`
`NTSC: The frame rate is chosen to be very close to the
`frequency of the power system. In the US, we use 60Hz power, so
`the NTSC frame rate is 59.94 Hz. The reason you want the same
`rate as the power frequency is to minimize interference. The
`line rate is 525 lines. The line frequency, frame frequency and
`color carrier frequency are all related to each other, and are
`actually locked to each other. All the needed timing signals
`can be divided from one master clock signal. The color carrier
`for NTSC is 3.58 MHz, for short. There are many more digits.
`The color information, consisting of Red, Green and Blue, are
`all present at the color TV camera. The black/white signal is
`made by mixing the three colors, 0.30Red, 0.59Green and
`0.11Blue. The two color signals needed to make a full color
`picture is R-Y (red minus black/white), and B-Y (blue minus
`black/white). If you transmit the Y (black/white) signal and
`the two combination colors, R-Y and B-Y, you can extract the
`green color using simple adding and subtracting. Green = Y-R-B
` For NTSC, the two color signals are modulated on the color
`carrier using quadrature AM modulation. It's possible to keep
`the two R-Y and B-Y signals on one carrier. To extract the two
`signals at the receive end, you must also transmit a color
`reference signal, called the color burst. This short burst of
`unmodulated color carrier is placed right after every horizontal
`sync pulse (about 15000 times per second). The color burst is
`used to lock the color demodulator in the TV set so the correct
`R-Y and B-Y signal can be demodulated. Now, the black/white
`signal and the two color signals can be combined to make Red,
`Green, and Blue, all the color information needed to make a full
`color picture on your TV set.
`
` PAL:
`
` PAL is fairly close to NTSC. Since the power frequency is
`50Hz, the frame rate is also 50 Hz. The line rate is 625 lines.
` However, the Europeans didn't like the color change that can
`occur if there is a phase change in the transmission of the
`signal. So on NTSC TV sets there is a HUE or TINT control to
`correct for any phase change of the color burst/color signal.
`One way of making an "automatic" hue control is to transmit the
`R-Y signal alternately with a phase shift of 90 degrees. In
`every other line the R-Y signal is transmitted inverted. Since
`our eyes are less sensitive to color compared to black/white,
`the resolution needed for color is less. As you know, the
`black/white resolution is about 5 MHz, however the color
`information transmitted on the color carrier is about 1.4 MHz
`wide. The frequency of the carrier is 4.43 MHz. So, in PAL,
`they assume the vertical resolution can be cut in half without
`"affecting" color resolution. By combining two horizontal
`lines, using a delay line in the TV set, two lines can be
`combined and any phase error can be cancelled. Severe phase
`changes in the transmission of a PAL signal will show up as weak
`colors, but correct colors. In NTSC it will show up as full
`color saturation, but the wrong colors! It's also a fact that
`our eyes are much more sesitive to color hue changes than to
`color saturation changes. So, you will not see green faces in
`PAL, but you might see weaker (!!!!!!!!!!) colors.
`
`Еще
`
`http://www.ee.surrey.ac.uk/Contrib/WorldTV/compare.html
`
`Итог (с) Никки
`
`Если в двух словах, то в PAL интенсивность цветов ослабляется,
`но зато цвета всегда правильные (кроме якростной составляющей).
`
`В NTSC напротив - интенсивность точек всегда правильная, но
`цвета - нет.
`
`Так что лица с брильянтовым оттенком - удел NTSC. А блеклость, но
`без зелени - PAL.
`
`http://www.dvdspecial.ru/cgi-bin/ultiweb.cgi?mode=show_message&id=11697
`
`Все. Надеюсь, все точки над i расставлены. Фокстри, ты прочел?
