JPH04324163A - Optical disk reproducing device - Google Patents

Abstract

PURPOSE:To attain the continuous reproduction by recording the regenerative signal at a high speed than the standard, reading out at the standard speed, cumulating the regenerator signal in the memory and interrupting the writing when the quantity is equal to the disk inversion time. CONSTITUTION:An optical disk 1 is read out at a high speed than the standard and the regenerative signal is written in the memory 7 with a clock WCK synchronized to it. The signal is cumulated in the memory 7 having a FIFO function since it is read out with a standard clock RCK from the memory. The cumulated signal quantity is detected with a detection circuit 11 and when the quantity is equal to the inversion time of the disk 1, the detection signal from the circuit 11 is sent to a pickup control circuit 10. The circuit 10 performs still or reverse jump at a proper time interval and the writing is interrupted during that period. Hence the memory capacity is made as much as the disk inversion time,so the over flow is prevented and the continuous reproduction is attained.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc reproducing apparatus, and more particularly to an optical disc reproducing apparatus having a double-sided disc reproducing function.

0002

[Background Art] In an optical disc playback device that optically reads and plays back information recorded on the surface of an optical disc via a pickup, a double-sided playback function reads out information recorded on both sides of the optical disc and plays back the information recorded on both sides. Conventionally, there are two methods for achieving this. That is, in the first method, the side to be played first (hereinafter referred to as side A) is played, and when the playback of side A is completed, the optical disc is turned over and the opposite side (hereinafter referred to as side B) is played. This is a reproduction method. In the second method, when the reproduction of side A is completed, the optical disc is left as it is, the pickup is reversed, and the direction of rotation of the turntable of the optical disc is reversed to reproduce side B.

0003

[Problems to be Solved by the Invention] As mentioned above, in conventional optical disc playback devices, in order to play back both sides, A
After the side has been reproduced, the optical disc is turned over or the pickup is reversed to reverse the rotation of the optical disc. However, in any of the conventional methods, it takes time to reproduce the B side after the A side has been reproduced, and it is impossible to reproduce the A side and the B side continuously. That is, turning over the optical disk is a mechanical operation that takes time, and reversing the pickup and reversing the rotation of the optical disk also takes time after the turntable starts reversing until it reaches a certain rotational speed necessary for playback. If the contents recorded on sides A and B are independent, there will be no major problem even if it takes time to play back from side A to side B, resulting in discontinuous playback. Optical discs on which opera and the like are recorded often have long content that cannot be recorded on one side, and many optical discs are recorded on both sides. When reproducing such an optical disc recorded on both sides, in the conventional method described above, the blank period accompanying discontinuous reproduction when reproducing from side A to side B is unsatisfactory for the user.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an optical disc reproducing apparatus that is capable of continuously reproducing both sides of an optical disc.

[0005]

[Means for Solving the Problems] In order to solve the above-mentioned problems, an optical disc reproducing apparatus according to the present invention has a double-sided reproducing function that starts reproducing the other side after completing reproducing one side of the optical disc. writing a reproduced signal obtained from the optical disk into a memory that performs first-in/first-out operation at a higher speed than a standard speed, reading the reproduced signal from the memory at the standard speed, and accumulating the reproduced signal in the memory; After the reproduction of one side is finished, the reproduction signal stored in the memory is read out and output during the period of time until the reproduction of the other side is started. Further, in an optical disc playback device having a playback function of restarting playback of one side of an optical disc after the playback of one side is completed, the playback signal obtained from the optical disc is subjected to a first-in/first-out operation at a higher speed than a standard speed. writing into a memory, reading out a playback signal from the memory at the standard speed, and reading and outputting the playback signal stored in the memory during the time from the end of playback of the one side until the start of playback of the one side again. Constructed as a feature.

[0006]

[Operation] In this invention, a reproduced signal obtained from an optical disk is written to a memory that performs first-in/first-out operation at a higher speed than the standard speed, and the reproduced signal is read from this memory at the standard speed to transfer the reproduced signal to the memory. After the reproduction of one side of the optical disc is completed, the reproduction signal stored in the memory is read out and reproduced and output during the period of time until the reproduction of the other side or that one side starts.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of an optical disc reproducing apparatus according to the present invention. optical disc 1
is placed on a turntable 2 and rotated by the turntable 2 which is rotationally driven by a spindle motor 3. The rotational speed of the spindle motor 3 is controlled by a spindle servo circuit 8. optical disc 1
A laser beam is emitted from the pickup 5 toward the surface of the pickup 5 , and the reflected light is detected by the pickup 5 and sent to the signal processing circuit 6 . The double-sided playback mechanism 4 is a mechanical means necessary for double-sided playback such as turning over the optical disc and reversing the pickup described above. The signal processing circuit 6 performs predetermined reproduction processing on the signal from the pickup 5 and reads the signal from the memory 7 in response to the write clock WCK synchronized with the reproduction signal.
to be recorded. A standard (reference) clock generation circuit 9 supplies a read clock RCK for outputting a reproduced signal to a memory 7 that performs first-in, first-out (FIFO) operation, and also supplies a reference clock to a spindle servo circuit 8. supply The spindle servo circuit 8 controls the rotational speed of the spindle motor 3 based on the reference clock from the standard clock generation circuit 9 and the synchronization clock SD of the reproduced signal obtained by the signal processing circuit 6. The detection circuit 11 determines the difference between the write address and the read address of the memory 7, and sends a detection signal to the pickup control circuit 10 when the difference reaches a certain value.

The configuration of this embodiment is as described above, but
The specific operation will be explained below. The optical disc 1 is played back at a speed faster than the standard speed (high speed playback) under the control of the spindle servo circuit 8, and the optical disc 1 is played back at a speed faster than the standard speed (high speed playback).
A reproduced signal S is obtained from the signal read out by the signal processing circuit 6. The reproduced signal S is written into the memory 7 by a write clock WCK synchronized with the reproduced signal. Signals are read from the memory 7 based on the read clock RCK from the standard clock generation circuit 9, and a reproduced output signal at the standard reproduction speed is obtained. memory 7
has a so-called FIFO function, and the writing speed to the memory 7 is faster than the reading speed, so the reproduced signal from the signal processing circuit 6 is stored in the memory 7. Since the accumulated signal amount can be known from the difference between the write address and the read address, the detection circuit 11 detects this accumulated signal amount D, and detects whether the accumulated signal amount is on the A side due to disk reversal, etc. It is detected that the disc inversion time required from the end of reproduction to the start of reproduction of side B is reached, and a detection signal is sent to the pickup control circuit 10. The pickup control circuit 10 performs still or reverse jump at appropriate time intervals, and also stops writing to the memory 7 during that time, thereby making the average write speed match the playback speed. By doing this, the capacity of the memory 7 is set to about the above-mentioned disc reversal time, and the disc is played back without overflowing, and the playback of one side is completed. At this time, the memory 7 has accumulated signals for the time required from the end of playback of the A side to the start of playback of the B side, such as when the disc is reversed. If processing such as disc reversal is performed while reading and outputting, continuous reproduction from side A to side B becomes possible.

[0009] In the embodiments described above, if similar operations and processing are performed when playing back side B (back side), continuous playback from side B to side A can be performed again, and endless playback is also possible. Furthermore, the present invention can be applied to single-sided repeat playback in which the same side is played back again after the playback of one side is completed. Furthermore, it is clear that the present invention has a function as a so-called time base collector (TBC), so a conventional TBC is not necessary. Note that since the amount of signals stored in the memory 7 can be considered to be proportional to the elapsed time from the start of reproduction, it can also be detected by measuring this elapsed time.

0010

As explained above, the optical disc playback device according to the present invention uses a memory with a FIFO function, records playback signals in this memory at a faster speed than the standard, and reads out the data from the memory at the standard speed. After the playback of the A side ends, the signal stored in the memory is read out and output as a playback signal during the time from the end of playing back the A side to the start of playing back the B side, making continuous playback of the optical disc possible. In addition, it also has a time base collector function, which simplifies the configuration.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an embodiment of an optical disc reproducing apparatus according to the present invention.

[Explanation of symbols]

1 optical disc 2
Turntable 3 Spindle motor 4
Double-sided playback mechanism 5 pickup
6 Signal processing circuit 7
memory 8
Spindle servo circuit 9 Standard clock generation circuit 10
Pickup control circuit 11 detection circuit

Claims (2)

[Claims] Claims: 1. An optical disc playback device having a double-sided playback function that starts playback of the other side after the playback of one side of the optical disc is completed, wherein a playback signal obtained from the optical disc is
Write data into a memory that performs first-in/first-out operation at a higher speed than the standard speed, read out the playback signal from the memory at the standard speed, store the playback signal in the memory, and after the completion of playback of the one side, write the playback signal to the other side. 2. An optical disc reproducing apparatus, characterized in that the reproduction signal stored in the memory is read out and outputted during the time until the start of reproduction. 2. An optical disc playback device having a playback function of restarting playback of one side of an optical disc after completion of playback of one side of the optical disc, wherein the playback signal obtained from the optical disc is first-in/first-out at a higher speed than a standard speed. write into a memory that operates, read out a playback signal from the memory at the standard speed, read out the playback signal stored in the memory during the time from the end of playback of the one side until the start of playback of the one side again, and output the playback signal. An optical disc playback device characterized by: