ABSTRACT
The transition from analogue to digital TV in recent years has significantly altered up-link operations. By enabling as many as eight digital channels to broadcast from a transponder which once delivered a single analogue channel, the economics and operation of broadcasting have changed fundamentally. Although the broadcasting world is rapidly going digital, analogue TV and radio are set to remain for several years yet. Indeed, for some services, analogue is still an attractive option due to the large installed audience base and the widespread existence of low-cost consumer equipment. Moreover, the capacity to transmit audio subcarriers of an analogue TV signal allows multilingual TV programmes or the parallel transmission of radio stations.
