THEORETICAL AND APPLIED ELECTRICAL ENGINEERING VOLUME: 15 | NUMBER: 5 | 2017 | DECEMBER OTRA-Based Multi-Function Inverse Filter Configuration Abdhesh Kumar SINGH 1 , Ashish GUPTA 2 , Raj SENANI 3 1 Department of Electronics and Communication Engineering, Delhi Technical Campus, Knowledge Park-III 28/1, 201308 Greater Noida, India 2 Department of Electronics and Communication Engineering, I.T.S Engineering College, Knowledge Park-III 46, 201308 Greater Noida, India 3 Division of Electronics and Communication Engineering, Netaji Subhas Institute of Technology, Azad Hind Fauz Marg, Sector 3, Dwarka, 110078 New Delhi, India abdheshks@yahoo.com, ashishguptaas@its.edu.in, senani@ieee.org DOI: 10.15598/aeee.v15i5.2572 Abstract. A new OTRA-based multifunction inverse ﬁlter conﬁguration is presented which is capable of re- alizing low pass, high pass and band pass ﬁlters using only two OTRAs and ﬁve to six passive elements. To the best knowledge of the authors, any inverse ﬁlter conﬁguration using OTRAs has not been reported in the literature earlier. The eﬀect of the major parasitics of the OTRAs and their eﬀect on the performance of the ﬁlter have been investigated and measured through sim- ulation results and Monte-Carlo analysis. The work- ability of the proposed circuits has been conﬁrmed by SPICE simulations using CMOS-based-OTRA realiz- able in 0.18 μm CMOS technology. The proposed cir- cuits are the only ones, which provide simultaneously the following features: use of reasonable number of ac- tive elements (only 2), realizability of all the three basic ﬁlter functions, employment of all virtually grounded resistors and capacitors and tunability of all ﬁlter pa- rameters (except gain factor, H 0 for inverse high pass). The centre/cut-oﬀ frequency of the various ﬁlter cir- cuits lying in the vicinity of 1 MHz have been found to be realizable, which has been veriﬁed through SPICE simulation results and have been found to be in good agreement with the theoretical results. Keywords Analogue signal processing, inverse active ﬁl- ters, Operational Transresistance Ampliﬁer. 1. Introduction Inverse ﬁlters are important from the view point of some applications in the areas of Communication, Con- trol and Instrumentation Systems where the distortion of the signal, caused by the signal processor or trans- mission systems, can be corrected by inverse ﬁlters, the frequency response of which is the reciprocal of the fre- quency response of the signal processors or transmis- sion systems which were responsible for creating the undesired distortion in the system. In digital systems, there are well known methods for the realization of inverse ﬁlters, however, in the continuous-time case, only a few methods/circuits have so far been proposed for the realization of inverse ﬁl- ters such as those in [1], [2], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17] and [18]. It is, therefore, useful to take a stock of the existing works in this area so that the present proposals can be seen in the right perspective. In [1], a general method for obtaining inverse trans- fer function for linear dynamic systems and the inverse transfer characteristics of nonlinear resistive systems using nullors as basic building block were presented. In [2], a procedure for transforming voltage-mode op- amp-based RC ﬁlter into a current mode, Four Termi- nal Floating Nullors (FTFN)-based inverse ﬁlter was given. In [3], another general procedure for the re- alization of FTFN-based inverse ﬁlter from the well- developed voltage-mode ﬁlters was presented. In [4], Abuelma’atti used a single FTFN to realize many ﬁl- ters including an inverse ﬁlter. In [5], Gupta, Bhaskar, Senani and Singh presented four new conﬁgurations which realize inverse low pass, band pass, high pass c  2017 ADVANCES IN ELECTRICAL AND ELECTRONIC ENGINEERING 846