Experimental Verification of Pseudo-Differential Electronically Controllable Multifunction Filter Using Modified Current Differencing/Summing Units

journal article in Web of Science

English

This paper presents synthesis and analysis of reconfigurable frequency filter with differential input and differential output terminals and its experimental verification. The inner structure of the filter has single-ended form, i.e. filter behaves as so-called pseudo-differential circuit. Filtering function can be electronically reconfigured between low-pass (LP) and band-pass (BP) response. Active elements of the filter are Differential Voltage Buffer (DVB) as an input stage and Modified Current Differencing Unit (MCDU) together with Modified Current Summing Unit (MCSU) as inner and also output stage. Each of important parameters of the filter (angular pole frequency, quality factor and pass-band gain) are electronically controllable by parameters of these active elements used. Some of the parameters of the filter are controlled by two independent parameters, i.e. are dual-controlled, which enables the extended electronic controllability. The proposed topology operates in the voltage mode and both input nodes have high input impedance. Expected behavior of the filter is analyzed and verified by PSpice simulations using CMOS models of above mentioned active elements. Moreover, features of the filter in both configurations were successfully verified also by experimental measurements using behavioral models of active elements.

Analogue filter; differential voltage buffer; dual-controlled; fully differential; modified current differencing unit; modified current summing unit; pseudo differential; reconfigurable filter; voltage mode.

JEŘÁBEK, J.; DVOŘÁK, J.; ŠOTNER, R.; HERENCSÁR, N.; KOTON, J.

15. 6. 2019

0218-1266

JOURNAL OF CIRCUITS SYSTEMS AND COMPUTERS

28

6

Republic of Singapore

1950098-1

1950098-30

30

https://www.worldscientific.com/doi/10.1142/S0218126619500981