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The green wire for color signal transmission in color TV

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dak-ju

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Hi all,

I have a querry on the color signal transmission in color TV.
While transmission, the color difference signal is used using the red and the blue component.The green component is not used.
My question is - why the green component is not used?

Thanks and regards,
dak-ju
 

Re: color TV

If in, say, NTSC Y=0.30R+0.59G+0.11B, you can see that green signal is the biggest component of the whole equation.
R-Y and B-Y and not G-Y were selected for colour transmission because G-Y is the smallest differentioal signal and using it would be the worst case scenario as far as signal to noise ratio is concerned.
As the green signal is coded in Y it will be retrieved in the receiver as:
Ug=Uy-051(Ur-Uy)-0.19(Ub-Uy)
Regards,
IanP
 

Re: color TV

IanP said:
If in, say, NTSC Y=0.30R+0.59G+0.11B, you can see that green signal is the biggest component of the whole equation.
R-Y and B-Y and not G-Y were selected for colour transmission because G-Y is the smallest differentioal signal and using it would be the worst case scenario as far as signal to noise ratio is concerned.
As the green signal is coded in Y it will be retrieved in the receiver as:
Ug=Uy-051(Ur-Uy)-0.19(Ub-Uy)
Regards,
IanP
Click to expand...

Hi IanP,

If you take a situation where R = 1, G = 0.1 & B = 1, then can we say that green signal is the biggest component of the whole equation?
I think biggest component depends on the value for R, G & B.

Best Regards,
dak-ju
 

Re: color TV

I am not talking about R, G or B, but the differential voltages U(R-Y), U(G-Y) and (U(B-Y). If you take into account max peak-to-peak value the U(G-Y) is only ≈46% of the U(B-Y) and ≈58% of the U(R-Y)..
Regards,
IanP
 

Re: color TV

In the RGB signal bandwidth of G is bigger than R & B. and Bandwidth of Red is bigger than blue.
because white color, consist of 59% green 30% red and 11%blue. in outher hand,
eye is more sensitive to luminance(Y) then green , red and blue resp.
this means we can use lower bandwidth for blue signals, and so on.
 

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