Dynamic information storage or retrieval – Condition indicating – monitoring – or testing – Including radiation storage or retrieval
Reexamination Certificate
1998-11-25
2001-03-13
Hindi, Nabil (Department: 2753)
Dynamic information storage or retrieval
Condition indicating, monitoring, or testing
Including radiation storage or retrieval
C369S053130
Reexamination Certificate
active
06201776
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical disc player, and more particularly, to an apparatus for reproducing program data recorded on an optical disc at a multiple velocity, which is capable of preventing deterioration of a screen quality even though a user reproduces the program data at the multiple velocity which is faster than a normal reproduction velocity.
2. Description of the Prior Art
In general, optical discs can be divided into discs for exclusive use of reproduction, discs for use of an additional record, and discs for use of erasing and rewriting according to functions and uses thereof.
The reasons these kinds of optical disc players are widely used are that they can reproduce signals with far better quality of picture and/or sound and that it is possible for them to randomly access to program data to be reproduced. In addition to these reasons, there is other reason that noise arising from unstable reproduction and modulation does not occur.
Furthermore, unlike a video cassette recorder or a cassette recorder, these optical disc players can directly move an optical pick-up unit toward a target track position in order to reproduce the data which is recorded on the optical disc within a very short time.
FIG. 1
is a view for showing a screen arrangement type of a group of picture (hereinafter, referred to as GOP) conventionally recorded on an optical disc. As shown in
FIG. 1
, in the program data recorded on the optical disc, I pictures are arranged at regular intervals. The program data such as B pictures and P pictures are arranged between the two I pictures to make one GOP.
FIG. 2
is a block diagram for showing a circuit diagram of an prior apparatus for reproducing program data at multiple velocity.
Referring to
FIG. 2
, the reproducing apparatus has a key inputting section
10
, a control section
20
, a reproducing section
30
, a spindle motor driving section
40
, and a spindle motor
50
.
When a user operates a key of key inputting section
10
to generate a reproduction signal, optical disc D is rotated at a constant linear velocity and the program data recorded on optical disc D is reproduced at a normal velocity. At this time, when a reproducing key signal from key inputting section
10
generated by the user's key operation indicates a multiple velocity, control section
20
detects a position of the I picture of the program data reproduced from optical disc D by reproducing section
30
.
When the position of the I picture is detected, control section
20
controls reproducing section
30
to read out or skip I pictures following the detected I picture according to the reproducing key signal indicating the multiple velocity. That is, when the reproduction key signal indicating the multiple velocity is a reproduction key signal indicating twice velocity, as shown in
FIG. 2
, control section
20
controls reproducing section
30
to read out the I pictures by skipping one by two after detecting a first I picture. When the reproduction key signal indicating multiple velocity is a reproduction key signal indicating three times velocity, control section
30
detects only one out of three I pictures after detecting the first I picture.
Accordingly, the program data recorded on optical disc D is possible to be reproduced at the multiple velocity even though optical disc D being rotated by spindle motor driving section
40
and spindle motor
50
rotates at the constant linear velocity.
However, the reproducing apparatus described above causes a loss of the program data because of skipping other I pictures among the respective I pictures for reproducing the program data at multiple velocity. Consequently, a screen quality of the program data reproduced from reproducing section is deteriorated.
SUMMARY OF THE INVENTION
Therefore, it is an object of the present invention to provide an apparatus for reproducing program data recorded on an optical disc at a multiple velocity, which is capable of preventing deterioration of a screen quality even though a user reproduces the program data recorded on the optical disc at the multiple velocity which is faster than a normal reproduction velocity.
In order to achieve the above object, the present invention provides an apparatus for reproducing data recorded on an optical disc at a multiple velocity, which comprises:
storing means for storing data which relates to a rotation velocity for normal and multiple velocity reproductions of the optical disc and to a reproduction velocity of the program data recorded on said optical disc;
control means for detecting whether or not a reproduction mode signal generated by a user's key operation is either the normal velocity reproduction or the multiple velocity reproduction, for reading out the rotation and the reproduction velocity data corresponding to the detected reproduction mode signal from said storing means to output rotation and reproduction velocity data signals;
clock generating means for generating a reference clock signal;
velocity control means for receiving the reference clock signal and for dividing the reference clock signal based on the rotation and reproduction velocity data signals to output rotation and reproduction velocity control signals and a memory control signal corresponding to the detected reproduction mode signal;
rotating means for receiving a present reproduction velocity signal and for rotating said optical disc at a rotation velocity determined by the present reproduction velocity signal and the rotation velocity control signal;
reproducing means for reproducing the program data recorded on said optical disc at a reproduction velocity determined by the reproduction velocity control signal and for providing said rotating means with the present reproduction velocity signal which represents a presently-reproduced velocity of the program data; and
a memory for storing the program data from said reproducing means and for outputting the stored program data in response to the memory control signal.
In the present invention, the velocity control means variably outputs a period of clock pulses of the reference clock signal based on the rotation and the reproduction velocity data.
In the apparatus for reproducing the program data recorded on the optical disc at the multiple velocity according to the present invention, the rotation velocity of optical disc D and the reproduction velocity of the program data recorded on optical disc D are variably controlled in accordance with the user's key operation. Also, the program data reproduced at the multiple velocity is outputted to a display apparatus after the program data is sequentially stored in memory. Accordingly, the loss of the program data which is reproduced from optical disc D does not occurred even though the user selects a mode for reproducing the program data recorded on optical disc D at the multiple velocity.
Therefore, the apparatus can prevent the deterioration of the screen quality caused by reproducing the program data recorded on optical disc D at the multiple velocity.
REFERENCES:
patent: 5956307 (1999-09-01), Koudo et al.
Daewoo Electronics Co. Ltd.
Hindi Nabil
Pillsbury & Winthrop LLP
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