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Re: [BP] channel loss difference

Great for silicon bad for boards!  I’m not willing to go to 20dB loss at 5.16GHz. A 23dB loss channel is going to be a stretch to get to 1m. 20dB sends me into a tail spin on the HVM systems.

… Rich

 

From: Steve Anderson [mailto:steve.anderson@XILINX.COM]
Sent: Thursday, January 26, 2006 2:10 PM
To: STDS-802-3-BLADE@LISTSERV.IEEE.ORG
Subject: Re: [BP] channel loss difference

 

 

 

            I second Shannon’s idea !

 

            Steve A.

 

 

From: Sawyer, Shannon [mailto:shannon.sawyer@intel.com]
Sent: Wednesday, January 25, 2006 7:15 PM
To: STDS-802-3-BLADE@listserv.ieee.org
Subject: Re: [BP] channel loss difference

 

Charles,

 

The difference (no pun intended) shows up in the differential vs single ended S-Parameters. I plotted SDD21 and S21 for modITTC23withCoupler.s4p, and there is 1.428dB difference at 5.160GHz. See attached.

 

Sorry I had to be at another meeting at noon, but I like the idea of going to a 20dB channel. In my opinion that’s the lever big enough to get a real system working. Unfortunately several (8 Molex, 4 Tyco, 3 Intel) channels violate that SDD21 up to 5GHz. See attached.

 

-Shannon

 

From: Charles Moore [mailto:charles.moore@avagotech.com]
Sent: Wednesday, January 25, 2006 5:24 PM
To: STDS-802-3-BLADE@listserv.ieee.org
Subject: [BP] channel loss difference

 

guys,

     There was some discussion during the teleconference about the relative
channel losses of various channels provided by me and simulated by joe
and matt.  I looked at several of them ad fit them to Amax per 69A and found:

    channel          loss at Nyquist  fit at Nyquist

AgilentITTC_1016         25.1         25.6dB        
"Agilent TC Measured"    26.4         26.4dB
modITTC23withCoupler.s4p 22.3dB       22.6dB
ITTC_23                  23.1dB       23.0dB

The simulations joe did which i was citing were on "Agilent TC Measured"
and ITTC_23, which differ in fit (smoothed) loss at Nyquist by 3.4dB. 

Note some channels differ from their nominal loss at Nyquist because i picked
channels with an Mtc which would give the correct loss but they have Btc
values which shifts the whole line a bit.  The ISI should still be the same as
expected with the nominal loss.

                                         charles

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|       Charles Moore 
|       Avago Technologies
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