Quadrature Oscillator Circuit Research Articles

CFOA-based first-order voltage-mode universal filters

In this paper, two new CFOA-based first-order voltage-mode universal filters are proposed. Both of the filters use an additional unity gain-inverting amplifier. The first proposed filter employs a minimum number of passive elements, while the second one includes one capacitor and two grounded resistors. The proposed filters can give universal filter responses with the selection of their relevant inputs. Both of the proposed filters enjoy the low output and high input impedances. Two quadrature oscillator circuits derived from the proposed filters are also considered as application examples. In order to see the performance of the circuits, many simulations are carried out via the SPICE program. Also, some experiments for the first proposed filter are done by using AD844s.

Tek CDBA Tabanlı Çok İşlevli Filtre Tasarımı

In this study, we proposed a second-order multifunction filter topology based on a current differencing buffered amplifier. With the proposed topology, five filter functions can be realized. Sensitivity and non-ideal state analyses of the proposed circuit have been performed. In addition to the proposed second-order multifunction filter topology, the third-order quadrature oscillator circuit was operated as the application circuit. In both circuits, the theoretical work and simulation results are in compliance. The proposed design has potential in the medical device design field.

Differential Input First-Order Universal Filter with Two DVCC+s

In this paper, a differential-input plus-type differential voltage current conveyor-based first-order universal filter is designed. This voltage-mode filter uses a grounded capacitor. In addition, it can provide all the noninverting and inverting first-order universal filter responses. The circuit provides high common-mode rejection ratio of about 76.5 dB. Nevertheless, it needs a single matching problem and comprises two floating resistors. Quadrature oscillator (QO) design is obtained using this filter as an application example. The designed filter and QO circuits are simulated through the SPICE program, and some experimental studies are carried out using AD844 ICs to verify the theory.

Novel Active-C Voltage-Mode Quadrature Oscillator Realization Employing CCCIIs

Acurrent controlled sinusoidal voltage-mode quadrature oscillator circuit is presentedherewhich has employed three second-generation current-controlled-conveyors (CCCIIs) and two grounded capacitors(GCs). The condition of oscillation (CO) and frequency of oscillation (FO) of the proposed circuit are uncoupled and can be electronically controllable through an external dc bias current of CCCII. Sensitivities of active and passive elements are very low and the voltage outputs which are in 90ophase difference have high output impedances. Moreover, if apply the input at terminal Y of CCCII-03 it behaves as biquad filter which produce the band-pass (BP) and low-pass (LP) responses instantaneously and it have high input impedance which is very useful in cascading. The PSPICE simulation resultsverify the workability of the oscillator and filter circuit.

Electronically Controlled Biquadratic Filter and Quadrature Oscillator Using CDTAs

This article presents a current-mode biquadratic filter and quadrature oscillator circuit based on current differencing transconductance amplifiers (CDTAs). The proposed circuit does not require changing the circuit topology. In addition to the low-pass filter, high-pass filter, band-pass filter, and sinusoidal quadrature signal, the proposed circuit has a pole frequency that can be controlled independently from the quality factor, while the oscillation frequency can be controlled non-interactively. The circuit impedance with high output can directly drive the load without using a current buffer. Furthermore, grounded capacitors can function without the use of external resistors. This qualification is ideal for the future development of integrated circuits (ICs). After the PSPICE simulation with 90 nm CMOS parameters and the experiments by commercial ICs, the results are consistent with the theoretical analysis of the proposed circuit.

New Resistorless Third-Order Quadrature Sinusoidal Oscillators

This paper introduces four new resistorless, third-order, electronically tunable, quadrature sinusoidal oscillators using three operational transconductance amplifiers (OTAs) and three capacitors. The proposed third-order quadrature sinusoidal oscillators (TOQSOs) provide noninteracting control of the oscillation condition (OC) and oscillation frequency (OF) by changing the transconductance of different OTAs, to produce sustained oscillations and offer quadrature output voltages and currents. Two of the proposed quadrature oscillator circuits have capacitor control of OF, a feature, useful in capacitive transducers. The presented TOQSO structures have good frequency stability and exhibit low active and passive sensitivities. PSPICE simulations using CMOS OTAs along with hardware results (using off-the-shelf available OTA IC LM13700) have also been provided to confirm the workability of the presented circuits.

Quadrature Sinusoidal Oscillators Using CDBAs: New Realizations

Four new circuits of fully uncoupled quadrature sinusoidal oscillators, using two current differencing buffered amplifiers (CDBAs), four/five resistors and two capacitors have been presented. In contrast to all previously published CDBA-based, fully decoupled, quadrature sinusoidal oscillators in which one of the input terminals is left unutilized, the presented circuits are realized by utilizing the intrinsic current differencing property of CDBAs, thus utilizing all the four terminals of the CDBA. All these quadrature oscillator (QO) circuits have an inherent feature of amplitude control of output voltages without using external control circuitry. Out of the four proposed QO circuits, two circuits have the additional feature of generating low-frequency oscillations, thus making them capable of generating wide range of frequency waveforms. The proposed oscillator circuits also possess additional functionalities not available in other CDBA-based quadrature sinusoidal oscillator circuits presented previously. The workability of the proposed circuits has been confirmed through experimental results where CDBAs are implemented using commercially available current feedback operational amplifiers (AD844).

Analytical Synthesis of High-Pass, Band-Pass and Low-Pass Biquadratic Filters and its Quadrature Oscillator Application Using Current-Feedback Operational Amplifiers

In this paper, a method of realizing voltage-mode (VM) non-inverting high-pass filter (HPF), band-pass filter (BPF), low-pass filter (LPF), and inverting low-pass filter (ILPF) transfer functions structure with two grounded capacitors and four resistors through an analytical synthesis method is presented. The synthesis structure of the VM biquadratic filter consists of a voltage proportional block and two voltage lossless integrators based on the use of current feedback operational amplifiers (CFOAs). It is demonstrated that the derived biquadratic filter structure can simultaneously realize VM HPF, BPF and ILPF transfer functions or VM BPF and LPF transfer functions at a high-input impedance terminal. The VM biquadratic filter can independently adjust the resonance angular frequency and quality factor. By slightly modifying the proposed biquadratic filter, a VM quadrature sinusoidal oscillator can be achieved. The proposed biquadratic filter and quadrature oscillator have been simulated by OrCAD PSpice and appropriate hardware has been implemented with AD844-type CFOAs. In order to reduce power consumption, reduce chip area, reduce costs, and improve system integration, integrated VM CFOA-based biquadratic filter circuits and quadrature oscillator circuits are very important. The proposed filter and quadrature oscillator have been further fabricated in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.18~\mu \text{m}$ </tex-math></inline-formula> 1P6M CMOS process technology. The entire chip area is 0.974 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , including a filter chip cell and an oscillator chip cell. Under the supply voltage of ±0.9 V, the total power dissipation of the filter chip cell is 5.4 mW, and the figure-of-merit (FOM) of filter chip cell is 66.7%. The measured value of the third-order intermodulation distortion of the filter chip cell is −55.29 dBc and the third-order intercept point is 19.9 dBm. The measured phase noise of CFOA-based filter chip cell at 1 kHz offset is less than −99.76 dBc/Hz.

Single VDGA-Based Dual-Mode Multifunction Biquadratic Filter and Quadrature Sinusoidal Oscillator

This article relates to the realization of voltage-mode and/or current-mode multifunction biquadratic filter and quadrature oscillator circuits each using one voltage differencing gain amplifier (VDGA), two resistors and two grounded capacitors. The proposed dual-mode filter having one output and three inputs can provide the three standard biquadratic transfer functions with both voltage and current output filter responses simultaneously. It also has the independent tuning of the angular resonance frequency and the quality factor . With a slight modification of the proposed filter, a new dual-mode quadrature sinusoidal oscillator can be obtained. The proposed quadrature oscillator provides orthogonal resistive/electronic control of both oscillation condition and oscillation frequency. Non-ideal and parasitic conditions are also examined and their effects on the circuit performance are discussed. In order to confirm the theory, several computer simulation results with PSPICE program are given .

Generalised approach for active‐RC quadrature oscillator circuit with grounded capacitors

This study introduces a new approach for realising a sinusoidal oscillator with three outputs, using an active-resistor-capacitor (RC) approach. Using the proposed approach, a new circuit employing three current feedback operational amplifiers and passive components is further introduced. The circuit employs two grounded capacitors and four resistors, out of which one is grounded. The new circuit based on the proposed generalised approach is relatively insensitive to the parasitic effects of active elements, and easy to design, by way of non-interaction of frequency and condition of oscillations. The proposed approach and the new proposed circuit provide three outputs, two of which are at low impedance nodes. The proposed generalised approach and the new circuit are verified through simulation and experimental results, using commercially available AD-844s integrated circuits and passive components. Thus, the work advances the existing knowledge on the active-RC oscillator design.

Fully Integrable/Cascadable CM Universal Filter and CM Quadrature Oscillator Using VDCC and Only Grounded Passive Elements

This paper proposes a current mode universal filter circuit, employing two active elements along with four grounded passive components only. The derived circuit realizes all five filtering responses, i.e., low pass (LP), band pass (BP), high pass (HP), band reject (BR) and all pass (AP), simultaneously from high-impedance ports along with the input being fed to low-impedance port, thus making it a fully cascadable filter. In addition, the designed circuit exhibits independent tunability of its quality factor. With the idea of making the proposed filter fully integrable, a resistor-less approach of the configuration has also been discussed. By making slight modifications in the filter configuration, a current mode single-resistance-controlled quadrature oscillator circuit has also been derived. The ideal, nonideal, sensitivity and parasitic analysis have been conducted for the designed configurations. The functionality of the proposed structures is verified by PSPICE simulations using 0.18[Formula: see text][Formula: see text]m CMOS technology. The designs have also been verified using PSPICE macro-model of the commercially available IC, i.e., OPA860.

ÜÇÜNCÜ DERECEDEN YENİ BİR QUADRATURE OSİLATÖR TASARIMI

Bu çalışmada, son zamanlarda oldukça fazla dikkat çeken bir aktif eleman olan Terslenmiş Akım Geri Beslemeli İşlemsel Yükselteç (ICFOA) kullanılarak üçüncü dereceden quadrature osilatör devresi sunulmuştur. Topoloji iki adet ICFOA, üç adet kapasitör ve üç adet direnç olmak üzere gerilim modlu ikinci dereceden alçak geçiren filtre ve gerilim modlu integratör yapısının kaskat bağlanıp kapalı çevrim oluşturması ile elde edilmiştir. Sunulan devrenin çalışabilirliği PSPICE benzetim programı ile denenmiş ve teorik sonuçlar ile örtüştüğü görülmüştür. Teorik kesim frekansı 3,979MHz ve benzetim sonucu ölçülen kesim frekansı ise 3,933MHz’dir. Benzetimde 0,35 μm MOSIS parametre seti ve ICFOA CMOS yapısı kullanılmıştır. Önerilen devrenin güç tüketimi 4,83mW’dır.

Realization Approach for Sinusoidal Signal Generation and Circuit with Easy Control

A new approach for realizing sinusoidal signal with quadrature property is proposed, which employs simple analog building blocks and facilitates easy tuning of the oscillation frequency, through a gain factor. The proposed approach is used for realizing a novel quadrature oscillator circuit, which requires three current feedback operational amplifiers and passive components. The proposed circuit provides outputs at low impedance terminals, and benefits from easy control over the frequency of oscillation (FO), which depends on resistive ratio, rather than absolute resistor values. The frequency control is also independent of the condition of oscillation (CO). The nonideal effects and the parasitic studies are presented. The verification of the proposed realization scheme for quadrature oscillators and the new circuit is carried out through both simulation studies and experimental results, using the commercially available chips.

Current-mode Quadrature Oscillator Using CFCC

In this communication, a Current Follower Current Conveyor (CFCC)-based quadrature oscillator circuit has been proposed which employs a resonator-negative resistor configuration and provides oscillations in quadrature from two high impedance current output terminals of the CFCCs. The workability of the quadrature oscillator has been verified using PSPICE simulations using a CMOS CFCC implementable in 0.18 micron TSMC technology.

Current and Voltage Mode Quadrature Oscillator Based on Voltage Differencing Buffered Amplifier

In this work, we present a current-mode and voltage-mode quadrature oscillator circuit using a voltage differencing buffered amplifier (VDBA), two grounded capacitors, and a grounded resistor. The oscillation condition and frequency are orthogonally (or independently) controllable. The current-mode and voltage-mode quadrature signals can be simultaneously obtained from the proposed circuit. The use of only grounded capacitors and resistors makes the proposed circuits ideal for integrated circuit implementation. The quadrature oscillator is simulated with SPICE simulation program using 0.35-µm technology parameters.

Novel CMOS Dual-X Current Conveyor Transconductance Amplifier Realization with Current-Mode Multifunction Filter and Quadrature Oscillator

This paper presents a novel active element, namely dual-X current conveyor transconductance amplifier. The CMOS implementation, parasitic model and characteristic performance parameters of the proposed dual-X current conveyor transconductance amplifier have been explored. The proposed active element has the advantages of good operational bandwidth, good dynamic range and low power consumption. Additionally, current-mode multifunction filter and quadrature oscillator are proposed to examine the applicability of the newly proposed active element. The proposed current-mode multifunction filter provides the responses, low-pass, high-pass and band-pass simultaneously without any circuit modification. The proposed quadrature oscillator circuit simultaneously generates three current outputs and three voltage outputs. The non-ideal analyses of both current-mode multifunction filter and quadrature oscillator are also included. Moreover, the active and passive sensitivities of both current-mode multifunction filter and quadrature oscillator are calculated which are found to be less than unity in magnitude. HSPICE simulation results are depicted to confirm the theoretical analyses. Moreover, practicality of novel dual-X current conveyor transconductance amplifier is examined through the experimental results of the proposed quadrature oscillator.

Four new oscillators using operational transresistance amplifier

In this paper, four new sinusoidal waveform generators based on the operational transresistance amplifier (OTRA) are presented. The first proposed circuit is a minimum component RC sinusoidal oscillator circuit with one OTRA and a few passive components. The second and third proposed circuits consist of one OTRA and a few passive components, among them two passive components are connected to ground. These circuits are able to control the condition of oscillation and frequency of oscillation independently. The fourth proposed quadrature oscillator circuit uses two OTRAs as main active building blocks and a few external passive components to generate the oscillations. The commercially available IC AD844AN has been adopted to implement the proposed circuits on a laboratory breadboard with external passive components. Both the SPICE simulation and experimental results are given to verify the theoretical analysis of the proposed circuits.

Two New Single-Resistor-Controlled Quadrature Sinusoidal Oscillators using Current-Differencing-Buffered-Amplifiers

Two new single resistor–controlled quadrature oscillator (SRCQO) circuits using only two current differencing buffered amplifiers (CDBAs) as active elements and only three resistors and two capacitors, are presented. First proposed circuit uses all input terminals of the CDBA to exploit full capacity of the CDBAs, offers better sensitivities with respect to active parameters and has wide frequency range of operation. The second proposed circuit provides very good low frequency performance with respect to total harmonic distortion. Separate single resistors can control both oscillation condition and the oscillation frequency of the proposed quadrature oscillator circuits independently. PSPICE simulation results based upon commercially available AD844 ICs, to construct the CDBAs, are included which confirm the practical workability of the new proposed quadrature oscillator circuits.

Voltage mode third order quadrature oscillators using OTRAs

In this paper, the authors present two topologies of voltage mode third order quadrature oscillator circuit using operational transresistance amplifier (OTRA). The first circuit is based on low-pass filter and integrator combination, whereas the second one is high-pass filter and differentiator combination. Both the circuits utilize two OTRAs and three resistors and capacitors each. The frequency of oscillation and condition of oscillation can be adjusted independent of each other in both the circuits. The non-ideality analysis of the circuits are also included. The PSPICE simulation and experimental results verify the theoretical proposition.

Second Order Current-mode Quadrature Oscillators Using OTAs

This article presents new current-mode quadrature oscillator circuits using OTA which are designed from block diagram. The proposed circuits consist of three OTAs and two grounded capacitors. The circuits have high output impedance appropriate for cascade connection application in current mode technique which is capable to directly drive load. The oscillators use only grounded capacitor which is very appropriate for further development into an integrated circuit. In addition, the condition of oscillation can be adjusted orthogonally from the frequency of oscillation. The results of PSPICE simulation program are corresponding to the theoretical analysis.