The composite video synchronous signal carries the luminance (typically referred to as black and white television) information of a television picture. To include color in the video signal, additional chrominance information needs to be overlaid. France introduced the SECAM standard (séquentiel couleur à mémoire, French for "sequential color with memory") to support this requirement. In comparison to PAL and NTSC − where an analog IQ-modulated carrier is used − SECAM utilizes two FM carriers at 4.25 und 4.406 MHz. Each of these carries one color-difference signal. The combination of the luminance as well as the chrominance information results in the composite color video signal (CCVS). SECAM is used in France and former Eastern Block states, for example.
