Title:
OPTICAL DISK APPARATUS
Document Type and Number:
Japanese Patent JP3500090
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To eliminate the need of changing over an offset correction value even when a gain setting value is changed over by a method wherein an offset adjusting signal is set in such a way that the offset amount of the output of an error-signal generation part, at the time when the gain of an amplifier is set at a first gain, is made identical to the offset amount of the output of the error-signal generation part, at the time when the gain of the amplifier is set at a second gain.
SOLUTION: A servo block control circuit 140 outputs a first offset correction signal 170 to an error-signal-generation-part control circuit 350 on the basis of an offset monitoring signal 190. The error-signal-generation-part control circuit 350 outputs offset correction values 360, 361 to offset adjusting circuits 310, 311. First, gains of gain changeover circuits 320, 322 are set at a maximum value, and monitoring signals 380, 381 are monitored. Then, the gains of the gain changeover circuits are set at a minimum value, and the monitoring signals are monitored. At this time, a value which is obtained at the time when the difference between a monitored value at the maximum gain and a monitored value at the minimum value is divided by a gain difference is used as an offset value to be corrected.
More Like This:
| JPH1027378 | OPTICAL PICKUP DEVICE AND SEMICONDUCTOR LASER APC CIRCUIT |
| JPH01144242 | PLATE-LIKE ACTUATOR |
Inventors:
Daiji Tamura
Application Number:
JP8521499A
Publication Date:
February 23, 2004
Filing Date:
March 29, 1999
Export Citation:
Assignee:
Sharp Corporation
International Classes:
G11B7/09; (IPC1-7): G11B7/09
Domestic Patent References:
| JP785483A | ||||
| JP7235072A |
Attorney, Agent or Firm:
Takaya Koike