scholarly journals Electronic Tuning Square-Wave Generators with Improved Linearity Using Operational Transresistance Amplifier

2020 ◽  
Vol 10 (2) ◽  
pp. 12
Author(s):  
Pittala Chandra Shaker ◽  
Avireni Srinivasulu
Keyword(s):  
Current Mode ◽  
Waveform Generator ◽  
Current Feedback ◽  
Passive Components ◽  
Square Wave ◽  
Generator Circuit ◽  
Duty Cycles ◽  
Electronic Tuning ◽  
Current Feedback Operational Amplifier ◽  
Square Wave Generators

Two new electronic tuning current-mode square-wave generators are introduced in the ensuing paper. In the first proposed square-wave generator circuit, one Operational Trans-resistance Amplifier (OTRA) and two passive components are involved, along with two NMOS depletion mode transistors. This circuit generates a square-wave with almost equal and fixed duty cycles. The second proposed circuit is able to control both on-duty and off-duty cycles independently with the help of two passive components, two NMOS depletion mode transistors, and two diodes connected to the circuit. The frequency of the proposed circuits can be adjusted with the passive components connected to the circuit. Moreover, electronic tuning can also be achieved with the proposed circuits. The measured results that are included in the paper show the linear variation of a time period as compared with existing OTRA based square waveform generator. The performance of the proposed circuits is examined while using SPICE models. These circuits are built on a laboratory breadboard using commercially available Current Feedback Operational Amplifier (AD844 AN) and passive components are connected externally and tested for square waveform generation. The obtained results demonstrate good agreement with the theoretical values.

A Novel FSK Generator Using a Second Generation Current Controlled Conveyor

2020 ◽  
Vol 10 (6) ◽  
pp. 902-908
Author(s):  
Syed Zahiruddin ◽  
Avireni Srinivasulu ◽  
Musala Sarada
Keyword(s):  
Biomedical Applications ◽  
Second Generation ◽  
Current Mode ◽  
Enabling Technology ◽  
Active Device ◽  
Passive Components ◽  
Existing Structures ◽  
Generator Circuit ◽  
Shift Keying ◽  
The Times

Objective: The interest concern towards the development of enabling technology towards new current mode devices has forced the designers and researchers for the invention of devices, which has having the characteristics like such as low power, robustness, compactness, efficiency and scalability. Methods: Second Generation Current Controlled Conveyor (CCCII) is the prevailing current mode device of the times today. Since its invention by A. Fabre, it has prominent applications in the field of analog signal processing and in biomedical applications too. In this manuscript, CCCII is used as an enabling device to design a Frequency Shift Keying (FSK) Generator. Results: The proposed topology is designed using a single active device CCCII with least passive components. The circuit enjoys the features of like electronic tunability of frequency using the bias current. Conclusion: It can be concluded that the FSK generator circuit designed using single CCCII confers better results in contrast to the existing structures. The maximum power consumption is 0.196 mW. The proposed circuit has the benefit of simple configuration, which is very much proficient for IC fabrication.

scholarly journals A memristor-based chaotic-masking for analog spread-spectrum communication

2019 ◽  
Vol 14 (2) ◽  
pp. 966
Author(s):  
Muhammad Taher Abuelma’atti ◽  
Abdullah Yousef Alnafisa
Keyword(s):  
Spread Spectrum ◽  
Operational Amplifier ◽  
Spread Spectrum Communication ◽  
Current Feedback ◽  
Square Wave ◽  
Chaos Generator ◽  
Current Feedback Operational Amplifier

<span>This paper presents a simple chaotic-masking system. The system uses a chaos generator built around a grounded memristor. The memristor is emulated using the current-feedback operational amplifier (CFOA). At the sending end the signal is masked by adding chaos. At the receiving end the signal is recovered by subtracting the chaos. The performance of proposed system is investigated using sinusoidal and square wave signals.</span>

Fully Electronically Tunable and Easily Cascadable Square/Triangular Wave Generator with Duty Cycle Adjustment

2019 ◽  
Vol 28 (06) ◽  
pp. 1950105 ◽  
Author(s):  
Bhartendu Chaturvedi ◽  
Atul Kumar
Keyword(s):  
Duty Cycle ◽  
Current Mode ◽  
Cmos Technology ◽  
Triangular Wave ◽  
Square Wave ◽  
Generator Circuit ◽  
Transconductance Amplifier ◽  
Wave Generator ◽  
Simulation Results ◽  
Triangular Wave Generator

A novel multiple-output dual-X current conveyor transconductance amplifier with buffer-based square/triangular wave generator is introduced in the paper. The proposed generator provides square wave in current mode and triangular wave in voltage mode. Outputs as square and triangular waves are available from terminals with appropriate impedance levels thereby making the proposed generator circuit easily cascadable in both current and voltage modes. The oscillation frequency and amplitude of output square wave are electronically and independently controllable. One more interesting feature of the proposed generator circuit is the adjustable duty cycle. The proposed circuit of square/triangular wave generator is verified through the HSPICE simulation results carried using 0.18[Formula: see text][Formula: see text]m CMOS technology. The simulation results show linear variation of duty cycle against external DC current over a range of 6.5–96%. The variation of square wave’s amplitude via bias current is found to be linear from 10[Formula: see text][Formula: see text]A to 80[Formula: see text][Formula: see text]A. Moreover, the proposed generator can operate very well up to 23.8[Formula: see text]MHz with nonlinearity less than 5%. The proposed generator circuit is also experimentally verified.

New current-feedback operational amplifier-based bandpass shadow filter

2016 ◽  
Vol 54 (1) ◽  
pp. 95-101 ◽  
Author(s):  
Muhammad Taher Abuelma’atti ◽  
Naif Almutairi
Keyword(s):  
Operational Amplifier ◽  
Bandpass Filter ◽  
Center Frequency ◽  
Electronic Control ◽  
Current Feedback ◽  
Feedback Path ◽  
Electronic Tuning ◽  
Voltage Amplifier ◽  
Current Feedback Operational Amplifier ◽  
Electronically Tunable

This article presents a new topology for implementing an electronically tunable bandpass filter using the current-feedback operational amplifier. The electronic tuning of the center frequency of the proposed circuit is achieved using an externally connected voltage amplifier in the feedback path without disturbing the constituents of the filter itself, that is a shadow filter. The proposed circuit can be used for developing an undergraduate experiment which illustrates the operation of bandpass filter and the electronic control of its center frequency using the concept of shadow filter. Experimental results obtained using the AD844 current-feedback operational amplifier are included.

CURRENT FEEDBACK OP-AMP UTILIZES NEW CURRENT CELL TO ENHANCE THE CMRR

2012 ◽  
Vol 21 (05) ◽  
pp. 1250038 ◽  
Author(s):  
AMR ABDALLAH TAMMAM ◽  
MOHAMED BEN-ESMAEL ◽  
MOHAMMED R. ABAZAB
Keyword(s):  
Operational Amplifier ◽  
High Speed ◽  
Circuit Simulation ◽  
Current Mode ◽  
Current Feedback ◽  
Output Resistance ◽  
Common Mode ◽  
Offset Voltage ◽  
Current Cell ◽  
Current Feedback Operational Amplifier

Despite excellent high frequency and high speed performance, current-feedback operational amplifiers (CFOAs) generally exhibit poor common-mode rejection (CMRR) properties, which limit their utility [Analogue IC design: The current–mode approach, IEE Circuits and Systems Series, Peter peregrinus, 1990]. A novel current feedback operational amplifier (CFOA) with improved performance is presented. The proposed CFOA has a new current-cell [Novel current-feedback operational amplifier Design Based on a floating circuit technique, IEE Colloquium on Analogue Signal Processing, 1998], to bias the entire circuit, which achieves an incremental output resistance twice that of the well-known "Wilson" circuit. Simulation results of this new CFOA architecture indicate that the amplifier exhibits performance characteristics superior to those obtained with an established input architecture: in particular, the CMRR (common-mode rejection ratio) is 91 dB, and the d.c. offset voltage less than 26 μV.

scholarly journals A Novel Current-Mode Multifunction Inverse Filter using Single CFA

2021 ◽  
Vol 10 (8) ◽  
pp. 64-67
Author(s):  
Anisur Rehman Nasir ◽  
S. N. Ahmad
Keyword(s):  
Theoretical Analysis ◽  
Current Mode ◽  
Simulation Program ◽  
Inverse Filter ◽  
Current Feedback ◽  
Passive Components ◽  
Feedback Amplifier ◽  
Current Feedback Amplifier ◽  
Highpass Filter ◽  
Filter Configuration

A novel current-mode multifunction inverse filter configuration using single current feedback amplifier (CFA) is presented. The proposed filter employs only one CFA and few passive components. The proposed circuit realizes inverse lowpass, inverse bandpass and inverse highpass filter functions with proper admittances. The characteristics of proposed multifunction inverse filter configuration are- current-mode realization; use of only one CFA; use of grounded passive components except one virtually grounded and realizing all three basic inverse filters. The proposed current-mode inverse filter circuit has been tested by TINA PRO simulation program and results justified the theoretical analysis.

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