JP3106696B2 - Disc playback 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 mini disk reproducing apparatus for reproducing an optical disk or a magneto-optical disk having a diameter of 64 mm stored in a cartridge.

[0002]

2. Description of the Related Art Diameter 64 mm stored in a cartridge
A mini disk (MD) system for recording / reproducing a digital audio signal using an optical disk or a magneto-optical disk has been developed. In a mini-disc, a digital audio signal is compressed to about 1/5 and recorded using an audio compression technique. As a result, recording / reproduction of a high-quality audio signal for about 74 minutes can be performed on a small-diameter disk having a diameter of 64 mm.

In a mini disc recording / reproducing apparatus,
At the time of data recording, it is necessary to control the laser power and the interleave length of the CIRC is longer than the length of one sector in 108 frames, so a linking area is required. For this reason, in the mini disc, recording / reproduction is performed in units of clusters composed of 36 sectors. Of the 36-sector cluster, data is recorded in 32 sectors. The remaining sectors are used for linking and sub data.

At the time of reproduction, data is reproduced from an optical disk at a transfer rate higher than that of a decoder that decompresses data. This reproduced data is temporarily stored in the buffer memory. This buffer memory is filled with digital signals in about 0.9 seconds. If the digital signal on the disk cannot be read due to vibration or the like, the reproduced signal is continuously output for about 3 seconds by the data stored in the buffer memory. In the meantime, by re-accessing the optical pickup to the original position and reading the signal again, it is possible to prevent the occurrence of so-called skipping. This buffer memory is
It is called shockproof memory.

[0005]

As described above, at the time of reproduction, data is reproduced from an optical disk at a higher transfer rate than a decoder that decompresses data in a mini disk.
This data is temporarily stored in the buffer memory. Therefore, even if the stop key or the eject key is pressed to set the stop state, the data remaining in the buffer memory continues to be reproduced for several seconds. Therefore, even if the stop key or the eject key is pressed, the music reproduction is not stopped immediately, giving the user an unnatural feeling.

Accordingly, it is an object of the present invention to provide a disk reproducing apparatus in which music reproduction is immediately stopped when a stop key or an eject key is pressed.

[0007]

According to the present invention, data is temporarily stored in a buffer memory from a disk on which data is compressed and recorded, and the data is expanded and read from the buffer memory at a predetermined clock. Is converted to an analog signal to obtain an analog audio signal, wherein the reproduction output is muted at the time of a stop or eject operation.

[0008]

[Action] By muting the playback output at the time of stop or eject operation, music playback is immediately stopped when the stop key or the eject key is pressed,
The user does not feel unnatural.

[0009]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing an entire mini disc recording / reproducing apparatus to which the present invention is applied.
In FIG. 1, a disc mounting tray 8 and a display 9 are arranged on a front panel 1A of the mini disc recording / reproducing apparatus 1. Also, a power key 2, an eject key 3, a play key 4, a pause key 5, a stop key 6, and a key A are provided on a front panel 1A of the mini disc recording / reproducing apparatus 1.
MS keys 7A and 7B and a recording key 10 are provided.

By operating the eject key 3,
As shown by the dashed line, the disc mounting tray 8 is pulled out. A mini-disc (not shown) is placed on the disc mounting tray 8. Then, when the disc mounting tray 8 is stored inside, a mini disc is loaded.

The display 9 displays time information such as the total playing time of the mounted mini-disc, the playing time of the music being played, the remaining playing time, and the track number of the playing music. For a disc on which a disc name or track name is recorded, the disc name or track name is displayed on the display 9.

FIG. 2 shows a configuration of a mini disc recording / reproducing apparatus to which the present invention is applied. In FIG. 2, reference numeral 11 denotes a mini disk. The mini disk 11
Optical disk 11 having a diameter of 64 mm in cartridge 11A
B is housed. In this mini disk 11,
There are three types: a read-only optical disk, a recordable magneto-optical disk, and a hybrid disk in which a read-only area and a recordable area are mixed.

The disk 11B of the mini disk 11 is rotated by a spindle motor 12. Mini disc 1
1 is provided with a shutter, and the mini disk 11
When is mounted, the shutter is opened. In the case of a recordable optical disk, a recording magnetic head 13 is arranged above the disk 11B so as to oppose it, and an optical pickup 14 is arranged below the disk 11B so as to oppose it.

The rotation of the spindle motor 12 is controlled by a servo control circuit 15. The optical pickup 14 is
The movement of the disk 11B in the radial direction is controlled by the feed motor 16. The servo control circuit 15 performs focus and tracking control.

The system controller 17 manages the entire operation. This system controller 17 includes:
An input is provided from a key 18. The key 18 includes a power key 2, an eject key 3, a play key 4, a pause key 5, a stop key 6, and an AMS key 7A on the front panel 1A.
, 7B, and the recording key 10. Also, time information such as the total playing time of the mini-disc, the elapsed time of the music being played, the remaining playing time, the track number of the music being played,
The disc name, track name, and the like are displayed on the display 9.

At the time of recording, an audio signal is supplied to the input terminal 21. This audio signal is digitized by the A / D converter 22 in 16 bits. The sampling frequency at this time is 44.1 kHz.

The digital audio signal is supplied to a voice compression encoder / decoder 23. In the audio compression encoder / decoder 23, the audio signal is compressed to about 1/5. A modified DCT (Modified Discreate Cosine Transform) is used as an audio signal compression technique.

The audio signal compressed by the audio compression encoder / decoder 23 is once stored in a DRAM 25 via a memory controller 24. DRAM 25
Has a data capacity of 1 cluster or more (1 M bits in this example). The output of this DRAM 25 is EF
It is supplied to the M / CIRC encoder / decoder 26.

The EFM and CIRC encoder / decoder 26 performs error correction processing of recording data, and performs EFM (8-14 modulation) on the error correction encoded data. As an error correction code, CIRC (Cross I
nterleave Reed Solomon Code) is used.

The recording data thus formed is:
It is supplied to the recording magnetic head 13 via the head drive circuit 27. Thereby, the magnetic field modulated by the recording data is applied to the disk 11B (the magneto-optical disk) of the mini disk 11.
Is applied to In addition, a laser beam from the optical pickup 14 is applied to the disk 11B of the mini disk 11. Thereby, the disk 11B of the mini disk 11
The data is recorded magneto-optically.

The recording of data is performed in cluster units. One cluster has 36 sectors, and one sector (corresponding to one subcode block of a compact disc) has 98 frames. This is because at the time of data recording, laser power control is required, and the interleave length of the CIRC is 108 frames, which is longer than the length of one sector, so that a linking area is required. 1
Of the cluster (36 sectors), the first three sectors are linking sectors. Then, the next one sector is used for sub data. Therefore, compressed data is recorded in 32 sectors in one cluster (36 sectors).

The position on the disk at the time of recording is specified by the address recorded in the groove provided along the track of the disk 11 by wobble recording. The address recorded in the groove in the wobble is detected by the address decoder 28. The address detected by the address decoder 28 is used for the EFM and CIRC encoder /
The data is supplied to the decoder 26.

At the time of reproduction, the recording signal of the disk 11B of the mini disk 11 is reproduced by the optical pickup 14.
The reproduction signal on the disk 11B is reproduced in cluster units. This reproduced signal is transmitted through the RF amplifier 29 to the EF.
M and CIRC encoder / decoder 26. At this time, the optical pickup 14 reads the digital signal on the disk 11B at a transfer rate of 1.4 Mbit / sec. The digital signal from the disk 11 is
EFM and ERC with CIRC encoder / decoder 26
Demodulated and error-corrected.

The output of the EFM and CIRC encoder / decoder 26 is supplied to the DRA via the memory controller 24.
It is temporarily stored in M25. The output of the DRAM 25 is supplied to the audio compression encoder / decoder 23. The audio signal is expanded by the audio compression encoder / decoder 23.

The audio compression encoder / decoder 23
If the data is obtained at 300 kbit / s, it is possible to release the compression and reproduce the uninterrupted sound.
On the other hand, as described above, the optical pickup 14
Reads a digital signal on the disk 11B at a transfer rate of 1.4 Mbit / sec. 1Mbit D
The digital signal is filled in the RAM 25 in about 0.9 seconds. Even if the digital signal on the disk 11B cannot be read due to vibrations or the like, the DRAM 2 can be read for about 3 seconds.
5, the reproduction signal can be continuously output. In the meantime, by re-accessing the optical pickup 14 to the original position and reading the signal again,
The occurrence of so-called skipping can be prevented.

The data decompressed by the audio compression encoder / decoder 23 is supplied to a D / A converter 31 via a digital filter 30 and returned to an analog signal. This analog audio signal is output from the output terminal 31.

A TOC (Table Of Contents) is provided on the innermost circumference of the disk 11B of the mini disk 11. In the TOC, information on where and what data is recorded on the disk 11B is recorded. FIG.
Indicates the structure of TOC. TOC includes a header area and a data area. The head of the header area is an area A1 of a fixed sync pattern, followed by an area A2 of header information indicating a cluster and a sector.

At the beginning of the data area, an area A3 of a fixed pattern is provided, in which an identifier indicating a mini-disc, a disc type (reproduction-only, recordable, reproduction-only area and recordable area are mixed), and recording are provided. An area A4 for identification information such as power, start track number, last track number, lead-out start address, used sector, power calibration start address, user TOC start address, and recordable user area start address is provided. Following this, the track number point (P-
An area A5 of TNO1, P-TNO2, P-TNO3,...) Is provided. This track number point (P-
TNO1, P-TNO2, P-TNO3,...) Are pointers indicating the information addresses of the start address and the end address of the track number. Following this,
An area A6 for track information is provided. In the track information area A6, information on the start address and end address of each track is recorded. The address of the information of the start address and the end address of each track is specified by a track number point (P-TNO1, P-TNO2, P-TNO2).
TNO3,...).

Further, the mini-disc 11 is provided with a user TOC for managing recorded audio signals. FIG. 4 shows the structure of the user TOC.
The user TOC has the same basic structure as the above-mentioned TOC. The user TOC includes information on each track with a link.
-P (indicated by B1) is included. This Li
nk-P indicates which track follows. Therefore, it is not necessary to change the order of the tracks to change the order of the songs. All the management of the track information can be performed on the user TOC.

The TOC information is stored in a part of the DRAM 25 at the time of the first access after loading the disk.
When updating the user TOC, the DRAM
25, the updated user TOC is recorded on a disc, for example, at the time of ejection.

As described above, in the minidisc, the outputs of the EFM and the CIRC encoder / decoder 26 are temporarily stored in the DRAM 25 via the memory controller 24.
For this reason, even if the playback from the disc is stopped by pressing the stop key or the eject key during the playback, the DRAM 25
If data remains, the data is reproduced and the audio output does not stop immediately. If the DRAM 25 is 1 Mbit, the reproduced sound continues for about 2 seconds, and if the DRAM 25 is 4 Mbit, the reproduced sound continues for about 8 seconds. Therefore, when the stop key 6 or the eject key 3 is pressed, the sound is immediately muted and the sound output is stopped immediately so that the sound output is immediately stopped when the recording is completed.

FIG. 2 shows a digital filter 30 for muting. When the stop key 6 or the eject key 3 is pressed, a mute signal is supplied from the system controller 17 to the digital filter 30. The mute signal controls the output data of the digital filter 30 to be 0. Therefore, D / A
The data supplied to the converter 31 becomes 0.

FIG. 5 shows an example in which mute is performed by an analog mute circuit. In FIG. 5, a mute circuit 33 is provided after the D / A converter 31. The output of the mute circuit 33 is taken out from the output terminal 34. When the stop key 6 or the eject key 3 is pressed, a mute signal is supplied from the system controller 17 to the mute circuit 33. The mute operation of the mute circuit 33 is set by the mute signal.

FIG. 6 shows a case where the output from the DRAM 25 is set to 0 to mute. When the stop key 6 or the eject key 3 is pressed, a mute signal MUTE is supplied from the system controller 17 to the memory controller 24. The output from the DRAM 25 is replaced with 0 by the mute signal MUTE. Thereby, the audio output is stopped.

The above-mentioned mute circuits may be arranged in combination. For example, if the mute by the digital filter 30 (FIG. 2) and the mute by the analog mute circuit (FIG. 5) are combined, S
/ N ratio is improved. The mute (FIG. 6) and the mute by the analog mute circuit (FIG. 5) may be combined by setting the output from the DRAM 25 to 0.

[0036]

According to the present invention, when the stop key or the mute key is pressed, the mute is applied immediately,
DRAM when stop key or mute key is pressed
Even if data remains, the audio output is stopped. For this reason, after the stop key or mute key is pressed,
It is possible to prevent the sound from being continuously output.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an entire mini disc recording / reproducing apparatus to which the present invention is applied.

FIG. 2 is a block diagram of one embodiment of the present invention.

FIG. 3 is a schematic diagram used for explaining TOC in one embodiment of the present invention.

FIG. 4 is a schematic diagram used for explaining TOC in one embodiment of the present invention.

FIG. 5 is a block diagram of another embodiment of the present invention.

FIG. 6 is a block diagram of still another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mini disk recording / reproducing apparatus 11 Mini disk 23 Audio compression encoder / decoder 24 Memory controller 25 DRAM 30 Digital filter 33 Mute circuit

Continuation of front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G11B 20/10 321

Claims (5)

(57) [Claims] 1. A disk on which data is recorded after being compressed
The compressed data is read out intermittently from
Is temporarily stored in the buffer memory at the first speed, and
During the period when data reading from the recording medium is stopped,
The data stored in the buffer memory is the first data.
Read at a second speed lower than the speed of
Output continuously as a analog audio data signal
In the disc playback device, the user stops playback or records on the disc.
Operating means for operating the ejection of the medium; and compressed data read from the buffer memory.
Decompression processing means for performing decompression processing, and digital audio output from the decompression processing means
The data signal is converted from analog to digital,
Digital-to-analog conversion output as audio data signal
Conversion means and an analog output from the digital-to-analog conversion means.
Muting means for muting audio data signals
When the playback stop or the de by operation of the operation means
When ejecting the disc-shaped recording medium is instructed,
If data is stored in the buffer memory,
Analog output from the digital-to-analog converter
The audio data signal is controlled by controlling the muting means.
Disk reproducing apparatus that comprises a control means for chute, the. 2. A disk on which data is recorded after being compressed.
The compressed data is read out intermittently from
Is temporarily stored in the buffer memory at the first speed, and
During the period when data reading from the recording medium is stopped,
The data stored in the buffer memory is the first data.
Read at a second speed lower than the speed of
Output continuously as a analog audio data signal
In the disc playback device, the user stops playback or records on the disc.
Operating means for operating the ejection of the medium; and compressed data read from the buffer memory.
Decompression processing means for performing decompression processing, and digital audio output from the decompression processing means
The data signal is muted by the analog audio data signal.
Digital audio data signal values
Mute means for converting, and digital audio output from the mute means
The data signal is converted from analog to digital,
Digital-to-analog conversion output as audio data signal
And switching means, reproduction stop, or the de by operation of the operation means
When ejecting the disc-shaped recording medium is instructed,
If data is stored in the buffer memory,
Analog output from the digital-to-analog converter
The muting is performed so that the audio data signal is muted.
And a control means for controlling the loading means . 3. The disk reproducing apparatus according to claim 1 , wherein said digital-to-analog conversion means outputs an analog signal.
Additional mute to mute audio data signal
Means, wherein the control means operates the operation means to operate a playback strike.
Ejected from the disc or the disc-shaped recording medium
Data is stored in the buffer memory when
Output from the digital-to-analog converter
The analog audio data signal is muted
Control the mute means so that
By controlling the mute means,
3. The output of claim 2, wherein the output from the stage is muted.
Disk reproducing apparatus. 4. A disk on which data is recorded after being compressed.
The compressed data is read out intermittently from
Is temporarily stored in the buffer memory at the first speed, and
During the period when data reading from the recording medium is stopped,
The data stored in the buffer memory is the first data.
Read at a second speed lower than the speed of
Output continuously as a analog audio data signal
In the disc playback device, the user stops playback or records on the disc.
Operating means for operating the ejection of the medium; and compressed data read from the buffer memory.
Digital audio data output after decompression processing
Mute means for converting a signal into a value to be muted; and decompression of compressed data output from the mute means.
Decompression processing means for performing long processing, and digital audio output from the mute means
The data signal is converted from analog to digital,
Digital-to-analog conversion output as audio data signal
And switching means, reproduction stop, or the de by operation of the operation means
When ejecting the disc-shaped recording medium is instructed,
If data is stored in the buffer memory,
Analog output from the digital-to-analog converter
The muting is performed so that the audio data signal is muted.
Disk reproducing apparatus that includes a controller for controlling over preparative means. 5. The disk reproducing apparatus according to claim 1, wherein the analog-to-digital converter outputs an analog signal output from the digital-to-analog converting means.
Additional mute to mute audio data signal
Means, wherein the control means operates the operation means to operate a playback strike.
Ejected from the disc or the disc-shaped recording medium
Data is stored in the buffer memory when
Output from the digital-to-analog converter
The analog audio data signal is muted
Control the mute means so that
By controlling the mute means,
5. The method of claim 4, wherein the output from the stage is muted.
Disk reproducing apparatus.