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Re: [10GBT] Request for Cat6 Emissions Characteristics

Hi Jose, All;
I agree that EMI characteristics of UTP "as a general rule" increase with frequency but I don't think its as easy as applying a simple 20log10(f) curve to the PSD. Depending on cable geometries, ground plane and component balance, the performance of a cable plant will most likely not have such a smooth function.
Therefore, its not quite so easy to say that PAM12 is better than PAM8 based strictly upon Jose's assertion. If you look at the figure below, you will see that PAM12 is higher in the range from 100MHz to 180MHz and both are above 1000BASE-T's spectrum in that region.
The FCC/CISPR don't really care if you pass their specs at 600MHz if you are failing at 180MHz.
Rather than drive a conclusion from this data, one expects the rational approach would be to determine this is an issue that requires attention/resolution prior to making *any* selection. Maybe the problem is not which PAM to use, but which cable to use? (FTP/STP?)
I will be investigating whether my employer will support some research into this area. I have access to a 10m chamber and think it would be a worthwhile investigation.
Thanks to Sailesh Rao and Vivek Telang for providing the data for this graph.