Dynamic information storage or retrieval – Control of storage or retrieval operation by a control... – Mechanism control by the control signal
Reexamination Certificate
1998-11-05
2001-02-20
Huber, Paul W. (Department: 2753)
Dynamic information storage or retrieval
Control of storage or retrieval operation by a control...
Mechanism control by the control signal
C369S124140
Reexamination Certificate
active
06192012
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method and apparatus for performing a recording/reproduction of an information on/from an optical recording medium having recording tracks each defined by wobbled grooves.
2. Description of the Related Art
Generally, in a recordable or rewritable optical recording medium, a rotation control information and/or an address information are recorded by means of the wobbled grooves in advance. In other words, a rotation and/or address information are preformatted on the wobbled grooves. An example of the optical recording medium having the wobbled grooves as mentioned above includes a DVD-RAM(digital versatile disc-random access memory) as shown in FIG.
1
.
In the DVD-RAM of
FIG. 1
, there are formed wobbled grooves
10
and lands
12
wobbled alternately with the wobbled grooves
10
. The grooves and lands
10
and
12
are used as recording regions. A certain period of wobbling signals are included in a wobbled portion
14
of each groove and land
10
and
12
, hereinafter referred to as “wobbled part”, that is, in each side of the land and groove
10
and
12
. A recording/reproducing apparatus for an optical recording medium generates a rotation control information about the DVD-RAM and a recording clock by means of the wobbling signals. Also, each of the land and groove
10
and
12
is alternated with a identification(ID) region consisting of a pre-pit train
16
. The pre-pit train
16
includes an address information for indicating the physical position of the groove and land
10
and
12
. The physical positions of all the grooves and lands
10
and
12
are indicated by means of such ID regions, thereby recording an information on all the grooves and lands
10
and
12
.
In order to detect the wobbling signal from the optical recording medium having such wobbled lands and grooves
10
and
12
, the optical recording/reproducing apparatus makes use of a band pass filter(BPF) having a filtering characteristic corresponding to a frequency band of the wobbling signal. In an optical recording/reproducing apparatus employing such a BPF, the wobbling signals are not detected when a rotation speed of the optical recording medium is different from a reference speed. Also, an optical recording/reproducing apparatus including a BPF having a filtering characteristic corresponding to an optical recording medium in a specified rotation speed mode fails to detect the wobbling signal from the optical recording when it drives an optical recording medium in a different rotation speed mode. In other words, an optical recording/reproducing apparatus can not be used changeably for all optical recording media in various rotation speed modes. Moreover, the optical recording/reproducing apparatus including a BPF having a specified filtering characteristic fails to drive an optical recording medium at a certain of multiple speed because it can not detect the wobbling signal from the optical recording medium when the optical recording medium is driven at a speed different from the reference speed.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a recording/reproducing method and apparatus for an optical recording medium that is adapted to accurately detect a wobbling signal from an optical recording medium having recording tracks defined by wobbled grooves independently of a driving condition of the optical recording medium.
In order to achieve this and other objects of the invention, a recording/reproducing method for a recording medium according to one aspect of the present invention includes the steps of picking up a wobbling signal from a wobbled part in the recording medium; detecting a frequency of the wobbling signal being picked up from the wobbled part; and controlling a frequency band of filtering means for detecting the wobbling signal in accordance with the detected frequency.
A recording/reproducing apparatus for a recording medium according to another aspect of the present invention includes a pickup for picking up a signal from the recording medium; frequency detecting means for detecting a frequency of a wobbling signal picked up from a wobbled part in the recording medium by the pickup; filtering means for filtering a n output signal of the pickup to detect the wobbling signal; and a filter controller for responding an output signal of the frequency detecting means to control a filtering frequency band of the filtering means.
REFERENCES:
patent: 5508985 (1996-04-01), Fairchild et al.
patent: 5615185 (1997-03-01), Horikiri
patent: 5754522 (1998-05-01), Kobayashi et al.
Huber Paul W.
LG Electronics Inc.
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