Extension of recently proposed two-CFOA-GC all pass filters to the realisation of first order universal active filters

Raj, Ajishek; Bhaskar, D. R.; Senani, Raj; Kumar, Pragati

doi:10.1016/j.aeue.2022.154119

Cited by 19 publications

(28 citation statements)

References 41 publications

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“…From Table 1, the following may be noted: The circuits of previous works 2,29–43 use more than one ABB, two ABBs 2,29–42 and three ABBs, 43 and, hence, do not belong to the class of single‐ABB‐based first‐order UAFs to which the circuits proposed in this article belong to. The single‐ABB‐based earlier works 3,10,12–14 use only a single ABB but realize a UAF only in CM, whereas other studies, 16–27 too, use only one ABB but realize an UAF only in VM. On the other hand, the single ABB configuration of Chaturvedi and Kumar 11 is in CM/TAM mode, whereas single ABB configuration of Maheshwari et al 15 and Singh et al 24 are in VM/TAM mode. None of the building blocks employed in previous works 3–24,26,27 are yet available as off‐the‐shelf ICs. The circuits of previous studies 5,14,20–22,24–27 do not employ a grounded capacitor. The UAFs in previous works, 5,16–19,21,23–25,27 do not have the appropriate Z in or Z out to enable cascadability. The only other earlier work which is based upon the use of a commercially available IC (namely, the LT1228 comprising an OTA followed by a CFOA) also realizes only VM UAF and does not employ a grounded capacitor. …”

Section: Introductionmentioning

confidence: 95%

“…Whereas the literature is flooded with second order UAFs of many different varieties realizable with CFOAs, CCIIs, and other modern analog circuit building blocks, some researchers have also focused upon realizing first‐order UAFs which can simultaneously realize a low pass (LP), high pass (HP), and all‐pass (AP) filter functions from the same circuit. Consequently, a variety of first‐order UAF configurations realized with different kinds of active elements have been reported in literature so far; for instance, see Raj et al 2 and the references cited therein. A brief overview of earlier published first‐order UAFs is now in order.…”

Section: Introductionmentioning

confidence: 99%

“…A brief overview of earlier published first‐order UAFs is now in order. However, in order to keep the overview of the earlier works 2–43 as brief as possible, we have compiled the relevant data in tabular form as shown in Table 1.…”

Section: Introductionmentioning

confidence: 99%

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CFOA‐based simple mixed‐mode first‐order universal filter configurations

Bhaskar

Raj

Senani

et al. 2022

Circuit Theory & Apps

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This brief communication presents two current feedback op-amp (CFOA)based simple first-order mixed-mode universal filter topologies-one of them providing first-order low-pass (LP), high pass (HP), and all pass (AP)-all the three filters in voltage-mode (VM)/trans-admittance-mode (TAM) while the other one realizing the quoted three functions in current-mode (CM)/transimpedance-mode (TIM). Except the all pass filter realization from the first configuration which needs a second CFOA also as gain-of-two amplifier, in all the remaining cases of both the configurations, only a single CFOA is needed. The other notable features of the circuits are employment of only three resistors and a grounded capacitor (as preferred for IC implementation) and the availability of independent tunability of the gain (H 0 ) and cut-off frequency/pole frequency (ω 0 ) of all the three filters, in both the cases. In spite of not offering ideally infinite input impedance in VM/TAM mode and ideally zero input impedance in CM/TIM mode, the circuits still possess easy cascadability due to providing a voltage output from a low-output impedance terminal W while the current output from the high output impedance terminal Z. Non-ideal and sensitivity analyses have also been carried out. The workability of the proposed circuits has been demonstrated through PSPICE simulations and experimental results using the commercially available AD844-type IC CFOA.

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Section: Introductionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

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CFOA‐based simple mixed‐mode first‐order universal filter configurations

Bhaskar

Raj

Senani

et al. 2022

Circuit Theory & Apps

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“…More recently, Senani et.al. (2022) presented six new all-pass lter circuits using the CFOA element [15]. Five universal lter circuits are created by making some simple modi cations to these lter circuits.…”

Section: Introductionmentioning

confidence: 99%

“…Five universal lter circuits are created by making some simple modi cations to these lter circuits. These proposed lter circuits are implemented as voltage-mode (VM) operated, and two CFOA elements are used in each lter circuit [13]- [15]. Regarding the aforementioned studies, the lter circuit designs use grounded capacitors and some resistors are used as oating components [13]- [15].…”

Section: Introductionmentioning

confidence: 99%

Implementation of Filter Structures in VLF Band for Remote Sensing Systems Using MCFOA

Sen

KIRÇAY

COBB

2022

Preprint

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Different analogue filter circuits were designed containing a current-mode first-order and a minimum number of grounded passive elements. These circuits are designed to be used in the very low frequency (VLF − 3 kHz and 30 kHz) band, which is employed in remote sensing systems. They are designed with the help of an active element, called the modified current feedback operational amplifier (MCFOA). For this, first, currentmode first-order low-pass, high-pass and all-pass filter circuits are designed. Second, a current-mode first-order single input and three-output universal filters are designed to provide simultaneous low-pass, high-pass and all-pass filter outputs. These filter structures contained only four grounded passive components and one MCFOA. The cut-off frequencies of the filters are measured at 10 kHz. It has been observed that the filter structures can be used in the VLF band, as can be understood from the cut-off frequency. Furthermore, the frequency and gain of the filters can be adjusted electronically, by changing the values of the parameters in these filter circuits. The total harmonic distortion (THD; (%)) of these generated circuits is THD (%) ≤ 1. Moreover, the presented filter circuits provided wide dynamic range (DR > 60 dB). In addition, the total power loss of these filters is less than 1 mW for 2.5 V single-supply. Accuracies of these structures were verified using the PSpice program.

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First‐order universal shadow filter designs with scaled time constants

Nako,

Psychalinos,

Minaei

2024

Circuit Theory & Apps

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First‐order generalized filter designs which simultaneously offer implementation of the low‐pass, high‐pass, and all‐pass filters basic functions with scaling of the associated time constant are presented in this work. These have been achieved thanks to the employment of the shadow filtering technique, which enables the utilization of a “hidden filter” for performing scaling of the time constant. The resulting filters offer also a high‐impedance input, and as the outputs are also taken from low‐impedance nodes, there is not any imposed restriction concerning their cascadability. The provided simulation and experimental results confirm the validity of the proposed concept.

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Extension of recently proposed two-CFOA-GC all pass filters to the realisation of first order universal active filters

Cited by 19 publications

References 41 publications

CFOA‐based simple mixed‐mode first‐order universal filter configurations

CFOA‐based simple mixed‐mode first‐order universal filter configurations

Implementation of Filter Structures in VLF Band for Remote Sensing Systems Using MCFOA

First‐order universal shadow filter designs with scaled time constants

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