| 摘要 |
PURPOSE:To prevent an audience from looking and listening free of charge in a charged TV system, by receiving the TV signal transmitted with partial horizontal synchronous signal eliminated in advance and producing the eliminated horizontal synchronous signal to supply it to the TV picture receiver. CONSTITUTION:The TV signal (b) of special type with partial horizontal synchronous signal eliminated is procuded by the scramble circuit 5 and then transmitted from the generator 4 of the standard TV signal (a). Then the horizontal synchronous signal is inserted to the original correct position by the descramble circuit 10 of the reception side device 2 to reproduce the signal (a). This signal is received by an ordinary TV picture receiver. For instance in a charged TV system of special type using the communication satellite 3 as shown in the diagram, the looking and listening become possible only with use of the device 2 of the circuit 10 provided especially. In such way, looking and listening free of charge can be prevented in the charged TV system, thus securing an accurate charging. |
