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Re: [10GBT] More on the PAM12 emissions


I already stated that I did not consider the specific requirements of the
FCC and CISPR emissions measurements since I didn't have the data on their

In general, if you can convince communications experts that sending a fixed
pattern repeatedly is a great idea, then it logically follows that we will
all be throwing away our scramblers, thus setting back the industry at least
fifty years. Besides, I know that this is not a big issue that a simple
scrambler on the fixed pattern cannot easily solve.

Instead of continuing this debate, I would really like to focus on the
bit-to-symbol mapping of the PAM12 system that causes a 0.5dB rise and fall
in its transmit PSD as a function of the THP filter coefficients. There are
technical consequences to this phenomenon that I think needs to be explored.

Sailesh Rao.

>From: Scott Powell <>
>Subject: Re: [10GBT] More on the PAM12 emissions
>Date: Mon, 26 Jul 2004 17:29:48 -0700
>I thought we were going to keep these discussions technical ...
> >>sailesh rao writes: 7/25/2004
> >
> > OK, I agree with you to keep these e-mails technical in order to advance
>the discussion.
> >
>Rather than change the subject, I, for one, would also like to see your
>analysis corrected for the errors that were pointed out.  Let's settle this
>so called ripple "issue" rather than leave it hanging.  If it is a problem
>for some reason not yet shown, there are solutions that can be explored.  I
>don't see where these frame sync's are a problem when the analysis is done
>correctly with a 120kHz resolution bandwidth.
>   - Scott
>Dr. Scott Powell
>Senior Manager, Ethernet PHYs
>Broadcom Corp.
>-----Original Message-----
>From: [] On
>Of sailesh rao
>Sent: Monday, July 26, 2004 4:58 PM
>Subject: Re: [10GBT] More on the PAM12 emissions
>I have a better idea: please withdraw the PAM12 proposal and let us all
>focus on the PAM8 proposal that doesn't have any of these issues.
>Sailesh Rao.
> >From: Glenn Golden <>
> >Reply-To:
> >To:
> >Subject: Re: [10GBT] More on the PAM12 emissions
> >Date: Mon, 26 Jul 2004 17:48:26 -0600
> >
> >sailesh rao writes:
> > >
> > > Same response as to Jose.
> > >
> >
> >I'm sorry Sailesh, I feel that the onus is on you now now.  Read my
> >email more carefully and I believe you'll see why your response to Jose
> >is incorrect.
> >
> >
> > > Please go ahead and fix it yourself. Your observations don't negate
> > > the point I've been trying to make for the past three days - if we
> > > keep
> >sending
> > > the same patterns repeatedly as proposed in powell_1_0704.pdf, spiky
> >stuff
> > > happens in the PSD.
> >
> >Yes, that's right, spikey stuff happens in the PSD. And the peaks of
> >the spikey stuff are 23 dB below the data, where no one doing EMI
> >testing can see them.
> >
> >Please fix the errors we've told you about, set the resolution
> >bandwidth in accordance to the EMI testing standard, and then show us
> >the ripple.
> >
> >- Glenn
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