RE: [10GBASE-T] PAR and 5 critters
Dan,
My January 2003 presentation to IEEE 10GBASE-T SG
http://www.ieee802.org/3/10GBT/public/jan03/babanezhad_1_0103.pdf
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
http://www.ieee802.org/3/10GBT/public/mar03/babanezhad_1_0303.pdf
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.
Regards,
Joseph N. Babanezhad
Plato Labs.
-----Original Message-----
From: "Booth, Bradley" <bradley.booth@intel.com>
To: <stds-802-3-10gbt@ieee.org>
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)" <dan.dove@hp.com>
> To: "'Sterling Vaden'" <sterlingv@bellsouth.net>
> Cc: stds-802-3-10gbt@ieee.org
> 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
> PSD
> 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 [mailto:sterlingv@bellsouth.net]
> Sent: Tuesday, July 29, 2003 6:43 AM
> To: stds-802-3-10gbt@ieee.org
> Cc: stds-802-3-10gbt@ieee.org
> 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