; fractional-order; frequency control; low-pass filter

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Online ISSN: 2029-5731