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Design >> RF Design >> Jitter noise simulation
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Message started by Paulin on Jun 1^st, 2007, 12:15pm

Title: Jitter noise simulation
Post by Paulin on Jun 1^st, 2007, 12:15pm

Hi, Ken,
I got a question regarding your application note: Predicting the Phase Noise and Jitter of PLL-Based Frequency Synthesizers
Ken Kundert (Designer’s Guide Consulting, Inc.).
On page 25, you mention about Metrics are unbounded with presence of flicker noise. Could I know what unbounded means?

Refer your application:
"
Cycle-to-cycle jitter is a metric designed to identify large adjacent cycle displacements.
It is like edge-to-edge jitter in that it is a scalar jitter metric that does not contain information
about the correlation in the jitter between distant transitions. However, it differs
in that it is a measure of short-term jitter that is relatively insensitive to long-term jitter
[13]. As such, cycle-to-cycle jitter is the only jitter metric that is suitable for use when
flicker noise is present. All other metrics are unbounded in the presence of flicker noise

"

Does that mean when we use edge to edge Jitter, Jitter is not accurate or at least under some condition is not accurate? Could we trust the simulation result?

Thanks!

Paulin

Title: Re: Jitter noise simulation
Post by Ken Kundert on Jun 1^st, 2007, 1:44pm

Unbounded means that the value has no bound, it goes to infinity.

-Ken

Title: Re: Jitter noise simulation
Post by mg777 on Jun 2^nd, 2007, 12:57am

Why would 1/f noise impact cycle-cycle (adjacent cycle) jitter? Flicker noise is a fractional integrated Brownian walk, so I expect that the total distance of the sailor from the bar shouldn't vary significantly between two steps.

Can someone help me understand this better?

M.G.Rajan

Title: Re: Jitter noise simulation
Post by Ken Kundert on Jun 2^nd, 2007, 10:44am

I think you have it right. Flicker noise affects cycle-to-cycle jitter only to the degree that it accumulates over a cycle. That is why cycle-to-cycle jitter is a metric that is suitable for use in the presence of flicker noise.

-Ken