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Parasitic Oscillations

December 30th Fact-of-the-Day

Spurious parasitic oscillation usually is caused by regeneration in a single amplifier stage, although sometimes regeneration results from feedback around two or more amplifier stages. Parasitic oscillations usually have frequencies that are different than the fundamental frequency or frequencies being amplified. They also usually are different than harmonics of those frequencies. In many cases parasitic oscillations are modulated both in frequency and amplitude to some extent by the signal or signals being amplified. All classes of amplifiers are subject to parasitic oscillations. Elimination requires blocking or canceling the feedback that is causing amplifier output signals to regenerate back through the amplifier. ©2004 Martek International All rights reserved.


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