| 摘要 |
PROBLEM TO BE SOLVED: To reduce sound generation at the time of seek of a magnetic head, and reduce settling time. SOLUTION: When a step pulse 1 is inputted, a phase (a) signal 14 and a phase (b) signal 15 are changed over by an exciting signal switching circuit 13. At the time of each change-over, a PWM signal generating circuit 16 generates a PWM signal 17. A phase PWM synthesizing circuit 19 combines the phase (a) signal 14 and the phase (b) signal 15 with the PWM signal 17, and outputs a phase PWMa signal 20 and a phase PWMb signal 21, which are inputted in a motor driving circuit 22 and make a stepping motor 23 rotate. Switching is arbitraily set by the step rate, and the torque and the rotational speed of the stepping motor are adjusted. Thus a magnetic head 24 is made to begin seek. |
