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Clock drawing equipment for optical disk reproducing device

A clock extraction and reproduction device technology, applied in beam reproduction, synchronization device, reproduction of non-user data, etc., can solve the impossible, extraction clock and other problems

Inactive Publication Date: 2002-06-19
PANASONIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Meanwhile, even when the frequency of the clock to be extracted from the information signal coincides with the output frequency of the voltage-controlled oscillator 5, in the worst case, it may become impossible to extract the frequency of the clock by oscillation due to the phase-lock operation of the phase comparator 3. state
[0026] Therefore, in the clock extracting device of the existing disc reproducing apparatus, there occurs such a disadvantage that although it is necessary to change the loop gain of the clock extracting circuit according to the continuously changing extraction rate of the information signal, only when the reading of the information signal has been set rate, only to change the loop gain of the clock extraction circuit

Method used

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  • Clock drawing equipment for optical disk reproducing device
  • Clock drawing equipment for optical disk reproducing device
  • Clock drawing equipment for optical disk reproducing device

Examples

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Comparison scheme
Effect test

no. 1 example

[0045] figure 1 A clock extracting device K1 of an optical disc reproducing apparatus according to a first embodiment of the present invention is shown. exist figure 1 Among them, the information signal that is taken out from the disk-shaped information recording medium such as optical disk 1 by such as information read-out apparatus of optical pickup 2 is input to an input terminal of phase comparator 3 and an input of a frequency comparator 8 end. The outputs of the phase comparator 3 and the frequency comparator 8 control the charge pump 4 so as to be converted into a current value by the charge pump 4 as described below. The current value from the charge pump 4 is applied to a series circuit of the resistor R1 and the capacitor C1 to be converted into a voltage value by the series circuit. This voltage value serves as a control voltage for the voltage-controlled oscillator 5 and is input to the voltage-controlled oscillator 5 .

[0046] In this embodiment, the other ...

no. 2 example

[0065] Figure 9 A clock extracting device K2 of an optical disc reproducing apparatus according to a second embodiment of the present invention is shown. exist figure 1 In the first embodiment, the clock extraction device K1 including the charge pump 4, the voltage controlled oscillator 5 and the resistor R1 and the capacitor C1 is of an analog type. On the other hand, the clock extraction circuit K2 includes a multiplier 4A instead of the charge pump 4, a digital filter 27 instead of the resistor R1 and capacitor C1, and a digitally controlled oscillator 5A instead of the voltage-controlled oscillator 5, to form a digital phase-locked loop (DPLL ). Since the alternative structure of the clock extracting device K2 is similar to that of the clock extracting device K1, their detailed descriptions are omitted for simplicity.

[0066] The multiplier 4A changes the multiplication factor according to the command of the gain command unit 7 . For example, when the multiplication...

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Abstract

A clock extracting device of a disc reproducing apparatus, comprising: an information read-out member for reading information signals from a disk-like information recording medium; a voltage control oscillator; a phase comparator; a frequency comparator; a speed sensor; a gain command unit; a charge pump; and a series circuit of a resistor and a capacitor, whose one end is connected to an output of the charge pump and the other end of which is grounded or is connected to a reference voltage; wherein an output voltage between the opposite ends of the series circuit acts as a control voltage for the voltage control oscillator and the gain command unit issues the gain command such that the loop gain of the clock extracting circuit secures a desired operating point in accordance with a read rate of the information signals.

Description

technical field [0001] The present invention relates to a clock extracting device for extracting a clock synchronized with an information signal read from a disc-shaped information recording medium (hereinafter referred to as "disc"), which is used in a disc reproducing apparatus for The extracted clock records the information signal. Background technique [0002] A constant linear velocity (CLV) recording method is known as a method for recording information signals on a disc. In order to read out an information signal recorded by CLV from the disc, it is necessary to provide a clock extracting circuit for extracting a clock synchronized with the information signal. [0003] Referring to the first example showing the clock extracting device of the conventional optical disk reproducing apparatus Figure 11 A conventional clock extraction circuit is described. exist Figure 11 In this case, the information signal taken out from the optical disc 1 by the optical pickup 2 is ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G11B5/012G11B7/005G11B11/105G11B20/14H03L7/087H03L7/089H03L7/093H03L7/113H04L7/027
CPCG11B20/1403H03L7/0898H03L7/093G11B7/0053G11B5/012G11B20/1025G11B11/10515H03L7/087H03L7/113
Inventor 中村正义北野绘美
Owner PANASONIC CORP