Dynamic information storage or retrieval – With servo positioning of transducer assembly over track... – Optical servo system
Reexamination Certificate
2007-05-29
2007-05-29
Tran, Thang V. (Department: 2627)
Dynamic information storage or retrieval
With servo positioning of transducer assembly over track...
Optical servo system
C369S044290, C369S044350
Reexamination Certificate
active
10902449
ABSTRACT:
Regions A–F of photodetectors output electric signals a–f respectively, in accordance with an amount of reflected light from an optical disc1. The electric signals a–f are input to A/D converters through an RF amplifier unit respectively. An arithmetic circuit subjects the electric signals a–f to arithmetic processing, so as to generate a focus error signal FE and a tracking error signal TE. A CPU measures a DC level of an output signal from the A/D converter, and transmits control signals OCa–OCf to a variable resistor in the RF amplifier unit so that a difference between the DC level and a median in a dynamic range of the A/D converter attains “0”. The CPU transmits control signals GCa–GCf to a variable resistor in the RF amplifier unit so that output amplitude of an output signal is within the dynamic range.
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Funai Electric Co. Ltd.
Osha & Liang LLP
Tran Thang V.
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