JPH08235792A - Data reproducing device - Google Patents

Abstract

PURPOSE: To prevent outputting erroneous data. CONSTITUTION: An optical disk 1 is reproduced, and a signal DS is supplied to a detecting section 4a, a delay section 9, and a detecting section 10 from an amplifier section 3. When the reference signal is detected from the signal DS in the detecting section 10, a window signal WD which is read-out timing and in which time variation is considered is outputted from a signal generating section 11. When a synchronizing signal is detected and the signal SD is outputted in the detecting section 4a in a period of the signal WD, the signal SD is selected by a selecting section 14 and supplied to a memory section 5, and a data signal of a signal DDS from the delay section 9 is written from the beginning. When a synchronizing signal is not detected, a signal ST from a signal generation section 13 outputted after finish of the signal WD is selected and supplied to the memory section 5, and a data signal of the signal DDS is written halfway. When a synchronizing signal is not detected, as data is written halfway, an error can be surely detected by a decoder section 6, and outputting erroneous data can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data reproducing device. More specifically, it is a data reproducing device that reads out a signal recorded on a recording medium such as an optical disc and outputs data with error correction, and detects a synchronization signal based on the signal read from the recording medium. When it is not detected, an error signal indicating that the error correction was not correctly made is generated.

[0002]

2. Description of the Related Art In an optical disc, for example, a 130 mm optical disc, the radius of the optical disc 1 is 30 m as shown in FIG. 3A.
A spiral track is formed in the recording area of m to 60 mm, and one track of the track is divided into 17 sectors. Data is recorded in each sector in the format shown in FIG. 3B.

In FIG. 3B, the 52-byte preformatted portion PF includes a sector marker SM and data VFO1 and VFO.
FO2, address marker AM, identification data ID, error detection code CRC and postamble PA. The sector marker SM indicates the beginning of the sector format, and the data VFO (variablefr)
equality osillator) is a P for generating a clock.
It is a single frequency signal used for pulling the operation of the LL oscillator. The address marker AM indicates the start position of the code data of the preformatted part. The identification data ID indicates a track number, a sector number, etc., and the error detection code CRC is an error detection code. The identification data ID and the error detection code CRC are repeated three times. This preformat part P
The F data is recorded on the optical disc in advance.

A 14-byte area following the pre-format section PF contains data O for detecting an offset of a tracking error signal, preventing double writing, and adjusting laser output.
It consists of DF, FLAG, and ALPC. The data portion DT of 1274 bytes following this 14-byte area is 12
Byte data VFO3 and 3-byte sync signal SYNC
And a 1259-byte data area DATA, and a 20-byte buffer area BUFFER in which no data is recorded is provided after the data section DT. The buffer area BUFFER forms a boundary with the preformat section PF. Be clarified.

The data area DATA of the optical disk is constructed as shown in FIG. In FIG. 4, the data area DATA after the 3-byte synchronization signal SYNC has 102
4 bytes of data D1 to D1024 are recorded. After the data D1024, 12-byte DM pointers P1,1 to P3,4, 4-byte CRC code C1 to C4 for error detection and 160-byte error detection / correction code (ECC) E1,1 to E10,16. Is recorded. Further, in order to prevent synchronization deviation in the data area DATA, a 1-byte synchronization code RS is recorded every 20 bytes.

A data reproducing apparatus for reading data from an optical disc on which data is recorded in such a format has a structure as shown in FIG. 5, for example.

In FIG. 5, an optical head unit 2 for reading a signal recorded on an optical disc 1 converts a laser diode or a reflected light obtained by irradiating the optical disc 1 with a laser beam from the laser diode into an electric signal. It is composed of an RF detector and the like. The electric signal output from the optical head unit 2 is amplified by the amplifier unit 3 and supplied to the synchronization detection unit 4 and the horizontal / vertical conversion memory unit 5 as a reproduction signal DS.

The sync detector 4 detects a 3-byte sync signal SYNC indicating the beginning of data from the reproduction signal DS. This sync detector 4 uses a 3-byte sync signal SYN.
When C is detected, the synchronization detection signal SD is supplied to the horizontal / vertical conversion memory unit 5.

In the horizontal / vertical conversion memory unit 5, the sync detection signal SD
Is supplied, the writing of the reproduction signal DS is started. For example, as shown in FIG.
The data D1 to D1024 are sequentially arranged in the horizontal direction in units of 0 bytes.
DM pointers P1,1 to P3,4, CRC code C1 to
C4 and error detection / correction codes E1,1 to E10,16
Is written. The data signal SD written in the horizontal / vertical conversion memory unit 5 includes data D1, data D11, and data D1.
21 ... Vertically read in the order of 21 ...
It is supplied to the ECC decoder unit 6 as DC.

In the ECC decoder unit 6, data error correction is performed using an error detection / correction code for each column of the horizontal / vertical conversion data signal SDC. For example, data D1, D11,
To D1021, the error detection and correction codes E1,1,
Error correction is performed using E1,2 to E1,16, and error correction is performed on the data D2 to D1022 using error detection / correction codes E2,1 to E2,16.
After that, the data D1 to D1021 and D2 are processed in the same manner.
The error correction of D1022, ... D10 to D1020 is performed.

The error-corrected data is supplied to the vertical / horizontal conversion memory unit 7 as vertical data DAV. In the vertical / horizontal conversion memory unit 7, the vertical direction data DAV is written in the vertical direction in the order of, for example, data D1, data D11, data D21. After that, the written data after error correction is data D1, data D2, data D3 ...
The data interface unit 8 is read in the horizontal direction in the order of
Is supplied to an external device (not shown).

[0012]

By the way, when an error occurs in the 3-byte sync signal SYNC detected by the sync detector 4, the sync detection signal SD is sent from the sync detector 4 to the horizontal-vertical conversion memory unit 5. Is not supplied to the playback signal DS
Is not written in the horizontal / vertical conversion memory unit 5.

Therefore, the ECC decoder unit 6 performs error correction on the data already written in the horizontal / vertical conversion memory unit 5 and supplies it from the vertical / horizontal conversion memory unit 7 to the external device via the data interface unit 8. Therefore, the data different from the data of the block to be read may be supplied to the external device.

In such a case, since the ECC decoder unit 6 does not detect that an error that cannot be corrected occurs, the data is abnormal even if it is not a desired block. I could not detect that.

Therefore, the present invention provides a data reproducing apparatus capable of preventing erroneous data output.

[0016]

A data reproducing apparatus according to the present invention comprises a memory means for storing at least a data signal reproduced from a recording medium in which a reference signal, a synchronizing signal and a data signal are sequentially recorded, and a memory means. Error correction means for correcting the error of the stored data signal and generating an error signal when an uncorrectable error occurs,
A window signal generating means for detecting a reference signal reproduced from the recording medium and generating a window signal in relation to the timing at which the synchronizing signal is reproduced, and a first writing start signal for starting the writing operation of the memory means. The synchronization detection means for generating the synchronization signal reproduced from the recording medium and the second write start signal for starting the writing operation of the memory means are related to the end of the window signal generated by the window signal generation means. The data start signal generating means additionally generated, and the write start signal of either the first write start signal or the second write start signal is selected based on the window signal and the first write start signal. Then, it has a signal selecting means to be supplied to the memory means.

[0017]

According to the present invention, when the synchronization signal is detected by the synchronization detection means and the first write start signal is generated during the generation period of the window signal by the window signal generation means, the first write start is started. The data signal is stored in the memory means from the beginning by the signal and the error correction is performed by the error correction means. Further, when the synchronization detecting means does not detect the synchronization signal and the first write start signal is not generated during the generation period of the window signal, the second write start signal generated in association with the end of the window signal is used. Since the data signal is stored in the memory means from the middle, an error signal is generated by detecting that an error that cannot be corrected by the error correction means is detected.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of an embodiment of a data reproducing apparatus according to the present invention will be described below with reference to FIG. In FIG. 1, parts corresponding to those in FIG. 5 are designated by the same reference numerals, and detailed description thereof will be omitted.

In FIG. 1, the reproduction signal DS from the amplifier section 3 is supplied to the synchronization detection section 4a which constitutes the synchronization signal detection means, and also to the delay section 9 and the reference detection section 10 which constitutes the window signal generation means. To be done. The reproduction signal DS is delayed for a predetermined time in the delay unit 9, and the delayed reproduction signal DS is supplied to the horizontal / vertical conversion memory unit 5 as a memory means as a delayed reproduction signal DDS. The reference detection unit 10 detects a reference signal (for example, a sector mark SM indicating the beginning of a sector) from the reproduction signal DS.
When the reference detection unit 10 detects the reference signal, the reference detection signal RFD constitutes the window signal generation unit 11 which constitutes the window signal generation means.
Is supplied to.

The window signal generator 11 generates a window signal WD having a predetermined time width τb after a predetermined time τa has elapsed since the reference detection signal RFD was supplied. This window signal WD is used for the synchronization detection unit 4a.
And a data start signal generating section 13 which is a data start signal generating means. The predetermined time τa is the synchronization signal SYN of 3 bytes after the reference signal is read.
The time width τb is set in accordance with the timing at which C is read, and the time width τb takes into consideration the time fluctuation caused by the jitter in the time required from the reading of the reference signal to the reading of the 3-byte synchronization signal SYNC. It is set.

In the synchronization detector 4a, the window signal WD
The reproduction signal D from the amplifier unit 3 during the period when the
The 3-byte sync signal SYNC of S is detected. Here, when the 3-byte synchronization signal SYNC is detected, the synchronization detection signal SD is supplied to the external synchronization detection unit 12 and the signal selection unit 14 which is the signal selection means.

On the other hand, in the data start signal generator 13, the start signal ST is generated with the end of the window signal WD and is supplied to the signal selector 14.

The external sync detector 12 generates a signal indicating whether or not the sync detection signal SD is supplied during the period in which the window signal WD is supplied. This signal is supplied to the signal selection unit 14 as the switching signal SE.

In the signal selection unit 14, the external synchronization detection unit 12
When the external synchronization detector 12 detects that the synchronization detection signal SD is supplied during the period when the window signal WD is supplied, the synchronization detection unit 4a supplies the synchronization detection signal. The signal SD is selected and supplied to the horizontal / vertical conversion memory unit 5. When the external synchronization detector 12 does not detect that the synchronization detection signal SD is supplied during the period when the window signal WD is supplied, the start signal ST supplied from the data start signal generator 13 is selected. It is supplied to the horizontal / vertical conversion memory unit 5.

In the horizontal / vertical conversion memory unit 5, the signal selection unit 14
The writing of the delayed reproduction signal DDS from the delay unit 9 is started based on the synchronization detection signal SD or the start signal ST from.

Thereafter, the delayed reproduction signal DDS written in the horizontal / vertical conversion memory unit 5 is processed by the ECC decoder unit 6 which is an error correction means as in the conventional data reproducing apparatus, and the data from the vertical / horizontal conversion memory unit 7 is processed. Interface section 8
Is supplied to an external device via.

Next, the operation will be described with reference to FIG. Figure 2
2A shows the reproduced signal DS and FIG. 2B shows the delayed reproduced signal DDS. First, when the reference detection unit 10 detects that the reproduction signal DS is the sector mark SM at time t1, the reference detection signal RFD from the reference detection unit 10 shown in FIG. 2C is set to the high level “H”. . In the window signal generator 11, the window signal WD shown in FIG. 2D is set to the high level “H” from the time point t2 after the elapse of the predetermined time τa from the rising of the reference detection signal RFD. The window signal WD is at the high level "H" during the time t2.
From the time t5 to the time t5.

During the high level "H" of the window signal WD from time t2 to time t5, the reproduction signal DS
Is detected as the 3-byte sync signal SYNC by the sync detector 4a, and the sync detection signal SD shown in FIG. 2E is set to the high level "H" at time t3, the external sync detector 12 outputs The signal selection unit 14 selects the synchronization detection signal SD from the synchronization detection unit 4a by the switching signal SE and supplies it to the horizontal / vertical conversion memory 5.

In the horizontal / vertical conversion memory 5, the delayed reproduction signal DDS is written from the data D1 in synchronization with the fall of the synchronization detection signal SD at time t4, the data D1 is error-corrected, and the data is supplied to an external device. It

Next, during the period of the high level "H" of the window signal WD from time t2 to time t5, the reproduction signal D
When the sync detecting unit 4a does not detect that the S is the 3-byte sync signal SYNC, the signal selecting unit 14 causes the data start signal generating unit 13 to switch the signal shown in FIG. 2F by the switching signal SE from the external sync detecting unit 12. The start signal ST shown is selected and supplied to the horizontal / vertical conversion memory 5.

The start signal ST is set to the high level "H" at the time point t5 when the period of the high level "H" of the window signal WD from the window signal generator 11 ends.
At time t6, the low level is set to "L". In the horizontal / vertical conversion memory 5, writing is started from the data D1 and subsequent data of the delayed reproduction signal DDS in synchronization with the fall of the start signal ST at this time t6.

The data written in the horizontal / vertical conversion memory 5 is error-corrected by the ECC decoder unit 6. However, the ECC decoder unit 6 indicates that an error that cannot be corrected occurs because the data was written from the middle. To be detected.
Therefore, the data supply to the external device is stopped. Since the start signal ST is for writing data after the data D1 of the delayed reproduction signal DDS into the horizontal / vertical conversion memory 5, after the time t5 when the high level "H" period of the window signal WD ends. It may be a high level "H".

As described above, according to the above-described embodiment, 3
If an error occurs in the byte sync signal SYNC,
Since an error is detected by the ECC decoder unit 6, it is possible to prevent the output of data that is not a desired block.

In the above-mentioned embodiment, the sector mark S
Although the reference detection unit 10 detects M as the reference signal, the reference signal is not limited to the sector mark SM, and may be the address mark AM or the like. Further, when the start signal ST is set to the high level “H”, the horizontal / vertical conversion memory 5 receives the ECC.
Writing dummy data that cannot be corrected by the decoder unit 6,
Alternatively, if the data in the horizontal / vertical conversion memory 5 is reset, the error can be reliably detected by the ECC decoder unit 6, so that it is possible to more reliably prevent output of data that is not a desired block.

Further, it goes without saying that the data reproducing apparatus may use not only an optical disk as a recording medium but also a magnetic disk or the like.

[0036]

According to the present invention, when the synchronization signal is detected by the synchronization detecting means during the generation period of the window signal by the window signal generating means, the data signal is stored in the memory means from the beginning and the error correction is performed. Error correction is performed by the means, and when the synchronization signal is not detected by the synchronization detection means during the generation period of the window signal, the data signal is stored in the memory means from the middle, so an error that cannot be corrected by the error correction means is generated. Is detected and an error signal is generated.

Therefore, when the sync signal is not detected, the error is surely detected by the error correction means, so that a data signal different from the desired data signal already stored in the memory means is erroneously supplied to the external device. Can be prevented. Further, since the signal of the pre-formatted portion pre-recorded on the optical disc is used as the reference signal, the process of recording the reference signal on the optical disc can be unnecessary and the signal of the pre-formatted portion pre-recorded is used. With, it is possible to detect the reference signal without error.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of a data reproducing apparatus according to the present invention.

FIG. 2 is a diagram showing an operation of the embodiment.

FIG. 3 is a diagram showing a recording format on an optical disc.

FIG. 4 is a diagram showing a structure of a data area.

FIG. 5 is a diagram showing a configuration of a conventional data reproducing device.

[Explanation of symbols]

 1 Optical Disc 2 Optical Head Section 3 Amplifier Section 4, 4a Synchronization Detection Section 5 Horizontal-Vertical Conversion Memory Section 6 ECC Decoder Section 7 Vertical-Horizontal Conversion Memory Section 8 Data Interface Section 9 Delay Section 10 Reference Detection Section 11 Window Signal Generation Section 12 External Synchronization Detection Part 13 Data start signal generator 14 Signal selector

Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number in the agency FI Technical display location G11B 19/04 501 G11B 19/04 501P 19/247 19/247 R 20/14 341 9463-5D 20/14 341B

Claims (2)

[Claims] 1. A memory means for storing the data signal reproduced from a recording medium in which at least a reference signal, a synchronization signal and a data signal are sequentially recorded, and error correction and correction of the data signal stored in the memory means. An error correction means for generating an error signal when an error that cannot be generated occurs, and a window signal generation for detecting a reference signal reproduced from the recording medium and generating a window signal in relation to the timing at which the synchronization signal is reproduced Means, a sync detecting means for generating a first write start signal for starting the write operation of the memory means when a sync signal reproduced from the recording medium is detected, and a write operation of the memory means. The second write start signal is related to the end of the window signal generated by the window signal generating means. Data start signal generating means for generating the first write start signal, and based on the window signal and the first write start signal, start writing of either the first write start signal or the second write start signal. Signal selecting means for selecting a signal and supplying it to the memory means, and when the first writing start signal is generated by the synchronization detecting means during the period in which the window signal is being generated,
The signal selection means selects the first write start signal,
The data signal is stored in the memory means from the beginning and the error correction means performs error correction, and the synchronization detection means generates a first write start signal during a period in which the window signal is generated. If not, the data selecting means selects the second write start signal, the memory means stores the data signal halfway, and the error correcting means generates an error signal. Playback device. 2. The data reproducing apparatus according to claim 1, wherein the recording medium is an optical disc, and the reference signal uses a signal of a pre-format section recorded in advance on the optical disc.