How do color signals work? An interactive explanation

[Penthode]

Thanks Nic for assembling this. I would like to add my thoughts on the dot crawl issue and compatibility with B&W systems.

The early black and white sets with 4MHz bandwidth did suffer. The dot crawl could be minimized by careful and exacting RF/IF alignment. If the carrier is placed at 50% and the response is flat through the color subcarrier, the dot crawl is not too bad.

Fortunately, since the DTV revolution, it is now possible to get the full 4 MHz back on pre-1955 TV's. Pretty well all DVD players and a few DTV over the air set top boxes are provided with Y, Pb, Pr or component analog interfacing. The Y output is luminance only and if fed to an RF modulator will provide full 4 MHz luminance bandwidth with no chroma and dot crawl interference.

The addition of color to a B&W channel would be a trade off. The 2nd NTSC (from 1951) realized luminance bandwidth would be reduced but felt the addition of color would more than compensate for the loss. It was a wise compromise which resulted in providing an excellent television delivery technology lasting more than 50 years.