scholarly journals Fractional-order low-pass filter with electronic tunability of its order and pole frequency

2018 ◽  
Vol 69 (1) ◽  
pp. 3-13 ◽  
Author(s):  
Lukas Langhammer ◽  
Jan Dvorak ◽  
Jan Jerabek ◽  
Jaroslav Koton ◽  
Roman Sotner
Keyword(s):  
Fractional Order ◽  
Current Mode ◽  
Proper Function ◽  
Electronic Control ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Internal Parameters ◽  
Current Follower ◽  
Low Pass ◽  
Experimental Laboratory

Abstract This paper presents novel solution of a fractional-order low-pass filter (FLPF). The proposed filter operates in the current mode and it is designed using third-order inverse follow-the-leader feedback topology and operational transconductance amplifiers (OTAs), adjustable current amplifiers (ACAs), auxiliary multiple-output current follower (MO-CF) as simple active elements. The filter offers the beneficial ability of the electronic control of its order and also the pole frequency thanks to electronically controlled internal parameters of OTAs and ACAs. As an example, five particular values of fractional order of the FLPF were chosen and parameters of the filter were calculated. Similarly, also electronic control of the pole frequency of the filter was studied. The design correctness and proper function of the filter are supported by simulations with CMOS models and also by experimental laboratory measurements. Comparison of the simulation results of the proposed filter for two different approximations of the parameter sα is also included.

Synthesis and Analysis of Electronically Adjustable Fractional-Order Low-Pass Filter

2017 ◽  
Vol 27 (02) ◽  
pp. 1850032 ◽  
Author(s):  
Jan Dvorak ◽  
Lukas Langhammer ◽  
Jan Jerabek ◽  
Jaroslav Koton ◽  
Roman Sotner ◽  
...  
Keyword(s):  
Current Mode ◽  
Experimental Results ◽  
Current Gain ◽  
Behavioral Models ◽  
Output Current ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Active Elements ◽  
Current Follower ◽  
Low Pass

A proposal of a fractional ([Formula: see text])-order low-pass filter is presented in this paper. The proposed filter operates in the current-mode and it is designed using Multi-Output Current Followers (MO-CFs), Dual-Output Current Follower (DO-CF), Dual-Output Adjustable Current Amplifier (DO-ACA) and Adjustable Current Amplifiers (ACAs) as active elements within the presented topology of the filter. The filter possesses ability to electronically control its order and also the pole frequency by changing the current gain of current amplifiers (ACAs) already present in the structure. Three different values of the order and pole frequency of the proposed low-pass filter were tested as an example. Design of the proposed filter is supported by simulation and experimental results. Simulations of the circuit are carried out in PSPICE simulator with behavioral models of used active elements. The experimental laboratory measurements are performed with the help of available devices forming equivalent circuits. Simulations and experimental results of the electronical control of the order and pole frequency are compared in this contribution.

An experimental analog circuit realization of Matsuda’s approximate fractional-order integral operators for industrial electronics

2021 ◽  
Author(s):  
Murat Koseoglu ◽  
Furkan Nur Deniz ◽  
Baris Baykant Alagoz ◽  
Ali Yuce ◽  
Nusret Tan
Keyword(s):  
Fractional Order ◽  
Analog Circuit ◽  
Low Cost ◽  
Electric Circuit ◽  
Partial Fraction ◽  
Circuit Realization ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Performance Improvements ◽  
Low Pass

Abstract Analog circuit realization of fractional order (FO) elements is a significant step for the industrialization of FO control systems because of enabling a low-cost, electric circuit realization by means of standard industrial electronics components. This study demonstrates an effective operational amplifier-based analog circuit realization of approximate FO integral elements for industrial electronics. To this end, approximate transfer function models of FO integral elements, which are calculated by using Matsuda’s approximation method, are decomposed into the sum of low-pass filter forms according to the partial fraction expansion. Each partial fraction term is implemented by using low-pass filters and amplifier circuits, and these circuits are combined with a summing amplifier to compose the approximate FO integral circuits. Widely used low-cost industrial electronics components, which are LF347N opamps, resistor and capacitor components, are used to achieve a discrete, easy-to-build analog realization of the approximate FO integral elements. The performance of designed circuit is compared with performance of Krishna’s FO circuit design and performance improvements are shown. The study presents design, performance validation and experimental verification of this straightforward approximate FO integral realization method.

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