pay television systems, implementation of the tv signmaksullinen television systems, implementation of the tv signal characteristics using the aalin properties using

摘要

In a closed TV system a text TV system or a data channel with NICAM signal form is used to send authorization messages concerning the right to view from the central apparatus 24 to the receivers 28. The receivers are specified with addresses in accordance with the receivers or receiver groups and the central apparatus grants viewing rights by generating authorization messages. The length of an authorization message corresponds to one line 10 of a particular text TV page on the command channel or information channel and it contains the address 11 of the receiver and the end time 12 of the right to view per channel. Ordering of the right to view is carried out by telephone 29. IMAGE