发明名称 |
Pay television system utilizing multi-frequency passive filters |
摘要 |
Selected interference frequency signals are inserted into the video or RF signal at the transmitter for scrambling purposes, either singly or in pairs. At the receiving end the signals are decoded by use of filters matched to the transmitted signal. The system allows different scrambling for each pay program thereby increasing the security relative to the prior art single frequency system.
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申请公布号 |
US4623918(A) |
申请公布日期 |
1986.11.18 |
申请号 |
US19830490434 |
申请日期 |
1983.05.02 |
申请人 |
TELEGLOBE PAY-TV SYSTEM, INC. |
发明人 |
CHOMET, MARC |
分类号 |
H04K1/02;H04N7/16;(IPC1-7):H04K1/02;H04N7/167;H03H7/00 |
主分类号 |
H04K1/02 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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