chrominance channel การใช้

It was necessary to assign a narrower bandwidth to the chrominance channel because there was no additional bandwidth available.
This results from high-frequency luminance detail crossing into the frequencies used by the chrominance channel and producing false coloration, known as color bleed.
If some of the luminance information arrived via the chrominance channel ( as it would have if RB signals were used instead of differential UV signals ), B & W resolution would have been compromised.
Understanding this human shortcoming, standards such as NTSC and PAL reduce the bandwidth of the chrominance channels considerably . ( Bandwidth is in the temporal domain, but this translates into the spatial domain as the image is scanned out .)
The luminance channel ( Y ) is encoded at full bandwidth ( 13.5 MHz in 270 Mbit / s SD, ~ 75 MHz in HD ), and the two chrominance channels ( Cb and Cr ) are subsampled horizontally, and encoded at half bandwidth ( 6.75 MHz or 37.5 MHz ).