[opendtv] Re: Patent application on 8-VSB equalizer
- From: "Allen Le Roy Limberg" <allimberg@xxxxxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Fri, 7 Jul 2006 08:29:37 -0400
U.S. patent No. 6,081,301, titled "DTV CIRCUITRY FOR MEASURING MULTIPATH
DISTORTION BASED ON GHOSTING OF DATA SEGMENT SYNCHRONIZING SIGNALS", issued
to me 27 June 2000 and is assigned to Samsung Electronics.
Al Limberg
----- Original Message -----
From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx>
To: <opendtv@xxxxxxxxxxxxx>
Sent: Thursday, July 06, 2006 3:45 PM
Subject: [opendtv] Patent application on 8-VSB equalizer
> Last week, I mused:
>
> > I'm stuck on the idea of using the frequent segment sync to
> > assist in training. These occur every 77.3 or so usec, so
> > very frequently, and much more frequently than the GI. But
> > they are short, only 4 symbols.
> >
> > What if the segment training sequences were not all
> > identical, but instead were a known series of PN symbols. A
> > number of these could be combined by a receiver, perhaps, to
> > be used as a reasonably good training sequence. I don't know
> > how many it would take, but even if you need to accumulate
> > 511 of these symbols, that would still occur more than
> > twice as often at the existing training segment.
>
> The business about the changing segment sync symbols related
> (potentially) to Chinese upgrades of 8-VSB, but I was surprised to run
> into this patent application from 2003:
>
> http://cxp.paterra.com/uspregrant20030223519.html
>
> If I understand the obtuse patent-ese, they are proposing something
> along these lines. In addition to using the basic training segment,
> which occurs once in every "field" (313 segments), store all the segment
> sync patterns, the standard ones in A/53, which occur within a field, to
> assist in training. That gives you an extra 4 * 312, or 1248 symbols,
> per "field."
>
> (I was also proposing to use the randomized data symbols for amplitude
> equalization, although without benefit of phase info, as Doug
> suggested.)
>
> This is the crux of what the patent describes:
>
> [0018] "In order to achieve the above and/or other aspects, an aspect of
> the present invention comprises an equalizer for a VSB receiver for use
> in compensating distortions of a VSB broadcast signal which occur in
> transmission channels and which include field synchronization
> information including synchronization information as to each field of
> the VSB broadcast signal and segment synchronization information
> including synchronization information of each data segment within the
> field, the equalizer including an extraction part to extract the segment
> synchronization information included in the VSB broadcast signal, a
> storage part to store the extracted segment synchronization information,
> and an equalization part to equalize the VSB broadcast signal based on
> the segment synchronization information stored in the storage part."
>
> Basically, they are proposing that in dynamic echo situations, you'd use
> some number N of these stored segment sync symbols, where N is less than
> 1248, for training.
>
> Sounds familiar, eh?
>
> And again, this is no doubt not as advanced as A-VSB, but it doesn't
> change the transmission standard.
>
> Bert
>
>
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