| 摘要 |
PURPOSE:To permit two magnetic heads to trace the same track in still mode, etc., without fail by using the signal, which corresponding to the ending position of the trace of either magnetic head as the trace starting signal for the next head. CONSTITUTION:Every time two rotary magnetic heads 6a and 6b trace magnetic tracks respectively, signals that correspond to their ending positions are obtained and then supplied as signals for trace starting positions of heads which are to trace next. For example, signals Pa and Pb obtained through the rotation of the drum turn of side (a) and side (b) of switching circuits 18 and 19 in trace periods of heads 6a and 6b respectively. Then, the output of head 6 passed through envelope detecting circuit 20 and the output of strain gauge 7 are supplied via synchronous detecting circuit 22 to integrating circuit 23, whose output is supplied to bimorph plate 7 to make alternate heads 6a and 6b trace and the trace starting position of head 6b right after point t1 in time is controlled according to the final position of head 6a right before point t1 in time. |
