| 摘要 |
PURPOSE:To prevent large rolling at the upper part of a screen excellently by providing a correcting device which equalizing the amount of jumping of a horizontal synchronizing signal caused by the switching of auxiliary heads all the time. CONSTITUTION:A 0.5 delay circuit 4 delays the playback output of an auxiliary head 12b or 22b by 0.5H (H; horizontal scanning period) in the 1st intermittent run of a magnetic tape. Consequently, an interval between horizontal synchronizing signals is increased forcibly from 0.75H to 1.25H in switching the heads 12b and 22b to secure an H jump of 0.25H. The circuit 4 is started by a switch 5 during the next intermittent run, but delay of 0.5H is not done in the next intermittent run, so subtraction between 0.75H and 0.5H is performed eventually to make an H jump of 0.25H. Therefore, a special reproducing device 1 fixes the H jump caused by the switching between the heads 12b and 22b to 0.25 in the same direction all the time. |
