Re: [10GBT] Updated Tables
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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