New Voltage Mode Universal Filters Using Only Two CDBAs

J K Pathak,Raj Senani,A K Singh

doi:10.1155/2013/987867

Abstract

Two new configurations for voltage mode universal filters (VMUFs) using only two current differencing buffered amplifiers (CDBAs) are proposed. Both of the new configurations can realize all the five standard types of the filters, namely, low pass (LP), high pass (HP), band pass (BP), band stop (BS), and all pass (AP), from the same topology. In contrast to previously known CDBA-based VMUFs, the new configurations do not need an additional active device for voltage inversion to realize all pass functions. The proposed configurations offer the tunability of the natural angular frequency(ωo), quality factor(Q), or the bandwidth (BW) through separate virtually grounded resistors. Moreover, both circuits have resistive input impedance (which can be made high) and a low output impedance to facilitate easy cascading without additional buffers. PSPICE simulation results, based upon commercially available AD844 ICs to implement the CDBA, are included which confirm the practical workability of the new VMUF configurations.

Highlights

Analog lters are widely used for continuous-time signal processing in communication, measurement, instrumentation, and control systems [1]
A practical current differencing buffered ampli ers (CDBAs) can be described by the following relationships that take into account the nonidealities of the device: IIzz = ββppIIpp − ββnnIInn, (2)
To verify the theoretical results, both of the proposed CDBAbased VMUF circuits of Figure 3 have been simulated in PSPICE using macro model of commercially available AD844 ICs employed to construct the CDBAs according to the schematic of Figure 2 with DC bias supply voltages of ±12 V

Summary

Introduction

Analog lters are widely used for continuous-time signal processing in communication, measurement, instrumentation, and control systems [1]. Additional voltage inversion is not required to realize all pass function, resulting in the saving of one active element

Effects of the CDBA Nonidealities and Their Parasitic Impedances

CC1RR4

Spice Simulation Results

Concluding Remarks