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RE: [10GBASE-T] PAR and 5 critters


My January 2003 presentation to IEEE 10GBASE-T SG

assumes that all the line-signals considered (MLT3, PAM5-to-PAM33) 
have the same minimum pulsewidth of 800ps. That is why all of them 
have notches at 1.25GHz and 2.5GHz.

If you were to review my March 2003 presentation

here various line signals considered have different minimum 
pulsewidth in order for all of them to achieve 2.5 Gb/s data rate. 
The minimum pulsewidth for both MLT3 and PAM5 is 800ps. For MLT3 
and PAM5 their notches are still at 1.25GHz and 2.5GHz while for 
PAM9-to-33 they are at different frequencies. When comparing
MLT3 and PAM5's frequency spectrums it becomes clear that MLT3
shows considerable peaking around pass-band and notch frequencies.

There was no additional filtering, such as TX pulse shaping, included 
in deriving these frequency spectrums.


Joseph N. Babanezhad
Plato Labs.

-----Original Message-----
From: "Booth, Bradley" <>
To: <>
Date: Tue, 29 Jul 2003 11:54:22 -0700
Subject: RE: [10GBASE-T] PAR and 5 critters

> Forwarded for Dan Dove without attachment... Dan, please give the URL
> for the presentation as our website doesn't accept attachments.
> Thanks,
> Brad
> -----Original Message-----
> From: "DOVE,DANIEL J (HP-Roseville,ex1)" <>
> To: "'Sterling Vaden'" <>
> Cc:
> Subject: RE: [10GBASE-T] PAR and 5 critters 
> Date: Tue, 29 Jul 2003 11:17:53 -0700
> Hi Sterling,
> I have been an outsider to the study group work, so please excuse me if
> I am
> bringing up an issue that has already been dealt with, but as I
> understand
> it the current proposals for coding rely upon a spectrum of > 400MHz.
> It
> is
> possible that companies manufacturing cable system infrastructure
> equipment
> like patch panels, wall jacks, and even the cable itself have qualified
> their products for FCC and EN compliance based upon measurements done
> with
> equipment that only uses <100MHz spectrum like 100BASE-T or 1000BASE-T.
> That
> said, the balance requirements for such equipment may never have been
> stressed at frequencies above 100MHz for longitudinal balance, and so
> the
> installed base of cable systems may have issues with EMI compliance if
> someone were to begin running equipment with a PSD that produces large
> energy above 100MHz on those systems.
> Has any work been done to characterize this issue? I found a
> presentation by
> Joseph Babanezhad but don't think he applied a full analysis in the
> sense
> that it appears he did not allow for natural filtering of the output
> by
> device capacitance and magnetics on the MLT-3 PSD. Check out the
> attachment.
> Clearly MLT-3 and PAM-5 (100 and 1000 speeds) can operate without
> energy
> above 125MHz and most implementations limit energy above that
> frequency.
> I
> believe the 10G designs will require substantially higher energy than
> those
> technologies in the region 100MHz < f > 400MHz.
> Again, please excuse me if this has been addressed. Just point me to
> the
> data.
> Regards,
> Dan Dove
> 802.3 member
> -----Original Message-----
> From: Sterling Vaden []
> Sent: Tuesday, July 29, 2003 6:43 AM
> To:
> Cc:
> Subject: Re: [10GBASE-T] PAR and 5 critters 
> OK, I'll bite,
> I think it has been "shown" that for the purposes of the PAR and 5
> critters,
> 10G will work over the following:
> ISO Class F without ammendment.
> ISO Class E (or Cat6) screened or SSTP (with extended limits to 500 or
> 625
> MHz) extended limits TBD by ISO or TIA
> (note that Class D and Class E screened (overall shield) and SSTP
> (individually shielded pairs) are commonly installed in Europe, so this
> is
> not a "fantasy cable". Screened cabling is also specified by TIA)
> ISO Class E (or Cat6) UTP to 50 meters (with extended limits to 500 or
> 625
> MHz) extended limits TBD by ISO or TIA
> ISO Class D (Cat5e) Screened? Perhaps up to 80 meters, but this is grey
> area.
> ISO Class D (Cat5e) UTP? Perhaps up to 40 meters,
> For ISO Class D (Cat5e) there is a basic problem in that the cabling
> standards groups are unwilling to standardize (create limits) beyond
> 100
> MHz, or expend further work on the cabling besides measure it. This
> poses a
> very real difficulty in specifying a protocol that relies upon
> performance
> beyond that specified by the cabling standard. (ask Geoff  Thompson)
> Cabling
> manufacturers may decide to forego warranting their cabling systems for
> such
> a protocol.
> Also, for the time being, lets pretend that alien crosstalk field
> testing
> does not exist (it doesn't). Also lets pretend that alien crosstalk
> mitigation techniques (all, retrofit and new cable designs) for the
> moment
> do not exist. These are considerations for the task group.
> Some may also contend that the protocol will run on longer lengths of
> Cat5e
> and Cat6 UTP. If so, that is fine, but it is a matter of dispute, and
> therefore cannot be considered. This is also a consideration for the
> task
> group.
> At the Plenary, on the last day we heard the PHY vendors backpedaling
> on
> their previously stated opiniion that it would run on Class F. If that
> is
> the case, and they insist on this position, then the project is dead.
> Therefore I propose that there must be an agreement that the protocol
> will
> run on at least Class F cabling to 100 meters, or we need to start
> over.
> If
> we can agree on that, then we can move forward to consider the other
> cabling
> classes.
> Sterling Vaden