SECURITY SYSTEM FOR TELEVISION SIGNAL ENCRYPTION

专利名称：SECURITY SYSTEM FOR TELEVISION SIGNAL

ENCRYPTION

发明人：MASON, Arthur, Gordon申请号：EP84902601.8申请日：19840702公开号：EP0151147B1公开日：19880420

摘要：a conditional access system for transmitting and receiving radio waves of ascrambled tv signals improves the reliability of the received key signal transmitting.it isfor the television signal in a block of information is also encrypted by the key signal.atthe time of reception, the receiver decodes the information after the block, comparesthe signal from the signal of the key pad key provided to the receiver to decrypt theblock.the d\ébrouillage shall be permitted only if the comparison shows that thetwo key signals are the same.the system can also provide information on the status ofthe credit of each user, which is transmitted by radio waves.in order to ensure a rapidoperation, the credit status signal is sent repeatedly and another signal is provided.at thelevel of the receptor which is used to prevent repeated accumulation of credits.anotherarrangement allows the transmitter to transmit a signal indicating the total amount ofcredit is purchased by a user as well as the inclusion of a meter at the receptor level ofthe user.will accumulate all program payments are viewed by the user. a simple

comparison between the two signals is sufficient to establish that the user can watch theprogram.

申请人：INDEPENDENT BROADCASTING AUTHORITY

代理机构：Crawford, Andrew Birkby

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