PLL(phase detector) - Electronic Circuits Projects Diagrams Free

Oluvision · 31st January 2004, 04:55 AM

Someone told me that I can use the phase detector of a PLL to implement a phase detector. I tried understanding the circuit to this end, but could not figure out to use the phase detector inside the PLL.

crust · 31st January 2004, 07:11 AM

With only the information given, I would guess that the idea was to use the PLL as a d(phi) to voltage converter. A pll could perhaps do this, since in many cases, the operate a VCO. You could perhaps measure the voltage driving the VCO. But my guess would be that you actually need to have the analog loop complete for this to work. I cannot otherwise understand how this might work.

**Nigel Goodwin** · 31st January 2004, 07:16 AM

A common phase detector in PLL's is simply an XOR gate, the pulse from the output represents the phase difference between the two inputs.

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31st January 2004, 04:55 AM	(permalink)
Oluvision	PLL(phase detector) Someone told me that I can use the phase detector of a PLL to implement a phase detector. I tried understanding the circuit to this end, but could not figure out to use the phase detector inside the PLL.

31st January 2004, 07:11 AM	(permalink)
crust	With only the information given, I would guess that the idea was to use the PLL as a d(phi) to voltage converter. A pll could perhaps do this, since in many cases, the operate a VCO. You could perhaps measure the voltage driving the VCO. But my guess would be that you actually need to have the analog loop complete for this to work. I cannot otherwise understand how this might work.

31st January 2004, 07:16 AM	(permalink)
Nigel Goodwin	A common phase detector in PLL's is simply an XOR gate, the pulse from the output represents the phase difference between the two inputs.