Servo apparatus for optical disk player having both open loop coarse gain control and closed loop fine gain control
AssigneePioneer Electronic Corporation
InventorsMunehiko Iwase, Noriyoshi Takeya
Life of this patent
Estimating the term…
Abstract
A servo apparatus for an optical disk player which coarsely adjusts the loop gain in advance in an open state of a servo loop, and then closes the servo loop to finely adjust the loop gain. This ensures accurate and sure gain control even if there are differences between reflection factors of the recording surfaces of disks being played or is a stain or the like on an objective lens of the player.
Claims7
A servo apparatus for an optical disk player, having a signal generator means for generating a predetermined error signal based on an output signal of a pickup that reads recorded information from an information-recorded disk and including a servo loop with amplifier means, said servo loop controllable to be selectively rendered operative for inoperative and, in an operative state, driving the pickup based on the error signal, the servo apparatus comprising:
- a loop gain coarse adjustment means connected within said servo loop for coarsely adjusting a loop gain of the servo loop , said loop gain coarse adjustment means rendering inoperative said servo loop and providing feedback for coarsely adjusting a gain of said amplifier means in response to generated error signals;
- and
- a loop gain fine adjustment means connected within said servo loop for finely adjusting the loop gain when said servo loop is operative, said loop gain fine adjustment means receiving output from said amplifier means in said coarse adjustment means and including means for providing feedback for fine adjustment of gain of said servo loop.
Dependencies are inferred from the claim text.