| 摘要 |
PURPOSE:To detect the clogging of a rotary head and a recording error at the time of clean join by providing a detecting period setting circuit which transmits the output of a comparator circuit only during a period when a detection position is not a reproduction signal switching position in terms of a comparator circuit acting period. CONSTITUTION:The detecting period setting circuit 7 connected between the comparator circuit 6 and a display device 8 sets a head switching signal as an input and limits the period when the output of the comparator circuit 6 is transmitted to the display device 8. Where a recording error occurs or the rotary head is blinded during a temporary stoppage period, the output (d) of an envelop detecting circuit 5 has a period when it is lower than a reference voltage V1, because a reproduced output cannot be obtained from the rotary head 1a or 1b. At this time, if the detecting position of the detecting period setting circuit 7 is any one of position tA-tC, a signal at a low level is transmitted to the display device 8 in a time tB. Although the comparator circuit 6 is acting, the display device 8 issues the alarm because of the low level of the output of the comparator circuit 6, and accordingly such a detection can be made that a recording error or the clogging of the rotary head occurs. |
