Jim,
On 12/04/2014 08:41 PM, Jim Lux wrote:
I'm looking for a real short (3-4 slides or a website, really)
description of why the phase noise of a PLL (microwave) looks the way it
does, explaining (in sort of qualitative terms) how the phase noise
transitions from the VCO (outside the loop bandwidth) to the reference
(inside the loop bandwidth)..
And in particular, what the phase noise curve looks like if the loop
bandwidth is chosen incorrectly, or if the VCO or reference has more or
less noise than expected.
I figured before I wrote one up, if someone knows of one that's already
out there, I could just point people to it.
I could not find any useful presentation out of Enrico's large
collection, but he and Ulrich is my usual suspects.
But then, the best presentation I've seen was at the NIST seminar.
Anyway, this TI paper gives you a good hint:
http://www.ti.com/lit/an/scaa113/scaa113.pdf
See how Fig 8 and Fig 9 provides two different cross-overs between the
noise responces, and how the higher bandwidth doesn't have a "hump" just
because the steered oscillators noise response get's sufficiently
high-passed by the loop PLL as for the lower PLL it humps up because of
them having comparable power (amplitudes yes, but their power adds, as
it is noice).
Maybe it is good enough for your purposes, but yes, I agree there should
be a better presentation about the problem.
Cheers,
Magnus
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