Re: [10GBT] THP Fixed Set TF
Hi Pedro and fellow 10GBASE-T-ers,
please note that the receive filter has two purposes: (1) attenuate the
received signal at frequencies beyond 1/2T in order to suppress out-of-band
noise and minimize the effect of sampling-phase dependent aliasing, and (2)
support the T-spaced FFE in its task of shaping the received signal towards
the target symbol response (=TH precoding polynomial).
The spectral shape of the receive filter has **no** influence on the optimum
target response to be employed for TH precoding (if one ignores effects of
sampling-phase dependent aliasing). The optimum target response is
determined by the spectral signal-to-noise function SNR(f) of the received
signal. Ideally, the receive filter does not change the SNR(f) function.
Regards,
Gottfried
-----Original Message-----
From: IEEE P802.3an Reflector [mailto:stds-802-3-10gbt@ieee.org] On Behalf
Of Reviriego, Pedro (Pedro)
Sent: Donnerstag, 16. Dezember 2004 13:06
To: STDS-802-3-10GBT@listserv.ieee.org
Subject: Re: [10GBT] THP Fixed Set TF
Hi Albert,
So far several precoder proposals have been presented: one is your proposal
and another one is Ungerboeck's.
They assume different Rx Architectures, namely analog high pass boosting is
used in yours but not in Ungerboeck's. I think we need to assess the
performance loss of your precoders with a receiver that does no boosting and
the performance of Ungerboeck precoders with a receiver that includes
boosting.
This will show if setting the precoder coefficients limits the options for
Rx implementation in which case we should consider making the precoder
programmable.
Regards,
Pedro
-----Original Message-----
From: Albert Vareljian [mailto:albertv@ieee.org]
Sent: Wednesday, December 15, 2004 7:36 PM
To: Reviriego, Pedro (Pedro); STDS-802-3-10GBT@listserv.ieee.org
Subject: Re: [10GBT] THP Fixed Set TF
Pedro,
I did not use the Rx filter you mentioned below primarily due to aliasing
associated with its not very steep roll-off.
(Also pointed by Gottfried during Nov meeting.)
Regards,
Albert
Reviriego, Pedro (Pedro) wrote:
>Albert,
>
>Have you tried using the receive filter presented in
"ungerboeck_1_1104"
>with your precoder? If so what kind of performance do you get?
>
>Regards,
>
>Pedro
>
>-----Original Message-----
>From: IEEE P802.3an Reflector [mailto:stds-802-3-10gbt@IEEE.ORG] On
>Behalf Of Albert Vareljian
>Sent: Saturday, December 11, 2004 2:14 AM
>To: STDS-802-3-10GBT@listserv.ieee.org
>Subject: [10GBT] THP Fixed Set TF
>
>Dear All,
>
>Further to our Nov meeting discussions on fixed THP TF set, pls find
>for evaluation attached material outlining 3 TF sets.
>This is aimed in combination with THP bypass option -- i.e.
>four THP modes in total.
>
>All simulations were performed in time domain as per "vareljian_1_1104"
>and showed reasonably good performance with relatively short (24-Tap
>and shorter) FFE. Performance impact due to 7-bit coefficient
>quantization effects was found to be very small.
>
>Similar results were observed in simulations for a 2nd order Tx LPF @
>200 MHz as per "ungerboeck_1_1104" in place of the 3rd order Tx LPF @
>400 MHz.
>
>Hope, the posting will stimulate discussion on our, otherwise
>relatively quiet, reflector.
>
>Happy Holidays to everyone.
>
>Regards,
>
>Albert
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