| 摘要 |
PURPOSE: A tracking servo device in an optical write/read apparatus is provided to write and read information at the tracks formed of lands and grooves. CONSTITUTION: A first adder(301) adds electrical signals(A,D) outputted from light detection elements. A first peak value detection unit(302) detects the maximum peak value from the output of the first adder(301). A second adder(304) adds electrical signals(B,C) outputted from light detection elements. A second peak value detection unit(305) detects the maximum peak value from the output of the second adder(304). A comparator(303) outputs a signal corresponding to the difference between the outputs of the first peak value detection unit(302) and the second peak value detection unit(305). A gain adjustment unit(306) adjusts the output gain of the first adder(301) as a gain value corresponding to the output voltage of the comparator(303). A subtracter(307) outputs a tracking error signal, getting the difference between the gain adjusted signal and the output of the second adder(304). A servo digital signal processor(308) controls an optical pickup according to the tracking error signal outputted from the subtracter(307). A microcomputer(300) controls the comparison of the comparator(303).
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