The Designer's Guide Community
Forum
Welcome, Guest. Please Login or Register. Please follow the Forum guidelines.
Nov 30th, 2021, 6:54am
Pages: 1
Send Topic Print
jitter measurement for phase domain model PLL (Read 477 times)
rezarmzn
New Member
*
Offline



Posts: 2

jitter measurement for phase domain model PLL
Aug 19th, 2020, 9:09am
 
Hi,
Following your guide-line (Predicting the Phase Noise of PLL-Based Frequency Synthesizers) we have created the phase domain model for our PLL. Those models require a certain parameters (fcorner, white_noise_spd, ...) to be measured on the real circuit and be used here. the question is when running the simulation (either noise or pnoise) to measure these parameters what frequency range we should integrate it for?

e.g. we have frequency divider (VCO frequency is 16GHz, 16G / 8 = 2G) and the bandwidth of the PLL is roughly 20MHz. The input reference frequency is 2GHz. How to measure fcorner and white_noise_spd.
Thanks,
Back to top
 
 
View Profile   IP Logged
Ken Kundert
Global Moderator
*****
Offline



Posts: 2316
Silicon Valley
Re: jitter measurement for phase domain model PLL
Reply #1 - Aug 19th, 2020, 4:22pm
 
The divider model takes the power spectral density as a parameter, so you do not integrate the noise before applying it to the model. Just measure the strobed noise in terms of phase, split into flicker and white regions, give frequency that partitions the two regions as the corner frequency fc and give the power spectral density of the white region as n.

-Ken
Back to top
 
 
View Profile WWW   IP Logged
rezarmzn
New Member
*
Offline



Posts: 2

Re: jitter measurement for phase domain model PLL
Reply #2 - Aug 20th, 2020, 10:08am
 
Is there any particular function in the Cadence which can calculate corner frequency? Or should I post-process the data?
Back to top
 
 
View Profile   IP Logged
Ken Kundert
Global Moderator
*****
Offline



Posts: 2316
Silicon Valley
Re: jitter measurement for phase domain model PLL
Reply #3 - Aug 20th, 2020, 10:47am
 
I don't know. I am not that familiar with the calculator. Conceptually the flicker noise has a -10dB/dec slope and the white noise is flat. The corner frequency is where the asymptotes for these two regions intersect.

-Ken
Back to top
 
 
View Profile WWW   IP Logged
Pages: 1
Send Topic Print
Copyright 2002-2021 Designer’s Guide Consulting, Inc. Designer’s Guide® is a registered trademark of Designer’s Guide Consulting, Inc. All rights reserved. Send comments or questions to editor@designers-guide.org. Consider submitting a paper or model.