Electronically controlled oscillator with linear frequency adjusting for four‐phase or differential quadrature output signal generation |
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Authors: | Roman Sotner Norbert Herencsar Jan Jerabek Jaroslav Koton Tomas Dostal Kamil Vrba |
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Affiliation: | 1. Department of Radio Electronics, Faculty of Electrical Engineering and Communication, Brno University of Technology, Brno, Czech Republic;2. Department of Telecommunications, Faculty of Electrical Engineering and Communication, Brno University of Technology, Brno, Czech Republic;3. Department of Electrical Engineering and Computer Science, College of Polytechnics Jihlava, Jihlava, Czech Republic |
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Abstract: | This paper introduces novel four‐phase oscillator employing two Dual‐Output Controlled Gain Current Follower Buffered Amplifiers (DO‐CG‐CFBAs), single Current Amplifier, three resistors, and two grounded capacitors suitable for differential quadrature signal production (floating outputs). To control the frequency of oscillation (FO) and condition of oscillation (CO), only the current gain adjustment of active elements is used. The circuit was designed by well‐known state variable approach. The oscillator employs three active elements for linear control of FO and to adjust CO and provides low‐impedance voltage outputs. Furthermore, two straightforward ways of automatic amplitude gain control were used and compared. Active elements with very good performance are implemented to fulfill required features. Suitable CMOS implementation of introduced DO‐CG‐CFBA was shown. Important characteristics of the designed oscillator were verified experimentally and by PSpice simulations to confirm theoretical and expected presumptions. Copyright © 2013 John Wiley & Sons, Ltd. |
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Keywords: | electronic control adjusting Current Amplifier Dual‐Output Controlled Gain Current Follower Buffered Amplifier (DO‐CG‐CFBA) differential signals quadrature oscillator |
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