Calrad Audio/Video Switches

Composite video is the format of an analog television (picture only) signal before it is combined with a sound signal and modulated onto an RF carrier. Composite video is often designated by the CVBS acronym, meaning any of "Color, Video, Blank and Sync", "Composite Video Baseband Signal", "Composite Video Burst Signal", or "Composite Video with Burst and Sync". It is usually in a standard format such as NTSC, PAL, or SECAM. It is a composite of three source signals called Y, U and V (together referred to as YUV) with sync pulses. Y represents the brightness or luminance of the picture and includes synchronizing pulses, so that by itself it could be displayed as a monochrome picture. U and V represent hue and saturation or chrominance, between them they carry the color information. They are first mixed with two orthogonal phases of a color carrier signal to form a signal called the chrominance. Y and UV are then combined. Since Y is a baseband signal and UV has been mixed with a carrier, this addition is equivalent to frequency-division multiplexing.

Separate Video, more commonly known as S-Video, and sometimes incorrectly referred to as "Super Video" and also known as Y/C, is an analog video signal that carries the video data as two separate signals, lumen (luminance) and chroma (colour). This differs from composite video which carries picture information as a single lower-quality signal, and component video which carries picture information as three separate higher-quality signals. S-Video carries standard definition video (typically at 480i or 576i resolution), but does not carry audio on the same cable.

High-definition television (or HDTV) is a digital television broadcasting system with higher resolution than traditional television systems (standard-definition TV, or SDTV). HDTV is digitally broadcast; the earliest implementations used analog broadcasting, but today digital television (DTV) signals are used, requiring less bandwidth due to digital video compression.