| 摘要 |
PURPOSE:To effectively operate a TV multiplex character broadcast, by making a picture of a character broadcast for scrolling display a part of a CRT with the key operation of the user when the character broadcast is a prescribed mode to make the normal broadcast to be viewed. CONSTITUTION:A display section Sd in parallel 8-bit is picked up from a control circuit. When this signal Sd is loaded to a register 102, it is serially picked up with a pulse Pb at each pulse. A mask signal Sm which is at ''1'' for the vertical scanning period of the lower 2-line block from the register 102. When this signal Sm is supplied to an AND circuit 103 and a signal Ss from an OR circuit 423 is applied to the AND circuit 103. Further, the signal Sm is applied to a switching gate 104 via the AND circuit 103 and also to the switch circuit 104 as a control signal. Thus, the picture of the character broadcast of the prescribed mode is scroll-displayed at the region of lower 2-line block of a CRT and the picture of normal broadcast can be reproduced on the upper region. |
