| 摘要 |
PURPOSE:To detect accurately a specific mark with the prescribed timing and also to prevent the misoutput of the detection signal due to the misdetection, by using a comparatively short space deciding time which is slightly longer than a space of a long time width following a pre-space for detection of this pre-space and using a comparatively short mark deciding time slightly longer than a mark of a longer than a long time width following the specific mark for detection of this specific mark. CONSTITUTION:The space deciding time Ts is set at about 0.2sec, for example, that is shorter than the time width of a normal pre-space in a reception signal, i.e., the time width of the longest space and also slightly longer than the time width of the 2nd longest space. While the mark deciding time Tm is set at about 0.5sec, for example, that is shorter than the time width of a normal specific mark in the reception signal, i.e., the time width of the longest mark and also slightly longer than the time width of the 2nd longest mark. The time Ts has the shorter time width than that of the time Tm. Therefore a mark identification signal and the 1st and 2nd latch signals are outputted with the prescribed timing of a specific mark. Then this specific mark can be detected accurately with the prescribed timing. |
