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[BP] FW: proposed channel model change



Forwarded on behalf of Charles Moore...

-----Original Message-----

folks,

     Last week i proposed basing the channel spec on fitting to Amax, as
is done for the interference tolerance test channel.  Since then i have
looked at the fit for the 23 channels in the task force data base.  I
did the fits over the range F1 to F2 as shown in table 69B-1 and also
over a range which i think would be more appropriate:

                     1000BASE-KX        62.5MHz-750MHz (.05*Fs-.6*Fs)
                      10GBASE-KX4      156MHz-1.875GHz (.05*Fs-.6*Fs)
                      10GBASE-KR         50MHz-6.1875GHz (Fmin-.6*Fs)

I chose the values because i do not think that it is important to go all
the way up to Fs, where there is a null in the data spectrum, and for
8B10B encoded data, disparity correction starts to drop the spectrum
around Fs/20.  For scrambled data the data spectrum goes all the way to
DC but Fmin is a practical limit to the available channel data.

Included are the results of my fitting.

                             charles

Charles Moore wrote:

> guys,
>
>   Rich Mellitz and i have been discussing changing the channel model, 
> to use a fit to Amax, as we are now doing for the interference 
> tolerance test channel (see moore_03_1105.pdf), instead of a fit to a 
> straight line.
>
>   This would have several advantages:
>
>   1.  It would use a common method for both the test channel and the
>       working channel
>   2.  It would allow us to replace three graphical tests:
>       i.   That the linear fit is better than Amax
>       ii.  That the insertion loss is always better than Amax +
something
>       iii. That the ripple is better than something
>       with one numeric test, that mc < 1.0, and the graphical ripple
>       test.  We may need an additional limit on bc.
>    3. Since the fit to Amax will be substantially better than the fit
>       to a straight line, the ripple will be smaller and more
meaningful.
>       This will reduce the number of false fails.  We should be able
>       to shrink the ripple bounds (Rich:  will you figure out by how
>       much?) which may also  reduce false passes.
>    4. Since the fit will be especially improved at low frequency, we
>       will be able to reduce f1, especially for 10GBASE-KR, which
>       actually uses low frequencies more than either 1000BASE-KX or
>       10GBASE-KX4.
>
>    Does anyone see any problems with this proposal?
>
>                     charles
>


-- 
|--------------------------------------------------------------------|
|       Charles Moore
|       Avago Technologies
|       Image Solutions Division
|       charles.moore@avagotech.com
|       (970) 288-4561
|--------------------------------------------------------------------|


Results of applying 2 possible revised specifications to channels for 1000BASE-KX

channels                               F1=125MHz F2=1.25GHz            F1=62.5MHz =750MHz
                                     Mc      Bc   |IUD/spec|max    Mc      Bc   |IUD/spec|max

peters_01_0605_B12_thru.s4p         0.551  -0.41dB   0.057        0.529  -0.31dB    0.054
peters_01_0605_B1_thru.s4p          0.368  -0.29dB   0.052        0.348  -0.19dB    0.027
peters_01_0605_B20_thru.s4p         0.687  -0.46dB   0.069        0.668  -0.37dB    0.066
peters_01_0605_M1_thru.s4p          0.372  -0.18dB   0.020        0.368  -0.16dB    0.016
peters_01_0605_M20_thru.s4p         0.719  -0.49dB   0.118        0.692  -0.37dB    0.064
peters_01_0605_T12_thru.s4p         0.585  -0.54dB   0.153        0.563  -0.42dB    0.123
peters_01_0605_T1_thru.s4p          0.358  -0.21dB   0.076        0.367  -0.24dB    0.062
peters_01_0605_T20_thru.s4p         0.723  -0.61dB   0.136        0.694  -0.47dB    0.099
1m_INBOUND_TRU/sj2k2g2h2_SPARS.s4p  0.946  -0.89dB   0.149        0.874  -0.56dB    0.230
1m_INBOUND_TRU/sj3k3g3h3_SPARS.s4p  0.951  -0.91dB   0.184        0.876  -0.56dB    0.226
1m_INBOUND_TRU/sj4k4g4h4_SPARS.s4p  0.953  -0.92dB   0.212        0.874  -0.55dB    0.223
1m_INBOUND_TRU/sj5k5g5h5_SPARS.s4p  0.956  -0.94dB   0.238        0.876  -0.56dB    0.223
1m_OUTBOUND_TRU/sj2k2g2h2_SPARS.s4p 0.933  -0.86dB   0.151        0.871  -0.57dB    0.236
1m_OUTBOUND_TRU/sj3k3g3h3_SPARS.s4p 0.941  -0.92dB   0.154        0.874  -0.61dB    0.233
1m_OUTBOUND_TRU/sj4k4g4h4_SPARS.s4p 0.937  -0.90dB   0.147        0.875  -0.61dB    0.235
1m_OUTBOUND_TRU/sj5k5g5h5_SPARS.s4p 0.937  -0.91dB   0.153        0.876  -0.62dB    0.236
Case1 FM 13SI 20 T D13SI L10.s4p    0.943  -0.52dB   0.151        0.923  -0.42dB    0.167
Case2 FM 13SI 20 T D13 L10.s4p      0.975  -0.55dB   0.179        0.949  -0.43dB    0.187
Case3 FM 13SI 20 T D6 L10.s4p       1.092  -0.67dB   0.227        1.042  -0.43dB    0.265
Case4 FM 13SI 20 T D13 L6.s4p       0.794  -0.43dB   0.191        0.792  -0.40dB    0.179
Case5 DS 13 10 T D13 L6.s4p         0.536  -0.27dB   0.114        0.541  -0.29dB    0.102
Case6 DS 13 10 T D13 L6.s4p         0.541  -0.34dB   0.140        0.541  -0.33dB    0.132
Case7 FM 13SI 1 T D13SI L6.s4p      0.327  -0.18dB   0.041        0.327  -0.18dB    0.036

Where an RMS fit has been made to the channel loss by the curve:  Mc*Amax+Bc over the 
range F1-F2
the specs will be:

               Mc <  1.0
               Bc    no spec yet
    |IUD/spce|max <  1.0

Only Case #3/Case3 FM 13SI 20 T D6 L10.s4p fails spec, gain is too low in both set of specs.

Results of applying 2 possible revised specifications to channels for 10GBASE-KX4

channels                        F1=312.5MHz F2=3.125GHz       F1=156.25MHz F2=1.875GHz
                                      Mc      Bc   |IUD/spec|max    Mc      Bc   |IUD/spec|max 
peters_01_0605_B12_thru.s4p          0.613  -0.91dB   0.510        0.547  -0.39dB    0.064
peters_01_0605_B1_thru.s4p           0.418  -0.62dB   0.249        0.379  -0.35dB    0.069
peters_01_0605_B20_thru.s4p          0.752  -0.97dB   0.320        0.685  -0.46dB    0.060
peters_01_0605_M1_thru.s4p           0.494  -0.92dB   0.547        0.401  -0.34dB    0.254
peters_01_0605_M20_thru.s4p          0.815  -1.19dB   0.551        0.732  -0.57dB    0.196
peters_01_0605_T12_thru.s4p          0.794  -2.13dB   1.169        0.605  -0.65dB    0.302
peters_01_0605_T1_thru.s4p           0.593  -1.77dB   0.646        0.430  -0.61dB    0.186
peters_01_0605_T20_thru.s4p          0.937  -2.23dB   0.946        0.745  -0.73dB    0.236
1m_INBOUND_TRU/sj2k2g2h2_SPARS.s4p   0.959  -0.83dB   0.476        1.014  -1.26dB    0.345
1m_INBOUND_TRU/sj3k3g3h3_SPARS.s4p   0.964  -0.85dB   0.596        1.013  -1.26dB    0.332
1m_INBOUND_TRU/sj4k4g4h4_SPARS.s4p   0.964  -0.86dB   0.485        1.016  -1.27dB    0.334
1m_INBOUND_TRU/sj5k5g5h5_SPARS.s4p   0.961  -0.86dB   0.368        1.002  -1.19dB    0.259
1m_OUTBOUND_TRU/sj2k2g2h2_SPARS.s4p  0.962  -0.98dB   0.277        0.974  -1.09dB    0.243
1m_OUTBOUND_TRU/sj3k3g3h3_SPARS.s4p  0.965  -1.00dB   0.358        0.974  -1.11dB    0.206
1m_OUTBOUND_TRU/sj4k4g4h4_SPARS.s4p  0.956  -0.96dB   0.270        0.971  -1.09dB    0.221
1m_OUTBOUND_TRU/sj5k5g5h5_SPARS.s4p  0.979  -1.16dB   0.213        0.964  -1.05dB    0.163
Case1 FM 13SI 20 T D13SI L10.s4p     0.992  -0.94dB   0.359        0.934  -0.48dB    0.158
Case2 FM 13SI 20 T D13 L10.s4p       0.999  -0.80dB   0.441        0.956  -0.45dB    0.208
Case3 FM 13SI 20 T D6 L10.s4p        1.117  -0.96dB   0.427        1.062  -0.51dB    0.275
Case4 FM 13SI 20 T D13 L6.s4p        0.814  -0.65dB   0.297        0.768  -0.29dB    0.209
Case5 DS 13 10 T D13 L6.s4p          0.563  -0.52dB   0.385        0.517  -0.17dB    0.119
Case6 DS 13 10 T D13 L6.s4p          0.653  -1.25dB   0.649        0.521  -0.23dB    0.149
Case7 FM 13SI 1 T D13SI L6.s4p       0.541  -1.82dB   0.676        0.337  -0.24dB    0.067

Where an RMS fit has been made to the channel loss by the curve:  Mc*Amax+Bc over the 
range F1-F2
the specs will be:

               Mc <  1.0
               Bc    no spec yet
    |IUD/spce|max <  1.0

The following channels fail due to low gain:
 
    1m_INBOUND_TRU/sj2k2g2h2_SPARS.s4p   F1=156.25MHz F2=1.875GHz
    1m_INBOUND_TRU/sj3k3g3h3_SPARS.s4p   F1=156.25MHz F2=1.875GHz
    1m_INBOUND_TRU/sj4k4g4h4_SPARS.s4p   F1=156.25MHz F2=1.875GHz
    1m_INBOUND_TRU/sj5k5g5h5_SPARS.s4p   F1=156.25MHz F2=1.875GHz
    Case #3/Case3 FM 13SI 20 T D6 L10.s4p  both ranges

One channel fails one spec for IUD:

    peters_01_0605_T12_thru.s4p          F1=312MHz    F2=3.125GHz 



Results of applying 2 possible revised specifications to channels for 10GBASE-KR

channels                             F1=1GHz F2=6GHz               F1=50MHz F2=6.1875GHz
                                      Mc      Bc   |IUD/spec|max    Mc      Bc  |IUD/spec|max

peters_01_0605_B12_thru.s4p          0.590  -0.51dB   0.655        0.589  -0.53dB  0.666
peters_01_0605_B1_thru.s4p           0.424  -0.50dB   1.081        0.428  -0.56dB  1.076
peters_01_0605_B20_thru.s4p          0.720  -0.44dB   0.656        0.721  -0.51dB  0.670
peters_01_0605_M1_thru.s4p           0.509  -1.02dB   1.018        0.509  -0.97dB  1.003
peters_01_0605_M20_thru.s4p          0.835  -1.49dB   0.544        0.815  -1.11dB  0.608
peters_01_0605_T12_thru.s4p          1.331  -9.00dB   2.015        1.236  -6.44dB  4.918
peters_01_0605_T1_thru.s4p           1.107  -8.21dB   2.613        1.064  -6.41dB  4.956
peters_01_0605_T20_thru.s4p          1.443  -8.70dB   1.887        1.347  -6.20dB  4.679
1m_INBOUND_TRU/sj2k2g2h2_SPARS.s4p   0.931  -0.44dB   0.449        0.943  -0.69dB  0.501
1m_INBOUND_TRU/sj3k3g3h3_SPARS.s4p   0.944  -0.56dB   0.567        0.951  -0.73dB  0.610
1m_INBOUND_TRU/sj4k4g4h4_SPARS.s4p   0.957  -0.67dB   0.429        0.964  -0.82dB  0.466
1m_INBOUND_TRU/sj5k5g5h5_SPARS.s4p   0.925  -0.36dB   0.333        0.935  -0.60dB  0.393
1m_OUTBOUND_TRU/sj2k2g2h2_SPARS.s4p  0.865   0.21dB   0.394        0.887  -0.27dB  0.420
1m_OUTBOUND_TRU/sj3k3g3h3_SPARS.s4p  0.873   0.15dB   0.394        0.897  -0.34dB  0.458
1m_OUTBOUND_TRU/sj4k4g4h4_SPARS.s4p  0.878   0.03dB   0.333        0.899  -0.41dB  0.357
1m_OUTBOUND_TRU/sj5k5g5h5_SPARS.s4p  0.866   0.20dB   0.408        0.890  -0.30dB  0.432
Case1 FM 13SI 20 T D13SI L10.s4p     0.927   0.02dB   0.680        0.941  -0.28dB  0.683
Case2 FM 13SI 20 T D13 L10.s4p       0.977  -0.33dB   0.504        0.986  -0.50dB  0.503
Case3 FM 13SI 20 T D6 L10.s4p        1.090  -0.35dB   0.766        1.101  -0.56dB  0.770
Case4 FM 13SI 20 T D13 L6.s4p        0.791  -0.14dB   0.632        0.804  -0.37dB  0.626
Case5 DS 13 10 T D13 L6.s4p          0.590  -0.62dB   0.854       0.594  -0.63dB  0.836
Case6 DS 13 10 T D13 L6.s4p          0.884  -3.94dB   1.140        0.851  -2.96dB  2.203
Case7 FM 13SI 1 T D13SI L6.s4p       0.593  -2.82dB   0.812        0.547  -1.86dB  1.317

Where an RMS fit has been made to the channel loss by the curve:  Mc*Amax+Bc over the 
range F1-F2
the specs will be:

               Mc <  1.0
               Bc    no spec yet
    |IUD/spce|max <  1.0

Both sets of spec show the following channels hav too much loss:

peters_01_0605_T12_thru.s4p
peters_01_0605_T1_thru.s4p
peters_01_0605_T20_thru.s4p
Case #3/Case3 FM 13SI 20 T D6 L10.s4p

IUD specs fail both sets of specs for:

peters_01_0605_B1_thru.s4p
peters_01_0605_M1_thru.s4p
peters_01_0605_T12_thru.s4p
peters_01_0605_T1_thru.s4p
peters_01_0605_T20_thru.s4p
Case #6/Case6 DS 13 10 T D13 L6.s4p

and the wider frequency range spec shows one more channel failing IUD

Case #7/Case7 FM 13SI 1 T D13SI L6.s4p