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What is a PLL used for?
A phase-locked loop (PLL) is an electronic circuit with a voltage or voltage-driven oscillator that constantly adjusts to match the frequency of an input signal. PLLs are used to generate, stabilize, modulate, demodulate, filter or recover a signal from a “noisy” communications channel where data has been interrupted.
What is meant by phase-locked loop PLL circuit?
What is a PLL lock detector?
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. There are several different types; the simplest is an electronic circuit consisting of a variable frequency oscillator and a phase detector in a feedback loop.
How does a phase locked loop ( PLL ) circuit work?
PLL circuits operate by comparing the phase of an external signal to the phase of a clock signal produced by a voltage controlled crystal oscillator (VCXO). The circuit then adjusts the phase of the oscillator’s clock signal to match the phase of the reference signal.
What are hardware connections required for PLL circuits?
What hardware connections are required for PLL circuits? A phase-locked loop (PLL) is a feedback circuit designed to allow one circuit board to synchronize the phase of its on board clock with an external timing signal.
How is a phase locked clock different from a reference clock?
Clocks are, with varying degrees of accuracy, phase-locked (time-locked) to a leader clock. Left on its own, each clock will mark time at slightly different rates. A wall clock, for example, might be fast by a few seconds per hour compared to the reference clock at NIST. Over time, that time difference would become substantial.
How is the output phase locked in a feedback loop?
The output is fed through an optional divider back to the input of the system, producing a negative feedback loop. If the output phase drifts, the error signal will increase, driving the VCO phase in the opposite direction so as to reduce the error. Thus the output phase is locked to the phase at the other input.