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Re: [10GBT] Updated Tables



Hiroshi,

I am afraid we need to integrate in order to go from the frequency domain to
time domain. If we assume that the optimum matched filter for PAM8 is a
frequency scaled version of the optimum matched filter for PAM12, then the
amount of noise power in the time domain for PAM8 is 0.84dB higher than that
for PAM12, for a given AWGN PSD.

Therefore, PAM8 is able to tolerate 1.84dB (for new cabling) to 3.24dB (for
existing cabling) higher AWGN power at the slicer than PAM12.

Regards,
Sailesh Rao.
srao@phyten.com

>From: hiroshi takatori <hiroshi.takatori@KEYEYE.NET>
>Reply-To: "IEEE P802.3an" <STDS-802-3-10GBT@listserv.ieee.org>
>To: STDS-802-3-10GBT@listserv.ieee.org
>Subject: Re: [10GBT] Updated Tables
>Date: Tue, 20 Jul 2004 14:21:04 -0700
>
>Sailesh,
>Again, do not integrate to fs/2. That is WRONG because it depends on
>spectral of the "EXTERNAL NOISE". My results say that PAM8 can tolerate
>1dB higher power spectral density than PAM12 if "EXTERNAL NOISE" is flat
>in frequency. In order to calculate how robust the receiver is against
>"EXTERNAL NOISE", we need to know the spectral of it. If it contains
>higher energy in higher frequency (400MHz or up), PAM8 could be worse
>than PAM12.
>
>Again, I would like to get Model-5 that tests the immunity against
>"EXTERNAL NOISE". As Dan suggested yesterday, this could be the
>transient noise, so no EQL adaptation can be assumed to this type of
>noise. Once EQL is trained over A-Crosstalk and BGN, freeze EQL and test
>receiver noise tolerance against noise pulses, such as 3~20mV with
>60~70Hz apart. Again, the key is the frequency content of the noise
>pulses.
>
>Hiroshi Takatori
>Keyeye Communications, Inc.
>
>-----Original Message-----
>From: stds-802-3-10gbt@IEEE.ORG [mailto:stds-802-3-10gbt@IEEE.ORG] On
>Behalf Of sailesh rao
>Sent: Tuesday, July 20, 2004 5:45 AM
>To: STDS-802-3-10GBT@listserv.ieee.org
>Subject: Re: [10GBT] Updated Tables
>
>Hiroshi,
>
>You are effectively getting 2.3dB Total EMI penalty for PAM12 over PAM8
>on
>Model 1 and 3.6dB penalty for PAM12 over PAM8 on Model 2.
>
>This is close to the 2.6dB and 4.0dB, respectively, that I was
>calculating.
>In other words, it looks like we are converging...
>
>Please call me once you take a look at the code I sent and we can sort
>out
>the discrepancies.
>
>Regards,
>Sailesh Rao.
>srao@phyten.com
>
> >From: hiroshi takatori <hiroshi.takatori@KEYEYE.NET>
> >Reply-To: "IEEE P802.3an" <STDS-802-3-10GBT@listserv.ieee.org>
> >To: STDS-802-3-10GBT@listserv.ieee.org
> >Subject: Re: [10GBT] Updated Tables
> >Date: Mon, 19 Jul 2004 21:31:15 -0700
> >
> >Sailesh,
> >
> >Following is my results of your requested simulation. Note that the
> >purpose of the simulation is to repeat what you did so that we can talk
> >with the same language. Although I am not sure why PAM12 has penalty in
> >coding gain, I used 10.2dB coding gain for PAM8 and 9.8dB for PMA12. I
> >think these are what you used (Correct me if I am wrong). I also added
> >your numbers in red for "BGN for 0dB margin" for the comparison.
> >
> >
> >
> >Model 1, CAT7 100m
> >
> >PAM Level
> >
> >TX Digital Shape
> >
> >Assumed Coding Gain
> >
> >TX Power
> >
> >Assuming 2Vpp with simple LPF at Fs/2
> >
> >SNR
> >
> >Noise margin with BGN =
> >
> >- 150dBm/Hz
> >
> >BGN for 0dB margin
> >
> >Difference between PAM8 and PAM12
> >
> >PAM8
> >
> >0.75+0.25/z
> >
> >10.2dB
> >
> >3.3dBm
> >
> >25.4dB
> >
> >5.5dB
> >
> >-137.4dBm/Hz
> >
> >
> >
> >2dB worse
> >
> >NONE
> >
> >4.8
> >
> >25.6
> >
> >25.5
> >
> >5.7
> >
> >5.6
> >
> >-135.4
> >
> >-133.2(Sailesh)
> >
> >Normalized to 0dB
> >
> >PAM12
> >
> >NONE
> >
> >9.8
> >
> >4.6
> >
> >29.7
> >
> >29.6
> >
> >5.9
> >
> >5.8
> >
> >-136.1
> >
> >-134.2(Sailesh)
> >
> >0.7dB worse
> >
> >1.0dB worse
> >
> >Note: Red is from Sailesh results
> >
> >
> >
> >Model 2, CAT6 55m
> >
> >PAM Level
> >
> >TX Digital Shape
> >
> >Assumed Coding Gain
> >
> >TX Power
> >
> >Assuming 2Vpp with simple LPF at Fs/2
> >
> >SNR
> >
> >Noise margin with BGN =
> >
> >- 150dBm/Hz
> >
> >BGN for 0dB margin
> >
> >Difference between PAM8 and PAM12
> >
> >PAM8
> >
> >0.75+0.25/z
> >
> >10.2dB
> >
> >3.3dBm
> >
> >26.0dB
> >
> >6.1dB
> >
> >-124.9dBm/Hz
> >
> >
> >
> >2.2dB worse
> >
> >NONE
> >
> >4.8
> >
> >26.0
> >
> >26.0
> >
> >6.1
> >
> >6.1
> >
> >-122.7
> >
> >-120.7(Sailesh)
> >
> >Normalized to 0dB
> >
> >PAM12
> >
> >NONE
> >
> >9.8
> >
> >4.6
> >
> >29.1
> >
> >29.1
> >
> >5.3
> >
> >5.3
> >
> >-124.7
> >
> >-123.1(Sailesh)
> >
> >2dB worse
> >
> >2.4dB worse
> >
> >
> >
> >
> >
> >I, intentionally remove your final columns because it is not CORRECT.
>We
> >will discuss later on the subject.
> >
> >
> >
> >First of all, SNR and noise margin matched very closely, within 0.1dB
> >error, however, BGN for 0dB margin are off by about 2dB. We have to
>find
> >out why but "Difference between PMA8 and 12" are about same. Yours are
>a
> >little more than what I got but they are off only 0.3 to 0.4dB. At this
> >stage, I agree with you that tolerable BGN is bigger for PAM8. However,
> >note that PAM8 is the simple one without 0.75+0.25/z that you are
> >proposing. Your proposal with 0.75+0.25/z filter is the worst. Albert
>is
> >now getting similar results witn mine in time domain simulation and he
> >is going to release it soon. In anyway, at this stage, I am not
>claiming
> >simple PAM or with digital filter and let us assume simple PAM for both
> >cases to compare. The important issue is whether that is 1~2dB or
>2~4dB.
> >Let's discuss the issues of intentionally removed columns in which you
> >integrated to fs/2. You assumed that "ERXTERNAL NOISE" is fitting just
> >fs/2 for both systems. That is not correct. The "EXTERNAL NOISE" could
> >be at the higher frequency up to 1GHz or higher. Let's assume that we
> >test performance with single tone at 450MHz in which PAM12 can tolerate
> >a lot better than PAM8. What I am saying that in order to argue EMI
> >tolerance, we need to define the spectral content of the "EXTERNAL
> >NOISE".
> >
> >
> >
> >
> >
> >We have had four models for the system comparison back in March
>meeting.
> >Those models do not have any "EXTERNAL NOISE" other than A-crosstalk.
>We
> >assumed 10GBaseT is the self-crosstalk limited system. We believed that
> >is reasonable and we did intensive study with the good IC
> >considerations. As everyone agreed, PAM12 is the best noise margin
> >solution in those criteria. Now, Sailesh raised the issue "Immunity for
> >the EXTERNAL NOISE" at the last meeting.
> >
> >
> >
> >I am very positive to improve IEEE standard within a reasonable time
> >frame. If A-crosstalk is not the biggest impairment or EMI noise is as
> >big as that, let's redefine that and create 5th model on the top of the
> >existing four models. Dan made a good point in his mail today. Will you
> >be able to get a data of the frequency content of the EMI noise that
> >everyone is comfortable with? I myself want to take a quick look at
>that
> >even if you can not claim that is the general universal conditions.
>That
> >should tell how many dB PAM8 is better in EMI tolerance (or non issue)
> >and people can judge both A-crosstalk immunity and EMI tolerance at the
> >same time.
> >
> >
> >
> >Hiroshi Takatori
> >
> >Keyeye Communications, Inc.
> >
> >
> >
> >
> >
> >
> >
> >-----Original Message-----
> >From: stds-802-3-10gbt@IEEE.ORG [mailto:stds-802-3-10gbt@IEEE.ORG] On
> >Behalf Of sailesh rao
> >Sent: Monday, July 19, 2004 11:16 AM
> >To: STDS-802-3-10GBT@listserv.ieee.org
> >Subject: [10GBT] Updated Tables
> >
> >
> >
> >10GBT'ers:
> >
> >
> >
> >In the attached, I've updated the 3 tables in our July presentation
> >based on
> >
> >the following:
> >
> >
> >
> >1. Change PAM12 symbol rate to 825Ms/s from 820Ms/s.
> >
> >2. Delete PAM10 entry.
> >
> >3. As Luc pointed out, add a 1.2dB emissions penalty for PAM12 due to
> >its
> >
> >higher transmit PSD.
> >
> >4. As Jose pointed out, subtract 0.4dB from the PAM12 emissions penalty
> >due
> >
> >to the THP peak voltage adjustment.
> >
> >
> >
> >Next, I integrated the WGN for 1E-12 BER over the Nyquist frequency
> >range to
> >
> >get a "wideband noise tolerance" measure for the two proposals.
>Finally,
> >I
> >
> >summed the noise immunity penalty and the emissions penalty for the
> >PAM12
> >
> >proposal to form a "Total EMI Penalty" metric over the PAM8 approach.
> >
> >
> >
> >In Models 1 and 3, the penalty works out to be 2.6dB and 2.2dB
> >respectively
> >
> >for PAM12 over PAM8. However, in Model 2, which represents the existing
> >
> >cabling infrastructure, the penalty for PAM12 over PAM8 works out to a
> >
> >whopping 4.0dB!!
> >
> >
> >
> >Regards,
> >
> >Sailesh Rao.
> >
> >srao@phyten.com
> >
> >
> >
> >_________________________________________________________________
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>
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