Phase Frequency Detector
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A phase frequency detector, in electronics, is a device which compares the phase of two input signals. It has two inputs which correspond to two different input signals, usually one from a voltage-controlled oscillator (VCO) and another from some external source. It has two outputs which instruct subsequent circuitry on how to adjust to lock onto the phase. The outputs are fed to a loop filter which integrates the signal to smooth it. This smoothed signal is fed to a voltage-controlled oscillator. The VCO provides an output clock with a frequency that is proportional to the level of the input voltage, which is then fed back to the PFD.
[edit] References
- Devon Fernandez and Sanjeev Manandhar (8 December 2003). "Digital Phase Locked Loop". Retrieved on 2006-04-25.
- Zilic, Zeljko. "Phase- and Delay-Locked Loop Clock Control in Digital Systems", TechOnLine, 2001-08-17. Retrieved on 2006-04-25.
- Mike Curtin and Paul O'Brien. "Phase Locked Loops for High-Frequency Receivers and Transmitters-3", Analog Dialogue, Analog Devices, July/August 1999. Retrieved on 2006-04-25.
