Amen. -- George Patrick Tektronix, Inc. Central Engineering, EDS Applications Support P.O. Box 500, M/S 39-512 Beaverton, OR 97077-0001 * 503-627-5272 (voice) * 503-627-5587 (fax) http://www.tektronix.com http://www.pcb-designer.com "Off-Grid and Proud of it!" -----Original Message----- From: icu-pcb-forum-bounce@xxxxxxxxxxxxx [mailto:icu-pcb-forum-bounce@xxxxxxxxxxxxx] On Behalf Of Gerry Meier Sent: Thursday, February 28, 2008 09:45 To: icu-pcb-forum@xxxxxxxxxxxxx Subject: [PCB_FORUM] Re: Length matching for DDR - was - RE: Realer V6.01 Constraint Manager Can you guys take this off-line please Gerry Meier, Sr. PCB Designer Freedom CAD Services. Inc Voice: (256)776-7470 or (603) 864-1350 Email:gerry.meier@xxxxxxxxxxxxxx visit us at http://www.freedomcad.com -----Original Message----- From: icu-pcb-forum-bounce@xxxxxxxxxxxxx [mailto:icu-pcb-forum-bounce@xxxxxxxxxxxxx] On Behalf Of Austin Franklin Sent: Thursday, February 28, 2008 11:42 AM To: icu-pcb-forum@xxxxxxxxxxxxx Subject: [PCB_FORUM] Re: Length matching for DDR - was - RE: Re:Allegro V6.01 Constraint Manager Hi Richard, > I gave you some examples and I gave you some reasons. You said > you were receptive to new ideas but apparently not. Of course I'm open to new information/understanding and the ensuing discourse, which is why I've spent the time to read what you wrote and read the information at the links you provided. The examples you gave, so far, haven't provided any information that supported your claim for tighter length match constraints for the T branches. In fact, the TI reference showed they were the same (though lacked any analysis or explanation for where they got their numbers from). > There is more to life than designing from timing diagrams, and > simulations do not always simulate real life and definitely not EMC. No doubt there is more to life than that but not when you need to provide proper constraints for high speed designs. In my experience, simulators are quite good these days, especially for SI and high speed design (at least up to the low to mid GHz which is the limit of my experience). If an SI simulation is inaccurate, and you're using a good simulator, there is something wrong with the parameters of the simulation. > I think you have to be careful giving advice on tolerances. I agree and I am ;-) I don't really want to argue, that's not the point. I just want the information presented to be substantiated and accurate, and if it isn't, to know that as well. No matter the source of the information. Regards, Austin ----------------------------------------------------------- To subscribe/unsubscribe: Send a message to icu-pcb-forum-request@xxxxxxxxxxxxx with a subject of subscribe or unsubscribe To view the archives of this list go to //www.freelists.org/archives/icu-pcb-forum/ Problems or Questions: Send an email to icu-pcb-forum-admins@xxxxxxxxxxxxx ----------------------------------------------------------- ----------------------------------------------------------- To subscribe/unsubscribe: Send a message to icu-pcb-forum-request@xxxxxxxxxxxxx with a subject of subscribe or unsubscribe To view the archives of this list go to //www.freelists.org/archives/icu-pcb-forum/ Problems or Questions: Send an email to icu-pcb-forum-admins@xxxxxxxxxxxxx ----------------------------------------------------------- ----------------------------------------------------------- To subscribe/unsubscribe: Send a message to icu-pcb-forum-request@xxxxxxxxxxxxx with a subject of subscribe or unsubscribe To view the archives of this list go to //www.freelists.org/archives/icu-pcb-forum/ Problems or Questions: Send an email to icu-pcb-forum-admins@xxxxxxxxxxxxx -----------------------------------------------------------