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Ed, Reminder that participation is by individual. John From: Ed Sayre <esayre@xxxxxxxx> To my colleagues: I agree with Marvel that this matter demands further investigation from both a fundamentals point of view as well as the usage of interconnect tools which combine chip models with properly specified transmission line models. I believe that the past reliance on overly simplified cable models does not contribute to a full understanding of the signaling and error performance between the Tx and Rx chip I/O signals and the multi-wavelength long cable effects on those signals. We know from the significant past work that 10 sections per wavelength, in this case, the wavelength of the data Nyquist frequency (adjusted for interconnect relative dielectric constant) is necessary for the accurate determination of impedance, Insertion Loss and Return Loss using a lumped constant model (or it’s functional equivalent as expressed in the tool used). Consideration of the use of the COM tool is also recommended. Sincerely, Ed Dr. Edward P. Sayre, P. E, President and CTO North East Systems Associates, Inc. 9 Maple Lane Marshfield, MA 02050 [T]: 781-837-9088 [C]: 978-314-4940 From: Ragnar Jonsson <rjonsson@xxxxxxxxxxx> Hi Conrad, Can you please clarify how you were able to construct a cable that has 3dB higher echo when combined with the MDI than the echo from the cable itself? You mentioned verbally that your analysis assumed lumped elements. It would be great if you could share the characteristics of the lumped elements you assumed. Ragnar To unsubscribe from the STDS-802-3-ISAAC list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=STDS-802-3-ISAAC&A=1 To unsubscribe from the STDS-802-3-ISAAC list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=STDS-802-3-ISAAC&A=1 To unsubscribe from the STDS-802-3-ISAAC list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=STDS-802-3-ISAAC&A=1 |