| 摘要 |
PURPOSE:To make it possible to obtain a few subordinate screens without increasing the number of tuners by successively applying a tuner, selecting subordinate screen channels with a channel selection voltage differing in level at intervals of fixed time. CONSTITUTION:Tuner 7 that selects subordinate screen channels is applied with alternate selection voltages VB and VC, differing in level, from control circuit 30 at intervals of fixed time, e.g. 0.3-1 seconds. Then, video signals of respective selected channels are written in corresponding memories 15-22. Further, video signals of respective channels read out of memories 15-22 are mixed with primary color signals of the main signal system by mixer circuit 27 in accordance with blanking signals BLB and BLC from control circuit 30. This composite signal is applied to cathoderay tube 29 to project two contracted subordinate screens on the main screen at fixed positions. |
