tailieunhanh - Two integrator loop quadrature oscillators: A review

A review of the two integrator loop oscillator circuits providing two quadrature sinusoidal output voltages is given. All the circuits considered employ the minimum number of capacitors namely two except one circuit which uses three capacitors. The circuits considered are classified to four different classes. The first class includes floating capacitors and floating resistors and the active building blocks realizing these circuits are the Op Amp or the OTRA. The second class employs grounded capacitors and includes floating resistors and the active building blocks realizing these circuits are the DCVC or the unity gain cells or the CFOA. The third class employs grounded capacitors and grounded resistors and the active building blocks realizing these circuits are the CCII. The fourth class employs grounded capacitors and no resistors and the active building blocks realizing these circuits are the TA. Transformation methods showing the generation of different classes from each other is given in details and this is one of the main objectives of this paper. | Journal of Advanced Research 2013 4 1-11 Cairo University Journal of Advanced Research REVIEW Two integrator loop quadrature oscillators A review Ahmed M. Soliman Electronics and Communication Engineering Department Faculty of Engineering Cairo University Giza 12613 Egypt Received 28 January 2012 revised 7 March 2012 accepted 7 March 2012 Available online 19 April 2012 KEYWORDS Two integrator loop oscillators Op Amp Operational transresistance amplifier Unity gain cells Current conveyor Current feedback operational amplifier Abstract A review of the two integrator loop oscillator circuits providing two quadrature sinusoidal output voltages is given. All the circuits considered employ the minimum number of capacitors namely two except one circuit which uses three capacitors. The circuits considered are classified to four different classes. The first class includes floating capacitors and floating resistors and the active building blocks realizing these circuits are the Op Amp or the OTRA. The second class employs grounded capacitors and includes floating resistors and the active building blocks realizing these circuits are the DCVC or the unity gain cells or the CFOA. The third class employs grounded capacitors and grounded resistors and the active building blocks realizing these circuits are the CCII. The fourth class employs grounded capacitors and no resistors and the active building blocks realizing these circuits are the TA. Transformation methods showing the generation of different classes from each other is given in details and this is one of the main objectives of this paper. 2012 Cairo University. Production and hosting by Elsevier . All rights reserved. Introduction Sinusoidal oscillators are basic building blocks in active circuits and have several applications in electronics and communication circuits 1-3 . The oscillator circuits are available in different forms which includes Colpitts oscillator Hartely oscillator two integrator loop oscillators .