A novel multifunction modified CFOA based inverse filter

Abstract

Inverse filter has been a topic of great interest and research. A novel multifunction inverse bi-quad configuration based on modified current feedback operational amplifiers (MCFOAs) and a minimum number of grounded passive elements are presented in this paper. To show the flexibility of the proposed MCFOA inverse Lowpass, inverse Bandpass and inverse Highpass filter functions employing MCFOA are reported. All the passive elements in the proposed scheme are grounded to benefit easier electronic tunability. The layout of the proposed MCFOA is also given. The workability of the proposed inverse filters is demonstrated by PSPICE simulations.Keyword�inverse active filters, modified current feedback operational amplifier (MCFOA), analogue signal processing.I.

Realization of Filter/Inverse Filter Topologies using single FTFNTA

“…As more ABBs have been used, the larger chip area would be required for fabrication. Inverse low-pass (ILPF), inverse high-pass (IHPF), and inverse band-pass (IBPF) filter function were implemented by [13,15,16] while topologies of [9,12,14] provide an additional filter function of IBRF.…”

“…Inverse filter functions of ILPF, IHPF, and IBPF were implemented by [18,[22][23][24], while topologies of [19,25] provide an additional filter function of IBRF. The topologies present in [9,14,16,21,24,25] possess electronic tunability. For better-integrated circuit design, the circuit must have a fixed topology [5-7, 10-12, 16-18, 20, 22, 24-28] to implement the different inverse filter functions.…”

“…• Some topologies are resistor-less [21,25] • The filter parameters are electronically tunable [9,14,16,21,24,25] • [5-7, 10, 11, 14, 20] provides single response at a time while [8, 9, 13-15, 19, 21, 23] provide multiple responses by altering the topology • [17,25] provides universal inverse filter without altering the topology So it is concluded from the literature survey, as detailed above, that no universal inverse filters have been proposed using the FTFNTA as an active element and there is only one topology was proposed for designing of both filter and inverse filter using the same circuit so far. Therefore, the main objective of the manuscript is to propose a set of topologies which can produce a universal inverse filter i.e.…”

“…In [26] two (CDBAs) and in [27] two Operational Trans-Resistance Amplifier (OTRAs) were used to design inverse band-reject filter (IBRF) and IAPF but the passive components count is large for both topologies. Even some of the existing topologies require more than two ABBs [9,[12][13][14][15][16] to construct the inverse filter functions. As more ABBs have been used, the larger chip area would be required for fabrication.…”

A novel Nth-order voltage-mode universal filter based on CMOS CFOA

“…Multifunction filter circuits have many possible applications such as three-way highfidelity loudspeakers in crossover networks, touchtone telephone systems, phase-locked loop FM stereo demodulators, analog sections of high-speed data communication systems, signal processing in cable modems, and so on [12]. Numerous analog circuits have been implemented based on CFOA [13,14,15,16,17,18,19,20,21]. The MOS-only circuits in [16] realize first-and second-order allpass filters without using any external passive components.…”