[opendtv] Re: Samsung Prototype ATSC Receiver Test Report
- From: "Allen Le Roy Limberg" <allimberg@xxxxxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Wed, 12 Oct 2005 11:11:36 -0400
The inability of the receivers to reject short-delay echoes is probably
because they use synchronous equalizers in which tap spacing is equal to the
reciprocal of symbol rate. Eventually, the industry may gravitate towards
fractional equalizers in which tap spacing is equal to the reciprocal of
twice symbol rate.
U.S. patent No. 6,377,312 titled "ADAPTIVE FRACTIONALLY SPACED EQUALIZER FOR
RECEIVED RADIO TRANSMISSIONS WITH DIGITAL CONTENT, SUCH AS DTV SIGNALS" is
on point, describing how such equalizers can accommodate data slicing in the
IIR filtering. The patent issued 23 April 2002 to Dr. C. B. Patel and me.
Samsung is the assignee.
Al Limberg
----- Original Message -----
From: "Richard Hollandsworth" <holl_ands@xxxxxxxxx>
To: <opendtv@xxxxxxxxxxxxx>
Sent: Tuesday, October 11, 2005 6:13 PM
Subject: [opendtv] Samsung Prototype ATSC Receiver Test Report
> CRC posted test results for two Linx (now Micronas) ATSC Receiver
Prototypes (Apr02 and Mar03) and a Zenith/LG ATSC Receiver Prototype
(Sep03).
>
>
>
> CRC has not posted the fol. report on a Samsung ATSC Receiver Prototype:
> http://www.crc.ca/en/html/crc/home/research/broadcast/rtnt
> "Lab. Eval. of a Prototype Samsung ATSC Receiver" dtg 30Aug05.
> The Samsung prototype uses a commercially available ALPS Tuner Module and
> Samsung's "Gemini" ATSC Decoder chip (whatever that is...)
>
> The ALPS Tuner Module has a desired signal overload point of +1.5 dBm and
> a sensitivity of -84.7 dBm (that's a Noise Figure of about 6 dB).
> Perhaps it's the Alps Electric TEQH Tuner Module???
>
> Samsung performance met all ATSC A/74 Guidelines (unlike other tested
prototypes),
>
> with performance under most test conditions, exceeding the performance of
both
> the Zenith/LG Prototype and the two versions of Linx (now Micronas)
Prototypes.
>
> Under marginal SNR conditions, the Samsung could not handle low delay
echos
> (< 1 usec, i.e. less than 0.2 mile path differential),
> where the multipath components are within a few dB of each other.
> This can occur when there are nearby reflecting objects
> (e.g. your neighbor's house and/or your interior/attic location).
>
> Nonetheless the Samsumg Prototype still outperformed the Linx and
> especially the Zenith/LG Prototypes under these so-called "zero echo" test
conditions.
>
> As always, these are results for PROTOTYPE equipments and may or may not
> be representative of (hopefully improved) production equipment.
>
> I also have been unable to determine exactly WHAT was in the Linx
(Micronas)
> and Zenith/LG Prototypes relative to production chips....
>
>
>
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