Engineer4ever
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Hi, 
I have a couple of questions about the PFD and the CP and I hope someone can help me:
1) How can I determine the required PFD range? In other words, is there a way to know if I should use a PFD which has a range from -2pi-->2pi or if it's enough to use a PFD circuit which has a range of -pi-->pi? How can I control that, if that could be controlled?
2) As far as I know, Ring VCO usually requires differential control voltage, which means that I should design a differential charge pump and two loop filters for each output and I already read that in many papers and references, but my project supervisor was shocked when I told him that and he said that no one does that, and that the Ring VCO needs a single control voltage. So, is it true or not?
Thanks in advance,
I have a couple of questions about the PFD and the CP and I hope someone can help me:
1) How can I determine the required PFD range? In other words, is there a way to know if I should use a PFD which has a range from -2pi-->2pi or if it's enough to use a PFD circuit which has a range of -pi-->pi? How can I control that, if that could be controlled?
2) As far as I know, Ring VCO usually requires differential control voltage, which means that I should design a differential charge pump and two loop filters for each output and I already read that in many papers and references, but my project supervisor was shocked when I told him that and he said that no one does that, and that the Ring VCO needs a single control voltage. So, is it true or not?
Thanks in advance,