SINGLE OTRA BASED INVERSE FILTER CONFIGURATION

Abstract

A new OTRA-based multifunction inverse filter configuration is presented which is capable of realizing inverse low pass, inverse high pass, inverse band pass and inverse band reject filters using only one OTRA and five to six passive elements. To the best knowledge of the authors, any inverse filter configuration using OTRA has not been reported in the literature earlier. The proposed inverse filters are meticulously validated through simulations in Cadence PSpice, implemented in TSMC 0.18µm CMOS technology. The theoretical frequency response characteristics of all the proposed configurations match very well with the simulated ones. The proposed circuits are the only ones, which provide simultaneously the following features : use of reasonable number of active elements (only 1), realizability of all the four basic inverse filter functions, employment of all virtually grounded resistors and capacitors and tunability of all filter parameters (except gain in case of inverse band reject filter). The effect of the major parasitics of the OTRA and their effect on the performance of the filter have been investigated and measured through simulation results and Monte-Carlo analysis. Layout of the proposed CMOS OTRA has also been made using Layout XL Suite of Cadence Virtuoso using 180nm technology. Noise analysis as well as sensitivity analysis has also been studied.