Dynamic information storage or retrieval – With servo positioning of transducer assembly over track...
Patent
1986-06-03
1988-08-16
McElheny, Jr., Donald
Dynamic information storage or retrieval
With servo positioning of transducer assembly over track...
360 78, 369 50, 369 54, G11B 708, G11B 2110
Patent
active
047648600
ABSTRACT:
A servo circuit for an information recording and reproducing apparatus such as a Compact Disc player detects relative mechanical vibrations of a pickup head with respect to a recording medium and changes a servo loop gain for positioning the pickup head to a high gain when the level of the detected mechanical vibration is high to obtain a high servo capacity and changes the servo loop gain to a low gain when the mechanical vibration is low to reduce power consumption and thereby minimize generation of heat. In one embodiment of the invention, an error signal due to mechanical vibration and one due to recording medium conditions such as spots and flaws of a disc are discriminated from each other by detecting acceleration applied to a main body of the apparatus. When the level of acceleration is large, the error signal is regarded to have been caused by the mechanical vibration and the servo loop gain is changed to a high gain whereas when the level of acceleration is small but the error signal is large, the error signal is regarded to have been caused by recording medium conditions and the servo loop gain is changed to a lower gain than normal.
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McElheny Jr. Donald
Nippon Gakki Seizo Kabushiki Kaisha
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