scholarly journals Versatile Voltage-Mode Biquadratic Filter and Quadrature Oscillator Using Four OTAs and Two Grounded Capacitors

Electronics ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1493
Author(s):  
San-Fu Wang ◽  
Hua-Pin Chen ◽  
Yitsen Ku ◽  
Chia-Ling Lee
Keyword(s):  
Integrated Circuit ◽  
Oscillation Frequency ◽  
Low Cost ◽  
Circuit Complexity ◽  
Low Noise ◽  
Active Components ◽  
Quadrature Oscillator ◽  
Voltage Mode ◽  
Biquad Filter ◽  
Oscillation Condition

This article presents a versatile voltage-mode (VM) biquad filter with independently electronic tunability. The proposed structure using one dual-output operational transconductance amplifier, three single-output operational transconductance amplifiers (OTAs) and two grounded capacitors was explored to derive a new VM quadrature oscillator with the independent control of the oscillation frequency and the oscillation condition. The proposed versatile VM biquad filter achieves nearly all of the main advantages: (i) simultaneous realizations of band-reject, band-pass, and low-pass from the same architecture, (ii) multiple-input and multiple-output functions, (iii) independent electronic adjustability of quality factor and resonant angular frequency, (iv) no resistor needed, (v) all input terminals with cascade functions, (vi) no additional inverting amplifier for input signals, (vii) using only grounded capacitors, and (viii) easy to implement a VM quadrature oscillator with independent electronically controlled oscillation frequency and oscillation condition. The proposed versatile VM biquad filter employs only four OTAs and two grounded capacitors. The active components of the proposed VM biquad filter are one less than that of recent reports. The proposed circuit also brings versatility and simplicity to the design of VM biquad filters and VM quadrature oscillators. Filters and oscillators with less active and passive components have the advantages of low cost, low power dissipation, low circuit complexity, and low noise. Commercially available integrated circuit LT1228 and discrete components can be used to implement the proposed OTA-based circuits. The simulation and experiment results validated the theoretical analysis.

scholarly journals Voltage-Mode Multifunction Biquad Filter and Its Application as Fully-Uncoupled Quadrature Oscillator Based on Current-Feedback Operational Amplifiers

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6681
Author(s):  
San-Fu Wang ◽  
Hua-Pin Chen ◽  
Yitsen Ku ◽  
Ming-Xiu Zhong
Keyword(s):  
Oscillation Frequency ◽  
Transfer Functions ◽  
Amplitude Ratio ◽  
Experimental Results ◽  
Control Factor ◽  
Current Feedback ◽  
Quadrature Oscillator ◽  
Voltage Mode ◽  
Biquad Filter ◽  
Oscillation Condition

This research introduces a new multifunction biquad filter based on voltage mode (VM) current-feedback operational amplifier (CFOA) and a fully uncoupled quadrature oscillator (QO) based on the proposed VM multifunction biquad filter. The proposed VM multifunction biquad filter has high impedance to the input voltage signal, and uses three CFOAs as active components, while using four resistors and two grounded capacitors as passive components. The VM CFOA-based multifunction biquad filter realizes band-reject, band-pass, and low-pass transfer functions at high-input impedance node simultaneously, which has the feature of easy cascading in VM operation without the need for additional voltage buffers. Additionally, the filter control factor parameter pole frequency (ωo) and quality factor (Q) of the proposed VM multifunction biquad filter can be independently set by varying different resistors. By slightly modifying the VM multifunction biquad filter topology, a VM fully-uncoupled QO is easily obtained. The difference from the previous VM CFOA-based multifunction biquad filter is that the proposed VM CFOA-based multifunction biquad filter can be independently controlled by the filter control factor parameters, ωo and Q. The proposed VM CFOA-based multifunction biquad filter can be transformed into a VM QO with fully-uncoupled adjustable of the oscillation condition and the oscillation frequency. The oscillation condition and the oscillation frequency can be fully-uncoupled and controlled by varying two sets of completely different resistors. The proposed VM fully-uncoupled QO solves the amplitude instability. The constant amplitude ratio of two quadrature sinusoidal waveforms can be realized when tuning FO. PSpice simulation and experimental results prove the performances of the proposed VM multifunction filter and VM fully-uncoupled QO. Simulation and experimental results confirm the theoretical analysis of the proposed circuits.

scholarly journals CDBA-Based Universal Biquad Filter and Quadrature Oscillator

2008 ◽  
Vol 2008 ◽  
pp. 1-6 ◽  
Author(s):  
Worapong Tangsrirat ◽  
Tattaya Pukkalanun ◽  
Wanlop Surakampontorn
Keyword(s):  
Sensitivity Analysis ◽  
Oscillation Frequency ◽  
Slight Modification ◽  
Angular Frequency ◽  
Active Components ◽  
Passive Components ◽  
Quadrature Oscillator ◽  
Biquad Filter ◽  
Oscillation Condition ◽  
Biquadratic Filter

The voltage-mode universal biquadratic filter and sinusoidal quadrature oscillator based on the use of current differencing buffered amplifiers (CDBAs) as active components have been proposed in this paper. All the proposed configurations employ only two CDBAs and six passive components. The first proposed CDBA-based biquad configuration can realize all the standard types of the biquadratic functions, that is, lowpass, bandpass, highpass, bandstop, and allpass, from the same topology, and can also provide orthogonal tuning of the natural angular frequency(ωo)and the bandwidth (BW) through separate virtually grounded passive components. By slight modification of the first proposed configuration, the new CDBA-based sinusoidal quadrature oscillator is easily obtained. The oscillation condition and the oscillation frequency are independently adjustable by different virtually grounded resistors. The sensitivity analysis of all proposed circuit configurations is shown to be low. PSPICE simulations and experimental results based upon commercially available AD844-type CFAs are included, which confirm the workability of the proposed circuits.

scholarly journals DDCC-Based Quadrature Oscillator with Grounded Capacitors and Resistors

2009 ◽  
Vol 2009 ◽  
pp. 1-4 ◽  
Author(s):  
Montree Kumngern ◽  
Kobchai Dejhan
Keyword(s):  
Theoretical Analysis ◽  
Oscillation Frequency ◽  
Current Conveyors ◽  
Quadrature Oscillator ◽  
Voltage Mode ◽  
Oscillation Condition ◽  
Simulation Results

A new voltage-mode quadrature oscillator using two differential difference current conveyors (DDCCs), two grounded capacitors, and three grounded resistors is presented. The proposed oscillator provides the following advantages: the oscillation condition and oscillation frequency are orthogonally controlled; the oscillation frequency is controlled through a single grounded resistor; the use of only grounded capacitors and resistors makes the proposed circuit ideal for IC implementation; low passive and active sensitivities. Simulation results verifying the theoretical analysis are also included.

scholarly journals Current-Mode Third-Order Quadrature Oscillator Using CDTAs

2009 ◽  
Vol 2009 ◽  
pp. 1-5 ◽  
Author(s):  
Jiun-Wei Horng
Keyword(s):  
Theoretical Analysis ◽  
Phase Difference ◽  
Oscillation Frequency ◽  
Current Mode ◽  
Third Order ◽  
Quadrature Oscillator ◽  
Oscillation Condition ◽  
Transconductance Amplifiers ◽  
Simulation Results ◽  
A Current

This paper describes a current-mode third-order quadrature oscillator based on current differencing transconductance amplifiers (CDTAs). Outputs of two current-mode sinusoids with90°phase difference are available in the quadrature oscillator circuit. The oscillation condition and oscillation frequency are orthogonal controllable. The proposed circuit employs only grounded capacitors and is ideal for integration. Simulation results are included to confirm the theoretical analysis.

scholarly journals Three-Input Single-Output Electronically Controllable Dual-Mode Universal Biquad Filter Using DO-CCCIIs

2007 ◽  
Vol 2007 ◽  
pp. 1-6 ◽  
Author(s):  
M. Siripruchyanun ◽  
W. Jaikla
Keyword(s):  
Integrated Circuit ◽  
Current Mode ◽  
Dual Mode ◽  
Voltage Mode ◽  
Single Output ◽  
Biquad Filter ◽  
Biquadratic Filter ◽  
Circuit Description ◽  
Electronically Controllable ◽  
The Given

This article presents a dual-mode (voltage-mode and current-mode) universal biquadratic filter performing completely standard functions: lowpass, highpass, bandpass, band-reject, and allpass functions, based on plus-type dual-output second-generation, current controlled, current conveyor (DO-CCCII+). The features of the circuit are that the bandwidth and natural frequency can be tuned electronically via the input bias currents: the circuit description is very simple, consisting of merely 2 DO-CCCIIs and 2 capacitors: the circuit can provide either the voltage-mode or current-mode filter without changing circuit topology. Additionally, each function response can be selected by suitably selecting input signals with digital method. Without any external resistors, the proposed circuit is very suitable to further develop into an integrated circuit. The PSPICE simulation results are depicted. The given results agree well with the theoretical anticipation. The maximum power consumption is approximately 1.81 mW at±1.5 V supply voltages.

New Voltage-Mode Sinusoidal Oscillators Using VDIBAs

2019 ◽  
Vol 29 (04) ◽  
pp. 2050052
Author(s):  
San-Fu Wang ◽  
Hua-Pin Chen
Keyword(s):  
Theoretical Analysis ◽  
Bias Current ◽  
Electronic Control ◽  
Active Components ◽  
Passive Components ◽  
Voltage Mode ◽  
Sinusoidal Oscillators ◽  
Oscillation Condition ◽  
Condition Of Oscillation ◽  
Minimum Number

This paper presents two new voltage-mode sinusoidal oscillators based on voltage differencing inverting buffered amplifier (VDIBA). The first proposed circuit exhibits independent and electronic control of oscillation condition by using the bias current of the VDIBA. The proposed configuration contains only single VDIBA, two grounded capacitors and two resistors, which are the least number of active components and the minimum number of passive components necessary for realizing voltage-mode oscillator topology. The second proposed circuit exhibits independent and electronic control on the condition of oscillation without affecting the oscillation frequency by adjusting the separate bias currents of the VDIBAs. The proposed configuration contains two VDIBAs, two grounded capacitors and one resistor, which can provide four quadrature voltage outputs simultaneously. Both proposed circuits enjoy only two grounded capacitors, which are suitable for monolithic integration. HSpice simulations and experimental results are included to confirm the theoretical analysis.

scholarly journals Electronically Tunable Quadrature Oscillator Using Grounded Components with Current and Voltage Outputs

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Hua-Pin Chen
Keyword(s):  
Integrated Circuit ◽  
Output Impedance ◽  
Passive Components ◽  
Quadrature Oscillator ◽  
Oscillation Condition ◽  
Transconductance Amplifier ◽  
High Output Impedance ◽  
Electronically Tunable ◽  
Current Differencing Transconductance Amplifier ◽  
High Output

The electronically tunable quadrature oscillator using a single multiple-output current controlled current differencing transconductance amplifier (MO-CCCDTA) and grounded passive components is presented. The proposed configuration uses a single MO-CCCDTA, two grounded capacitors and one grounded resistor. Two high-output impedance quadrature current signals and two quadrature voltage signals with 90° phase difference. The oscillation condition and oscillation frequency of the proposed quadrature oscillator are independently controllable. The use of only grounded passive components makes the proposed circuit ideal for integrated circuit implementation.

scholarly journals A CFOA-Based Voltage-Mode Multifunction Biquadratic Filter and a Quadrature Oscillator Using the CFOA-Based Biquadratic Filter

2019 ◽  
Vol 9 (11) ◽  
pp. 2304 ◽  
Author(s):  
San-Fu Wang ◽  
Hua-Pin Chen ◽  
Yitsen Ku ◽  
Po-Yu Chen
Keyword(s):  
Integrated Circuit ◽  
Input Impedance ◽  
Angular Frequency ◽  
High Input ◽  
High Input Impedance ◽  
Current Feedback ◽  
Quadrature Oscillator ◽  
Voltage Mode ◽  
Biquadratic Filter ◽  
Band Pass

This paper proposes a new high-input impedance current feedback operational amplifier (CFOA)- based voltage-mode multifunction biquadratic filter and a voltage-mode quadrature oscillator using the proposed high-input impedance CFOA-based biquadratic filter. The proposed high-input impedance CFOA-based voltage-mode multifunction biquadratic filter uses three CFOAs, three resistors, and two grounded capacitors with two inputs and three outputs. The filter can simultaneously realize non-inverting low-pass, non-inverting band-pass, and non-inverting band-reject filtering functions at the high-input impedance terminal while the inverting band-pass and non-inverting high-pass filtering functions can also be obtained by applying another high-input impedance terminal. The filter offers orthogonal control of resonance angular frequency and quality factor. The proposed high-input impedance CFOA-based voltage-mode multifunction biquadratic filter can be used to implement a voltage-mode quadrature oscillator with an independently controlled the frequency of oscillator and the condition of oscillation. The OrCAD PSpice simulation and experimental results of the commercially available integrated circuit, AD844AN, are used to confirm the characteristics of the proposed filter and oscillator.

Single-Resistance-Controlled Quadrature Oscillator Using CFOAs for GMI Magnetic Sensors

2013 ◽  
Vol 712-715 ◽  
pp. 1881-1885
Author(s):  
Lei Zhang ◽  
Zhong Ming Pan
Keyword(s):  
Oscillation Frequency ◽  
Magnetic Sensors ◽  
Good Sensitivity ◽  
Quadrature Oscillator ◽  
Pspice Simulations ◽  
State Variable ◽  
Oscillation Condition ◽  
Sinusoidal Oscillator ◽  
Sensitivity Performance

A class of single-resistance-controlled (SRC) quadrature sinusoidal oscillator using CFOAs for GMI magnetic sensors is presented in this paper. By means of state variable, the proposed circuits are designed and analyzed which has the advantages such as noninteractive control of the oscillation condition (CO) and the oscillation frequency (FO), good sensitivity performance and minimum components including grounded capacitors. Moreover, the workability of the proposed circuit has been verified by PSPICE simulations.

Transmission Electron Microscopy of oriented Co84Cr14Ta2 thin films for longitudinal magnetic recording

1991 ◽  
Vol 49 ◽  
pp. 756-757
Author(s):  
T. P. Nolan
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Low Cost ◽  
Low Noise ◽  
Information Storage ◽  
High Coercivity ◽  
Magnetic Alloy ◽  
Magnetic Media ◽  
Transmission Electron

Thin film magnetic media are being used as low cost, high density forms of information storage. The development of this technology requires the study, at the sub-micron level, of morphological, crystallographic, and magnetic properties, throughout the depth of the deposited films. As the microstructure becomes increasingly fine, widi grain sizes approaching 100Å, the unique characterization capabilities of transmission electron microscopy (TEM) have become indispensable to the analysis of such thin film magnetic media.Films were deposited at 225°C, on two NiP plated Al substrates, one polished, and one circumferentially textured with a mean roughness of 55Å. Three layers, a 750Å chromium underlayer, a 600Å layer of magnetic alloy of composition Co84Cr14Ta2, and a 300Å amorphous carbon overcoat were then sputter deposited using a dc magnetron system at a power of 1kW, in a chamber evacuated below 10-6 torr and filled to 12μm Ar pressure. The textured medium is presently used in industry owing to its high coercivity, Hc, and relatively low noise. One important feature is that the coercivity in the circumferential read/write direction is significandy higher than that in the radial direction.

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