| 摘要 |
PURPOSE:To attain surely efficient head drive control, by using a speed correcting value at each fixed period in a deceleration period when the head is shifted to an objective track so as to reduce the amplitude of fluctuation in the objective speed signal between tracks. CONSTITUTION:When the head reaches the center of a prescribed track, an objective speed signal generating circuit 13 sets a track value Tc. Taking the value Tc as 10 and a variable (a) as ''0'', the objective speed signal V is K.101/2. When the head is shifted from the center of the track value 10 by >=1/4, an off- track signal Tf is outputted from the circuit 10. A pulse Tb is outputted at a point between track values 10 and 11, and in taking the (a) as ''1'', the signal V is K.9.51/2. The (a) being the speed correcting value is set to be ''1'' between the pulses Tb and Ta at the output period of the signal Tf. Thus, the circuit 13 outputs the signal V of the head shifted to the objective track value Td. This signal V is set with very small speed regulation by using the correcting value (a). |
