On 16 Dec 2011, at 2:18 AM, Christian Corti wrote:
Probably I'm wrong. I was under the impression that the only purpose of the NTSC was
to define a new colour standard (Never The Same Colour). Whatever, I don't know of
anything they did afterwards.
No. The NTSC was originally created under the RMA's sponsorship and held it's
first meeting on 31 July 1940 for the purpose of sorting out the competing broadcast
standards that had resulted in the FCC rescinding its previous authorization for limited
commercialization. In the end the NTSC proposed the 1938 RMA standard with two changes:
audio was to be FM and the line count was to be increased from 441 to 525 lines; hearings
on that were held on 20 March 1941 with adoption in April and an effective date of 1 July
1941 (it's interesting to note that 525 was a compromise between RCA's 441 lines
and the Philco-DuMont faction that wanted either 605 or 800).
The NTSC committee was reassembled in 1950 in order to address color television; in 1953
it approved what later became known as RS-170a.
So, in the end the NTSC was responsible for two entirely different but related systems: A
television signal standard and a color encoding standard. RS-170a was referred to as
"compatible" because in theory it didn't modify the definition of the
television system but it actually did with the field refresh frequency being changed from
60Hz to 59.94Hz in order to avoid stationary dot patterns that could result from the
difference frequency between the existing sound and new color carriers.
--
Dr. Christian Kennedy
chris at
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