| 摘要 |
PURPOSE:To produce scramble effect without operating an image signal itself by switching the number of a video signal relative to plural carrier waves so that respective picture sources are on different carrier waves for every one field. CONSTITUTION:An originating side sends out picture sources up to #1-#N1 as N number of TVRF signals by N number of TV modulators 2. Where a switch 3 synchronized for every vertical synchronizing period of TV, switches the picture sources according to its assignment relative to channels ch-1,...ch-N. While, switching information of the switch 3 is taken out as a data signal by a data converter 4, is mixed with signals by a mixer 5 in a TVR and is sent out to each terminal. A receiving side changes carrier wave of each picture and changes a VT voltage of an oscillating circuit 7 in a converter 6 synchronized in a step form for every vertical synchronizing period to convert the picture into an IF signal. |
