Design of square‐root domain filters by substituting the passive elements of the prototype filter by their equivalents

Abstract

SUMMARYA novel technique for designing square-root domain (SRD) filters is introduced in this paper. The concept of the proposed method is based on the substitution of the passive elements of the corresponding prototype filter by their SRD equivalents. The signal processing performed by the proposed SRD equivalents achieves that the voltage at each terminal of the SRD equivalent is the compressed version of the voltage at the corresponding terminal of the passive element, and that the current that flows through the SRD equivalent is the same as that flows through the passive element. The main attractive characteristic of the proposed method is that a quick procedure for designing SRD filters is offered. The validity of the proposed technique was verified by studying the behaviour of a 5th-order SRD low-pass filter. In order to demonstrate the benefits offered by the proposed technique, a SRD leapfrog filter was also designed and its performance is compared with that of the active filter that topologically simulates the same prototype filter.

Electronically tunable current-mode square-root-domain first-order multifunction filter

“…In companding systems, the input signals are first compressed, then properly processed and finally expanded at the output (Frey, 1993;Kircay & Cam, 2006, 2008Mulder, 1996Mulder, , 1998Mulder et al, 2000;Seevinck, 1990;Tsividis, 1990). This class of filters has been gaining popularity due to their suitability for application areas which demand low voltage and low power, their large dynamic range and operability in high frequency applications and being electronically tunable.…”

“…Companding (compressing-expanding) filters are new generation filters and constitute one of the most important classes of the analog circuit family (Frey, 1993;Kircay & Cam, 2006, 2008Mulder, 1996Mulder, , 1998Mulder, Serdijn, Woerd, & Roermund 2000;Seevinck, 1990;Tsividis, 1990). In companding systems, the input signals are first compressed, then properly processed and finally expanded at the output (Frey, 1993;Kircay & Cam, 2006, 2008Mulder, 1996Mulder, , 1998Mulder et al, 2000;Seevinck, 1990;Tsividis, 1990).…”

A low-voltage square-root domain n-th order multifunction FLF filter topology

“…This approach has been followed in the case of SRD filters and the derived systematic methods have been already published in [7][8][9].…”

Design simplifications for bi notch filters

“…Designing an analog/digital filter from a prototype filter is a well known design approach. Many such designs can be found in the literature [2,3]. A number of design approaches for notch/multi NFs have been suggested in literature [3][4][5][6][7][8][9][10][11][12][13].…”