Verfahren, System und Vorrichtung zur Datenübertragung

摘要

Apparatus for transmitting signals to video or other terminals 2 has coding means 5 for receiving the signals to generate a base signal stream B which is a coarse representation of the signal to be transmitted and at least one higher order stream E1, E2 containing finer detail of the signal not present in any lower order stream. These streams are sent by transmitting means 6 to the terminals, but at least some of the terminals do not receive all of the higher order streams. Control means 7 receives signals xk indicative of the data-receiving capacity of the terminals and calculates, based on the measured capacities, an adjustment for the coding means to make to the data rates of the streams.