I did a small study on jitter parameters from various sources. Mike Labonte was kind enough to post the spreadsheet to the IBIS web site. Personally, I think we have good coverage in BIRD 123.4. http://www.eda.org/pub/ibis/macromodel_wip/archive/20120925/gregedlund/Jitter%20Models%20Sanitized/Jitter_Models_Sanitized.xls Greg Edlund Senior Engineer Signal Integrity and System Timing IBM Systems & Technology Group 3605 Hwy. 52 N Bldg 050-3 Rochester, MN 55901