公开(公告)号：US5745469A

公开(公告)日：1998-04-28

申请号：US805726

申请日：1997-02-25

Applicant: Chun-Sup Kim ,  Yong-Serk Kim

Inventor： Chun-Sup Kim ,  Yong-Serk Kim

IPC: G11B19/00 ,  G11B7/00 ,  G11B7/005 ,  G11B20/10 ,  H03G3/30

CPC classification number: H03G3/3005 ,  G11B20/10009

Abstract: A preamplifier for an optical disc system. The preamplifier is based on an automatic gain control (AGC) system for obtaining a constant response and a stable output signal for input signals of a certain amplitude. The preamplifier includes a radio frequency amplifier for amplifying an output signal from the pick-up unit, an AGC unit for amplifying an output signal from the radio frequency amplifier to a desired level, an AGC detector unit coupled at its input terminal to an output terminal of the AGC unit and at its output terminal to an input terminal of the AGC unit. The AGC detector unit serves to rectify an output signal from the AGC unit, compare the rectified signal with a reference signal having a predetermined level, and send the resultant signal obtained by the comparison to the AGC unit. A mode selecting unit is coupled to the AGC detector unit and adapted to select one of several modes of operation, respectively corresponding to different equalization characteristics.

Abstract translation: 用于光盘系统的前置放大器。 前置放大器基于用于获得恒定响应的自动增益控制（AGC）系统和用于一定幅度的输入信号的稳定输出信号。 前置放大器包括用于放大来自拾取单元的输出信号的射频放大器，用于将来自射频放大器的输出信号放大到期望电平的AGC单元，在其输入端耦合到输出端子的AGC检测器单元 的AGC单元，并在其输出端连接到AGC单元的输入端。 AGC检测器单元用于对来自AGC单元的输出信号进行整流，将经整流的信号与具有预定电平的参考信号进行比较，并将通过比较获得的合成信号发送到AGC单元。 模式选择单元耦合到AGC检测器单元，并且适于分别对应于不同的均衡特性来选择若干操作模式之一。