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Re: [802.3EEESG] 10BASE-T question



Mike-

We would have to make sure that any such "chirp" avoided the various spaces 
reserved for:
         - Conventional 10BASE-T linkbeat
         - 10/100... Auto-neg FLP
         - The probe pulse for PoE
I claim we already have "a 0M mode which exchanges a modified link pulse"
whose...
"idea is to send a very low energy signal that would not be confused with 
link pulse"
and can be used to start up a link, That is the PoE probe pulse.

 From the discussion in EEE that I have heard from the DSP types I am not 
confident that we can do a very low power "chirp" that will keep the 
parameters up-to-date without a massive redesign.

But then I am no expert in this area.

Geoff


At 03:54 PM 3/28/2007 , mike mcconnell wrote:
>I believe the conversation about changing voltages was stimulated when
>10BASE-T was mentioned as candidate for the minimum operating speed.
>Legacy 10BASE-T voltages are indeed a problem for current silicon
>processes. I think the real question is not the level of difficulty to
>modify the standard but rather what is the motivation to do that and are
>there alternatives.
>
>The advantage of 10BASE-T was that during idle periods it only sends
>link pulses. One suggestion might be to exclude 10BASE-T due to voltages
>and adopt a 0M mode which exchanges a modified link pulse. Indeed I
>would suggest a "chirp pulse." The idea is to send a very low energy
>signal that would not be confused with link pulse but would permit the
>collection of enough information about the channel so that the startup
>time for 100M or even potentially a 1G PHY could be reduced. Of course
>timing and phase information is necessary too but maybe that acquisition
>time could be reduced too with a cleverly design chirp. I'm thinking
>radar link pulses - low energy, broad spectrum, spread over time.
>
>I don't know if this is technically feasible or what kind of power it
>would take to implement it but it seems to be worth a look and
>completely side steps the questions about modifying any legacy modes
>beyond the creation of alternative entry points in the startup state
>machines as already discussed.
>
>
>Mike
>
>
>
>-----Original Message-----
>From: Mike Bennett [mailto:mjbennett@LBL.GOV]
>Sent: Wednesday, March 28, 2007 1:46 PM
>To: STDS-802-3-EEE@listserv.ieee.org
>Subject: [802.3EEESG] 10BASE-T question
>
>Folks,
>
>For those of you who were able to attend the March meeting, you may
>recall we had a discussion on 10BASE-T (in the context of having a low
>energy state mode) and what we might change to specify this, which
>included possibly changing the output voltage.  Concern was raised that
>the work required to specify a new output voltage for 10BASE-T would far
>
>outweigh the benefit.  Additionally, there was a question regarding the
>use of 100BASE-TX instead of doing anything with 10BASE-T.  Would
>someone please explain just how much work it would be to change 10BASE-T
>
>and what the benefit would be compared to using 10BASE-T with the
>originally specified voltage or 100BASE-TX for a low energy (aka
>"0BASE-T" or "sleep") state?
>
>Thanks,
>
>Mike