Title:
DISK SERVO CONTROL METHOD
Document Type and Number:
Japanese Patent JPH03118617
Kind Code:
A
Abstract:
PURPOSE:To equivalently and extremely improve the servo characteristic by storing the focus error signal data of the rotational frequency lower than a normal level into a RAM, then increasing the rotational frequency up to the normal level, and adding the RAM data to a focus error signal for compensation. CONSTITUTION:A disk 1 is revolved at the 1/2 normal rotational frequency. Under such conditions, a focus servo drive is applied and the focus error signal received from a focus error detector 4 is converted into a digital signal via an A/D converter 10. This digital signal is stored in a RAM 12. Then the disk 1 is revolved at a normal rotational frequency. The data on the RAM 12 is converted into an analog signal via a D/A converter 11 and added to the focus error signal received from the detector 4 via an adder 9. As a result, the target settling accuracy is secured even if the face wobbling characteristic of the disk is considerably inferior less than the specifications in a comparatively low frequency region (rotational frequency and its higher harmonics of low orders) by applying the compensating input to a focus servo system at normal revolution with the focus error signal data stored at the low rotational frequency.
Inventors:
TAKAHASHI SATORU
Application Number:
JP25520689A
Publication Date:
May 21, 1991
Filing Date:
October 02, 1989
Export Citation:
Assignee:
FUJI ELECTRIC CO LTD
International Classes:
G05D3/12; (IPC1-7): G05D3/12
Attorney, Agent or Firm:
Namio Akio (1 person outside)