ABSTRACT
Television systems can be divided into two groups for the purpose of describing how they function: analogue TV systems have been with us for over 70 years, and all depend on being able to transmit a continuously varying signal level over a distance, representing the picture information. Several digital TV systems have been developed in the last 20 years. All transmit the picture information by changing the continuously varying signal levels from the camera, or other source equipment, into a series of codes consisting of two or more discrete signal states. Some digital systems are suitable for local distribution in studios, and others, described here, are suitable for broadcast transmission.
