Page "Analog television" Paragraph 30

Each line of the displayed image is transmitted using a signal as shown above.

The same basic format ( with minor differences mainly related to timing and the encoding of color ) is used for PAL, NTSC and SECAM television systems.

A monochrome signal is identical to a color one, with the exception that the elements shown in color in the diagram ( the color burst, and the chrominance signal ) are not present.