| 摘要 |
PURPOSE:To know the positions where dropouts arise on the surface of video discs by storing the track addresses and rotating angles of the video discs at the start and end timings of the dropouts. CONSTITUTION:The RF signal reproduced with a player 9 is inputted via a video signal separating circuit 10 and an envelope detecting circuit 11 to a comparator 15, and is compared with the output of an attenuating circuit 13 to which the output of an average value circuit 12 is inputted. The dropout signal from the comparator 15 is inputted to rise and fall detecting circuits 16, 17. The outputs of a detecting circuit 27 for track addresses and a detecting circuit 30 for rotating angles of discs are stored in storage circuits 18-21 by the output pulses of the circuits 16, 17. When the width of the time when the dropout arises is longer than a specified time, the outputs of the circuits 18-21 are supplied to large capacity storage circuits 22-25 by the output of a detecting circuit 26 for time width, and the coordinates and shapes of defects owing to flaws on the disc surfaces are displayed on a display circuit 31. |
