Consumer Electronics

COMPATIBILITY CONSIDERATIONS

An unmodified black-and-white TV receiver cannot reproduce the image carried by a colour video signal in monochrome because the signal does not carry the component corresponding to a black-and-white picture. But it is possible by suitably adjusting a monochrome receiver, to reproduce one of the colour images (red, green or blue) in black-and-white. However, these cannot replace a black-and-white picture. For compatibility it is, therefore, necessary that in addition to information about colour, the transmitter of a colour television system should send a signal corresponding to black-and-white. This is usually called the luminance signal because the various areas of a black-and-white picture only differ in luminance. ...