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

[Robert Orban]

At 07:16 PM 7/15/2005, 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: <42D7D180.21909.1303699 at localhost>
>Content-Type: text/plain; charset=us-ascii
>
>On 13 Jul 2005 at 20:53, Kevin Tekel wrote:
>
> > Phil Alexander wrote:
> > > There are many reasons for moving to digital and we
> > > are doing it very late in the game. IBOC is clearly not the best
> > > way to make the transition, but it will get us there. Since it is
> > > what we have, perhaps we should take advantage of that. It will
> > > be gone soon enough and be replaced by real digital anyway.
> >
> > You sound eerily similar to a proponent of the CBS "spinning disc"
> > color TV system, circa 1950....
>
>That's one that can (and has been) argued both ways. Sarnoff got his
>way the old fashioned way. He bought it, same a Ibiquity, and CBS was
>left behind.
>
>NTSC was not that good compared with what could have been done, but
>I'm not sure CBS sequential color was that great either. SECAM was
>probably the best of the day, but it needed too much bandwidth.

Not to beat a dead horse (there was a thread about this with the last 
year), but NTSC was a brilliant piece of engineering that allowed color to 
be broadcast on the same 6 MHz channel as monochrome and that had adequate 
compatibility with existing B&W sets. It was absolutely cutting edge in its 
time for its use of psychovisual knowledge to cut down the required RF 
bandwidth -- an early form of lossy coding. NTSC's basic soundness is 
underlined by the fact that PAL is a relatively minor modification of it 
(and, in fact, the folks who designed NTSC were aware of the possibility of 
a phase-alternation-by-line modification but felt that  ca. 1953 hardware 
couldn't support it at reasonable cost).

SECAM has excellent robustness against differential phase and gain errors 
but its monochrome compatibility is significantly poorer than NTSC -- the 
"barberpole" artifact is particularly nasty. And SECAM is stuck with its 
compromises to this day, despite the disappearance decades ago of 
significant differential phase and gain errors in transmission systems.

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.)

As for the CBS system, its rainbow artifacts with motion were severe enough 
to be noticed and found objectionable even at the time of its 
implementation, when standards of television picture quality were a whole 
lot lower than they are today.

Bob Orban