Importance

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Abstract

In a transmission system authorization codes are transmitted to authorize subscribers to receive scrambled signals in an intelligible manner, such a system being a television transmission system. If each subscriber were assigned a unique authorization code an extremely long period of time would be required to transmit these codes for a national broadcast system. With the present arrangement, the authorizing code includes a multi-bit binary code word (18,20) which is unique to a group of subscribers, this code word being followed by a train of binary pulses (19',19';21', 21',) the number of pulses in the train being not less than the number of subscribers in the group. Each subscriber is allocated a unique pulse position in the pulse train (19',19';21',21',) at which position the state of the pulse either authorizes or inhibits the subscriber from receiving the scrambled signal intelligibly.

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First Claim