KR19990033798A - Disc data playback method and its playback method - Google Patents

Abstract

The present invention relates to a data reproducing apparatus for a disc and a method of reproducing the disc. More particularly, when an optical pickup device misses a current track due to a disc defect or the like, a disc capable of performing continuous reproducing of the disc is compensated for. A data reproducing apparatus and a reproducing method thereof.

When the data reproducing apparatus of this disc determines that the error corrected value of the identification data of the sector data read from the optical pickup apparatus and the value that judges that the error corrected sector address is continuous with the previously inputted sector address are all normal, Determine the track slip.

Description

Disc data reproducing apparatus and its reproducing method

The present invention relates to a data reproducing apparatus for a disc and a method for reproducing the disc. More particularly, when an optical pickup device misses a current track due to a disc defect or the like, a disc capable of performing continuous disc reproducing is provided. A data reproducing apparatus and a reproducing method thereof.

Digital Video Disc (hereinafter referred to as 'DVD') is a recording medium developed for the purpose of recording about two hours of digital images on an optical disc of 12 cm in diameter. That is, it is a recording medium having a very large capacity of 6 to 8 times the capacity of a compact disc (hereinafter referred to as 'CD'), which is currently in the spotlight as a large capacity recording medium.

At this time, as a medium for recording data information, a large capacity can be achieved, and a data compression technique or a light source with a short wavelength can be used. This is because the pitch is dense so that it is about 2/1 less than that of the CD. Usually, the track pitch of a DVD is 0.725 탆, whereas the track pitch of a CD is 1.6 탆. That is, in DVD, information is recorded in finer pit than in CD, and the recorded information is reproduced.

In order to read the information recorded in the fine pit, the numerical aperture of the objective lens mounted in the optical pickup device is required to be higher than a predetermined value, and at the same time, the information track on which each pit is positioned with high precision is highly accurate. Tracking control was required to track.

Next, the reproduction operation of the conventional digital video disc will be described in detail with reference to the accompanying drawings.

1 is a block diagram showing the configuration of a general optical disc reproducing apparatus.

The structure reads the data recorded on the DVD 1 storing the data, the rotation drive motor 25 of the DVD 1, and the data recording surface of the DVD 1, and converts the data into an electrical signal for output. And an high frequency signal processor 29 for inputting an electrical signal output from the optical pickup device 3 and performing basic signal processing for reproduction.

In addition, the high frequency signal processor 29 inputs an electrical signal output from the optical pickup device 3 to calculate a tracking and focus error signal of the optical pickup device 3.

The calculated tracking error signal is input to the servo unit 7, and the tracking servo included in the servo unit 7 controls to maintain the position in the recording surface of the laser beam on the information pit row, that is, on the track, based on this signal. . The focus error signal is also input to the servo unit 7, and the focus servo included in the servo unit 7 controls the focus position of the laser beam to be maintained on the path recording surface of the disc based on this signal. And a microprocessor unit 9 which overall manages the system.

The reproduction high frequency signal output from the high frequency signal processor 29 is demodulated by the demodulation circuit 5, and after the error correction is performed in the error correction circuit 11 in which error correction is performed in units of 16 sectors, the VBR buffer 27 Is temporarily saved. The VBR buffer 27 stores data in FIFO (First-In First-Out) order and outputs the stored data. In other words, it is a memory based on the principle of outputting the first stored data for the first time.

In the above process, the data stored in the VBR buffer 27 is output to each decoding circuit under the control of the microprocessor unit 9, and the configuration is as follows. A video decoding circuit 13 which inputs, decodes and outputs a video data stage from a reproduced digital signal output from the VBR buffer 27, and a caption data stage is input from a reproduced digital signal under the control of the microprocessor unit 9; And a graphics circuit 15 for signal processing and output, and an audio decoding circuit 17 for inputting, decoding and outputting an audio signal terminal from a reproduction digital signal under the control of the microprocessor unit 9.

The video signal output from the video decoding circuit 13 is converted into an analog signal by the digital-to-analog converter 19 for video, and then converted into a broadcast signal according to the NTSC / PAL standard by the NTSC / PAL encoder 23 and output. do. The audio signal output from the audio decoding circuit 21 is also converted into an analog signal by the audio digital / analog converter 21 and then output.

The following describes the reproduction operation of the conventional digital video disc according to the above configuration.

When a user command is input by an external key signal input, the microprocessor unit 9 applies a control signal to each load device to control the system to the initial state of reproduction. At this time, the servo unit 7 drives the motor 25 to rotate the DVD 1, and at the same time, the optical pickup device 3 applies a tracking and focus control signal to the information track of the rotated DVD 1. Accurately track and adjust the focus position.

Then, the optical pickup device 3 reads the data recorded on the DVD 1, and the read optical signal is converted into an electrical signal and input to the high frequency signal processor 29. After the basic signal processing for reproducing the signal is performed by the high frequency signal processing unit 29, the high frequency signal processing unit 29 is input to the demodulation circuit 5 at a high speed of 26.26 Mbps. After the signal is demodulated in the demodulation circuit 5, it is input to the VBR buffer 27 through the error correction circuit 11 or the like.

Since the VBR buffer 27 is a memory in which the output is performed while the input is performed, the error corrected data is input from the error correcting circuit 11 and the microprocessor unit 9 is controlled. Transfer to the decryption circuits 13, 15 and 17. Data input to each of the decoding circuits is displayed after the original decoding process is performed.

In order for the user's desired data to be displayed on the screen, data recorded on the digital video disc must be sequentially read by the optical pickup device 3.

However, as described above, the DVD has a very small track pitch of 0.725 mu m. As a result, when there is a small defect or scratch on the surface of the disc, the optical pickup device 3 is positioned on another track, deviating from the current playback track. This other case occurs.

If the data recorded on the disc is not sequentially read as described above, the data reproduced from the digital video disc having the minimum data unit that can be accessed by adding identification information (ID) in units of predetermined sectors will eventually be different units. (I.e., a block), which causes an error in the decoding circuit signal-processed at a later stage, resulting in fatal damage to the displayed image.

Although this is briefly described above, the data processed in a predetermined unit is stored in the VBR buffer 27 as the error correction circuit 11 constitutes 16 blocks as one block to correct error of user data. This is because the decoding circuit performs the data decoding process in units of 16 sectors.

Therefore, a means for determining whether the data input to the VBR buffer 27 is continuity with the data already stored is required in the playback device of the digital video disc.

Fig. 2 shows a circuit configuration diagram for detecting a track error signal during a reproduction operation of a digital video disc in the related art, and it is possible to determine the continuity of the reproduction data described above in Fig. 2.

Since the track error signal should be detected before data is input to the VBR buffer 27, it is made between the demodulation circuit 5 shown in Fig. 1 and the error correction circuit 11 for error correction in units of 16 sectors. .

The configuration comprises an ID ECC 31 for error correction of the identification information (ID) of the sector output from the demodulation circuit 5 to determine whether or not the sector data is defective, and after error correction in the ID ECC 31. And a track error signal detection device 33 for judging whether or not the sector data determined to be a normal sector has been normally reproduced or if an error due to track slip has occurred.

The following describes the track error signal detecting operation during the disc reproducing operation.

First, prior to the operation description, the structure of a sector of a DVD is largely divided into identification information which is a sector address and user data. The sector address has six digits as a hex (HEX) value. More specifically, the digital video disc has a minimum data unit that can be accessed by adding identification information ID by a predetermined sector unit. As in the error correction circuit 11 or the like, 16 sectors are gathered into one block. And data processing is performed in units of blocks.

The address of the head of the block is represented by XXXXX0, and the five digits before the sector address in one block always have the same value. Therefore, the sector data mentioned above or mentioned later is usually processed in 16 sector units, and if track slip occurs during the reproduction of sector data in a single block, the signal is processed again by returning to the first sector of the block. Will be.

Next, the sector data read from the optical pickup device 3 and applied through the high frequency signal processing unit 29 is demodulated and output by the demodulation circuit 5, and the identification information of this sector is inputted to the ID ECC 31. Error correction).

The sector data corrected by the ID ECC 31 is input to the track error signal detecting apparatus 33, and the track error signal detecting apparatus 33 compares the address of the input sector data with a previously stored sector address. The track slip is judged.

At this time, the track error signal detecting apparatus 33 determines the track slip only by sector data determined to be a normal sector after error correction by the ID ECC 31, and at this time, the sector address is taken from the data input to the normal sector. The data is stored until the next sector data is input.

If it is detected that the track slip is detected by the comparison of the inputted address, the track error signal detecting device 33 generates a track error signal to the microprocessor unit 9. The microprocessor unit 9 which inputs the track error signal generates a control signal for temporarily stopping data storage in the VBR buffer 27 and simultaneously moves the optical pickup device 3 to the first position of the track before the track error occurs. Generates a control signal.

The servo unit 7 which inputs this signal moves the optical pickup device 3 to the initial position of the information track before the track error signal is generated. The first position of the track to which the optical pickup device 3 is moved is calculated from the sector address stored in the track error signal detection device 33, and the address of the block (track) is performed to perform the back track jump to that position.

By the above operation, the optical pickup apparatus 3 performs an operation of reading a signal again from the initial position of the track which was played before the track error occurred, and the detected data is applied to the high frequency signal processor 29 again. Signal processing is again performed.

16 sector data processed by the high frequency signal processor 29 are sequentially rewritten to the VBR buffer 27 through the demodulation circuit 5 and the error correction circuit 11, and simultaneously output to the respective decoding circuits. Is done.

Of course, even in the state where the data input to the VBR buffer 27 is stopped, the VBR buffer 27 continues to output, and this output data is input to each decoding circuit under the control of the microprocessor unit 9, and thus the original It is displayed after being decoded by the signal of.

That is, in the conventional reproducing operation of the digital video disc, the presence or absence of track slip detection of the sector data reproduced from the optical pickup device 3 is achieved only by the sector data in which the identification information of the sector is corrected by the ID ECC 31. ought. In other words, since the identification information uses the error corrected sector data address as a condition for determining the track error, performance is entirely dependent on the accuracy of the sector address.

However, due to system instability, there may be a problem in that error correction may occur in error correction of the ID ECC step, in which case track slip detection becomes inaccurate. In other words, the conventional track slip detection performance is only dependent on the accuracy of the error-corrected sector data.

Accordingly, an object of the present invention is to provide a data reproducing apparatus and method for a disc that can accurately detect track slips during a reproducing operation of an optical pickup device in a short time and thereby suppress an error in the continuous reproducing operation.

1 is a block diagram showing the configuration of a general digital video disc player;

2 is a circuit configuration diagram for detecting a track error signal during a playback operation of a conventional digital video disc;

3 is a circuit diagram for detecting a track error signal during a playback operation of a digital video disc according to the present invention;

4 is a detailed circuit diagram of the track error signal detecting apparatus shown in FIG. 3;

Fig. 5 is a flowchart showing a data reproduction process in which track slip compensation is performed according to the present invention.

* Explanation of symbols for the main parts of the drawings

1: optical disc 3: optical pickup device

5,50 demodulation circuit 7 servo unit

9,61: microprocessor unit 11,57: error correction circuit

13: video decoding circuit 15: graphics circuit

17: audio decoding circuit 19: digital to analog converter

23: NTSC / PAL encoder 21: digital / analog converter

25: motor 27,59: VBR buffer

29: high frequency signal processor 31, 51: ID ECC

33,53: Track error signal detection device 55: Synchronization signal detection unit

In accordance with another aspect of the present invention, a data reproducing apparatus of a disc includes: an optical pickup device for reading data recorded on the disc; an error correction value for identification information of sector data read from the optical pickup device; The track error signal detecting means for determining a track slip point and when the track error signal is generated from the track error detecting means when all of the values for determining that the corrected sector address is continuous with the previously inputted sector address are normal; Control means for controlling the back track jump of the device.

The disc playback method according to the present invention includes the steps of continuously inputting an address of data read from the disc, determining whether the input data is normal by an error correction result and continuity of the input address data; Compensating for the input data according to the determination result.

In the disk data reproducing apparatus and method according to the present invention, a value for correcting a sector address (ID-FLAG) as a condition for determining whether or not sector data reproduced from the optical pickup apparatus is continuous with previously reproduced sector data, A value obtained by comparing the continuity of the currently input sector address with the previous sector address is used.

When a track error occurs, the current block address is detected from the value of comparing the continuity of the sectors according to the two conditions, and the block address of the currently inputted sector and the block address of the previously inputted sector are not made. To generate a track error signal.

That is, the apparatus and method for reproducing data of a disc according to the present invention accurately determines that a track error occurs due to a disc defect, scratch, or the like, and controls the data to be continuously reproduced.

DETAILED DESCRIPTION Hereinafter, a data reproducing apparatus and method for a disc according to the present invention will be described in detail with reference to the accompanying drawings.

3 is a circuit diagram for detecting a track error signal during a disc reproducing operation according to the present invention. The necessary configuration of the disc playback apparatus will be described with reference to FIG.

The track error detection for detecting whether the sector data to be reproduced during the disc reproducing operation is continuous with the previous sector data should be performed before the data input to the VBR buffer 59 is made, so that the digital signal processing demodulation circuit 50 ) And the error correction circuit 57. That is, the demodulated sector is input to the ID ECC 51 by the demodulation circuit 50 which inputs the high frequency reproduction signal, and the error correction of the sector address is performed by the ID ECC 51.

On the other hand, the high frequency signal processing unit 29 includes a synchronization signal detection unit 55 for detecting sector synchronization signals and block synchronization signals from the reproduction high frequency signal, which is primarily processed by the reproduction signals, and detected by the synchronization signal detection unit 55. The two synchronized signals are input to the track error signal detection device 53. In other words, the synchronization signal detection unit 55 is a sector synchronization signal that is located at the beginning of the sector data to indicate the input of the sector data, and a block which is located at the part of the block data which combines these sectors in units of 16 sectors to indicate the input of the block. The synchronization signal is detected from the reproduction high frequency signal.

The track error signal detection apparatus 53 inputs an error corrected value of the identification information ID in the ID ECC 51, and tracks the track based on both the sector sync signal, the block sync signal, and the error corrected signal. If it is determined that an error has occurred and a track error has occurred, the track error signal is applied to the microprocessor unit 61.

The sector data determined to be a normal color by the ID ECC 51 is stored in the VBR buffer 59 after error correction of the user data is performed in the error correction circuit 57.

The configuration thereafter is the same as in the prior art.

4 shows the detailed circuit configuration of the track error signal detecting apparatus 53. As shown in FIG.

The configuration includes a sector address register 71 for storing the sector address included in the sector data output from the ID ECC 51 in synchronization with the sector synchronization signal detected by the synchronization signal detection unit 55. The sector address register 71 latches a sector address every time a sector synchronization signal is input.

And a sector address continuity comparison section 73 which detects a sector address from the sector data continuously output from the ID ECC 51 and compares the sector address with the previous sector address latched in the sector address register 71. The comparison unit 73 determines whether the currently input sector address is one greater than the previous sector address.

The block address is detected from the sector address included in the sector data output from the ID ECC 51, and the result of error correction of the value compared by the comparison unit 73 and the sector address by the ID ECC 51 is obtained. And a block address detecting unit 75 for transmitting the detected block address to the block address register 77 or to the track error signal generating unit 79 in accordance with the value determination condition.

And a block address register 77 that stores a block address applied by the block address detector 75. The block address register 77 latches a block address input whenever a block sync signal detected by the sync signal detector 55 is input.

And a track error signal generator 79 for generating a track error signal when the block address output from the block address detector 75 is not continuously compared with the address stored in the block address register 77.

The following describes in detail the process of detecting the track error signal generated when the data discontinuity of the present invention according to the above configuration.

Fig. 5 is a flowchart showing a data reproduction process in which track slip compensation is made according to the present invention.

The information recorded on the digital video disc 1 is read through the pickup device 3, and the read data is input to the demodulation circuit 5 after predetermined signal processing by the high frequency signal processing unit 29. The reproduced data input to the demodulation circuit 5 is demodulated, and the demodulated data is input to the ID ECC 51 so that the address of the sector data is error corrected. Sector data including the error correction value of the sector address is input to the track error signal detecting apparatus 53 (step 100 of FIG. 5).

On the other hand, the sector synchronizing signal and the block synchronizing signal are detected by the synchronizing signal detecting unit 55 from the reproduction high frequency signal output from the high frequency signal processing unit 29 and input to the track error signal detecting apparatus 53. That is, the track error signal detection apparatus 53 inputs the sector data, the sector synchronization signal and the block synchronization signal with ID ECC.

The sector address register 71 takes a sector address stage from the input sector data and latches the sector address in synchronization with the input sector synchronization signal.

Next, the sector address continuity comparison unit 73 compares the sector address previously inputted from the ID ECC 51 with the sector address previously stored in the sector address register 71, so that the currently input sector address is 1 than the previous address. It judges whether it is large, and outputs this determined result as a logic signal (step 101 of FIG. 5).

The logic signal output from the continuity comparator 73 of the sector address is input to the block address detector 75. In addition, the detector 75 also inputs the determination value ID-FLAG according to whether the sector address included in the sector data output from the ID ECC 51 is normally input to another input terminal (step 102 of FIG. 5). .

When both determination signals are normal, that is, when the currently input sector data is normal and is continuous with the previously input sector data, the block address detection unit 75 returns the detected block address to the block address register 77. Is applied.

Block address detection by the block address detection unit 75 is further performed by sector data output from the ID ECC 51. The block address represents five digits from the front of the sector address. This is because, as described above, the sector address is expressed in hexa, has 6 digits, and since these sectors are grouped into 16 units in blocks, all sectors included in the block of honey have the same block address.

The block address applied to the block address register 77 latches the block synchronization signal input in synchronization with the block synchronization signal detected by the synchronization signal detection unit 55.

When the current block address output from the block address detection unit 75 is one greater than the block address stored in the block address register 77, the track error signal generator 79 performs normal data reproduction. The determination is made (step 104 and step 106 of FIG. 5).

However, while the optical pickup device is controlled by the tracking servo and reads the data recorded in the pit while accurately tracking the track on which the information is recorded, the optical pickup device reproduces the track control error due to defects or scratches on the surface of the disc. Occasionally a track may be missed or data stored in another track may be read.

In this case, when the current block address output from the block address detection unit 75 is compared with the block address stored in the block address register 77, at least one difference is generated. At this time, the track error signal generation unit 79 generates a track error. It is determined that slip has occurred, and a track error signal is generated.

This is because an error in tracking control due to defects on the surface of the disc causes errors in the block address when the track being played back is missed and the optical pickup device is located on another track. In this case, therefore, data compensation is required.

In the data compensation operation (step 108 of FIG. 5), the track error signal generated by the track error signal generation unit 79 is input to the microprocessor unit 61. At this time, the microprocessor unit 61 reads the block address stored in the block address register 77, applies a signal to the servo unit 7, and places the optical pickup device 3 at the beginning of the read block. To control.

Therefore, the optical pickup device 3 reads data again from the first position of the previously reproduced block, and the read data is transmitted to the high frequency signal processor 29.

When the data read back is reproduced in this manner, the data is continuously reproduced.

As described above, the disc data reproducing apparatus and method according to the present invention provide the ECC information (ID-FLAG) of the sector address and the sector address as a condition for determining a track error due to defects or scratches on the surface of the disc. By using the continuity of, there is an effect that the track error can be detected early by this condition and a fatal error can be prevented from occurring in the continuous reproduction of the signal.

In particular, in the disc data reproducing apparatus and method according to the present invention, when a track error is detected, by using the resultant stage of ECC addressing of the sector data, if the system is unstable, error correction of the sector address is wrong and error occurs. In order to compensate for the failure to judge the continuous playback of the signal, it is advantageous to perform accurate judgment by using the continuous condition of the sector address and the continuous condition of the block address.

Claims (4)

An optical pickup apparatus for reading data recorded on the disk, an error correction value for identification information of sector data read from the optical pickup apparatus, and a value for determining that the error corrected sector address is consecutively inputted into sector addressing. Data of a disc comprising a track error signal detection means for determining track slip when judged to be normal and a control means for controlling a backtrack jump of the optical pickup device when a track error signal is generated from the track error detection means. Playback device. 2. The track error signal detecting means according to claim 1, wherein said track error signal detecting means comprises: a sector address register which takes a sector address from sector data in which identification information is error-corrected and stores it in synchronization with a sector synchronization signal, a sector address currently input and said sector address register; A comparison unit for comparing the sector address stored in the storage unit to determine whether the difference signal is 1, and an error correcting value for identifying the identification data of the sector data as normal, and when the output value of the comparing unit is also determined to be normal, A block address detector for detecting a block address from data, a block address register for storing the block address detected by the block address detector in synchronization with a block synchronization signal, a block address stored in the block address register, and the block address detector Block Address Detected Compared to the car when the signal is not the first data reproduction apparatus of the disc, it characterized in that it comprises parts of the track error signal generator for generating a track error signal. Continuously inputting an address of data read from the disc, determining whether the input data is corrected by error correction result and continuity of the input address data, and compensating the input data according to the determination result. A data reproducing method of a disc comprising the step. The method of claim 3, wherein the compensating of the input data comprises reading data having an address consecutive to the previously input address when the error correction result of the data is not normal or there is no continuity of the input address. A data reproducing method of a disc comprising the step.