JPH0782706B2 - Disc recording / reproducing device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a disc recording / reproducing apparatus suitable for enabling simultaneous monitoring of audio signals.

[Conventional technology]

In recent years, optical discs have been used in various fields in various fields. Optical discs are roughly classified into read-only discs such as compact discs and video discs, and optical recording discs such as document files.

Further, there are two types of optical recording discs: a write-once optical disc that becomes a permanent recording once recorded, and a rewritable optical disc that can be erased and written.

In the latter rewritable optical disc, for example, when recording / reproducing / erasing an audio signal (music signal or the like), three optical heads of a recording head, a reproducing head and an erasing head are used.

However, an optical recording / reproducing device using three optical heads is large and expensive. For this reason, a method of recording / reproducing / erasing information on / from an optical disc with a single optical head is being studied.

Conventionally, as an example of a single optical head system for an optical disc, as described in, for example, Japanese Patent Laid-Open No. 61-214265, by alternately recording and erasing a signal between a pair of adjacent sectors, There is a method of realizing signal overwriting with a single optical head.

FIG. 5 is a block diagram showing a configuration of an example of a conventional optical disk recording / reproducing apparatus. In the drawing, 1 is a magneto-optical disk, 2 is a semiconductor laser, and 3 is a semiconductor laser 2. Coupling lens,
Reference numeral 4 is a polarizing prism, 5 is a focusing lens for irradiating the magneto-optical disc 1 with the laser light transmitted through the polarizing prism 4, 6 is an electromagnetic coil for applying an external magnetic field to the surface of the magneto-optical disc 1, and 7 is an optical An analyzer that allows only the polarized light component polarized by the polarizing prism 4 to pass the reflected light from the magnetic disk 1, 8 is a photodetector that converts the light into an electric signal, 9 is an amplifier that amplifies the output of the photodetector 8, and 10 Is a level slice circuit for extracting a signal having a certain amplitude or more from the signal light from the magneto-optical disk 1.
The output signal of 10 is designed to be sent to a signal processing system (not shown) and to the address decoder 11.

The address decoder 11 is an address decoder for decoding the track number and the sector number where the magneto-optical head is located, 12 is the address information decoded by the address decoder 11, 13 is a recording / erasing controller, and 14 is a semiconductor memory module. Yes, recording / erasing controller 13
It is possible to store / rewrite information relating to the state of the magneto-optical disk 1 to an arbitrary address by a command from the.

FIG. 6 shows an example of a disc form for implementing the disc recording / reproducing apparatus. In FIG. 6, the magneto-optical disk 1 is divided into an even number of sectors, and a header is provided at the beginning of each sector. The header contains a sector mark, a self-locking synchronization signal, a track number, and a sector number, and the information in these header areas is recorded by uneven bits.

FIG. 8 is a schematic diagram showing a magnetization direction and a recorded / erased state of each sector of FIG. 7. Reference numerals 30 to 34 in FIG. 7A indicate header areas provided at the head of each sector. Data area of each sector
The arrows in 35 to 38 indicate the magnetization direction of the perpendicular magnetization film.

Next, the operation will be described. The light emitted from the semiconductor laser 2 is converted into a parallel light flux by the coupling lens 3, is incident on the focusing lens 5 via the polarization prism 4, and is condensed as a minute spot on the perpendicular magnetization film of the magneto-optical disk 1.

When information is recorded, the drive current of the semiconductor laser 2 is modulated by the information signal to be recorded, and the temperature of the perpendicular magnetization film on the optical disk 1 is locally raised by the heat of the optical pulse corresponding to the information, and the magnetization is magnetized. When the magnetic field is lost, by applying a magnetization in the opposite direction to the magnetization of the unrecorded portion from the outside by the electromagnetic coil 6, only the light-irradiated portion becomes a portion having the opposite magnetization, and a so-called magnetization domain is formed. It

In order to erase the information written on the magneto-optical disk 1, a magnetic field in the direction opposite to the magnetization direction of the recording magnetization domain is applied by the electromagnetic coil 6 at the same time as the light irradiation onto the magneto-optical disk 1.

Information reproduction corresponds to the upper and lower sides of the magnetization direction of the perpendicular magnetization film,
The magneto-optical effect represented by the so-called Kerr effect, in which the planes of polarization of incident light slightly rotate in opposite directions, is used.

The reflected light from the magneto-optical disk 1 whose polarization plane has rotated is separated by the polarizing prism 4 via the aperture lens 5 and guided to the analyzer 7. The analyzer 7 is an optical element that passes only a specific polarized component. Therefore, when the reflected light from the magneto-optical disk 1 enters the analyzer 7, it is converted into a change in the light amount.

This change in the amount of light is converted into an electric signal by the photodetector 8 and then amplified by the amplifier 9 to a desired level. Since the signal light from the magneto-optical disk 1 contains noise and the like, the level slice circuit 10 outputs only a signal having a certain amplitude or more.

The signal digitized by the level slice circuit 10 is guided to the signal processing system and the address decoder 11. The address decoder 11 has a function of decoding the track numbers and sector numbers written in the header areas 30 to 34.

Therefore, the track number and sector number where the light spot is currently located can always be known. The address decoder 11 is also used in the write-once type optical disc and is well known, so the detailed description thereof will be omitted.

The address information 12 output from the address decoder 11 is input to the recording / erasing controller 13. On the other hand, the address bus of the semiconductor memory module 14 corresponds to the track number and sector number of the magneto-optical disk 1.

In accordance with a command from the recording / erasing controller 13, it is possible to store and rewrite the magnetization direction information and the recording / erasing state to an arbitrary address.

Consider the case where the magnetization direction is set in the state of FIG. 7A in the magneto-optical disk 1. Furthermore, with sector number No. 1 and No. 2 and sector number No. 3 in FIG.
Consider the case where No.4 is paired. As the contents of the memory addresses corresponding to the sector numbers No. 1 and No. 3 in the semiconductor memory module 14, the upward magnetization direction information and the fact that it is in the erased state are stored.

On the contrary, the contents of the memory addresses corresponding to the sector numbers No. 2 and No. 4 store the downward magnetization direction and the recording state. Now, consider a case where an information recording command is given to the data area of the pair of sector numbers No. 1 and No. 2.

In FIG. 7B, the data area 35 of the sector number No. 1
It can be confirmed from the content of the corresponding address of the semiconductor memory module 14 that the is upward from the erased state in the magnetization direction.

Therefore, in the section of the data area 35, the direction of the external magnetic field is set downward, and at the same time, the light pulse modulated corresponding to the information is irradiated to perform recording.

In the section of the data area 36 of the sector number No. 2 that follows, as shown in FIG. 7 (d), the externally applied magnetic field direction is set upward, and at the same time, as shown in FIG. 2 (c), Is erased by irradiating.

At the same time, the contents of the semiconductor memory module address corresponding to sector number No. 1 are rewritten so that sector number No. 1 faces downward in the magnetization direction and is in the recording state. The content of the memory module address is rewritten so that it is in the erased state with the magnetization direction facing upward.

Next, consider the case where a rewrite command for new information is given to the pair area of sector numbers No. 1 and No. 2. In FIG. 7 (e), contrary to the case of FIG. 7 (b), an upward magnetic field is applied to the data area 35 of the sector number No. 1 as shown in FIG. 7 (g). As shown in FIG. 7 (f), a laser light pulse is applied to erase the already recorded data,
A downward magnetic field and an optical pulse modulated corresponding to new information are applied to the data area 36 of the sector number No. 2 to rewrite the information. Also in this case, the contents of the semiconductor memory module 14 are changed in the same manner as shown in FIG. 7 (b).

By performing the above processes alternately, it is not the overwrite in the complete sense, but by introducing the concept of the alternate sector, it is possible to realize the pseudo overwrite by the recording equal erase.

[Problems to be solved by the invention]

Since the conventional disk recording / reproducing apparatus using a single optical head is configured as described above, the sector area provided on the magneto-optical disk 1 is divided into even-numbered sectors and odd-numbered sectors to record information. Since the erasing is alternately performed between the even-numbered sector and the odd-numbered sector, there is a problem that the memory capacity of the magneto-optical disk is halved, which is inefficient.

Further, when recording or erasing an audio signal using the disc recording / reproducing apparatus, in order to confirm whether or not the recording or the erasing is surely performed, a portion where the erasing and recording are performed on the magneto-optical disc 1 When attempting to perform so-called simultaneous monitoring that immediately reproduces the data, the recording head
There is a problem that three optical heads, a reproducing head and an erasing head, are required.

The present invention has been made in order to solve the above-mentioned problems, and a disk capable of simultaneously monitoring audio signals with a single optical head and without reducing the memory capacity of a magneto-optical disk. The purpose is to obtain a recording / reproducing apparatus.

[Means for solving problems]

A disc recording / reproducing apparatus according to the present invention divides a rewritable disc and a continuous input signal at regular time intervals, and within a prescribed time, a single head drives a single head N times (N is 1 (A larger integer) a first means for tracing, and an input signal divided every predetermined time in a predetermined one trace during the N times of tracing, and compressed and recorded to 1 / N or less of the predetermined time. 2 means and the signal recorded by time-compressing the disk in another one-time trace during the N times of tracing is read out, and the read-out signal is time-expanded corresponding to the time compression to continuously reproduce. And a third means for reproducing as a signal, wherein the single head is provided for the specified time.
The same position on the track of the disk is traced during the time of 1 / N or less, and the single head is track-jumped from the trace end point to the track before the trace start point. The above-mentioned same portion is repeatedly traced, and the focus servo and the tracking servo are settled at the end point of the track jump.

[Action]

A disc recording / reproducing apparatus according to the present invention performs a trace by rotating a disc at a high speed, and performs a track jump from an end point to a start point of a trace to continuously trace the same portion on the disc a plurality of times. Etc. are compressed and recorded or erased, and at the time of reproduction, the signal read by the head is temporally expanded and reproduced, so that even a single optical head can continuously record, reproduce and erase audio signals. Simultaneous monitoring can be performed. At this time, since the track jump landing point is configured to be a track before the trace start point, the trace time from the track jump landing point to the trace start point can be used without adding special conditions. The focus servo and tracking servo can be settled easily.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, the same parts as those in FIG. 5 are designated by the same reference numerals. In FIG. 1, reference numeral 1 is a disk, and the description will be given below as a magneto-optical disk. Further, 42 is a disk motor that constitutes a rotating system for controlling the high-speed rotation of the first magneto-optical disk 1, 43 is a laser light pulse irradiating the surface of the magneto-optical disk 1 when recording / erasing / reproducing an audio signal. This is an optical pickup that constitutes an optical system for doing so, and a single head is included in this.

Further, 44 is a controller for controlling the intensity of the laser light pulse, the position of the optical head, etc. for the optical pickup 43, and 45.
Is a controller for recording / reproducing / erasing audio signals
It is a sequencer having clock pulses for timing the driving of 44. Data is exchanged between the controller 44 and the optical pickup 43.

On the other hand, 46 is an input terminal. An analog audio signal is input to the input terminal 46, and 47 is an analog / digital converter (hereinafter referred to as A / D conversion) that converts the analog audio signal input to the input terminal 46 into a digital signal. ), 48 is an encoder for encoding the audio signal digitally converted by the A / D converter 47.

49 is a compression circuit that temporally compresses the digital signal encoded by the encoder 48, and 50 is a modulator that modulates the digital signal compressed by the compression circuit 49 so as to be suitable for recording. Is output to the controller 44.

Reference numeral 7 is an analyzer for passing the reflected light detected by the optical pickup 43 as a change in the amount of light corresponding to the concave and convex pits of the magneto-optical disk 1 and guiding it to the photodetector 8. The photodetector 8 converts an optical signal into an electric signal.

Reference numeral 9 is an amplifier for amplifying an electric signal output from the photodetector 8, and 10 is a level slice circuit, which is an electric signal output from the amplifier 9, that is, a signal from the magneto-optical disk 1 having a certain amplitude or more. It is for taking out a signal. The output of the level slice circuit 10 is output to the address decoder 11 and the demodulator 51.

The address decoder 11 is for decoding the track and sector numbers where the magneto-optical head 1 is located, as shown in FIG.
It is designed to send to 44.

A demodulator 51 demodulates the output of the level slice circuit 14. Reference numeral 52 denotes a decompression circuit for restoring the digital signal temporally compressed by the compression circuit 49, and 53 receives the output of the decompression circuit 52 and decodes the signal encoded by the encoder 48. Decoder 54 is a digital-analog converter (hereinafter referred to as D / A converter), which converts the digital output of decoder 53 into an analog signal and sends an audio signal from output terminal 55.

Reference numeral 6 is an electromagnetic coil for applying external magnetism to the surface of the magneto-optical disk 1, which is controlled by the controller 44.

The form of the magneto-optical disk 1 for carrying out the present invention is as follows.
For example, the conventional one as shown in FIG. 6 can be dealt with. That is, it is divided into a plurality of sectors, a header portion is provided at the head of each sector, and information such as a sector number and a track number is recorded in the header portion in concave and convex pits.

Next, the operation will be described. Magneto-optical disk 1
Consider the case of trying to perform simultaneous monitoring above. The continuous input audio signal input to the input terminal 46 is divided into regular time intervals, and the track intervals of the magneto-optical disk are nominally divided into regular steps corresponding to the specified time. Erasing, recording, and reproducing are performed at each of the separated track intervals.

First, the controller is controlled by the pulse generated by the sequencer 45.
Driven by 44, the disk motor 42 is controlled to rotate the magneto-optical disk 1 at a rotational speed three times or more higher than usual. For example, if it is usually 600 RPM, rotate it at 1920 RPM.

Next, the controller 44 controls the optical pickup 43 to irradiate the magneto-optical disk 1 with laser light to read the track number recorded in the header portion.

That is, the reflected light from the concavo-convex pit recorded as the track number in the header portion is converted into a change in the light quantity by the analyzer 7, then converted into an electric signal by the photodetector 8, and further amplified by the amplifier 9. After that, it is input to the level slice circuit 10 and, after noise and the like are removed, it is input to the address decoder 11 to become the final address information 12.

The controller 44 receives the address information 12 and controls the optical pickup 43 to detect the address of the track for which simultaneous monitoring is to be started, and controls the optical pickup 43 to position it on the track corresponding to this address.

Further, FIG. 1 will be described in detail with reference to FIG. Second
The figure shows the optical pickup 43 for simultaneous monitoring in the present invention.
It is a conceptual diagram of the operation of. Now, consider a case where there are 10 tracks between the simultaneous monitoring start point b and the simultaneous monitoring end point c.

First, the controller 44 is driven by the timing of the clock generated by the sequencer 45, the position of the simultaneous monitoring start point b is accessed, and the optical pickup 43 and the electromagnetic coil 6 are controlled to track from the simultaneous monitoring start point b to the end point c. The upper part is traced by the optical pickup 43, and the signal is erased by irradiating the laser beam and applying the external magnetic field by the electromagnetic coil 6.

The address information 12 corresponding to the track number of the track for which the simultaneous monitoring is to be ended is input to the controller 44, and the erasing of the signal recorded during the 10 tracks from the simultaneous monitoring start point b to the end point c is completed. When this is detected, the operation of the controller 44 is switched in synchronization with the clock timing generated by the sequencer 45, the optical pickup 43 is controlled, and the simultaneous monitoring end point c to the arrival point a.
Perform a track jump to.

The reason that the landing point a does not match the simultaneous monitoring start point b is because the time of the focus servo and the tracking servo is taken into consideration. For example, when the magneto-optical disk 1 is rotating at 1920 RPM, the trace time of 10 tracks. Is about 1/3 second, and if it is set so that the settling of the track jump, focus servo and tracking servo is completed while the magneto-optical disk 1 makes one revolution, it will be between the landing point a and the simultaneous monitoring start point b. Is 1 track, and a track jump for 11 tracks may be performed.

In this case, the time required for the magneto-optical disk to make one rotation is about 30 ms, which is a sufficient time for setting the focus servo and the tracking servo.

As with erasing, the optical pickup is made by address information 12.
When the 43 reaches the simultaneous monitoring start point b, the controller 44
When it is detected by, the operation of the controller 44 switches,
The laser beam is radiated onto the track from the simultaneous monitoring start point b to the end point c, and the external magnetic field in the opposite direction to that when the signal is erased is applied by the electromagnetic coil 6 and the electromagnetic pickup 43. The coil 6 is controlled to record a signal.

That is, the analog audio signal input from the input terminal 46 is converted into a digital signal by the A / D converter 47, further encoded by the encoder 48, and then compressed by the compression circuit.
It is compressed to less than 1/3 in time by 49.

After this compression code is modulated by the modulator 50, the drive current of the laser light is modulated by the controller 44, the drive current is detected by the optical pickup 43, and the laser light pulse having the power corresponding to the signal to be recorded is emitted. Magnetic disk 1
Is irradiated on the surface of.

At the same time, the electromagnetic coil 6 is controlled by the controller 44 which receives the input from the modulator 50 and detects that it is in the recording state, and the external magnetic field is applied to the surface of the magneto-optical disc 1 to record a new signal. It

When the controller 44 detects from the address information 12 that the optical pickup 43 has reached the simultaneous monitoring end point c, the track jump, the focus servo and the tracking servo are set in the same process as after the end of the erasing. , The newly recorded information is reproduced as follows.

Laser light is emitted from the optical pickup 43 controlled by the controller 44 between the simultaneous monitoring start point b and end point c on the magneto-optical disk 1, and the light reflected by the surface of the magneto-optical disk 1 is analyzed by the analyzer 7. After being converted into an electric signal by the photodetector 8, the signal is amplified by the amplifier 9, noise and the like are removed by the level slice circuit 10, and then demodulated by the demodulator 51.

The signal demodulated by the demodulator 51 is expanded three times or more by the expansion circuit 52, is decoded by the decoder 53, becomes an analog audio signal by the D / A converter 54, and is output terminal.
Output from 55.

After the series of erasing / recording / reproducing operations on the magneto-optical disk 1 is completed, next, the simultaneous monitoring end point c is set as the start point, and a point 10 tracks after the end point c is newly set as the end point. By repeating a series of operations, it is possible to continuously monitor simultaneously at an arbitrary track length.

FIG. 3 shows the time required for simultaneous monitoring of audio signals on the magneto-optical disk 1 in comparison between the case of performing the conventional three-head configuration and the case of performing the one-head configuration of the present invention. It is a time chart.

In the three-head configuration, three erasing heads, recording heads, and reproducing heads are arranged adjacent to each other and trace the tracks almost at the same time. In this case, it takes about 1 second to trace 10 tracks.

On the other hand, in the one-head configuration, the single optical head first traces 10 tracks in about 1/3 second in the erase mode to erase the signal.

Next, it takes about 10 ms to perform a track jump for 11 tracks, and subsequently it takes about 30 ms to trace one track to set the tracking servo.

After that, in order to record the signal, the single optical head traces 10 tracks in the recording mode in about 1/3 second.

Next, it takes about 10ms to perform a track jump and settling the tracking servo as after erasing.
It takes 30ms.

Subsequently, even when the signal just recorded is reproduced, it takes about 1/3 second for the single optical head to trace 10 tracks in the reproduction mode.

As a result, when performing simultaneous monitoring with the one-head configuration of the present invention, it is understood that the same simultaneous monitoring effect can be obtained in the same time as the conventional three-head configuration.

FIG. 4 is a schematic diagram showing how continuous recording and reproduction of an audio signal is actually performed by comparing the case of performing with a conventional three-head configuration and the case of performing with one-head configuration according to the present invention. It is a figure.

In the case of the three-head configuration, the digitized audio signal is directly modulated and recorded, and when reproduced, the demodulated signal is directly decoded and reproduced.

On the other hand, in the case of the one-head configuration according to the present invention,
As shown in FIG. 1, when the signal is recorded, the encoded signal is compressed to 1/3 or less by the compression circuit 49 and recorded, and when the signal is reproduced, the demodulated signal is reproduced. Is expanded three times or more by the expansion circuit 52 and reproduced.

In FIG. 4, a3 is the time length of 10 tracks of the input audio signal, a2 is the time required for tracing when the signal of a3 is recorded by the conventional three-head configuration, and a1 is the one-head configuration of the present invention in which a3 is a3. The time required for tracing when recording a signal is shown.

Also, b3 is the time length of 10 tracks of the reproduced audio signal, b2 is the time required for tracing when the signal of b3 is reproduced by the conventional 3-head configuration, and b1 is the signal of b3 reproduced by the 1-head configuration of the present invention. This is the time required for the trace to be performed.

In the one-head configuration of the present invention, the magneto-optical disk 1
Is rotated at a high speed to reduce the time required for tracing, and the operation of compressing and decompressing the audio signal is added in accordance with this operation, so that continuous recording / reproduction similar to the case of the three-head configuration is possible.

In the above embodiment, the example in which the rotation speed of the magneto-optical disk 1 is controlled to be constant is shown, but the linear velocity may be controlled to be constant during execution.

Further, in the above embodiment, the case where information is erased / recorded / reproduced continuously has been described. However, the present invention may be used when only recording / reproduction is performed without erasing a signal. The same effect as the embodiment is exhibited.

Further, although the magneto-optical disk 1 is used as the recording medium in the above embodiment, a phase change type optical disk may be used, or a pre-formatted magnetic disk and a magnetic head may be used. It has the same effect as the example.

In addition, when the input signal divided by the system of the compression circuit 49 and the modulation circuit 50 is divided into 1 / N (N is an integer larger than 1) and recorded on the magneto-optical disk 1, the input signal is recorded at specified time intervals. The divided input signal may be stored in the storage means, and the stored signal may be read and recorded at a time of 1 / N of the specified time.

Furthermore, in the system of the demodulator 51 and the decompression circuit 52, when the reproduction signal at every specified time is expanded N times or more to obtain a continuous reproduction signal, the specified time reproduced in 1 / N or less of the specified time It is also possible to store a reproduction signal for each of them and read the stored signal at a prescribed time to reproduce it as a continuous signal.

〔The invention's effect〕

As described above, according to the present invention, the input signal is divided at every prescribed time, and the same position on the recording track is traced N times (N is an integer larger than 1) within the prescribed time by the single head. The input signal, which is divided at specified time intervals during a predetermined one-time tracing, is compressed to 1 / N or less of the specified time for recording, and at the same time during another N times tracing. Since the compressed signal recorded in the trace is read and the read signal is expanded for the time corresponding to the time compression to obtain the original continuous playback signal, only one head is needed, and the audio signal Simplification of the device for simultaneous monitoring of
The price can be reduced. Also, since the track jump landing point is configured to be a track before the trace start point, the trace time from the track jump landing point to the trace start point can be used without any special configuration. Thus, the focus servo and the tracking servo can be easily settled, and the apparatus can be simplified.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a disc recording / reproducing apparatus according to an embodiment of the present invention, FIG. 2 is a conceptual diagram of the operation of an optical pickup in the present invention, and FIG. 3 is a time required for simultaneous monitoring in the present invention. FIG. 4 is a time chart comparing the present invention with a conventional one, FIG. 4 is a schematic diagram comparing the continuous recording / reproducing state of an audio signal in the present invention with the prior art, and FIG. 5 is a block of a conventional disk recording / reproducing apparatus with a single optical head. 6 and 6 are plan views of a magneto-optical disk divided into sector units applied to a conventional disk recording / reproducing apparatus,
FIG. 7 is a conceptual diagram showing the relationship between the perpendicular magnetization direction on the disk, the irradiation light pulse, and the external magnetic field in the conventional example. 1 is a disk, 43 is an optical pickup (first means), 44 is a controller (first means), 49 is a compression circuit, 51 is a demodulator (third means), and 52 is an expansion circuit (third means). In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A rewritable disc and a continuous input signal are divided at regular time intervals, and a single head is traced N times (N is an integer greater than 1) at the same location on the track of the disc within the regular time. The first means for controlling the input signal and the input signal divided at each of the specified times in a predetermined one trace during the N times of traces,
The second means for compressing and recording to N or less, and the signal that is time-compressed and recorded on the disk in another one trace during the N times of tracing, and the read signal corresponds to the time compression And a third means for reproducing as a continuous reproduction signal by time-expanding the same, the first means is the same on the track of the disk during the time when the single head is 1 / N or less of the specified time. By tracing a point and making the single head perform a track jump from the trace end point to a track before the trace start point, the same point on the track is repeatedly traced N times and the end point of the track jump. 2. A disk recording / reproducing apparatus, characterized in that the focus servo and the tracking servo are settled.