| 摘要 |
PURPOSE:To prevent a character multiplex signal at recording and reproduction from being deteriorated by splitting the character multiplex signal, adding a clock line signal and a framing code signal and transmitting the added result superimposingly during a vertical blanking period in a low transmission rate. CONSTITUTION:A composite video signal inputted to an input terminal 10 and on which a character multiplex signal is superimposed is separated synchronizingly and applied to a gate pulse generating circuit 12 and an analog switch 18. When the pulse generating circuit 12 generates a pulse deciding the superimposed position of the character multiplex signal and an extracting signal so as to extract the character multiplex signal, which is stored in a memory 17. On the other hand, the superimposed position start signal is generated from a superimposing gate generating circuit 13, the switch 18 changes over the composite video signal and the synchronizing signal in the superimposed section and synthesizes a CRI signal from a generating circuit 15, an FC signal, a same packet identification signal and a signal train of 1/3 of the character multiplex signal and the synthesized result is outputted superimposingly during the vertical blanking period of the composite video signal. |
