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Mehmet – I take a different view of such analyses. One has to very carefully consider all the assumptions made in any such analysis to determine feasibility. Assumptions one-way or the other change the result. One thing I think we can
all agree on is that the devil here is in the details. I’ve seen more than a few of these analyses, and I know you have too. When everyone is thinking similarly about the general form of the solution (e.g., echo cancelled PAM modulation at on with a transformer
interface to specified twisted pair cabling), it is easy to get consensus on such assumptions. When duplex or transmission modes are perhaps more varied, or media and interfaces are less standardized, consensus on assumptions which make this analysis useful
is far harder to achieve. Hence, the discussion is better had when more of these specifics are nailed down – a subject for task force. A result of “it is not feasible” is, in my experience, more sensitive to the assumptions made than a result of “it is feasible”. You only need one set of assumptions that works to invalidate it. A result of ‘not feasible’ usually shows
you what you have to change to make something feasible. There are several assumptions, that while reasonable at first glance, I would take issue with, and, if changed would provide the necessary improvement – rendering a conclusive “it is not feasible” inaccurate.
Some of these were mentioned either by German or in discussion or in the below. Examples include reach, transmit power, transmit PSD, coding, implementation loss, and whether the coax modeled is the best economically that is expected (and whether coax is
even needed on all channels is an interesting question in itself, given that the main support of coax is that it is used in the incumbents, and now you’re saying at > 10G there are no incumbents). I think these are key elements to discuss and is the kind of discussion you have with particular proposed solutions – something for Task Force. This discussion is indicative of the kind of discussion we could NOT have if the PAR scope did not allow > 10 Gbps.
George Zimmerman, Ph.D. President & Principal CME Consulting, Inc. Experts in Advanced PHYsical Communications 310-920-3860 From: Mehmet Tazebay <00002b0d1a6e9d74-dmarc-request@xxxxxxxxxxxxxxxxx>
Hi Ragnar, My takeaway is quite different. German and Ahmad’s presentation showed what is theoretically feasible without any in-car noise contribution, aging, temperature effects and etc. Also, it clearly states that the in-car noise measurements
and an analysis is required for automotive channels in order to understand and conclude the technical feasibility. If you believe that the automotive noise for the new and aged cables can be completely rejected -as assumed in German and Ahmad’s presentation-
then, please provide the data to the group. I believe this is required in order to conclude the technical feasibility for 25Gbps. Without that information, I do not agree that we can conclude 25bps is feasible for automotive applications. Thanks, Mehmet Ps. Regarding to increased TX power, I’d theoretically agree with you for the benefit but how much higher power can be attained for high speed transceivers at small geometry process technologies? Also, how will the increased power affect
the camera side in terms of power and heat?
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