JP2009009661A - Optical disc apparatus and control method thereof - Google Patents

Abstract

An optical disc apparatus capable of establishing synchronization early and improving the reliability of wobble signal detection even when non-detection of a synchronization signal due to noise or the like occurs.
An optical disc apparatus according to the present invention reproduces an optical disc in which a data sequence of a predetermined length composed of a synchronization signal and subsequent data is recorded as wobble, or records and reproduces an optical disc wobble. The wobble reproduction unit that reproduces the wobble signal, the synchronization detection unit that detects the synchronization signal included in the wobble signal, and the synchronization signal protection window at the predicted arrival position of the synchronization signal based on whether or not the synchronization signal is detected. A protection window generation unit that generates data and an error determination unit that performs error detection of data, and the protection window generation unit outputs information about the presence or absence of synchronization detection output from the wobble synchronization detection unit and the error determination unit. The protection window is generated based on error detection information of data.
[Selection] Figure 9

Description

  The present invention relates to an optical disc apparatus and a control method thereof, and more particularly, to an optical disc for reproducing an optical disc in which an address is recorded by wobble and a control method thereof.

  Recording type optical discs such as HD DVD-R and HD DVD-RW have grooves with waviness called wobbles on the tracks, and record the physical address of the optical disc by phase modulation of the waviness. . When recording / reproducing on an optical disk, a wobble signal is read from the wobble, and a physical address modulated therein is demodulated to determine a recording / reproducing position.

  The wobble signal is provided with a synchronization signal prior to a data string such as a physical address. This synchronization signal is detected from the wobble signal reproduced from the optical disc, and data such as a physical address following the synchronization signal is extracted from the timing of the detected synchronization signal. If the synchronization signal is erroneously detected, data such as the subsequent physical address cannot be correctly extracted, and as a result, recording / reproduction with respect to the optical disc cannot be performed normally. Therefore, prevention of erroneous detection of the synchronization signal of the wobble signal is a very important technical problem, and various erroneous detection prevention measures have been studied conventionally.

For example, as disclosed in Patent Document 1 and the like, a technique of providing a protection window at a predicted generation position of a synchronization signal is one of techniques related to prevention of erroneous detection of the synchronization signal.
JP 2003-123257 A

  In a wobble signal such as HD DVD-R and HD DVD-RW, a synchronization signal and subsequent data such as a physical address are recorded in a recording length unit called WAP (Wobble Address in Periodic Position). All the WAPs have the same recording length, and the WAPs are continuously recorded at a period of this recording length. Therefore, the protection window for the synchronization signal can be generated using the periodicity of WAP.

  That is, once a synchronization signal is correctly detected, a protection window can be provided at a position after a delay time corresponding to the WAP cycle from the position of the detected synchronization signal.

  However, a protective window cannot be provided as a matter of course when the synchronization signal is first detected, such as immediately after the optical disk is inserted into the optical disk apparatus or when a track jump operation is performed. That is, there is no protection window in the first synchronization detection, and a protection window can be provided from the second synchronization detection.

  Since the first synchronization detection is a synchronization detection without a protection window, there is a relatively high possibility of erroneous detection (detection that erroneously determines that a data string that is not a synchronization signal is a data string of a synchronization signal). Therefore, the reliability of the first protection window (the protection window used for the second synchronization detection) generated by the first synchronization detection is not necessarily high. Therefore, conventionally, when the second synchronization detection cannot be performed, the first protection window generated by the first synchronization detection is the correct protection window (the protection window generated at the position where the original synchronization signal should arrive). ), The process of releasing this protective window was once performed.

  However, the reason why the second synchronization detection cannot be performed is as follows. (1) In addition to the case where the first protection window is not the correct protection window as described above. In some cases, the synchronization signal could not be detected despite the arrival of the original synchronization signal (this is hereinafter referred to as non-detection of the synchronization signal). For example, when a part of the bit pattern of the synchronization signal is distorted due to the influence of noise or the like, it may be undetected.

  In the case of the latter (2), the synchronization window is once released despite the arrival of the original correct synchronization signal, so that the synchronization process takes time. In addition, once the synchronization window is canceled, the next synchronization detection is the synchronization detection without the protection window, so that the possibility of erroneous detection of the synchronization signal is increased.

  The present invention has been made in view of the above circumstances, and an optical disc apparatus capable of establishing synchronization early and improving the reliability of wobble signal detection even when synchronization signal non-detection due to noise or the like occurs An object is to provide a control method thereof.

  In order to solve the above problems, an optical disc apparatus according to the present invention reproduces an optical disc in which a data sequence of a predetermined length composed of a synchronization signal and subsequent data is recorded as wobble, as described in claim 1. Alternatively, in the optical disc apparatus for recording and reproducing, based on the presence / absence of detection of the synchronization signal, a wobble reproduction unit that reads the wobble of the optical disc and reproduces a wobble signal, a synchronization detection unit that detects a synchronization signal included in the wobble signal, and A protection window generation unit that generates a protection window of the synchronization signal at a predicted arrival position of the synchronization signal, and an error determination unit that detects an error of the data, and the protection window generation unit includes the wobble synchronization detection unit The protection based on the information on the presence or absence of synchronization detection output from the error detection information of the data output from the error determination unit Generating a, characterized in that.

  In order to solve the above-described problem, the optical disk apparatus control method according to the present invention records a data sequence of a predetermined length including a synchronization signal and subsequent data as a wobble, as described in claim 5. In a control method of an optical disc apparatus for reproducing or recording and reproducing an optical disc, (a) reading a wobble of the optical disc and reproducing a wobble signal, (b) detecting a synchronization signal included in the wobble signal, and (c) A synchronization signal protection window is generated at a predicted arrival position of the synchronization signal based on whether or not the synchronization signal is detected, and (d) error detection of the data is performed. In step (c), synchronization detection is performed. The protection window is generated on the basis of information on presence / absence of data and error detection information of data.

  According to the optical disk device and the control method thereof according to the present invention, synchronization can be established at an early stage even when non-detection of a synchronization signal due to noise or the like occurs, and the reliability of wobble signal detection can be improved.

  Embodiments of an optical disc apparatus and a control method thereof according to the present invention will be described with reference to the accompanying drawings.

(1) Optical Disc Device FIG. 1 is a block diagram showing a configuration example of an optical disc device 1 according to an embodiment of the present invention.

  An optical disk 10 shown in FIG. 1 is a write-once or rewritable optical disk such as HD DVD-R and HD DVD-RW. In this type of optical disc 10, a track having a sine wave-like undulation called wobble is formed.

  When recording / reproducing data on an optical disc, a substantially sinusoidal wobble signal corresponding to the shape of the wobble is extracted from the optical disc, data such as a physical address modulated in the wobble signal is demodulated, and data recording / reproduction is performed. Used for address confirmation during playback. In the case of HD DVD-R and HD DVD-RW, the wobble signal is subjected to binary phase modulation by data such as a physical address.

  As shown in FIG. 1, the optical disc apparatus 1 includes a disc motor 11 that rotates the optical disc 10, a laser diode 13 that generates laser light to irradiate the optical disc 10, an objective lens 12 that focuses the laser light on the optical disc 10, A photodetector 14 that photoelectrically converts reflected light from the optical disc 10 and a preamplifier 15 that amplifies the output signal of the photodetector 14 are provided.

  The wobble reproduction unit 16 generates a difference signal (referred to as a push-pull signal) from the light amount of each half surface in the radial direction detected by the photodetector 14. This push-pull signal becomes a wobble signal corresponding to the wobble waveform applied to the track. Since the amount of movement of the track in the radial direction can be detected by the push-pull signal, it is used as a tracking error signal in a tracking servo system (not shown).

  A signal obtained by adding the outputs of all the divided surfaces of the photodetector 14 is input to the reproduction processing unit 17 as an RF signal.

  The reproduction processing unit 17 performs waveform equalization processing, reproduction signal processing, error correction processing, data conversion processing, and the like. Through these processes, reproduction data is obtained, and the reproduction data is sent to an external host device 100 such as a personal computer via the interface unit 19.

  The waveform equalization process gives a frequency-dependent amplitude characteristic to the input RF signal in order to compensate for the attenuation of the short frequency of the recording wavelength, and relaxes the difference in amplitude depending on the recording wavelength.

  In the reproduction signal processing, the original digital modulation data is reproduced from the waveform equalized signal using a waveform discrimination method such as Viterbi decoding, and further, ETM (Eight to Twelve Modulation) modulation is demodulated.

  In the error correction processing, error correction processing is performed on the demodulated data. Further, the data subjected to error correction is subjected to a data conversion process adapted to the data format with the host device 100.

  On the other hand, the optical disc apparatus 1 includes a recording processing unit 18 that processes recording data input from the host device via the interface unit 19. The recording processing unit 18 performs recording signal processing, recording compensation processing, and the like.

  In the recording signal processing, the recording data input from the host device is rearranged in an order suitable for physical recording on the optical disc 10. Further, a code for error correction is added to the recording data, and the recording data is further modulated according to the ETM modulation rule.

  The recording compensation process generates a laser intensity waveform that minimizes distortion due to recording in accordance with the physical characteristics of the optical disc 10.

  On the other hand, the wobble signal output from the wobble reproduction unit 16 is input to the wobble detection unit 20. The wobble detection unit 20 demodulates the binary phase modulation wave by performing phase detection using a PLL or the like on the input wobble signal. A sync pattern (predetermined data pattern constituting the synchronization signal) is detected from the demodulated phase detection signal, and physical address information and the like are extracted from the phase detection signal based on the detection timing of the sync pattern.

  The extracted physical address information and the like are supplied to the recording processing unit 18 and the reproduction processing unit 17 and used to determine the recording address and the reading address for the optical disc 10.

  When extracting physical address information and the like from a wobble signal, it is necessary to detect the synchronization signal with high reliability based on the detection timing of the synchronization signal. For this reason, in the optical disc apparatus 1 according to the present embodiment, a synchronization signal detection method using a protection window is adopted, and the detection error of the synchronization signal is reduced by the protection window and the reliability is improved.

  Generation of a protection window, a synchronization signal using the protection window, and the like are performed by the wobble detection unit 20. Hereinafter, the detailed configuration and operation of the wobble detection unit 20 will be described.

(2) Wobble Detection Unit Prior to the description of the configuration and operation of the wobble detection unit 20, the data format of HD DVD-R and HD DVD-RW will be outlined.

  FIG. 2 is a diagram illustrating wobble modulation rules defined for HD DVD-R and HD DVD-RW. In this wobble modulation rule, the unmodulated wobble shown in FIG. 2A is NPW (bit information “0”), and the modulated wobble shown in FIG. 2B is IPW (bit information “1”). Are combined to represent a sync or address modulation code.

  FIG. 3 is a diagram illustrating a data format of physical address information embedded one by one for each recording length unit called WAP (Wobble Address in Periodic Position). In HD DVD-R and HD DVD-RW, the WAP shown in FIG. 3 is embedded as a wobble waveform. A WAP is provided for each division unit called a physical segment.

  As shown in FIG. 3, the WAP has a structure divided into 17 sets of units called WDUs (Wobble Data Units). The first WDU is “Sync field” having synchronization information, and then 11 sets of WDUs are “Address field” having address modulation code information. The remaining five sets of WDUs are “Unity field” of the wobble non-modulation section.

  Each WDU is composed of 84 wobbles (84 wobbles), and the WAP as a whole is composed of 1428 wobbles (84 wobbles × 17 WDU = 1428 wobbles).

  FIG. 4A is a diagram illustrating an internal configuration of the “Sync field” WDU. In the “Sync field” WDU, the 6 wobble waves from the top are IPW, and the phase detection value is negative (“−”). The subsequent four waves are NPW, and the phase detection value is positive (“+”). Further, the next six waves are IPW and become negative (“−”). Of the 84 wobble waves constituting the “DU” of the “Sync field”, the remaining 68 waves are all NPW (“+”) and are not shown.

  FIG. 4A shows a sign bit when the phase detection value is expressed in two's complement. That is, the sign bit “1” when the phase detection value is negative (“−”) is expressed as a high level, and the sign bit “0” when the phase detection value is positive (“+”) is expressed as a low level. (The same applies to FIG. 4B).

  On the other hand, FIG. 4B is a diagram illustrating an internal configuration of each WDU of “Address field”. In each WDU of “Address field”, four wobble waves from the top are IPW, and the phase detection value is negative (“−”). The following 12 waves are configured to express 3 bits of data of bit 2, bit 1 and bit 0 by 4 waves, respectively, by either 4 waves of IPW or NPW. The remaining 68 waves are all NPW (“+”) and are not shown in the same manner as in FIG.

  Each WDU of the “Address field” can represent 3-bit data as described above, and 33 bits of data can be represented by 11 sets of WDUs of the “Address field”.

  FIG. 5 is a diagram showing a breakdown of the 33-bit data. The left end is MSB and the right end is LSB. From the MSB side, “Segment Infomation” is 2 bits, “PS Block address” is 19 bits, “Physical segment order” is 3 bits, and “CRC” is 9 bits, for a total of 33 bits.

  The 2 bits of “Segment Infomation” are composed of 1 bit indicating the segment type and 1 spare bit. The 19 bits of “PS Block address” and the 3 bits of “Physical segment order” represent the physical address on the optical disc 10. “Physical segment order” corresponds to a lower address of the physical address, and a value from 0 to 7 is repeatedly counted every time one physical segment is changed.

  “CRC” is a 9-bit CRC (Cyclic Redundancy Check) code, and the presence or absence of a data error can be detected based on this CRC code.

  At the head of one WAP composed of wobble 1428 waves, there is a sync pattern (6T (IPW) -4T (NPW) -6T (IPW) represented by wobble 16 waves, that is, "------ ++++"). -------) "is always provided, and this is a synchronization signal. Synchronization detection is performed by detecting this sync pattern by pattern matching or the like.

  Next, for comparison with the configuration and operation of the wobble detection unit 20 according to the present embodiment, the configuration and operation of the conventional wobble detection unit 200 will be schematically described.

  FIG. 6 is a block diagram illustrating a configuration example of a conventional wobble detection unit 200. The wobble detection unit 200 includes a phase detection unit 21, a sync pattern detection unit (synchronization detection unit) 22, a sync continuous detection counter 23, a sync continuous non-detection counter 24, a synchronization window generation unit 25, an AND circuit 26, and a flywheel counter 27. , A wobble PLL unit 28, and a physical address extraction unit 29.

  The wobble signal input to the wobble detection unit 200 is phase-detected by the phase detection unit 21. The phase-detected signal is input to the sync pattern detection unit 22 where matching between the sync pattern sequence held in advance and the input sync pattern sequence is performed. If they match, a temporary synchronization detection signal is output to the AND circuit 26.

  FIGS. 7A, 7B, and 7C are diagrams illustrating the phase detection signal input to the sync pattern detection unit 22. At the top of each WAP, 6T (IPW) -4T (NPW) There is a −6T (IPW) sync pattern. When this sync pattern is detected, a temporary synchronization detection flag having a length of 1T is set at a position after a predetermined processing delay time has elapsed (this position is called a detection determination position). Here, T indicates the length of one wobble.

  On the other hand, as shown in FIG. 7D, the protection window generator 25 generates a protection window having a width of 3T, for example, with the detection determination position as the center. This protection window is output to the AND circuit 26. If the provisional synchronization detection flag is within the protection window, it is determined that synchronization is truly detected, and is input to the flywheel counter 27 as a true synchronization detection flag.

  The flywheel counter 27 is supplied with the wobble clock generated by the wobble PLL unit 28 (clock having one wobble length as a unit length). The flywheel counter 27 uses the true synchronization detection flag as a reference. The data extraction timing is generated by counting up the wobble clock. The data extraction timing is input to the physical address extraction unit 29, and physical address data following the sync pattern is extracted from the phase detection signal.

  The protection window is generated in order to prevent erroneous detection of the sync pattern. FIG. 8 is a diagram illustrating a conventional method for generating, maintaining, and canceling a protection window.

  FIG. 8A shows how the sync pattern is repeatedly input for each WAP. FIG. 8B shows an output signal of the sync pattern detection unit 22. “Detected” indicates that the provisional synchronization detection flag is output, and “not detected” indicates that the provisional synchronization detection flag is not output.

  “Detection” at the left end in FIG. 8B corresponds to the first sync pattern detection immediately after the optical disc 10 is inserted or when a track jump occurs. In the first sync pattern detection, since the protection window has not been generated yet, the protection window valid flag is “invalid” as shown in FIG. Further, as shown in FIG. 8D, before the first sync pattern is detected, the synchronization processing permission range is the entire WAP range. That is, the protection window is not generated.

  On the other hand, after the first sync pattern is detected, the first protection window is generated based on the detection of the first sync pattern. However, when the second sync pattern that should arrive in the first protection window is not detected, the generated first protection window is immediately canceled. This state is shown in the area surrounded by circles in FIG. This is because the detection of the first sync pattern is detection in a state where there is no protection window, so there is a possibility of erroneous detection (detection that erroneously determines that a data string that is not a sync pattern is a data pattern of a sync pattern). This is because the reliability of the first protection window generated by detecting the first sync pattern (the protection window used for the second sync pattern detection) is not necessarily high. Therefore, conventionally, when the second sync pattern detection cannot be performed, it is determined that the first protection window is not a correct protection window (a protection window generated at a position where the original sync pattern should arrive). A process of releasing this protective window was performed.

  On the other hand, when the sync pattern detection is repeated a plurality of times, for example, twice or more, it can be considered that the reliability of the protection window generated by these is sufficiently high. Therefore, in this case, as shown in FIG. 8, even if the third time and the fourth time are “detected” and the fifth time is “not detected”, the protective window is not released and the input is maintained. ing.

  In this case, the fifth “undetected” could not be detected as a result of a part of the sync pattern being distorted by the influence of noise or the like even though the original sync pattern arrived in the protection window. (The above-mentioned “non-detection” case) and is based on the determination that the sync pattern is likely to be detected in the next sixth time. In other words, it is based on the idea that more reliable sync pattern detection is possible by maintaining the current protection window than by releasing the protection window and increasing the possibility of erroneous detection.

  However, even in this case, when “undetected” continues for a plurality of times, for example, when “undetected” continues for three times or more as illustrated in FIG. 8, a large slip of the wobble signal reading position occurs. In addition, since it is considered that a track jump or the like has occurred, the protective window is temporarily released.

  Next, the configuration and operation of the wobble detection unit 20 according to the present embodiment will be described. FIG. 9 is a block diagram illustrating a detailed configuration example of the wobble detection unit 20 according to the present embodiment. The difference from the conventional wobble detection unit 200 is that an error determination unit 30 is newly provided.

  The error determination unit 30 determines the error detection of the physical address data following the sync pattern based on the CRC code (9-bit CRC code shown in FIG. 5). The protection window generation unit 25 considers the result of this error detection and determines whether to maintain or cancel the first protection window.

  A specific operation of the protection window generation unit 25 will be described with reference to FIGS. 10 and 11. FIG. 10 and FIG. 11 show the operation when the sync pattern is not detected for the second time even though the sync pattern is detected first.

  As described above, conventionally, if a sync pattern is first detected and then a protection window is generated, and if no sync pattern is detected within the range of the first protection window, the reliability of synchronization processing is low. The protective window was supposed to be released immediately. However, with this method, even when the sync pattern has actually arrived at the correct position, even if the sync pattern cannot be detected due to distortion of the sync pattern signal or the like, the protection window is released. . In this case, the synchronization processing takes time, and the sync pattern detection returns to the detection in the entire range without the protection window, so that the possibility of erroneous detection is increased. become. Therefore, in this embodiment, it is determined whether or not the synchronization is correctly established, other than the sync pattern detection. If the sync pattern is correct, the protection window is not canceled even if the sync pattern is not detected.

  As described above, the sync pattern and the physical address data are embedded at fixed intervals at fixed relative positions on the disk. If synchronization is not correctly detected by the sync pattern, the physical address cannot be read correctly. In other words, if the physical address can be read correctly, it is considered that the synchronization is correct.

  In other words, if no error is detected as a result of error detection using the CRC code, it can be determined that the WAP is correctly synchronized. Using this concept, a protection window of the next WAP is generated by detecting the sync pattern of the first WAP and no error is detected by the CRC code of the first WAP (error detection result in FIG. 10C) In the case of “OK”), it can be determined that the synchronization is correctly performed. Even if the sync pattern is not detected in the protection window of the next WAP, the sync is detected only by chance. It is determined that it is correctly removed, and the protective window is maintained as shown in FIG. Then, the protection window is released only when the sync pattern is not detected at the position of the protection window continuously a plurality of times (for example, three times).

  On the other hand, the protection window of the next WAP is generated by detecting the sync pattern of the first WAP, the sync pattern is not detected within the protection window of the next WAP, and an error is detected by the CRC code of the first WAP. In the case (in the case of the error detection result “NG” in FIG. 11C), it can no longer be determined that the synchronization is correct, and the protection window is immediately released as shown in FIG. 11E.

  In the above description, error detection based on a CRC code has been described as an example of a synchronization determination method other than sync pattern detection, but other error detection methods may be used.

  For example, a method of detecting an error using a physical address extracted by the physical address extraction unit 29 may be used. As described above, when the WAP is reproduced continuously, the physical address is counted up by one for each physical segment. Therefore, the physical address included in the newly input WAP can be estimated. By comparing the physical address estimated from the already extracted physical address with the newly input physical address, it is possible to determine whether or not there is an error in the newly input physical address. If there is no error in the physical address, it can be determined that the synchronization is correct, while if there is an error in the physical address, it can be determined that the synchronization is not correct. This determination can be used for the protection window maintenance and release process instead of the above-described error detection by CRC.

  As described above, according to the optical disc device 1 and the control method thereof according to the present embodiment, even when synchronization signal non-detection due to noise or the like occurs, synchronization is established early and the reliability of wobble signal detection is improved. Can be improved.

  Note that the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, the constituent elements over different embodiments may be appropriately combined.

1 is a block diagram illustrating a configuration example of an optical disc device according to an embodiment of the present invention. The figure which shows the wobble modulation rule prescribed | regulated to HD DVD-R and HD DVD-RW. The figure which shows the layout of WAP prescribed | regulated to HD DVD-R and HD DVD-RW. The figure which shows the sync pattern and address data pattern which are prescribed | regulated to HD DVD-R and HD DVD-RW. The figure which shows the layout of the address field prescribed | regulated to HD DVD-R and HD DVD-RW. The block diagram which shows the structural example of the conventional wobble detection part. Explanatory drawing which shows the protection window production | generation concept of a sync pattern. Explanatory drawing of operation | movement of the production | generation of the protection window in the conventional wobble detection part, cancellation | release, and maintenance. The block diagram which shows the structural example of the wobble detection part which concerns on this embodiment. The 1st operation explanatory view of generation, release, and maintenance of a protection window in a wobble detection part concerning this embodiment. The 2nd operation explanatory view of generation, release, and maintenance of a protection window in a wobble detection part concerning this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical disk apparatus 16 Wobble reproduction | regeneration part 17 Reproduction | regeneration processing part 18 Recording process part 20 Wobble detection part 21 Phase detection part 22 Sync pattern detection part (synchronization detection part)
25 protection window generation unit 27 flywheel counter 28 wobble PLL unit 29 physical address extraction unit 30 error determination unit

Claims (8)

In an optical disc apparatus for reproducing an optical disc in which a data sequence of a predetermined length composed of a synchronization signal and subsequent data is recorded as wobble, or recording and reproducing,
A wobble reproduction unit that reads the wobble of the optical disc and reproduces a wobble signal;
A synchronization detection unit for detecting a synchronization signal included in the wobble signal;
Based on the presence or absence of detection of the synchronization signal, a protection window generation unit that generates a protection window of the synchronization signal at the predicted arrival position of the synchronization signal;
An error determination unit for detecting an error in the data;
With
The protective window generator
Generating the protection window based on information on the presence or absence of synchronization detection output from the synchronization detection unit and error detection information of the data output from the error determination unit;
An optical disc device characterized by the above. The protective window generator
After the first synchronization signal is detected, when trying to generate the first protection window at the predicted arrival position of the next synchronization signal,
When the next synchronization signal is not detected and an error is detected in the data following the first synchronization signal, the first protection window is canceled,
If the next synchronization signal is not detected and no error is detected in the data following the first synchronization signal, the first protection window is maintained without being released.
The optical disc apparatus according to claim 1, wherein: The protective window generator
If the protection window is generated by detecting multiple consecutive sync signals,
When the synchronization signal is not detected continuously for a predetermined number of times, the generated synchronization window is canceled.
The optical disc apparatus according to claim 1 or 2, wherein Error detection performed by the error determination unit is performed using a CRC code included in the data.
The optical disc apparatus according to claim 1, wherein: In a control method of an optical disc apparatus for reproducing an optical disc in which a data sequence of a predetermined length composed of a synchronization signal and subsequent data is recorded as wobble, or recording and reproducing,
(A) Read the wobble of the optical disc to reproduce the wobble signal,
(B) detecting a synchronization signal included in the wobble signal;
(C) generating a protection window for the synchronization signal at the predicted arrival position of the synchronization signal based on whether the synchronization signal is detected;
(D) performing error detection of data;
With steps,
In step (c)
Generating the protection window based on information on presence or absence of synchronization detection and error detection information of the data;
A method of controlling an optical disk device, comprising: In step (c)
After the first synchronization signal is detected, when trying to generate the first protection window at the predicted arrival position of the next synchronization signal,
When the next synchronization signal is not detected and an error is detected in the data following the first synchronization signal, the first protection window is canceled,
If the next synchronization signal is not detected and no error is detected in the data following the first synchronization signal, the first protection window is maintained without being released.
6. The method of controlling an optical disk device according to claim 5, wherein: In step (c)
If the protection window is generated by detecting multiple consecutive sync signals,
When the synchronization signal is not detected continuously for a predetermined number of times, the generated synchronization window is canceled.
7. A method for controlling an optical disk apparatus according to claim 5, wherein the optical disk apparatus has a control method. In step (d), error detection is performed using a CRC code included in the data.
6. The method of controlling an optical disk device according to claim 5, wherein:

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