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RE: [10GBASE-T] clarification on voltage level

This is true. Moreover, the emission levels can be meaningfully measured only at the "system" level and not at the transceiver level. For example, a prototype of a switch or a NIC is used to make sure that the final shippable product meets the FCC requirements.

So it is extremely difficult (if not impossible) to answer the question : "does this line code meet FCC requirements". But what you can do, is compare the transmitted spectra of two line codes, and *assuming all other things being equal*, make the claim that one line code will have XdB more margin to the FCC requirement, if its transmitted spectrum is XdB lower than that of the other line code.

Note that the shape of the transmitted spectrum, and the peak transmitted power are as important (and IMHO more important) than the average transmitted power.



Vivek Telang
Cicada Semiconductor
811 Barton Springs Road, Suite 550
Austin, TX 78704.
(512) 327-3500 x114

> -----Original Message-----
> From:
> []On Behalf Of John
> DeAndrea
> Sent: Monday, January 13, 2003 8:56 PM
> To:;
> Subject: RE: [10GBASE-T] clarification on voltage level
> We will need more information on cable balance and shielding to answer
> this question. It is not a simple calculation of pp voltage to FCC
> emission levels, but related to differential to common mode conversion
> in the cable and integrity of the grounding of the cable to the MDI.
> John DeAndrea
> iTerra Communications
> -----Original Message-----
> From: [] 
> Sent: Monday, January 13, 2003 6:16 PM
> To:
> Subject: Re: [10GBASE-T] clarification on voltage level
> Can anybody who is familiar with FCC requirement give a careful
> calculation on the highest possible voltage and launch power that meet
> the FCC regulation.
> Xiaopeng Chen
> Marvell Semiconductor Inc.