Quote:
Originally Posted by NewVista
Actually NTSC wider - 1.3m vs 1 m
With regards to monitoring in PAL-S...
Come to think of it, some monitors had PAL-S & PAL-D switch for convenient signal evaluation (clever).
|
I think you are sadly misinformed. The IBA Technical Review Volume 2 (a reliable reference) specifies 1.3MHz (-3dB) point for PAL chroma. In System I countries the upper sideband is fully present on transmissions too. In System B/G countries it's a bit marginal.
SMPTE 170M(1993) gives more or less the same figures as for PAL but the USB isn't transmittable in a standard M channel. 170M notes the earlier NTSC standard where Q is 2dB down at 0.4MHz. A lot of NTSC coding has been done with narrowband 600kHz U/V axes rather than the complication of I/Q. This is discussed in SMPTE EG27. I would attach a copy but it's SMPTE copyright. Here's a quote from EG27:
Quote:
The NTSC encoder described in ANSI/SMPTE
170M uses equal-bandwidth color-difference signals
(either B--Y and R--Y or I and Q). This removes the
need for a delay line in the color-difference signal. A
shorter delay line than required for NTSC 1953 is used
in the luminance (Y) signal (see figure 4).
When this signal is transmitted, a low-pass filter in the
transmitter bandwidth limits the luminance (Y) signal
and the upper sidebands of the color-difference sig-
nals (either B--Y and R--Y or I and Q) to 4.2 MHz.
Transmission of equal-bandwidth color-difference sig-
nals to the receiver has the effect of limiting the
recoverable chroma bandwidth to 0.6 MHz as a result
of the truncation of the upper sidebands of the chroma
modulation in the transmitter’s 4.2 MHz filter. This is
considered acceptable since there are no modern
receivers that utilize the theoretically possible wide-
band I demodulation made possible by maintaining
|