[opendtv] Re: COFDM and equalization
- From: Bob Miller <bob@xxxxxxxxxx>
- To: opendtv@xxxxxxxxxxxxx
- Date: Wed, 21 Apr 2004 23:03:47 -0400
John Shutt wrote:
>----- Original Message -----
>
>From: "Doug McDonald" <dtvmcdonald@xxxxxxxxx>
>
>
>
>
>
>>The REAL penalty in that single anecdotal test
>>you mention is that a crappy 8-VSB receiver was used.
>>
>>
>
>
>
>Doug, we have at our station the latest commercially available Zenith and
>Samsung 8-VSB receivers, and neither one of them could duplicate the
>demonstration that Mark Aitken performed at those July 2000 hearings. He
>held a Radio Shack single bowtie antenna connected by a long wire to a COFDM
>receiver, and walked from the back of the room to the front witness table
>without losing lock once. Neither our Samsung or our Zenith receivers can
>even tolerate anyone walking near the indoor antenna without losing lock,
>let alone trying to pick it up and move it.
>
>
>
>
>
>>You keep mentioning anecdotal tests, and never
>>the TRULY SYSTEMATIC grid-based ones ... THAT WENT
>>ALL THE WAY OUT TO THE FAR FIELD, which 8-VSB
>>always won.
>>
>>
>
>
>
>The 1999 Baltimore tests included far field tests, and there was no
>measurable difference in performance between the two, with the exception
>that 8-VSB had a narrower angle of acceptance for it's antenna orientation
>to the transmit antenna.
>
>
>
>
>
>>This includes both Brazil and Australia,
>>by the way ... remember that the Aussies did an
>>incorrect scaling of 8-VSB from 6 to 7 MHZ, and
>>their mistake is still repeated over and over,
>>even by the BBC.
>>
>>
>
>Including those tests conducted by the MSTV using a COFDM modulation
>monitor? Even that crippled unit outperformed 8-VSB with simple antenna
>outdoors at 6 ft., where the front end of the modulation monitor was least
>likely to be overloaded.
>
>
>
>http://www.dtg.org.uk/news/archive/mstv.pdf
>
>
>
>It is time to declare that all future tests of "next generation" 8-VSB
>chipsets be conducted in a Sinclair-like by side test with COFDM. Same
>transmitter, Same antenna, Same peak power available from that transmitter
>(a handicap for COFDM) and only the exciters change. What 8-VSB receiver
>manufacturer or chip maker would take on such a comparison? NONE!
>
>
>
>A newest generation COFDM receiver will still blow away the performance of
>any miracle chipped 8-VSB receiver in all real world reception conditions.
>I would even bet that the original 1998 vintage Nokia receiver used in the
>Sinclair Baltimore tests, with it hacked front end modified for 6 MHz
>channels, would still outperform any 8-VSB receiver on the market today.
>
>
>
>It has been 5 years since Baltimore, and in spite of promises and measurable
>advances, 8-VSB still is nowhere near the real world performance of COFDM.
>But even more alarming is the fact that ATSC is nowhere near achieving the
>sophistication and flexibility of DVB-T.
>
>
>
>John Shutt
>
>
NONE!!! No 8-VSB receiver manufacturer including Linx will go head to
head with COFDM. I have personally invited Linx to come to Manhattan
where we could do a direct comparison. They were all for it until it
dawned on them that this was not someday but right then. I actually had
a transmitter and it could actually happen.
No one called back after that.
We still have those original Nokia receivers so bring then on. Nokia
made receivers for us in 1999 and they will beat anything 8-VSB has
today IMO.
And COFDM has not stood still. What we are working with now is far far
superior to 1999. I am much more confident in my challenge that at the
same power level we will drive around any location that 8-VSB can be
received at while receiving COFDM mobile. ANY LOCATION.
----------------------------------------------------------------------
You can UNSUBSCRIBE from the OpenDTV list in two ways:
- Using the UNSUBSCRIBE command in your user configuration settings at
FreeLists.org
- By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word
unsubscribe in the subject line.
Other related posts:
