Phase Locked Loop definitions

Phase-locked loop

A phase-locked loop or phase lock loop (PLL) is a control system that generates an output signal whose phase is related to the phase of an input signal. While there are several differing types, it is easy to initially visualize as an electronic circuit consisting of a variable frequency oscillator and a phase detector. The oscillator generates a p...
Found on http://en.wikipedia.org/wiki/Phase-locked_loop

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phase locked loop

feedback circuit for synchronizing an oscillator with the phase of an input signal
Found on http://www.electropedia.org/iev/iev.nsf/display?openform&ievref=713-10-48

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Phase Locked Loop

A circuit containing a voltage-controlled oscillator whose phase or frequency can be 'steered' to keep it in sync with a reference source. A PLL circuit is generally used to lock onto and 'up-convert' the frequency of a stable source.
Found on https://www.encyclo.co.uk/local/20850

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