[BC] the Deja VU meter is pegging (was: IBOC)

[Robert Orban]

At 07:54 AM 7/20/2005, you wrote:
>From: "Phil Alexander" <dynotherm at earthlink.net>
>Subject: Re: [BC] the Deja VU meter is pegging (was: IBOC)
>To: Broadcast Radio Mailing List <broadcast at radiolists.net>
>Message-ID: <42DDE368.20626.9CAFEF4 at localhost>
>Content-Type: text/plain; charset=us-ascii
>
>On 15 Jul 2005 at 20:30, Robert Orban wrote:
>
> >
> > If NTSC was "not that good compared to what could have been done" in 1953,
> > then what, pray tell, was the correct solution? ("Component" is not an
> > acceptable answer because the technology to bring that to consumers in a
> > practical way via lossy digital coding in a 6 MHz bandwdith was about 40
> > years in the future in 1953.)
>
>At the time UHF was in its infancy. The number of channels was far greater
>than needed. The problem was catering to the legacy b&w sets. Color might
>have gone to UHF in greater bandwidth. PAL would have been useful also.
>We might have had a system transmitting 750-800 lines in color. I don't
>argue the fact that the fundamentals of the NTSC system were well conceived
>for that day, but additional bandwidth and a shift to UHF would have made
>a better system IMHO. However, the General wanted to sell a TV transmitter
>and studio gear to every radio station in the country.

The original proposal was to devote 14.5 MHz wide channels in UHF 
(before RCA invented the principles of frequency interleaving that 
made color work well in 6 MHz). Of course, using 14.5 Mhz channels 
would have seriously impacted the number of stations that could have 
been allocated. And even _if_ 14.5 MHz has been allocated, the NTSC 
system is completely scalable and would have been able to create the 
most detail within a given RF bandwidth.

1953 was probably too early for PAL technology to have been practical 
in receivers because proper PAL decoding requires a one-line delay in 
the RX and the technology for doing that at a price acceptable to 
consumers wasn't around back then. Anyway, as long as the 
transmission system doesn't have excessive differential gain and 
phase, there is nothing wrong with using the color burst as an 
accurate reference for decoding the color--NTSC works fine with 
present-day technology. And PAL has disadvantages when used for 
production, starting with a 8-field SCH sequence that seriously 
impacts the ability of videotape editors to make tight cuts. Indeed, 
Yves Faroudja has been quoted as saying that NTSC is substantially 
easier than PAL to decode with high quality in a receiver -- it's 
much easier to make 3D comb filters for NTSC than for PAL.

http://www.ieee.org/organizations/history_center/milestones_photos/colortv.html

Bob Orban