JPH04181561A - Data recorder/reproducer - Google Patents

Abstract

PURPOSE:To precisely set check reference at the time of reading all written data by measuring the counts of bit interval which does not satisfies a modulation rule in a reproducing signal, and deciding propriety of written data. CONSTITUTION:Outputs of decoders A 33, B 34 are inputted to a counter B 36 through an AND circuit 35. The counter B 36 counts only when the output 35a of the circuit 35 is 'H'. Thus, it counts the counts of bit interval which does not satisfy the rule of 2-7 code generated in a binary signal of the output 35a. The output value 36a of the counter B 36 is supplied to a controller, and if the value 36a exceeds a predetermined count, its sector is malfunctioned as that more than the predetermined number of the bit patterns except the rule is in the written data, and rewritten in other sector. Accordingly, the propriety of the written data is decided.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is capable of determining the quality of written data on a recording medium such as an optical card for all data, and is capable of determining the reliability of written data. The present invention relates to a data recording and reproducing device that can improve the performance of the data.

[Prior Art] Generally, the format shown in FIG. 5 is used as a recording format of one sector in a recording medium such as an optical card.

Bit synchronization patterns 51a and 51b for generating a PLL clock are provided at both ends, and byte synchronization patterns 52a to 52e are provided before and after data blocks 53a, 53b, and 53c for byte synchronization of data demodulation. It is being This data block 53a, 5
Data that should originally be written is recorded in 3b and 53c.

When reproducing data recorded in such a recording format, for example, if the byte synchronization pattern becomes undetectable due to a defect in the recording medium or an abnormality in the recording/reproducing device, the data recorded after that will be Demodulation byte synchronization becomes impossible, and normal playback becomes impossible.

As a means to solve such a problem, as shown in FIG. 6, the byte synchronization pattern 54 is formed into an elliptical pattern by a plurality of (two types in FIG. 6) different patterns 54a and 54b that are consecutively recorded. During reproduction, if even one of the plurality of patterns is detected, it is assumed that a byte synchronization pattern has been detected, and the byte synchronization timing of data demodulation is determined based on this.

Additionally, when recording data on a recording medium, the data is generally read out immediately after the data is written to check whether or not it was recorded correctly. If it is not written correctly, the data is re-written in an alternative data area. I am trying to write.

This check immediately after writing is distinguished from normal data reading, and the data is checked more strictly. This is because, due to aging of the recording medium, the error rate is generally higher when reading data after an interval has elapsed after writing than when reading data immediately after writing. In this case, when reading data immediately after writing, even if the read result is within a range that can be judged as normal, when reading normal data, the error rate worsens over time and is outside the range that can be judged as normal. To prevent this from happening, the check criteria when reading data immediately after writing are set to be stricter than the check criteria when reading normal data.

Optical recording media such as the optical cards generally have a higher error rate than magnetic recording media, so error correction encoding with high correction ability is applied to the written data to prevent errors during reading. Corrections have been made. Such an error correction code is determined so as to be able to sufficiently correct errors at the expected error rate of the recording medium. However, when reading data immediately after writing, for the reasons mentioned above, the error is not corrected using the original correction ability, but the error is corrected by lowering the correction ability, and if the error cannot be corrected, the data is written again. That's what I do. This allows the recorded data to be strictly checked and improves the reliability of the data.

[Problems to be Solved by the Invention] In the conventional example described above, check criteria are not set for all data actually recorded when reading data immediately after writing.

That is, in the conventional write data quality determination method, the check criteria are set based on the data block 5 in FIG.
3a, 53b, 53c, etc., and other bit synchronization patterns 51a, 51b, byte synchronization patterns 52a to 52e, etc. are not considered at all.

For this reason, during normal data reading after writing, the byte synchronization pattern cannot be detected or the PL
There are cases where the L clock is not generated normally, and there is a problem in that the reliability of the written data decreases.

The present invention has been made in view of these circumstances, and provides a data recording and reproducing device that can set strict check criteria for all written data when reading data immediately after writing, and that can improve the reliability of written data. is intended to provide.

[Means for Solving the Problems] A data recording/reproducing device according to the present invention reads modulated data immediately after writing it to a recording medium, and records the data while determining the writing state based on the read result. a bit interval measuring means for measuring the number of bit intervals that do not satisfy the modulation rule in a reproduced signal of written data; The present invention is characterized by comprising a data quality determination means for determining the quality of the data.

[Operation] Immediately after the modulated data is written to the recording medium, the data is read out, the bit interval in the reproduced signal of the written data is measured by the bit interval measuring means, and the number of bit intervals that do not satisfy the modulation rule is determined by the bit interval. The interval measuring means outputs. The quality of the written data is determined by the data quality determining means depending on whether the output of the bit interval measuring means exceeds a predetermined number of times.

[Example 1 Hereinafter, the present invention will be described in detail with reference to the drawings.

1 to 4 relate to embodiments of the present invention, and FIG. 1 (A,) is a configuration diagram of an optical card recording/reproducing device, and FIG.
) is a configuration diagram of the bit interval measurement circuit, Figure 2 is a configuration diagram of the sector position detection circuit, Figure 3 is an explanatory diagram of the optical card, and Figure 4 is a time chart of the bit interval measurement circuit of Figure 1 (B). It is.

The data recording/reproducing apparatus of the present invention is constituted by an optical card recording/reproducing apparatus using an optical card 1 as a recording medium, as shown in FIG. 1(A), for example.

As shown in FIG. 3, this optical card 1 has a plurality of tracks 2 extending in the longitudinal direction of the card, which are formed in the width direction of the card. Each track 2 is composed of one sector or a plurality of sectors depending on the track format, and the data former of this one sector has a h-7h synchronization pattern and a byte synchronization pattern as shown in FIG. and data blocks. As the track format, a plurality of formats with different numbers of sectors per track are prepared, and data is recorded by selecting a format according to the application used on each card.

The optical card recording/reproducing device places the optical card 1 on track 2.
The optical head 10 is moved in a direction perpendicular to the track 2 to record and reproduce data.
is attached to a predetermined position on a conveyor belt 4 which is passed between pulleys 3a and 3b, and is transported back and forth in the direction of the track 2 by driving a motor 6 by a motor drive circuit 5. .

A -encoder 7 is attached to the motor 6 for detecting the position of the optical card 1 with respect to the optical head IO, and the output of the encoder 7 is supplied to a sector position detection circuit 8. A sector position detection signal 20 indicating a recording/reproduction start point for each sector is output from the sector position detection circuit 8 to the controller 18. This controller 18 controls the motor drive circuit 5, laser drive circuit 11, etc. based on the sector position detection signal 20.

Here, as shown in FIG. 2, for example, the sector position detection circuit 8 includes a format selector 23 to which a format selection signal 19 output from the controller 18 is input, and an encoder output 21 of the encoder 7. The counter 22 is input, and the comparator 24 is input with the output of the format selector 23 and the counter 22.
It is composed of. The format selector 23 is configured to input a predetermined value corresponding to the sector separation position on the optical card according to the format selection signal 19 to one input terminal of the comparator 24.

Further, the encoder output 21 is counted by the counter 22, and this count value is input to the other input terminal of the comparator 24.

The comparator 24 is connected to the format selector 2.
3 and the output value of the counter 22 are compared, and if these output values match, a sector position detection signal 20 is output to the controller roller 18.

The optical head 10 includes a laser diode (LD) 12
The writing or reading light emitted from the optical system 1
3 and onto the optical card 1. The light reflected from the optical card is transmitted to detector 1.
The output of the detector 14 is demodulated by the demodulation circuit 15 and temporarily stored in the RAM 16. Moreover, the output of the detector 14 is
The light is also supplied to a focus/track servo circuit 17, which controls the optical head 10 so that the incident light always follows the focus and track directions in a focused state.

The demodulation circuit 15 is provided with a bit interval measuring circuit as shown in FIG. 1(B), for example. In this embodiment, a case will be described in which a 2-7 code is used as a modulation method for data to be recorded. In addition, generally, the byte synchronization pattern and the bit synchronization pattern are designed to satisfy the modulation rules of the modulation method of the data to be recorded, so this embodiment also satisfies the modulation rules of the 2-7 code. shall be taken as a thing.

At the front of the bit interval measuring circuit, a binary signal 26 generated from the output signal of the detector 14 is synchronized with the reference tally 25 of the device, and the pulse width is normalized to one cycle of the reference tally 25. A pulse width normalization circuit is provided, which includes two fringe flops 27 and a NOT circuit 28.
and an AND circuit 29.

The binary signal 26a normalized by the pulse width normalization circuit is input to a counter A31 and a register 32. The counter A31 is
A reset is applied every time the value signal 26a becomes active, and otherwise a counting operation is performed in synchronization with the reference clock 25, and the output of this counter A31 is input to the register 32. The register 32
is used to hold the output value of the counter A31 each time the binary signals 2 and 6a become active, and the output of this register 32 is input to the decoder A33 and decoder B34.

This decoder A33 determines whether or not the output value held by the register 32 satisfies the modulation rule of 2 to 7 codes, and when the modulation rule is not satisfied, the register 32 is configured to output a high level. The output value of the AND circuit 35 is input to one input terminal of the AND circuit 35. Further, when the count value input to the register 32 is IH, the decoder B34 performs
It decodes to output high level, and AN
It is input to the other input terminal of the D times FI@35.6 The AND circuit 35 takes the logical product of the output value of the decoder A33 and the output value of the decoder B34. The output of the AND circuit 35 is input to a counter B36.

This counter B36 performs a counting operation only when the output of the AND circuit 35 is at a high level, and outputs to the controller 18 the number of bit intervals that do not satisfy the data modulation rules.

The controller 18 also includes write data quality determining means that compares and determines whether the number of bit intervals that do not satisfy the data modulation rule exceeds a predetermined number of times, and determines the quality of the written data based on this result. have.

Next, the operation of this embodiment will be described.

Data is recorded and reproduced by moving the optical card 1 in the track direction and moving the optical head 10 in a direction perpendicular to the tracks so that a desired sector position of a desired track is irradiated with a laser beam. At this time, the controller 18
The track format of the optical card 1 on which data is to be recorded and reproduced is selected, and a format selection signal 19 is output to the sector position detection circuit 8.

In this sector position detection circuit 8, the format selector 2
3 outputs a predetermined value corresponding to the sector separation position on the optical card 1 according to the format selection signal 19, and the counter 22 outputs an encoder output 2.
1 is counted, these outputs are compared by a comparator 24, and when they match, a sector position detection signal 20 is output to the controller 18. Here, the counter 22 is reset at a point, such as the edge of the optical card 1, that serves as a reference point for the position of the optical card 1 with respect to the optical head 10. Sector break positions according to the above track format are detected. And controller 1
8, by counting the sector position detection signal 20, a desired sector in which data is to be recorded or reproduced can be determined.

During data reproduction, the controller 18 controls the laser drive circuit 11 to output low-power reading light from the laser diode 12, and also controls the motor drive circuit 5 to output track address information demodulated by the demodulation circuit 15. and the sector position detection signal 20 from the sector position detection circuit 8, a desired sector of a desired track is sought and data is reproduced.

Also, when recording data, as in the case of playback, after seeking the desired sector of the desired track on which to record the data,
By controlling the laser drive circuit 11, the laser diode 12
The high-output writing light from the controller is modulated according to the data to be recorded and output, thereby recording the data in the desired sector.

When recording the data, the data is read out immediately after the data is written, and it is determined whether or not the data has been recorded correctly. In this embodiment, the quality of the written data is determined by measuring the number of times the bit interval in the written data does not satisfy the 2-7 code modulation rule using a bit interval measuring circuit, and The quality of the written data is determined based on whether or not the number of times exceeds a predetermined number of times.

The bit interval measuring circuit operates as shown in FIG.

When the binary signal 26a generated in response to the data written on the optical card 1 becomes active, the counter A3
1 is reset in synchronization with the reference clock 25, and the output value 31a becomes OH. This counter A31 is then set to 2
A counting operation is performed every reference clock 25 until the value signal 26a becomes active. Further, the register 32 is
When the binary signal 26a becomes active, the counter A3
The output value 31a of 1 is taken in and held.

Then, the decoder A33 outputs a high level when the output value 32a held by the register 32 does not satisfy the 2-7 code modulation rule, that is, in this example, when it is OH-2H1 or OEH or more. . here,
In the binarized signal 26a in FIG. 4, (a) is a case where one extra pulse is generated due to dust or scratches on the card, and (b) is a case where, for example, dust or scratches are present on the card. This shows a case where the bit cannot be formed on the card due to the influence and one pulse is missing. In these cases, since the bit interval does not satisfy the 2-7 code modulation rule, the decoder A33 outputs a high level.

On the other hand, the decoder B34 outputs a high level when the count value input to the register 32 is lH.

This is for generating the timing for determining the output 33a of the decoder A33, for example, the output 33a of the decoder A33.
When a continues to be at a high level, it is possible to accurately measure the number of bit intervals that do not satisfy the modulation rule.

The outputs of the decoder A33 and the decoder B34 are each input to an AND circuit 35, and the AND circuit 35 performs a logical product, and the result is input to a counter B36. This counter B36 performs a counting operation only when the output 35a of the AND circuit 35 is at a high level. Therefore, the number of pulses of the output 35a of the AND circuit 35 is 2.
The number of pit intervals that do not satisfy the 2-7 code modulation rule that occur in the digitized signal is counted.

The output value 36a of this counter B36 is
8.

This controller 18 reads the output value 36a of the counter B36, and if this exceeds the specified number of times,
If the written data contains a predetermined number or more of bit patterns outside the modulation rules, this sector is determined to be defective and rewritten to another sector.

In this way, by detecting the pattern of bits outside the modulation rules in the write data and determining whether the write data is good or bad based on whether the number of bits exceeds a specified value, it is possible to perform not only data block but also byte synchronization. Even if the pattern is a bit synchronization pattern, the write state can be checked. Therefore, it is possible to set strict check criteria for all written data when reading data immediately after writing, and it is possible to improve the reliability of written data.

Note that in this embodiment, the determination of the quality of written data is as follows:
For all written data, a method is used in which a pattern of bits outside the modulation rules is detected5 in the written data, and whether or not this number exceeds a specified value is used to determine pass/fail, but this method is not limited to this method. For example, in a data block, it is possible to determine the quality of written data based on the result of error correction using an ECC code, and it is also possible to use both methods in combination.

. Furthermore, the data recording medium is not limited to an optical card, but any device that uses a medium that modulates and records data can improve the reliability of written data in the same manner as in this embodiment. In addition, the data quality determination means is not limited to the configuration of this embodiment, as long as it is possible to measure the bit interval that does not satisfy the modulation rule and determine whether or not it exceeds the specified number of times. do not have.

Furthermore, the modulation method is not limited to the 2-7 code, but any modulation method such as MFM modulation that can determine whether or not it satisfies the modulation rules by measuring the bit interval may be used. Similarly to this embodiment, strict checking criteria can be set for all written data when reading data immediately after writing.

[Effects of the Invention] As described above, according to the present invention, it is possible to set strict check criteria for all written data when reading data immediately after writing, and the reliability of written data can be improved.

[Brief explanation of the drawing]

1 to 4 relate to embodiments of the present invention, FIG. 1 (A> is a configuration diagram of an optical card recording and reproducing device, and FIG. 1 (B)
is a block diagram of the bit interval measuring circuit, FIG. 2 is a block diagram of the sector position detection circuit, FIG. 3 is an explanatory diagram of the optical card, and FIG. 4 is a time chart of the pit interval measuring circuit of FIG. 1 (B).
FIG. 5 is an explanatory diagram of the recording format of one sector on a recording medium, and FIG. 6 is an explanatory diagram of the byte synchronization pattern of FIG. 5. 8...Sector position detection circuit 10...Optical helad 15...Demodulation circuit 18...
Controllers 51a, 51b...Bit synchronization patterns 52a to 52
e... Byte synchronization pattern 53a-53c... Data block Figure 2 P Figure 3 Figure 5 □ Byte tautology Bathone --

Claims (1)

[Scope of Claims] A data recording and reproducing device that reads modulated data immediately after writing it to a recording medium, and records the data while determining the writing state based on the read result, comprising: a reproduction signal of the written data; bit interval measuring means for measuring the number of bit intervals that do not satisfy a modulation rule; and data quality for determining the quality of the written data depending on whether the output of the bit interval measuring means exceeds a specified number of times. 1. A data recording/reproducing device comprising: determination means.