| 摘要 |
A METHOD AND AN APPARATUS FOR SIMULTANEOUSLY DISPLAYING TWO INDEPENDENT VIDEO SIGNALS ARE DESCRIBED. THE APPARATUS COMPRISES VEDLO SIGNAL INPUT TERMINALS (2, 6) FOR RECEIVING FIRST AND SECOND VIDEO SIGNALS IN PAL SYSTEM HAVING THE FIELD FREQUENCY OF 50 HZ, Y/C PROCESSORS (7, 8) CONNECTED TO THE VIDEO SIGNAL INPUT TERMINALS (2, 6), A/D CONVERTERS (16, 24) CONNECTED TO THE Y/C PROCESSORS TWO PORT FIELD MEMORIES (17, 22)( HAVING A RANDOM BLOCK ADDRESSING MODE FOR STORING THE DIGITAL Y/U/V SIGNALS FROM THE A/D CONVERTERS, A D/A CONVERTER (19) CONNECTED TO AN OUTPUT OF THE FIELD MEMORIES (17, 22) AND DERIVING ANALOG Y/U/V SIGNALS WHICH ARE CONVERTED TO R/G/B SIGNALS AND SUPPLIED TO A DISPLAY (10), A WRITE AND READ CONTROL SIGNAL GENERATOR (14; 20, 21) FOR GENERATING FIRST AND SECOND WRITE CONTROL SIGNALS SO THAT THE FIRST AND SECOND DIGITAL Y/U/V SIGNALS ARE WRITTEN INTO THE FIRST AND SECOND DIGITAL Y/U/V SIGNALS ARE WRITTEN INTO THE FIRST AND SECOND FIELD ,MEMORIES (17, 22) AT A FIRST PREDETERMINED FREQUENCY IN SYCHRONISM WITH THE SYNCHRONIZING SIGNALS OF THE FIRST AND SECOND VIDEO SIGNALS, RESPECTIVELY, AND FOR GENERATING FIRST AND SECOND READ CONTROL SIGNALS SO THAT THE FIRST AND SECOND DIGITAL Y/U/V SIGNALS ARE ALTERNATELY LINEWISE READ-OUT FROM THE FIRST AND SECOND FIELD MEMORIES (17, 22) AT FOUR TIMES THE FIRST PREDETERMINED FREQUENCY IN SYCHRONISM WITH A MASTER SYNCHRONIZING SIGNAL OF EITHER THE FIRST OR SECOND VIDEO SIGNALS AND WHICH ARE DISPLAYED EACH IN AN ASPECT RATIO OF 4:3 OR 3:3 ON THE SCREEN HAVING A WIDE ASPECT RATIO OF 16:9 IN A 100 HZ FLICKERLESS MODE. (FIG. 2)
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