NTSC standard:

An RGB signal may be converted to a television signal by using an NTSC encoder, which converts RGB values to YIQ values, then modulates and superimposes the I and Q information on the Y signal. The conversion from RGB values to YIQ values is accomplished with the transformation

This transformation is depends on the NTSC standard RGB phosphor. The larger proportions of red and green assigned to parameter Y mention the relative significance of these hues in determining brightness, compared to blue.

An NTSC Video signal may be converted to an RGB signal by using an NTSC decoder, which separates the video signal into the YIQ components, then converts to RGB values. We convert from YIQ space to RGB space with the inverse matrix transformation from above Equation.