Universal Biquad Filter Research Articles

New Electronically Tunable Voltage-Mode Lowpass, Highpass, Bandpass Filter Using Simple OTAs

This paper presents a new electronically tunable voltage-mode universal biquad filter based on simple CMOS operational transconductance amplifiers (OTAs) and grounded capacitors. The proposed filter provides second-order lowpass, bandpass and highpass voltage responses at a high impedance input terminal, which enable easy cascadability. The circuit enjoys realization using a low number of active and passive components, no requirement with the component choice conditions to realize all filtering functions, and low active and passive sensitivities performance. The performances of the proposed filter are simulated with PSPICE to confirm the presented configuration.

CDTAs Based Current-Mode Universal Biquad Filters with Orthogonal Control of Quality Factor and Pole Frequency

This article presents current-mode universal biquad filters based on CDTAs. The filter circuits using four CDTAs and two grounded capacitors which are able to provide low-pass, high-pass, band-pass, band-reject and all-pass functions. The pole frequency can be orthogonally controlled from quality factor and the circuits have high output impedance appropriate for cascade connection application in current mode which is capable to directly drive load. This qualification is very appropriate for further development into an integrated circuit. The results of PSPICE simulation program are corresponding to the theoretical analysis.

New OTRA-Based Generalized Impedance Simulator

Operational transresistance amplifier (OTRA) has attracted considerable attention in the recent literature in several applications such as impedance simulation, universal biquad filter realization, realization of sinusoidal oscillators and multivibrators. However, to the best knowledge of the authors, any OTRA-based generalized impedance simulator circuits have not been reported so far. The purpose of this paper is to present such a circuit.

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.

Current Processing Current Tunable Universal Biquad Filter Employing Two CCTAs and Two Grounded Capacitors

This paper presents a current processing current-tunable universal biquad filter employing two current conveyor transconductance amplifiers (CCTAs) as active element and two grounded capacitors as passive element. It realizes all the five standard filtering responses such as low pass (LP), band pass (BP), high pass (HP), band reject (BR) and all pass (AP) through appropriate selection of applied current inputs. Proposed circuit does not require minus input current signal and double input current signal to realize different filtering responses. It also does not require component matching condition to realize any filtering responses. Moreover, the circuit offers the advantage of orthogonal electronic tunability of pole-frequency and quality factor. The circuit exhibits low active and passive sensitivities. The circuit performance is verified through P-SPICE simulation software.

An Active-Only Temperature-Insensitive Current-Mode Biquad Filter Based on Differentiator Structures Employing CCCCTAs

This article presents an active-only current-mode universal biquad filter performing three standard functions: low-pass, high-pass and band-pass function, which can be readily modified to achieve the rest functions (band-stop and all-pass). The circuit principle is based on active-only circuit designed by using differentiators which are constructed from current controlled current conveyor transconductance amplifier (CCCCTA) cooperating with an internally frequency compensated operational amplifier (OA). The features of the circuit are that: the pole frequency and quality factor can be independently tuned via the input bias currents and it is ideally temperature-insensitive, its circuit description is very simple, consisting of 3 CCCCTAs and 2 operational amplifiers, and the proposed circuit is very appropriate for further developing into integrated circuit architecture. The PSpice simulation results are shown. The given results agree well with the theoretical anticipation.

Electronically tunable low-voltage mixed-mode universal biquad filter

This study presents an electronically tunable low-voltage mixed-mode universal biquad filter. The proposed filter employs only three current controlled current conveyor trans-conductance amplifiers (CCCCTAs) and two grounded capacitors. The proposed filter can realise low pass, band pass and high pass responses in all the four possible modes, that is, voltage-mode, current-mode, trans-admittance-mode and trans-impedance-mode from the same configuration. The filter can also realise regular notch, low-pass notch, high-pass notch and all pass responses in current and trans-admittance-mode, with interconnection of relevant output currents. The filter parameters namely pole frequency, quality factor, bandwidth and filter gains can be tuned electronically. Moreover, the circuit parameters such as pole frequency and quality factor can be simultaneously current controlled without affecting bandwidth. Effects of non-idealities and parasitic are also discussed. The circuit possesses low active and passive sensitivity and can be operated at low power supply (±1 V). The validity of the proposed filter is verified through computer simulations using PSPICE, the industry standard tool. Possible experimental setup for CCCCTA using commercial available integrated circuits is further discussed.

Multiple Input Single Output Universal Biquad Filter with Current Feedback Operational Amplifiers

A novel Multiple Input Single Output (MISO) universal biquad filter topology realized using Current Feedback Operational Amplifiers (CFOAs) is introduced in this paper. With regards to the corresponding already published MISO universal biquads with CFOAs, the proposed topology simultaneously offers the benefits of employing only grounded capacitors, absence of any imposed constraint related to the values of input signals, and orthogonal adjustment between the quality factor and resonant frequency of the filter. The operation of the proposed biquad has been verified through experimental results by utilizing the commercially available AD844 CFOA discrete component.

Universal Current-Controlled Current-Mode Biquad Filter Employing MO-CCCCTAs and Grounded Capacitors

This paper presents a universal current-controlled current-mode biquad filter employing current controlled current conveyor trans-conductance amplifiers (CCCCTAs). The proposed filter employs only three MO- CCCCTAs and two grounded capacitors. The proposed filter can simultaneously realize low pass (LP), band pass (BP), high pass (HP), band reject (BR) and all pass (AP) responses in current form by choosing appropriate current output branches. In addition, the pole frequency and quality factor of the proposed filter circuit can be tuned independently and electronically over the wide range by adjusting the external bias currents. The circuit possesses low active and passive sensitivity performance. The validity of proposed filter is verified through PSPICE simulations.

Multiple-Mode OTA-C Universal Biquad Filters

Two new multiple-mode (including voltage, current, transconductance, and transresistance modes) OTA-C universal biquad filters are proposed. The first proposed circuit uses only four operational transconductance amplifiers (OTAs) and two grounded capacitors. The second proposed circuit uses five OTAs and two grounded capacitors. Both the proposed circuits can realize voltage, current, transconductance, and transresistance mode universal filtering responses (low-pass, high-pass, band-pass, notch, and all-pass) from the same topology. The first proposed circuit uses the least number of components. This represents an attractive feature from a chip area and power consumption point of view. The second proposed circuit has no need of extra inverting and non-inverting amplifiers for special input signals. Moreover, both the proposed biquads still have (i) the employment of two grounded capacitors, (ii) cascadable connection of the former voltage-mode stage and the latter current-mode stage, and (iii) low sensitivity performance. H-SPICE simulation results confirm the theoretical analysis.

Voltage mode universal filters employing single FDCCII

In this paper, four new voltage-mode universal biquad filters configuration are proposed. First of two circuits proposed high-input impedance universal filter with single-input and three-outputs, which can simultaneously realize voltage mode low-pass, band-pass and high-pass filter responses employing all grounded passive components. The third proposed universal filter three-input and single-output, which also can realize all the standard filter functions. The fourth circuit proposed universal filter with three-input and five-outputs, which can be used as either a three-inputs single-output or a two-inputs five-outputs universal filters. It can realize all five different generic filtering signals: low-pass, band-pass, high-pass, band-stop and all-pass. Simulation results are given to confirm the theoretical analysis. The proposed biquad filters are simulated using TSMC CMOS 0.35 μm technology.

Single CCII-based voltage-mode universal filter

A new voltage-mode universal biquad filter is presented which can realize all the five standard filter functions namely lowpass, bandpass, highpass, notch, and allpass employing only one CCII as ac...

ELECTRONICALLY TUNABLE CURRENT-MODE UNIVERSAL BIQUAD FILTER USING DUAL-X CURRENT CONVEYORS

In this paper, an electronically tunable current-mode (CM) universal biquad filter is proposed. The proposed filter employs three dual-X second-generation current conveyors (DXCCIIs), two grounded capacitors and four NMOS transistors acting as resistors. The proposed filter simultaneously realizes standard filter functions such as low-pass (LP), band-pass (BP), and high-pass (HP) responses. The notch (NH) and all-pass (AP) functions can also be obtained by connecting appropriate output currents directly without using additional active elements. The output signals are obtained at high output impedance terminals, which is important for easy cascading in CM operation. SPICE simulation results are given to verify the theoretical analyses.

Current-controlled current differencing transconductance amplifier and applications in continuous-time signal processing circuits

This article presents the design for a basic current-mode building block for analogue signal processing, named as Current Controlled Current Differencing Transconductance Amplifier (CCCDTA). Its parasitic resistances at two current input ports can be controlled by an input bias current. As it can be applied in current-mode of all terminals, it is very suitable to use in a current-mode signal processing, which is continually more popular than a voltage one. The proposed element is realized in a bipolar technology and its performance is examined through PSPICE simulations. They display usability of the new active element, where the maximum bandwidth is 65 MHz. The CCCDTA performs low-power consumption and tuning over a wide current range. In addition, some examples as a current-mode universal biquad filter, a current-mode multiplier/divider and floating inductance simulator are included. They occupy only single CCCDTA.

Single-resistance-controlled quadrature oscillator and universal biquad filter using CFOAs

This paper presents new single-resistance-controlled (SRC) sinusoidal quadrature oscillator and universal biquad filter circuits with reduced number of passive elements using only two current-feedback operational amplifiers (CFOAs). The first proposed oscillator configuration comprising two CFOAs, three resistors and two capacitors provides two sinusoidal voltage outputs in phase quadrature. The circuit has the advantage of independent control of the condition of oscillation and the oscillation frequency through a single resistor. The second proposed biquad filter configuration consisting of only two CFOAs, two resistors and two capacitors realizes all the standard types of the biquadratic filter functions at low-impedance output without any component matching conditions. The filter also provides orthogonal control of the natural angular frequency ( ω 0 ) and the bandwidth (BW). In addition, both proposed circuit configurations have good active and passive sensitivity performances. PSPICE simulations and experimental results based on commercially available AD844-type CFOAs are included, showing the excellent performance of the proposed configurations.

Cascadable Current-Mode Biquad Filter and Quadrature Oscillator Using DO-CCCIIs and OTA

This article introduces a circuit which can function both as a quadrature oscillator and as a universal biquad filter (lowpass, highpass, bandpass). When the circuit functions as a universal biquad filter, the quality factor and pole frequency can be tuned orthogonally via the input bias currents. When it functions as a quadrature oscillator, the oscillation condition and oscillation frequency can be adjusted independently by the input bias currents. The proposed circuit can work as either a quadrature oscillator or a biquad filter without changing the circuit topology. The amplitude of the proposed oscillator can be independently controlled via the input bias currents. The proposed oscillator can be applied to provide amplitude modulated/amplitude shift keyed signals with the above-mentioned major advantages. The circuit is very simple, consisting of four dual-output second generation current controlled current conveyors (DO-CCCIIs), one operational transconductance amplifier (OTA), and two grounded capacitors. Without any external resistors and using only grounded elements, this circuit is therefore suitable for IC architecture. PSPICE simulation results are depicted here, and the given results agree well with the theoretical analysis. The power consumption is approximately 7.32 mW at ±2.5 V supply voltages.

A CMOS Digitally Programmable Universal Current-Mode Filter

A new digitally programmable universal current-mode biquad filter is proposed. The filter is based on digitally controlled current followers (DCCFs). It utilizes gains of the DCCFs to provide precise frequency and/or gain characteristics that can be digitally tuned over a wide range. All parameters of the proposed filter can be adjusted independently. Experimental results obtained from a 0.35-mum standard CMOS chip are provided.

Current controlled current conveyor transconductance amplifier (CCCCTA): a building block for analog signal processing

This article presents a basic current-mode building block for analog signal processing, namely current controlled current conveyor transconductance amplifier (CCCCTA). Its parasitic resistance at current input port can be controlled by an input bias current. It is very suitable for use in current-mode signal processing, which is becoming more popular than voltage mode. The proposed element is realized in a bipolar technology and the performances are examined through PSPICE simulations, displaying usabilities of the new active element. The CCCCTA performs tuning over a wide current range. The description includes some examples as a current-mode universal biquad filter, voltage-mode universal biquad filter, a grounded inductance simulator, a current-mode multiplier/divider and an oscillator. They occupy only a single CCCCTA.

Electronically tunable versatile voltage-mode universal filter

A novel electronically tunable versatile voltage-mode universal biquad filter by using two single-output-operational transconductance amplifiers (OTAs), one differential difference current conveyor (DDCC) and two capacitors is proposed. The proposed circuit, which can be used as either a four-input single-output universal filter or a single-input three-output multifunction filter with the same topology. Besides, the new circuit offers the following advantageous features: realization of all the non-inverting and inverting biquadratic filter signals from the same configuration, no need to employ inverting-type input signals, no need to component-matching conditions and low passive sensitivity performance.

CMOS current-controlled current differencing transconductance amplifier and applications to analog signal processing

This article presents design of a basic current-mode building block for analog signal processing, named as current-controlled current differencing transconductance amplifier (CCCDTA). Its parasitic resistances at two current input ports can be controlled by an input bias current. Owing to working in current-mode of all terminals, it is very suitable to use in a current-mode signal processing, which is continually more popular than a voltage one. The proposed element is realized in a CMOS technology and is examined the performance through PSPICE simulations. They display usability of the new active element, where the maximum bandwidth is 311 MHz. The CMOS CCCDTA performs low power consumption and tuning over a wide current range. In addition, some examples as a current-mode universal biquad filter, floating inductance simulator and quadrature oscillator are included. They occupy only single CCCDTA.