Voltage to frequency converter NOISE

[justanengineer]

Hello,

I implement a VFC but i want to ask how can i measured the noise of the circuit?
I have a frequency in the output, so i cannot make a normal noise measurment.

thanks

 

[Dominik Przyborowski]

You should to measure a jitter (phase noise) of your signal

 

[justanengineer]

and how i can do it?
Thanks

 

[erikl]

See here: View attachment VCO_workshop_instruction.pdf

 

[FvM]

Rather visually with a digital oscilloscope. Trigger with N periods delay, get a broadened pulse that shows the jitter.

 

[justanengineer]

PHASE NOISE (JITTER) of a Voltage to Frequency converter.

Hello,

The phase noise of a Voltage to frequency converter is calculate in the same way that we calculate it in a VCO or there is some difference??

Thanks

 

[erikl]

Actually a VFC is a VCO, just with a broader frequency range, and without the feedBack control mechanism via PFD.
So the noise calculation should be similar.

 

[justanengineer]

But eh VCO is an Autonomous circuit, the VFC depend on the input ( the frequency in the output depend on the input signal), so it should not be the same! or maybe i am wrong.
Thanks

 

[erikl]

Doesn't the VCO's output frequency depend on its input voltage? At least it should, I think! Not really autonomous ;-)