JPS63122064A - Optical disk reproducing device - Google Patents

Abstract

PURPOSE:To quicken access time by providing a buffer circuit converting a signal from plural pickups into a prescribed speed. CONSTITUTION:The signal from the pickups 3 is inputted to the buffer circuit 7 through a clock extraction pit extraction circuit 6. The input clock is changed by a frequency of a reproduced signal by the circuit 7 but the output clock is a clock of a prescribed frequency formed by a clock generating circuit 11. The output of the circuit 7 is inputted to a signal processing circuit 8, where the processing such as error correction or the like is applied, and a signal is outputted by a prescribed form and given to a digital data output terminal 12 via a digital data processing circuit 9 and an analog data output terminal 12 via a D/A conversion circuit 10. The CLV servo is applied normally in matching with the pickup locked at the inner circumference. Thus, a frequency signal higher than the normal frequency is outputted from the pickup at the outer circumference. Thus, the access time is quickened and the data transfer speed is increased.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a so-called optical disc reproducing device that reproduces signals from a disc-shaped recording medium using laser light or the like.
The rotational speed of the disk is constant linear velocity (hereinafter referred to as CLV)
The present invention relates to an optical disc replaying device that maintains the performance of the optical disc.

[Conventional technology]

Conventionally, this type of CL/V servo type optical disc playback device requires a one-to-one correspondence between the position on the disc where the pickup detects the signal and the rotational speed of the disc, making it difficult to use multiple pickups. I never had one.

[Problem that the invention seeks to solve]

The conventional CLV type optical disc reproducing apparatus described above has only one pickup, so when randomly accessing any position on the disc, it is necessary to wait until the pickup moves to a designated position.

Therefore, it is impossible to continuously reproduce signals recorded at distant positions, and it is also impossible to reproduce a plurality of signals simultaneously.

[Failure to solve the problem]

In order to solve the above problems, the optical disc playback device of the present invention includes a plurality of pickups for detecting one signal,
It has a buffer circuit so that the signal can be reproduced even if the linear velocity is not a specified value.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. Optical disc 1 is CL
A signal is recorded at v, and the motor 2 rotates the motor. The motor 2 is controlled by a motor drive servo 5. The controller 14 determines which position of the pickup 3 the linear velocity is adjusted to.

The optical system servo 4 performs focus servo, tracking servo, and feed servo. The signal output from pickup 3 is clock extracted.

The signal passes through the pit extraction circuit 6 and is input to the buffer circuit 7. In this buffer circuit, the input and output clocks are asynchronous. The clock on the input side changes depending on the frequency of the reproduced signal, but the clock on the output side is a clock with a constant frequency generated by the clock generation circuit 11.

The output of the buffer circuit 7 is input to a signal processing circuit 8. The signal processing circuit 8 performs processing such as signal error 9 correction,
Outputs a signal in a certain format. 9 is a digital data processing circuit in this embodiment, and 10 is an L/A conversion circuit in this embodiment. 12 is a digital data output terminal, 13
is an analog data output terminal.

In this optical disc playback device, the C
Apply LV servo. This is Q.

The outer pickup always outputs a signal with a frequency υ higher than the normal frequency. If the CLV servo is applied to the pickup located on the innermost circumference, and the other pickup is on the outermost circumference, the frequency of the signal output from the pickup on the outermost circumference will be approximately twice the normal frequency. become.

Therefore, the capacity of the buffer circuit 7 only needs to be the same amount as the amount of data to be reproduced in - times of access.

FIG. 2 shows an example of data recording on an optical disc reproduced by this optical disc reproducing apparatus, in which digital audio data is recorded on the inside, and code data or image data is recorded on the outside.

When this disc is played back by the optical disc playback device of the present invention, while continuously playing audio data,
Code data, image data, etc. can be randomly reproduced when necessary.

〔Effect of the invention〕

As explained above, according to the present invention, the shortcoming of the CLV method, which is slow access time, can be solved, and moreover, it is possible to read multiple pieces of data from different locations on the disk at the same time. This has the effect of increasing the data transfer speed.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention, and FIG. 2 is a diagram showing an example of data recording on an optical disc. 1... Optical disk, 2... Motor,
3...Pickup, 4...Optical system servo, 5...Motor drive servo, 6...
・・Clock extraction, bit extraction circuit, 7・・・・・・
Buffer circuit, 8...Signal processing circuit, 9...
・Digital data processing circuit, 10...D/A
Conversion circuit, 11...Clock generation circuit, 12.
...Digital data output terminal, 13...
・Analog data output terminal, 14... Controller, a ''' - Code data, image data recording area, b... Audio data recording area. Agent Patent attorney Hara Uchi -゛゛゛゛'4゛゛Day

Claims (1)

[Claims] An optical disc playback device that plays back signals recorded on a disc while controlling the rotational speed of the disc to keep the linear velocity constant. An optical disc playback device characterized by comprising a buffer circuit for converting an output signal to a constant speed.