Universal Filter Configuration Research Articles

Single VDGA-Based Mixed-Mode Electronically Tunable First-Order Universal Filter.

This article presents a mixed-mode electronically tunable first-order universal filter configuration employing only one voltage differencing gain amplifier (VDGA), one capacitor, and one grounded resistor. With the appropriate selection of the input signals, the proposed circuit can realize all three first-order standard filter functions, namely low pass (LP), high pass (HP), and all pass (AP), in all four possible modes, including voltage mode (VM), trans-admittance mode (TAM), current mode (CM), and trans-impedance mode (TIM), from the same circuit structure. It also provides an electronic tuning of the pole frequency and the passband gain by varying transconductance values. Non-ideal and parasitic effect analyses of the proposed circuit were also carried out. PSPICE simulations and experimental findings have both confirmed the performance of the design. A number of simulations and experimental observations confirm the viability of the suggested configuration in practical applications.

Mixed-Mode Electronically-Tunable First-Order Universal Filter Structure Employing Operational Transconductance Amplifiers

In this paper, a new mixed-mode first-order universal filter configuration is presented that employs three operational transconductance amplifiers (OTAs) and one grounded capacitor (eminently suitable for IC chip fabrication). All three first-order generic filter functions, namely low pass filter (LPF), high pass filter (HPF) and all pass filter (APF) in all the four possible modes, namely voltage mode (VM), current mode (CM), transresistance mode (TRM) and transconductance mode (TCM) can be realized. The proposed configuration offers high input impedance and high output impedance. The pole frequency of the filter can be controlled electronically by varying a single transconductance. Nonideal analysis of the proposed filter structure has also been carried out and the results have been compared with those obtained from ideal analysis. The performance of the presented filter configuration has been corroborated through PSPICE simulations as well as experimental results. The various simulation and experimental results validate the practical viability of the proposed configurations.

Electronically tunable DV-EXCCCII-based universal filter

ABSTRACT A new analog block, Differential Voltage Extra-X Current Controlled Conveyor (DV-EXCCCII) based current mode universal filter configuration is introduced in this paper. Only one current mode analog block DV-EXCCCII, three grounded components are used to design proposed filter configuration. This circuit provides high output impedance, which allows cascading feature to circuit without need of extra buffer circuit. This configuration realise all five (Low Pass, High Pass, All Pass, Band Pass and Band Reject) second-order filter functions with an appropriate selection of input. Bias current of DV-EXCCCII provides the electronic tuning characteristic to proposed circuit. Sensitivity due to passive components and non-idealities of the analog block is low and magnitude is below unity. The proposed filter circuit configuration is designed in CADENCE and simulated with SPECTRE using 180 nm UMC CMOS process technology.

Grounded capacitor based fully cascadable electronically tunable current-mode universal filter

A novel current-mode (CM) universal filter configuration composed of five plus-type second-generation current conveyors (CCII+s) as active components besides three resistors and three grounded capacitors as passive elements is proposed in this paper. The proposed filter can simultaneously provide high-pass, band-pass and low-pass responses. Also, it can realize all-pass and notch responses with interconnection of convenient output currents. It can be cascaded with other CM ones easily because it has low input and high output impedances. It offers orthogonal control of angular resonance frequency and quality factor. An electronically tunable universal filter can be easily obtained if plus-type current controlled current conveyors are replaced instead of each of the five CCII+s and all the three resistors are removed. Nevertheless, it needs a single passive element matching constraint for notch and all-pass filter responses. Some simulation and experimental test results are included to confirm the theory.

Low-voltage low-power FGMOS based VDIBA and its application as universal filter

This paper presents Floating gate MOS (FGMOS) based low-voltage low-power variant of recently proposed active element namely Voltage Differencing Inverting Buffered Amplifier (VDIBA). The proposed configuration operates at lower supply voltage ±0.75V with the total quiescent power consumption of 1.5mW at the biasing current of 100µA. Further the operating frequency of the proposed VDIBA is improved by using the resistive compensation method of bandwidth extension in Operational Transconductance Amplifier (OTA) stage of the block. By using resistive compensation method of bandwidth extension, the bandwidth of OTA stage increases from 92.47MHz to 220.67MHz. As an application, proposed FGMOS based VDIBA has been used to realize a novel resistorless voltage mode (VM) universal filter. The proposed universal filter configuration is capable of realizing all the standard filter functions in both inverting and non-inverting forms simultaneously without any matching constraint. Other important features include independently tunable filter parameters, cascadibility and low sensitivity figure. The proposed filter is tunable over the frequency range of 4.1MHz to 12.9MHz and is capable of compensating for process, voltage and temperature (PVT) variation. The simulations are performed using SPICE and TSMC 0.18µm CMOS technology parameters with±0.75V supply voltage to validate the effectiveness of the proposed circuit.

Reconfigurable Mixed Mode Universal Filter

This paper presents a novel mixed mode universal filter configuration capable of working in voltage and transimpedance mode. The proposed single filter configuration can be reconfigured digitally to realize all the five second order filter functions (types) at single output port. Other salient features of proposed configuration include independently programmable filter parameters, full cascadability, and low sensitivity figure. However, all these features are provided at the cost of quite large number of active elements. It needs three digitally programmable current feedback amplifiers and three digitally programmable current conveyors. Use of six active elements is justified by introducing three additional reduced hardware mixed mode universal filter configurations and its comparison with reported filters.

A new universal biquad filter using differential difference amplifiers and its practical realization

The differential difference amplifier (DDA) was introduced more than two decades back and its several applications as well as bipolar/CMOS implementations have been reported so far. This paper presents a new second order multiple-input---single-output type universal filter configuration using only two DDAs along with only five passive components which can realize all the five generic filter functions from the same configuration under various conditions in terms of the four input signals. Furthermore, it is demonstrated that DDA-based circuits can be practically implemented using commercially available video differencing amplifier IC AD830.

Voltage Mode OTRA MOS-C Single Input Multi Output Biquadratic Universal Filter

In this paper, an Operational transresistance amplifier (OTRA) based MOS-C voltage mode single input multi output (SIMO) biquadratic universal filter configuration is proposed. The configuration is made fully integrated by implementing the resistors using matched transistors operating in the linear region. It exhibits the feature of orthogonal controllability of angular frequency and quality factor through gate bias voltage. The non-ideality analysis of the circuit is also given. Workability of the universal filter is demonstrated through PSPICE simulations using 0,5 μm CMOS process parameters provided by MOSIS (AGILENT).

Configuration for realising a current-mode universal filter and dual-mode quadrature single resistor controlled oscillator

A new universal single input multiple output (SIMO)-type universal filter configuration using three dual output current conveyors (DOCCII) and five grounded passive elements is proposed which can realise all the five basic filtering functions namely low pass, high pass, band pass, band stop and all pass in current mode from the same configuration. With appropriate modification of one connection, the circuit can also be converted into a quadrature oscillator capable of providing two voltage mode outputs and as well as two current mode outputs in quadrature. The workability of the new configuration has been demonstrated by simulation program with integrated circuit emphasis (SPICE) simulation results based on a complementary metal oxide semiconductor field effect transistor current conveyor II (CMOS CCII) implemented in 0.35-µm technology.

Single-input three-output electronically tunable universal current-mode filter using current follower transconductance amplifiers

In this paper, an electronically tunable universal filter configuration with single input and three outputs (SITO) employing a recently introduced active device namely current follower transconductance amplifier (CFTA) is described. The proposed filter is composed of four CFTAs and two grounded capacitors, and is capable of realizing all the standard functions of the universal filter without requiring any component matching criterions and any extra active components. It exhibits low-input and high-output impedances, which is highly desirable for cascading in current-mode. It also offers the advantage feature of an independent electronic adjustment of the natural angular frequency ( ω o ) and the quality factor ( Q) by means of tuning the external bias currents. Moreover, a high Q-value filter can be obtained by simply adjusting the appropriate ratio of bias currents. The analysis of active and passive sensitivities is shown to be low. In order to demonstrate the performance of the proposed circuit, PSPICE simulation results are provided.

A new mixed mode biquad using reduced number of active and passive elements

The configuration that can work in mixed mode may be useful from IC realization viewpoint and application adaptability. This paper proposes a generalized mixed mode universal filter configuration that may be used in all possible modes i.e. voltage mode, current mode, trans-impedance mode and trans-admittance mode. The architecture uses minimum number of active and passive components reported till date and can realize all generic filter functions: low pass, band pass, high pass, notch and all pass. PSPICE simulation results agree well with experimental values.

Multi-input single-output filter with reduced number of passive elements employing single current conveyor

A new biquadratic universal filter configuration realising second-order low-pass, band-pass, and high-pass functions employing single current conveyor is proposed. Using this configuration high-pass, low-pass and band-pass filters can be realized with little modifications. The circuit employs a second-generation current conveyor (CCII+), and only four passive components. Since the current conveyor is a high performance active element, the circuit proposed is suitable for wide band applications. The derived filters can be easily cascaded and use reduced number of passive components compared to previously reported counterparts. To illustrate the design possibilities provided by the introduced circuit current mode multifunction filters are constructed and tested.

First-order allpass sections-based current-mode universal filter using ICCIIs

An inverting type current conveyor (ICCII) is presented and its usefulness in active filter synthesis illustrated by presenting a new current-mode universal filter using this element. The universal filter configuration based on the implementation of first-order allpass sections employs the absolute minimum number of passive and active components and hence leads to a filter circuit with very simple implementation.

ACTIVE RC FILTERS USING OPERATIONAL TRANSRESISTANCE AMPLIFIERS

A new generalized universal filter configuration using the Operational Transresistance Amplifier is proposed. Twelve different filter circuits are derived from the general configuration. The circuits are designed to provide Low-pass, Band-pass, High-pass, All-pass and Notch responses through appropriate choice of admittances. The feasibility of this configuration in operating at high frequencies is presented. A detailed analysis taking the effect of the finite transresistance gain into consideration is presented. Self-compensation that requires no additional elements of some of the proposed filters is presented. The effectiveness of the proposed configuration is demonstrated by HSpice simulations.