JPH10112143A - Digital data recording/reproducing device and digital data record decision method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve reliability in data recordihg/reproducing by always deciding a recording medium having the probability that errors occur ranging a long term so as to become anti-reproducible at a regular reproducing time as a (defect) at a verification processing time. SOLUTION: This recording/reproducing device at least performs the verification processing for deciding a normal/defective condition of recording for an optical disk 1, and is provided with a comparator 16 comparing a slice level for deciding the normal/defective condition of the recording in the verification processing with an integration output level of a regenerative RF signal reproduced from the optical disk g and a control circuit 7 distinguishing the reproduction for the verification processing from the regular reproduction and deciding the normal/defective condition of the recording based on the comparison result of the comparator 16 when the reproduction for the verification processing is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a digital data recording / reproducing apparatus for recording and reproducing digital data on a recording medium, and a method for judging whether or not recording on the recording medium is good or bad.

[0002]

2. Description of the Related Art In a normal digital data recording / reproducing method, an error correction code (hereinafter, referred to as ECC) is added to data, and the data to which the ECC is added is recorded. If this ECC is used, the number of erroneous data can be detected in the process of error correction, and the number of errors that can be corrected differs depending on the amount of ECC.

Here, conventionally, when digital data is recorded on a recording medium, a verifying process (recording confirming process) for determining whether or not the recording has been correctly performed has been performed.

This determination is often made immediately after data is recorded on the recording medium. In the verifying process, for example, if the number of errors for 2048-byte data is up to 16 bytes (or 32 bytes), “ Good (O
K) ". In addition, the number of errors serving as a criterion of good or bad in the verification process is smaller than the number of errors allowed during normal reproduction. That is, as described above, the number of errors allowed during the verification process is 16 (or 3) for 2048 bytes of data.
2) Up to bytes, but the number of errors allowed during the normal reproduction is up to 128 bytes for the 2048 bytes of data.

[0005] As described above, if the criterion of good / bad in the verifying process is set to be stricter than that in the normal reproduction, the reproduction from the recording medium due to the deterioration of the recording medium over time or the adhesion of dust, for example, is performed. Even if signal deterioration occurs, it is extremely unlikely that the recording medium determined to be "good" in the above-described verification processing will be unable to be reproduced at the time of normal reproduction later, and the recording data recorded on this recording medium will not be reproduced. Can be read.

[0006] When it is determined as "defective (no)" in the above-mentioned verification processing, recording is performed again on the same recording medium, or recording is performed by exchanging the recording medium. Is performed.

[0007]

However, in the following cases, for example, the signal cannot be reproduced from the recording medium during the subsequent normal reproduction even if it is determined to be "good" during the verification processing. Something like that can happen.

For example, when there is a scratch or dust on the recording medium, or when there is a portion where the performance of the reflective film of the recording medium is low over a certain range, as shown in FIGS. In addition, the RF signal reproduced from the recording medium is
The signal level in the area corresponding to the area where the scratch or dust is present or the area where the performance of the reflective film is reduced becomes low.

Here, when error correction of digital data is performed, a signal level at which error correction is highly unlikely, that is, a level at which the probability of being detected as an error increases (hereinafter, a line indicated by this level is subjected to error detection) 3) will be superimposed on the reproduced RF signal as shown in FIG. Of course, if the original meaning of the error detection is strictly interpreted, it is unnatural to represent such an error detection line on the reproduced RF signal, but here, for the sake of simplicity, the reproduction is performed for convenience. R
It is shown superimposed on the F signal. For example, in the case of an RF signal as shown in FIG. 3A, a portion of the digital signal extracted from the reproduced RF signal below the error detection line in FIG. It cannot be reproduced accurately and is detected as an error. On the other hand, even if a part of the reproduced RF signal has a low signal level, for example, as in the case of the RF signals of FIGS. If it exceeds, it shall not be detected as a data error.

In the above-described verifying process,
When it is determined that the number of errors exceeds the 16 bytes (or 32 bytes), the pass / fail determination signal is set to the “H” level, and when it is determined that the number is not exceeded, the pass / fail determination signal is set to the “L” level. If it is obtained, the above-mentioned FIG.
In the example, the pass / fail judgment signal goes to the “H” level corresponding to a portion below the error detection line. On the other hand, in the examples shown in FIGS. 3B and 3C, all the pass / fail judgment signals are at the “L” level. In the verifying process, when the "H" level exists in the pass / fail judgment signal, it is determined that the recording on the recording medium is "bad", and the recording is performed again as described above, or the recording is performed on another recording medium. Do something to record.

By the way, the scratches on the recording medium are very long (especially, scratches long in the track direction),
The presence of large dust, or the presence of a portion where the performance of the reflective film of the recording medium is low over a wide range exists, and the level of the reproduced RF signal in the area corresponding to these scratches, dust, or the portion where the performance of the reflective film is reduced becomes low In such cases,
For example, as in the example of FIG.
It is assumed that the signal level exceeds (slightly exceeds) the error detection line and is determined to be “good” in the verification processing.

However, digital data recording / reproducing apparatuses have variations, and when a recording medium determined to be "good" in a verifying process in a certain apparatus is to be used in another apparatus for normal reproduction as described above. Can not be reproduced. That is, FIG.
In the case of a reproduced RF signal having an area whose level decreases over a long period of time as described above, the level decreases over a long period of time due to, for example, variations in the signal reading capability and error correction capability of the digital data recording / reproducing apparatus. In some cases, error correction of data in a region to be corrected cannot be performed. For example, when the period during which error correction cannot be performed exceeds the error correction capability during normal reproduction, reproduction cannot be performed. Similarly, a recording medium determined to be “good” at the time of the verification process may not be able to be reproduced later even by the same recording / reproducing device due to a temporal change, a scratch, dust, or the like of the recording medium. Note that, as shown in FIG. 3C, when the area whose level has decreased is short, the area is determined to be “good” during the verification process, and the area is determined to be erroneous during the subsequent normal reproduction. Even if the error correction is performed, if the period of the area detected as the error (the number of errors) is within the range of the error correction capability at the time of the normal reproduction, there is no problem because the reproduction can be performed.

Accordingly, the present invention has been made in view of such a situation, and a recording medium in which an error is likely to occur for a long period of time that cannot be reproduced during normal reproduction is verified. A digital data recording / reproducing apparatus which can always be judged as "defective" and as a result can improve the reliability of data recording / reproducing, and a digital data recording judgment for judging good / bad of recording on a recording medium The aim is to provide a method.

[0014]

SUMMARY OF THE INVENTION A digital data recording / reproducing apparatus and a digital data recording judging method according to the present invention distinguish between reproduction for recording confirmation processing and normal reproduction, and determine whether recording is good or bad in recording confirmation processing. A predetermined comparison level for determination is compared with the level of a reproduction RF signal reproduced from a recording medium, and when reproduction for recording confirmation processing is being performed, the quality of recording on the recording medium is determined based on the comparison result. The above-described problem is solved by determining the defect.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic configuration of a disk recording / reproducing apparatus as one embodiment to which the digital data recording / reproducing apparatus and the digital data recording judging method of the present invention are applied. Note that the configuration of the recording system of the disk recording / reproducing apparatus of the present embodiment is the same as that of the normal configuration, and therefore is omitted, and FIG. 1 shows the main configuration of the reproducing system.

In FIG. 1, a disc-shaped recording medium as an example of a recording medium, for example, a write-once optical disc 1 such as a so-called write-once disc (WO disc)
Is driven to rotate by a spindle motor 3 via a shaft 2. The spindle motor 3 is driven to rotate and performs spindle servo by a spindle drive signal supplied from a spindle control system (not shown). The spindle control system can change the rotation speed of the spindle motor 3 under the control of the control circuit 7.

The optical head 5 includes an optical system including a laser light source such as a laser diode, a collimator lens, an objective lens, an optical component such as a polarizing beam splitter, a multi-lens, and a photodetector having a light receiving section having a predetermined pattern. It comprises a two-axis actuator for driving the lens in the vertical direction, ie, the focus direction, and for driving the lens in the horizontal direction, ie, the tracking direction. Further, the optical head 5 is movable in the disk radial direction by a thread mechanism including a thread motor and a thread rail.

In the optical head 5, the laser beam emitted from the laser diode is converted into a parallel beam by a collimator lens, the optical path of the parallel beam is bent by the polarization plane of the polarizing beam splitter, and the laser beam passes through the polarizing beam splitter. A parallel light beam is condensed and irradiated on the optical disc 1 by an objective lens. At this time, the optical head 5 focuses on the disk recording surface by moving the objective lens in the focus direction by the biaxial actuator, and moves the objective lens in the tracking direction by moving the objective lens in the tracking direction. The focal position is set on the track on the disk recording surface. On the other hand, the reflected light from the optical disc 1 is guided to a polarizing beam splitter via an objective lens, passes through the polarizing beam splitter, passes through a condenser lens and a cylindrical lens constituting the multi-lens, and passes through the photodetector. Guided above. In this photodetector, the guided light is converted into an electric signal by photoelectric conversion.

The output signal of the optical head 5 is sent to a servo signal generation circuit 6. The servo signal generation circuit 6 detects, for example, a focus error signal by a so-called astigmatism method and a tracking error signal by a so-called push-pull method from the output signal of the optical head 5.
The focus error signal and the tracking error signal from the servo signal generation circuit 6 are sent to the control circuit 7.

The control circuit 7 operates based on the focus error signal and the tracking error signal.
The biaxial actuator of the optical head 5 is driven. That is, the control circuit 7 controls the driving of the biaxial actuator of the optical head 5 so that both the focus error signal and the tracking error signal become zero. Thereby, focus servo and tracking servo are realized.

The control circuit 7 also generates a thread drive signal for moving the optical head 5 to a target position in the disk radial direction, and sends the thread drive signal to a thread driver provided in the optical head 5. send. The thread driver receiving the thread drive signal drives the thread motor of the thread mechanism. Thereby, the optical head 5 moves along the sled rail.

In the disk recording / reproducing apparatus of the present embodiment in which the above-described spindle servo, focus servo, and tracking servo are performed, when the signal recorded on the optical disk 1 is reproduced, the following operation is performed. FIG. 2 shows signal waveforms of main parts of the apparatus shown in FIG. 1, and the operation during reproduction of the optical disk will be described with reference to FIG.

The light irradiated onto the optical disk 1 by the optical head 5 and reflected by the optical disk 1 is guided to the photodetector of the optical head 5 as described above. In this photodetector, the signal recorded on the optical disc 1 is extracted as an RF signal by converting the guided light into an electric signal by photoelectric conversion. The reproduced RF signal output from the optical head 5 is amplified by the RF amplifier 9.

Here, as shown in FIG. 2A, the reproduced RF signal amplified by the RF amplifier 9 is determined to be "good" at the time of verify processing in the conventional digital data recording / reproducing apparatus described above. Although it is determined, there is a possibility that an error may occur during normal playback later, and if an error occurs, the level decreases over a long period of time beyond the error correction capability during the normal playback. It is assumed that That is, the optical disc 1 from which the reproduced RF signal as shown in FIG. 2A is obtained should always be determined to be "defective" at the time of the verification process.

The reproduced RF output from the RF amplifier 9
The signal Sa is sent to the DC cut circuit 10 and also sent to the verify control circuit 20.

The DC cut circuit 10 is provided with the reproduction RF
The DC (direct current) component of the signal Sa is cut, and FIG.
A DC cut signal Sb as shown in FIG. The DC
The cut signal Sb is sent to the clock generation circuit 11 and to the data extraction circuit 12.

The clock generation circuit 11 includes a PLL (Ph
It has an ase-locked loop (phase-locked loop) circuit and the like, and extracts a clock component included in the DC cut signal Sb. The clock signal output from the clock generation circuit 11 is sent to the data extraction circuit 12.

The data extracting circuit 12 extracts a signal Se as shown in FIG. 2E from the DC cut signal Sb based on the clock signal. The data extraction signal Se output from the data extraction circuit 12 is supplied to one input terminal of a two-input AND (logical product) gate 13 of the verify control circuit 20.

The reproduced RF signal Sa input to the verify control circuit 20 is converted into an integrated output Sc as shown in FIG. 2C by an integrator including a resistor R and a capacitor C. It is sent to the non-inverting input terminal.

A slice level as shown in FIG. 2C is supplied from the terminal 18 to the inverting input terminal of the comparator 16 as a comparison reference. The comparator 16 compares the integral output Sc with the slice level to obtain a compare output Sd as shown in FIG. 2D.

The comparator output Sd from the comparator 16 is sent to one input terminal of an OR (logical sum) gate 17.

Here, the other input terminal of the OR gate 17 is set to the "L" level during the verify process from the control circuit 7, and is set to the "H" level during the normal reproduction.
A level signal is supplied. Therefore, at the time of the verify processing, the comparison output Sd of the comparator 17 is output as it is from the O gate 17, while a signal which is always at the “H” level during normal reproduction is output.

The output of the OR gate 17 is the two-input A
The signal is supplied to the other input terminal of the ND gate 13. Therefore, the two-input AND gate 13 outputs the data extraction signal Se as it is only when the output of the OR gate 17 is at the "H" level. On the other hand, when the output of the OR gate 17 is at the "L" level, A signal that becomes “L” level is output. That is, at the time of the normal reproduction, the data extraction signal Se is directly output from the two-input AND gate 13, but the two-input AND gate 13 at the time of the verify process outputs the data extraction signal Se of FIG.
As shown in the figure, only when the comparator output Sd is at the "H" level, the data extraction signal Se is output as it is, and when the comparator output Sd is at the "L" level, the signal Sf which is at the "L" level is output. You.

The output signal S of the two-input AND gate 13
f is sent to the decoding circuit 14. The decoding circuit 14 performs demodulation corresponding to the predetermined modulation on the signal, since the signal reproduced from the optical disc 1 has been subjected to predetermined modulation at the time of recording. An error detection process and an error correction process using the ECC added at the time of recording are performed.

The data output from the decoding circuit 14 is sent to the control circuit 7. The control circuit 7 counts the number of errors from the supplied data. At the time of the verify process, if the number of errors is up to 16 bytes (or 32 bytes) for the 2048-byte data as described above, “good ( OK) "and 1
If it exceeds 6 bytes (or 32 bytes), it is determined as "defective (NG)".

Here, the signal recorded on the optical disc 1 is, for example, a so-called RLL (Run Length Limite).
d) Assuming that the code is a so-called (1.7) RLL code, for example, a code having a length of 2T to 8T, the decoding circuit 14 decodes the (1.7) RLL code. Become.

For this reason, when the signal supplied to the decoding circuit 14 is no longer a signal inverted in the above 2T to 8T (for example, the signal Se in FIG. 2E), that is, for example, in FIG. (1, 7) RLL like the signal Sf of
When the signal has a unique pattern in the code, decoding by the decoding circuit 14 becomes impossible.

Therefore, the control circuit 7, which makes a "good" or "bad" determination at the time of the verify process based on the number of data errors from the decode circuit 14, is controlled by the control circuit 7 shown in FIG.
For the optical disc 1 from which the reproduced RF signal Sa which may exceed the error correction capability at the time of normal reproduction as shown in FIG. Becomes possible.

The judgment result at the time of the verifying process in the control circuit 7 is sent to a CPU (central processing unit) via an output terminal 8. The CPU receives the above determination result, and the determination result is, for example, “bad”
In such a case, the user is notified by performing a process of displaying the fact on display means (not shown), for example.

In the above-described embodiment, the portion of the output signal of the data extraction circuit 12 corresponding to the "L" level of the output of the comparator 16 is forcibly set to the "L" level, and (1,7) RLL An example is described in which the decoding rule is disabled so that the decoding in the decoding circuit 14 is disabled. On the other hand, the "1,7" RLL coding rule is broken by forcibly setting the level to "H". It is also possible to make decoding impossible. Alternatively, the same effect as described above can be obtained by, for example, forcibly setting a portion corresponding to the “L” level output of the comparator 16 to erroneous data in the decoded signal.

In another embodiment, the structure of FIG. 1 is simplified. For example, the 2-input AND gate 13 of the verify control circuit 20 is deleted to directly connect the data extracting circuit 12 and the decoding circuit 14. In addition, it is also possible to directly send the output of the OR gate 17 to the control circuit 7 as shown by a path indicated by a dotted line a in the figure. In this case, the control circuit 7 Even if correct data is supplied from the decoding circuit 14, the OR gate 17
Is determined to be erroneous during the period when the output is at the "L" level. Of course, at this time, the control circuit 7 makes the above determination by associating the period during which the output of the OR gate 17 is at the "L" level with the actual number of data errors.

Further, as a further simplified configuration of another embodiment, not only the two-input AND gate 13 but also the O
The R gate 17 can also be omitted. In this case, the output of the comparator 16 is sent directly to the control circuit 7 as shown by a path indicated by a dotted line b in FIG. That is, since the control circuit 7 originally knows whether the verifying process or the normal reproduction is being performed, even if correct data is supplied from the decoding circuit 14 during the verifying process, It is also possible to determine that data during the period when the output is at the “L” level is erroneous.

The signal recorded on the optical disk 1 is not limited to the RLL code, but may be another signal. In any case, the output of the comparator 16 is "L".
If it is possible to prevent decoding at a portion corresponding to a level, the above-described effect can be maintained.

In the above description, the conventional digital data recording / reproducing apparatus is described as an example of a recording medium which is determined to be "good" during the verifying process and may not be able to be reproduced during the subsequent normal reproduction. However, if the conventional recording / reproducing apparatus is determined to be "defective" at the time of the verify process, the disk recording / reproducing apparatus of the embodiment of the present invention can naturally be determined to be "defective".

As described above, in the present embodiment, the optical disk 1 which is likely to cause an error for a long period of time such that the optical disk 1 cannot be reproduced at the time of normal reproduction is always "bad" during the verification process. , And as a result, the reliability of data recording and reproduction can be improved.

In the above description, the optical disk 1 is taken as an example of the recording medium. However, the present invention may be applied to a magnetic disk such as a hard disk or a floppy disk, or a tape-shaped recording medium. Is similarly applicable.

[0048]

As is apparent from the above description, in the present invention, reproduction for recording confirmation processing and normal reproduction are distinguished from each other, and a predetermined comparison for judging the quality of recording in the recording confirmation processing is performed. By comparing the level and the level of the reproduced RF signal reproduced from the recording medium, and performing reproduction for the recording confirmation processing, by judging the quality of recording on the recording medium based on the comparison result, A recording medium in which an error may occur over a long period of time that cannot be reproduced during normal reproduction can always be judged as "defective" during the recording confirmation processing, and as a result, the reliability of data recording and reproduction Can be improved.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram showing a schematic configuration of a reproducing system which is a main part of a disk recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a waveform diagram showing signal waveforms at various parts of the disk recording / reproducing apparatus according to the embodiment of the present invention.

FIG. 3 is a waveform diagram used to explain a problem at the time of conventional digital data recording and reproduction.

[Explanation of symbols]

1 optical disk, 2 shaft, 3 spindle motor, 5 optical head, 6 servo signal generation circuit,
7 control circuit, 9 RF amplifier, 10 DC
Cut circuit, 11 clock generation circuit, 12 data extraction circuit, 13 2-input AND gate, 14
Decoding circuit, 16 comparators, 17 OR
Gate, 20 verify control circuit

Claims (8)

[Claims] 1. A digital data recording / reproducing apparatus for performing at least a recording confirmation process for judging whether recording on a recording medium is good or bad, comprising: a reproduction discriminating unit for distinguishing reproduction for the recording confirmation process from normal reproduction. A comparing means for comparing a predetermined comparison level for determining whether the recording is good or bad in the recording confirmation processing with the level of a reproduction RF signal reproduced from the recording medium; and performing reproduction for the recording confirmation processing. A digital data recording / reproducing apparatus, characterized in that the digital data recording / reproducing apparatus further comprises: a recording judging means for judging whether the recording on the recording medium is good or not based on a comparison result of the comparing means. 2. The recording judging means demodulates a reproduction RF signal reproduced from the recording medium, and controls the demodulation means to disable demodulation in accordance with a comparison result indicating a recording failure from the comparison means. 2. The digital data recording / reproducing apparatus according to claim 1, further comprising: demodulation control means for judging whether the recording on the recording medium is good or bad according to the number of errors in the output from the demodulation means. 3. The digital data recording / reproducing apparatus according to claim 2, wherein said demodulation control means generates a signal that violates a demodulation rule in said demodulation means and disables the demodulation means. 4. An integrated circuit for integrating the reproduced RF signal, wherein the comparing means compares an integrated output from the integrating means as a level of the reproduced RF signal with the predetermined comparison level. Item 2. A digital data recording / reproducing apparatus according to Item 1. 5. A digital data recording judging method for judging the quality of recording on a recording medium by reproducing the recording medium, wherein a reproduction discriminating step for discriminating the reproduction for judging the recording from the normal reproduction. And a comparing step of comparing a predetermined comparison level for the determination of good or bad of the recording with the level of the reproduced RF signal reproduced from the recording medium, and when performing the reproduction for the recording determination, A recording determination step of determining whether the recording on the recording medium is good or not based on a result of the comparison in the comparison step. 6. The recording judging step comprises: a demodulating step of demodulating a reproduced RF signal reproduced from the recording medium; and a demodulating step in which the demodulating step is disabled in accordance with a comparison result indicating a recording failure from the comparing step. 6. A digital data recording determination method according to claim 5, further comprising a demodulation control step of controlling, and determining whether the recording on the recording medium is good or defective according to the number of errors in the output from the demodulation step. 7. The method according to claim 6, wherein the demodulation control step generates a signal that violates a demodulation rule in the demodulation step and disables the demodulation in the demodulation step. . 8. An integrating step for integrating the reproduced RF signal, wherein the comparing step includes comparing an integrated output obtained in the integrating step as a level of the reproduced RF signal with the predetermined comparison level. 6. The method according to claim 5, wherein the digital data is recorded.