Thread Links Date Links
Thread Prev Thread Next Thread Index Date Prev Date Next Date Index

Re: [10GBT] Request for Cat6 Emissions Characteristics

sailesh rao writes:
> Frankly, I think you are being too cavalier about the peaky PSDs in the
> PAM12 proposal in the 200MHz-300MHz frequency range. Given the peaky PSDs
> at the start of each frame in your proposal (i.e., once every 52,833 bits),
> I'm afraid that at 10Gb/s these peaks occur often enough for the FCC to
> become very interested in them.

On slide 26 of tellado_1_0704.pdf (plot attached), which shows the proposed
frame alignment symbols, there is a light blue line which may be a little
difficult to make out (it's around -82 dB) but it shows the average data
symbol power.  The peaks you are referring to are around 20 dB below this.
I don't think the FCC would be interested in them.

If you're concerned about the rep rate, it's below 1 MHz (1e10/52833 ~= 1.9e5).

> If you now think that you will "scramble the frame start bits", may I ask
> why you didin't think of this scrambling last month? It is blatant omissions
> like these that can sink a standard.

Since the FAS peaks are more than 20 dB below the average signal power,
it probably isn't necessary to scramble them.

But I agree that whether the standard sinks or swims will relate to how
carefully we all do our work.

Glenn Golden
Principal Engineer
Teranetics, Inc.