The Designer's Guide Community
Forum
Welcome, Guest. Please Login or Register. Please follow the Forum guidelines.
Apr 19th, 2024, 3:10pm
Pages: 1
Send Topic Print
JEE not matching with Pnoise Time-domain (strobed) analysis (Read 7923 times)
rajkumar palwai
Community Member
***
Offline



Posts: 46
Sunnyvale, California
JEE not matching with Pnoise Time-domain (strobed) analysis
Oct 19th, 2011, 9:50am
 
Hi all,
For driven circuits like dividers, we see JEE as the jitter metric. In spectre Pnoise analysis we can see the JEE directly using the "Jitter" analysis. Ideally this number should be equal to the (total sampled rms noise voltage/ (dv/dt)). I have calculated the total sampled noise using the Pnoise "Time-domain' (also referred as strobed noise analysis) and then tried to match the number with the JEE number. But they are not coming out same.

Please suggest me if am doing anything wrong in the calculations.

Regards
rajkumar
Back to top
 
 
View Profile   IP Logged
msr
New Member
*
Offline



Posts: 1

Re: JEE not matching with Pnoise Time-domain (strobed) analysis
Reply #1 - Mar 25th, 2012, 12:33am
 
Hi,

1) Formulae Jee = Vn-rms-dsb / (dv/dt at threshold crossing)

2) Vn-rms-dsb :
Spectre takes Noise BW = (Maximum Sidebands + 0.5) * F-clk. Vn-rms-dsb = SQRT( (Maximum Sidebands + 0.5) * F-clk ) * PSD-dsb
For example PSD-dsb = SQRT(4KTR) for a resistor.

But if the circuit band-width is less than the noise bandwidth then circuit bandwidth should be considered in Vn-rms calculations.

3) Calculate dv/dt in a very small voltage range around threshold at output.

Thanks
Srinivas
Back to top
 
 
View Profile   IP Logged
Pages: 1
Send Topic Print
Copyright 2002-2024 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.