Scrambling unit for a digital transmission system

摘要

An independant scrambling unit 1 for a digital audiovisual transmission system, the scrambling unit 1 comprising an input for receiving an assembled transport packet stream from a physically separate multiplexer 4, a scrambling device for scrambling the received transport stream according to a randomising control word and an output for sending the scrambled transport stream to a transmitter means for subsequent transmission. The scrambling unit 1 may also be used to introduce other packet data in the data stream.