| 摘要 |
PURPOSE:To prevent malfunctions dependent upon vertical synchronizing components included in the horizontal synchronizing signal, by comparing synchronizing signals, where vertical synchronizing components in synchronizing separation outputs are eliminated, in phase by respective vertical synchronizing signals of two receivers in case that it is decided whether receiving channels of two TV receivers are the same channel or not. CONSTITUTION:Horizontal synchronizing signals 20 and 20' of the first and the second receivers are supplied to horizontal synchronizing agreement detecting circuit 8. In circuit 8, output 21 is low-level if phase of synchronizing separation outputs 20 and 20' of two receivers do not agree with each other, and output 21 becomes high-level and is input to AND gate 12 if they agree with each other. Outputs 22 and 22' of vertical synchronizing separating circuits 6 and 6' of the first and the second receivers are applied to data terminal D and clock terminal CK of D latch circuit 11. When output 21 of circuit 8 and output 25 of circuit 11 become high- level, the output is output to AND gate 12 to discriminate that receiving channels of two receivers are the same channel. |
