JP2500727B2 - Magneto-optical disk device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magneto-optical disk device for recording / reproducing data using a data compression technique and a magnetic field modulation method.

[0002]

2. Description of the Related Art A magneto-optical disk for audio recording and reproduction has been developed by utilizing a data compression technology and a magnetic field modulation method. The digital audio signal to be recorded is data-compressed by utilizing the auditory characteristic. Recording (recording) of compressed data on a magneto-optical disk is performed by irradiating a laser beam from one surface of the disk and applying a magnetic field from the other surface. At the time of reproduction, the compressed data read from the magneto-optical disk is expanded and returned to the time axis information.

In such a recordable / reproducible magneto-optical disk device, it has been proposed to insert a buffer memory between the optical pickup and the compression decoder to prevent skipping due to vibration during reproduction. (For example, NIKKEI E
LECTRONICS 1991.12.9, NO.542, p.160). This is because if the track-jumped optical pickup returns to its original position within a prescribed time, the difference between the read-out transfer rate of the data on the optical disc by the optical pickup and the transfer rate from the buffer memory to the decoder is used.・ It utilizes the ability to ensure the continuity of reading from memory.

[0004]

However, in the magneto-optical disk device of this type which has been conventionally proposed, no measures have been taken against the track jump when recording data on the magneto-optical disk. The present invention has been made in consideration of such circumstances, and an object of the present invention is to provide a magneto-optical disk device provided with a measure against a track jump at the time of recording.

[0005]

SUMMARY OF THE INVENTION A magneto-optical device according to the present invention.
The disk device is a magneto-optical disk and this magneto-optical disk.
An optical pickup for recording and reproducing data of
A magnetic field that applies a magnetic field during data recording on a magneto-optical disk.
And the digital data to be recorded is compressed and played back.
Encoder / Decoder for expanding digital data to be processed
This encoder / decoder and the optical pickup
And a semiconductor memory provided between the magnetic head, and
Track to detect track jump of optical pickup
Jump detection means and the track jump detection at the time of recording
The output signal of the optical output means outputs the output power of the optical pickup.
Lower the power and position of the optical pickup
Track jump to read address of the semiconductor memory
Return to the position before the position, and
Control means for restarting recording again from the data recording device .

[0006]

According to the present invention, writing defects due to track jumps (needle jumps) due to vibrations during data recording are prevented. Since the magneto-optical disk can be rewritten by overwriting, it is possible to record data again from the beginning even if there is a track jump. However, according to the present invention, for example, when recording 60 minutes of audio data in real time, even if there is a track jump, it can be recorded in 60 minutes without any problem.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the configuration of a magneto-optical disk device according to an embodiment of the present invention. Reference numeral 1 is a rewritable magneto-optical disk using a polycarbonate substrate, for example.
Pregrooves are formed in advance on the magneto-optical disk 1 for tracking control, and addresses are formed in advance along the pregrooves. Reference numeral 2 is a disk motor for rotating the magneto-optical disk 1. Below the magneto-optical disk 1, an optical pickup 3 for irradiating a laser beam for recording / reproducing is provided on the lower surface thereof. Output control and feed control of the optical pickup 3 are performed by the feed motor 4 and the servo control circuit 7. A magnetic head 5 for applying a magnetic field simultaneously with light at the time of recording is provided above the magneto-optical disk 1, and is driven by a head driving device 6.

Compression / decompression encoder / decoder 13
Is an encoder unit for compressing digital data obtained by converting the input audio signal by the A / D converter 14, and a decoder for expanding the output signal from the magneto-optical disk and transferring it to the D / A converter 15 connected to the audio output terminal. It is composed of parts. The modulation / demodulation encoder / decoder 10 also applies EFM modulation or CIRC to the compressed data to be recorded.
It is composed of an encoder section that performs modulation and a decoder section that demodulates a reproduction output. This encoder / decoder 1
The print data from 0 is supplied to the head drive device 6.
Also, during reproduction, the output signal obtained by the optical pickup 3 and amplified by the RF amplifier 8 and the output of the address decoder 9 for decoding the address data on the disk extracted from this output signal are the encoder / decoder 1
0 to the decoder section.

Between the two encoders / decoders 10 and 13, as a semiconductor memory for eliminating the influence of a track jump (needle skip) at the time of recording, for example, a 1 Mbit D
RAM 11 is provided. The DRAM 11 is also used to eliminate the influence of needle skipping during reproduction. This D
It is the DRAM that controls the reading and writing of the RAM 11.
The controller 12. The system controller 16 controls the entire system, and controls the recording / playback switching and the operation timing in each mode according to an instruction from the key 19. Information necessary for the system controller 16 is displayed on the display device 18.

In order to detect a track jump of the optical pickup 3, a track jump detection circuit 17 is provided at the output terminal of the RF amplifier 8. The track jump detection circuit 17 monitors the tracking error signal obtained at the output of the optical pickup 3 so that the laser beam becomes 1
A track jump detection signal is output by detecting that the track has deviated. The output of the track jump detection circuit 17 is supplied to the system controller 16, which controls the reading of the DRAM 11 during recording and the output power of the optical pickup 3 as described later.

The operation of the magneto-optical disk device thus constructed will be described below. The input audio signal is converted into, for example, 16-bit digital data by the A / D converter 14, and this is compressed by the encoder / decoder 13. The data compression rate is set in consideration of the auditory characteristics, and for example, as shown in FIG. 2, it is time-compressed to 1/4 to 1/5. Thus, the data compressed on the time axis at every predetermined time is the sector data A1, A2, ... And when this data is recorded on the magneto-optical disk as it is, intermittent recording is performed.

The compressed data is sequentially written in the DRAM 11. The data written in the DRAM 11 is read, for example, in a block unit in which a plurality of sector data are collected, modulated by the encoder / decoder 10, and then given to the head drive device 6, where it is read by a magnetic field modulation method. The data is sequentially recorded on the magnetic disk 1. Writing and reading of the DRAM 11 are controlled by the system controller 16 and the DRAM controller 12. In the case of this embodiment, D
The data read speed is faster than the data write speed of the RAM 11. During recording, the laser light output power of the optical pickup 3 is set to a larger value than during reproduction.

The operation when the needle jump occurs due to vibration or the like during the above recording will be described below. The track jump detection circuit 17 monitors the tracking error signal as described above, and when the needle jump for one track occurs,
A track jump detection signal is issued as shown in. The tracking error signal shown in FIG. 3 is the difference between the reflected output signals of the two sub-beams in the normal three-beam method, and as shown in the figure, it oscillates from positive to negative (or negative to positive) for one cycle. It means that one track has been skipped. When this track jump detection signal is transferred to the system controller 16, a DRA different from that during normal operation is obtained.
Reading control of M11, tracking control of the optical pickup 3, and output power control are performed.

The control by the system controller 16 at this time is conceptually shown in FIG. By the 1-track jump detection (S1), the output power of the optical pickup is first lowered to, for example, the output power at the time of reproduction (S2). This is to prevent data destruction in one track of the already recorded area, but to prevent further data destruction. Then, it is judged whether or not the track jump is to the outer circumference (S3), and if the track jump is to the inner circumference, the address pointer is returned to the position before one round (S4).
). The address pointer indicates the address on the memory of the data to be output next for recording on the disk. When the data is output from the memory, the address pointer moves up one position,
When new data is input, it shall move down one level. Then, the optical pickup is returned to the position one round ahead of the jump position (S5), and after the reproduction operation is performed to the target position, that is, the position one round before the track jump position (S6).
), And overwrite (S7). When jumping to the outer circumference, move the address pointer back one step (S8),
Return the optical pickup position to a position before the jump position (S
9) The reproduction operation is performed up to the target position (S10), and then the overwriting is performed (S11). It should be noted that even if the jump to the unrecorded area or the jump to the already recorded area is preceded, the power control of lowering the output power of the optical pickup to the reproduction power is not performed when the jump is made to the unrecorded area. Good. This is because it will be overwritten after that.

The recording operation at the normal time and when the track jump occurs will be described with reference to FIGS. 5 to 7, focusing on the read / write operation of the DRAM 11. Figure 5 shows DRAM during normal operation
11 conceptually shows data reading and writing. As described above, in this embodiment, recording is sequentially performed for each block data in which a plurality of sector data is collected. That is, data is written in the DRAM 11 in the order of A block, B block, .... At a predetermined timing with respect to the data writing to the DRAM 11, the data of the A block, the B block, ... Are sequentially read and recording on the magneto-optical disk 1 is performed. Since the DRAM 11 is restored (rewritten) at the same time as the data is read, if the write address is continuously updated, the data read and already recorded on the magneto-optical disk 1 remains within the range where the DRAM 11 does not overflow. Has been done.

Writing data to the DRAM 11
The timing of reading (that is, disk recording) is as shown in FIG. 7, for example. The data writing and reading of the DRAM 11 do not necessarily need to be synchronized. Also D
If the RAM 11 is a dual port type capable of writing and reading at the same time, it is possible, for example, to write data to the DRAM 11 continuously with A block, B block, ... Is.

In contrast to FIG. 5, the read / write operation of the DRAM 11 when a track jump occurs is as shown in FIG. That is, if a track jump occurs while the data of the B block is read from the DRAM 11 and is recorded on the disk, the optical pickup 3 is returned from the track jump position to one block data before, and D
The read address of the RAM 11 is returned to the B block data and overwriting is performed. The track jump position can be known, for example, from the absolute time information recorded in advance on the magneto-optical disk 1, and the position for returning the optical pickup is also determined based on this information and the data structure. Similarly, the return amount of the read address of the DRAM 11 can be determined based on the data structure and the absolute time information. While this overwrite control is being performed, D
Data can be written in the RAM 11 as usual.

Up to this point, for the sake of simplicity, the case has been described in which the data of one block is returned and the data is overwritten. However, when a track jump occurs on the side of the disk 1 where data has already been recorded. Data on one track adjacent to the position where the track jump has occurred is destroyed, so it is necessary to return to the previous track and overwrite. Therefore, the DRAM 11 needs to have a capacity of at least the data of the outermost track of the magneto-optical disk 1. If the read speed is set higher than the write speed of the DRAM 11,
While writing to the DRAM 11 as usual, the same disk recording as in the case where there is no track jump can be performed.

The reproduction of the audio data thus recorded is performed by setting the output power of the optical pickup 3 to that for reproduction. The explanation of the operation is omitted,
The DRAM 11 is also used as a buffer memory for preventing skipping during reproduction. That is, while the reproduction data from the magneto-optical disk 1 is written in the DRAM 11, read out and transferred to the encoder / decoder 13, the DRA
Since there is a time margin equivalent to the capacity of M11, skipping of sounds can be prevented if the optical pickup 3 can be returned to the original position and the reproduction can be resumed within a predetermined time when a needle skip occurs.

The present invention is not limited to the above embodiment. For example, in the embodiment, the track jump detection circuit 17 is provided separately from the system controller 16, but it is possible to detect the track jump by monitoring the address information in the system controller 17. Further, instead of the DRAM 11, another semiconductor memory such as SRAM or EEPROM can be used. Others The present invention can be implemented with various modifications without departing from the spirit thereof.

[0021]

As described above, according to the present invention,
It is possible to eliminate the influence of the track jump at the time of recording in the magneto-optical disk device using the data compression technique and the magnetic field modulation method.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a magneto-optical disk device according to an embodiment of the present invention.

FIG. 2 is a diagram showing how data is compressed in the same embodiment.

FIG. 3 is an operation waveform of track jump detection in the embodiment.

FIG. 4 is a diagram showing a control flow when a track jump occurs in the embodiment.

FIG. 5 is a diagram for explaining write / read operations of the DRAM of the embodiment.

FIG. 6 is a DRAM of the same embodiment when a track jump occurs.
FIG. 7 is a diagram for explaining the write / read operation of FIG.

FIG. 7 is a timing chart of DRAM writing and disk recording of the same embodiment.

[Explanation of symbols]

1 ... Magneto-optical disk, 2 ... Disk motor, 3 ... Optical pickup, 4 ... Feed motor, 5 ... Magnetic head,
6 ... Head drive device, 7 ... Servo control circuit, 8 ... RF amplifier, 9 ... Address decoder, 10 ... Modulation / demodulation encoder / decoder, 11 ... DRAM, 12 ... DRAM controller, 13 ... Compression / expansion encoder / decoder , 14 ... A / D converter, 15 ... D / A converter, 16 ...
System controller, 17 ... Track jump detection circuit, 18 ... Display device, 19 ... Key.

Claims (1)

(57) [Claims] 1. A magneto-optical disk, an optical pickup for recording and reproducing data on and from the magneto-optical disk, a magnetic head for applying a magnetic field to the magneto-optical disk during data recording, and compression of digital data to be recorded, An encoder / decoder for expanding digital data to be reproduced, a semiconductor memory provided between the encoder / decoder and the optical pickup and the magnetic head, track jump detection means for detecting a track jump of the optical pickup, and recording. By the output signal of the track jump detection means at the time, while reducing the output power of the optical pickup,
A magneto-optical disk device comprising: a control unit that returns the position of the optical pickup and the read address of the semiconductor memory to a position before the track jump position and restarts recording again from the data before the track jump position. .