DETECTOR FOR MOVING SPEED OF MANENTIC HEAD

摘要

PURPOSE:To attain the speed detection sufficiently even at high speed moving, by providing a phase shifting circuit. CONSTITUTION:In a speed detector 8 detecting the speed of a servo head by using a position signal generated when the head crosses a track, the phase shifting circuit 19 having nearly the same phase characteristic as that of a differentiating circuit 13 differentiating the position signal of head is provided in parallel with the differentiating circuit. Since the increase in the phase lag of the differentiating circuit 13 caused due to the increase of the head moving speed is compensated in this way, the shift in the timing at sampling is eliminated, and the speed is detected accurately even at the high speed moving of the head.