RELAY APPARATUS, DECODER AND SECURITY BROADCASTING APPARATUS

摘要

In a head end (3) for sending pay satellite broadcasts received through a BS antenna to a cable, a separation portion (11) separates scrambled video and audio signals from the received signals and another separation portion (13) separates descrambling information signals multiplexed with the audio signals and associated information packets. The descrambling information signal is packeted by a packeting portion (45). When this packeting is made, the descrambling information signal is encoded and a corresponding error correcting code is read out from a ROM and added to the encoded information signal. Next, this descrambling information packet and the associated information packet separated by the separation portion (13) are multiplexed by a VBI multiplexing portion (51) during the vertical blanking period of the video signals and in this case, the descrambling information packet is multiplexed prior to the associated information packet. The multiplexed packets of scrambled video signals from the VBI multiplexing portion (51) and the received audio signals descrambled by a descrambler (39) are subjected to frequency multiplexing in a frequency multiplexing portion (53) and are sent to the cable.