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Design >> RF Design >> what is the physical meaning of Φ(s) in pll
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Message started by Hejia on Jan 15^th, 2016, 6:27pm

Title: what is the physical meaning of Φ(s) in pll
Post by Hejia on Jan 15^th, 2016, 6:27pm

When designing a PLL, we will try to get the closed-loop transfer function:
H(s)=Φout(s)/Φref(s).
I can't really understand the physical meaning of the Laplace Domain interpretation of phase.
For example, what does |Φ(jw)| mean? The magnitude of phase at different frequency? It just doesn't make any sense to me.

Title: Re: what is the physical meaning of Φ(s) in pll
Post by loose-electron on Jan 16^th, 2016, 9:57pm

IF I am not mistaken -

First one is static phase error, input to output.

The other one is phase error as a function of frequency, where if the reference frequency coming in is changed, the phase error changes as a function of that reference frequency.

I think that is what you are looking for?

Title: Re: what is the physical meaning of Φ(s) in pll
Post by Hejia on Jan 18^th, 2016, 10:22am

Thanks, Jerry.

Your reply really gives me some useful thinking toward my question. ;D

Title: Re: what is the physical meaning of Φ(s) in pll
Post by loose-electron on Jan 21^st, 2016, 8:29pm

happy to help