RE: [10GBASE-T] channel model
Larry,
Thanks, for the plot and data. Using your data and Class D&E equations, we
have ploted the channel up to 1GHz{see attached(channel1G.doc)}.Please
compare this plot with your measurement data beyond 500 MHz. Do you have
measurement data from DC to 1 GHz?
If this is a reasonable representation of the channel from DC to 1GHz, then
it can be used for feasibility study simulations.
regards,pirooz
Plato Labs,Inc
Pirooz Hojabri
V.P Mixed Signal
408-379-4900
> Attached is a proposed 100 meter Cat 5e channel model for 10GBaseT
> study (CHANMOD.TXT). This model is defined by complex-valued (X +
> jY format) insertion gain in the at 500 kHz intervals from DC to 1
> GHz.
>
> The proposed model is derived from measurement (at 20 C) of a 100
> meter channel (with Cat 5e patch cords and 4 Cat 5e RJ45 connector
> interfaces). The baseline 100 meter channel model was temperature
> corrected to 50 C. (122 F.) using the procedure defined in ASTM
> D4566 Section 26.4. The above mentioned temperature correction
> method modifies the magnitude but not the phase of the insertion
> loss. Experimental measurements confirm that temperature effects on
> the phase are minimal so the approximation is sufficiently accurate.
>
> The most recent proposed model is an extrapolation of the ISO 11801
> Class D channel loss limit. The ISO 11801 Class D limit is designed
> to accommodate expected worst-case measurements below 100 MHz and
> consequently includes some additional margin to meet this
> requirement. Since this limit is only specified below 100 MHz,
> extrapolation of the limit through smooth curve fitting becomes
> less accurate as it is extended farther beyond its defined
> boundaries. The new proposed model is based upon measurements
> beyond 500 MHz and thus validated to at least 500 MHz (and somewhat
> beyond 500 MHz). As shown in the attached graphs (CHANMOD.DOC), the
> insertion loss for the proposed model differs from the ISO 11801
> Class D 2002 channel limit by less than 0.2 dB from DC to 50 MHz and
> less than 0.5 dB from 50 to 100 MHz. While it does not represent an
> absolute worst-case channel, it represents a reasonable model for a
> feasibility study simulating a maximum length channel under worst-
> case temperature conditions.
>
> -Larry
>
> -----Original Message-----
> From: William Jones
> Sent: Wednesday, January 22, 2003 11:19 PM
> To: stds-802-3-10gbt@ieee.org
> Subject: RE: [10GBASE-T] channel model
>
> Xiaopeng
>
> How are the calculations coming? Are you using the models Chris
> sent out last week?
>
> regards
> Bill
>
> -----Original Message-----
> From: William Jones
> Sent: Wednesday, January 15, 2003 4:08 PM
> To: stds-802-3-10gbt@ieee.org
> Subject: [10GBASE-T] channel model(part 2)
>
> Bill,
>
> Sure. Once the common channel model (I only need the frequency
> domain characteristics) is available, I can begin to work on it.
>
> Regards,
> Xiaopeng
> ----------
>
> Xiaopeng
>
> Would you be willing to sign up for technical feasibility based on an
> optimal DFE calculation?
>
> regards
> Bill
> -----------
>
> Bill,
>
> I has no problem to use TIA or ISO based channel and noise model
> once it is standardized. My point is that even using the frequency-
> domain model we can still give a quite good estimation of the
> practically achievable distance at a throughtput of 10Gbps over CAT-
> 5E or CAT-6 cables.
>
> Regards,
>
> Xiaopeng
> -------------
>
> Xiaopeng
>
> We believe, as George discussed in his part of the tutorial in Kauai,
> that with an adequate amount of crosstalk cancellation, the
> throughput is achievable. The question then becomes can this level
> of cancellation be practically achieved, hence, my interest in time
> domain models.
>
> Until we get the models from the channel modeling Ad Hoc, we could argue
> this point endlessly. Until then, I still believe we should not use
> DSL models, but, rather something from TIA 568b or ISO 11801.
>
> regards
>
> Bill
channel1G.doc