Dynamic information storage or retrieval – Condition indicating – monitoring – or testing – Including radiation storage or retrieval
Reexamination Certificate
1998-10-26
2001-04-10
Edun, Muhammad (Department: 2753)
Dynamic information storage or retrieval
Condition indicating, monitoring, or testing
Including radiation storage or retrieval
C369S044290, C369S044350
Reexamination Certificate
active
06215749
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to digital signal recording and reproducing devices. Specifically, this invention is an apparatus for minimizing the signal distortion, caused by the difference in pick-up and disc characteristic of a high speed optical disc reproducing device.
2. Description of the Related Art
In digital signal recording and reproducing devices, especially optical disc reproducing devices which read data of optical disc at a high speed, such as CD-ROM, DVDP (Digital Versatile Disc Player), DVD-ROM, etc., a signal (input signal) read from an optical disc by a pick-up mechanism has various levels in accordance with its frequency area. This is because the picked-up signal has high frequency components whose amplitudes are lower than that of other frequencies. In addition, the level of the picked-up signal varies with the kind of pick-up (depending on its speed, for example), and kind of disc (CD or DVD).
Therefore, it is preferable to compensate for the attenuation of input signal, and get rid of the group delay deviation. However, a conventional boost circuit allows the gain to be amplified, simultaneously causing the group delay to be altered. As a result, the output signal is distorted. The conventional boost circuit can not be used in optical disc reproducing device which reads data from an optical disc at a high speed, such as CD-ROM, DVDP (Digital Versatile Disc Player), DVD-ROM, etc.
A device which is applicable to high speed optical disc players and CD-ROM, DVD, etc., is required to solve the above-mentioned problem.
SUMMARY OF THE INVENTION
An objective of the present invention is to provide an apparatus which reads data from an optical disc at a high speed and minimizes the signal distortion, caused by the difference in the pick-up and the disc characteristics.
Another objective of the present invention is to provide an apparatus for preventing the signal distortion, by boosting and group-delaying a read signal, so as to be applicable to various kinds of disc players.
To achieve the objective of the present invention, a high speed optical disc reproducing device includes: a gain amplifier for amplifying data picked-up from an optical disc with a specific amplification gain; a frequency and boost control unit for outputting frequency and boost gain control signal under the control of a main control unit in accordance with the kind of pick-up and disc used; and a boost filter which serves the functions of boosting the high frequency signals of output signal of the gain amplifier according to the frequency and a boost gain control signal, and specifically group-delaying of all the frequency areas of the output signal.
REFERENCES:
patent: 5808979 (1998-09-01), Ishibashi et al.
Edun Muhammad
Samsung Electronics Co,. Ltd.
Sughrue Mion Zinn Macpeak & Seas, PLLC
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