Experimental comparison of phase‐noise in cross‐coupled RC‐ and LC‐oscillators |
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| Authors: | Luis Bica Oliveira Ahmed Allam Igor M Filanovsky Jorge R Fernandes Chris J M Verhoeven Manuel M Silva |
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| Affiliation: | 1. INESC‐ID/Universidade Nova de Lisboa, Rua Alves Redol no 9, 1000‐029 Lisbon, Portugal;2. Department of Electrical and Computer Engineering, University of Alberta, AB T6G 2V4, Alberta, Canada;3. INESC‐ID/TU Lisbon, Rua Alves Redol no 9, 1000‐029 Lisbon, Portugal;4. Electronics Res. Lab./Dimes, Delft University of Technology, Mekelweg 4, 2628 CD Delft, The Netherlands |
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| Abstract: | Relaxation RC‐oscillators are notorious for their poor phase‐noise performance. However, there are reasons to expect a phase‐noise reduction in quadrature oscillators obtained by cross‐coupling two relaxation oscillators. We present measurements on 5 GHz oscillators, which show that in RC‐oscillators the coupling reduces both the phase‐noise and quadrature error, whereas in LC‐oscillators the coupling reduces the quadrature error, but increases the phase‐noise. A comparison using standard figures of merit indicates that quadrature RC‐oscillators may be a viable alternative to LC‐oscillators when area and cost are to be minimized. Copyright © 2009 John Wiley & Sons, Ltd. |
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| Keywords: | relaxation oscillators RC‐oscillators LC‐oscillators quadrature oscillator phase‐noise phase error |
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