| 摘要 |
PURPOSE:To make the tracking accurate at high speed scanning, by rotating and displacing two rotary heads in reverse direction orthogonally to the lengthwise direction of the tracks. CONSTITUTION:A drum pulse in response to the phase of rotation of a rotary drum of a head is inputted from a terminal 25. This pulse is adjusted for the phase at monostable multivibrators(MM) 26 and 27 and converted into a triangle wave at an integration circuit 28. This triangle wave takes a 2-track scanning period synchronized with the rotating phase of the rotary drum as the period. This triangle wave is applied to a polarity changeover switch circuit 30 via a low pass filter and the polarity is switched in response to forward and reverse reproducing direction. The switch output is applied to a head moving mechanism via a low pass filter 32 and an amplifier 33. Thus, the location of the head in high speed scanning is displaced for accurate tracking. |
