Newbie with a technical question re: NTSC.

[U4K61]

NTSC: Encoding/Decoding

When they added color to the B&W signal in 1953, the American system became known as NTSC - National Televison Standard Committee. PQ could be spotty and the color was not always on the mark, so it was also called Never Twice the Same Color.
Analogue Video Signals

NTSC:
525 lines, 59.94Hz 262.5 line interlaced fields.
line frequency of 15,734 Hz (59.94 x 262.5).
Color subcarrier frequency: 3.579545(3.85).
Color of Grey 6500K.

Encoding NTSC:
To fit in a 6MHz bandwith that was for B&W(Y= luminance), the RGB color output of a camera, where each video signal can be up to 100 IRE. This is reduced by the Matrix Coder to the luminance signal: Y = 0.3R + 0.59G + 0.11B, that when added together, has a max amplitude of 100 IRE. Lots of green, some red, a little blue with Y containing most of the picture information. G is removed to save space. We end up with Matrix Coder outputting Y and 1.3Mz for R-Y, 0.5MHz for B-Y, to be transformed by the Color Encoder to I(in-phase) = 0.877(R-Y)[orange-blue] and Q(quadrature) = 0.493(B-Y)[purple-green]. This is modulated together with Y by the Adder as NTSC composite, Y+I&Q.

Decoding NTSC:
This signal goes though the comb (Y/C ) filter in the TV to be seperated out as Y,C. PQ is reduced by constructive/destructive interference and dot crawl or cross-luma - where chroma is incorrectly interpreted as high frequency luma information. The degree of degration depends on filter type being used: Two-line, Three-line, or 3D Y/C comb filter. The outputted Y/C signal, Y is delayed and the Color Decoder takes C and outputs R-Y, B-Y. The Matrix Decoder converts Y, R-Y, B-Y to RGB.

1080p Blu-ray/480p DVD passed though the composite limits it to NTSC.
See - Informative page on NTSC listed below.

What NTSC made for:

• The Sharpness Controle
• Best HD Setup
• My First Game System
• The Cable Guy

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