JP4499372B2 - Information recording method, information reproducing method, information recording apparatus, information reproducing apparatus, and computer-readable recording medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention provides an information recording method for recording information on a recording medium such as a CD-R disc, a CD-RW disc, a DVD + R disc, a DVD + RW disc, an information reproducing method for reproducing information recorded on the recording medium, An information recording apparatus which is an optical disk drive such as a CD-R drive, a CD-RW drive, a DVD + R drive, a DVD + RW drive, etc. for recording information on a recording medium, a CD-R drive for reproducing information recorded on the recording medium, and a CD The present invention relates to an information reproducing apparatus that is an optical disk drive such as an RW drive, a DVD + R drive, and a DVD + RW drive, and a computer-readable recording medium such as a CD-R disk, a CD-RW disk, a DVD + R disk, and a DVD + RW disk.
[0002]
[Prior art]
With regard to conventional clock extraction and synchronization signals, even if a bit slip due to a defect on the bitstream occurs, the bitstream is correctly byteified to prevent the occurrence of unnecessary data errors (for example, patents) Reference 1). In addition, regarding the necessity of the clock mark at the time of multi-level recording, a multi-level data portion in which multi-level information is recorded and a demodulation clock for obtaining timing for reproducing the multi-level information recorded in the multi-level data portion are provided. A synchronization bit for generating in advance, generating the demodulated clock from an electrical signal corresponding to the synchronized bit, and synchronizing the demodulated clock with the electrical signal corresponding to the multilevel information The signal level is detected (see, for example, Patent Document 2).
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 7-320419 [Patent Document 2]
JP-A-4-219626 [0004]
[Problems to be solved by the invention]
However, in the synchronization method when recording / reproducing information on a recording medium, particularly in the synchronization method in which information is recorded in multiple values, the clock extraction mark used when reproducing information and the bit slip caused by defects, etc. In an encoding / decoding method and a recording / reproducing apparatus using a synchronization mark that recovers data, when information is recorded in multiple values on an information recording medium (recording medium), it is difficult to extract a clock from the reproduced signal. A dedicated mark for extracting the clock is recorded on the recording medium. At the time of reproduction, the clock mark interval fluctuates due to uneven rotation of the recording medium, so a mark having a window width larger than the fluctuation is necessary. Further, a mark that does not cause false synchronization is required within the window width, and a synchronization mark that recovers a bit slip caused by a defect is also a necessary synchronization signal. The two types of synchronization signals are recorded on the recording medium in different forms. However, since the fluctuation of the synchronization mark is larger than that of the clock mark, there is a problem that a larger window is required.
[0005]
The present invention has been made in order to solve the above-described problem. By making a part of the synchronization mark the same shape as the clock mark, the bit slip detection and the clock detection are simultaneously performed with one mark, thereby providing redundancy. The purpose is to be able to lower.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides the following information recording method, information reproducing method, information recording apparatus, information reproducing apparatus, and computer-readable recording medium.
In an information recording method for recording information on a recording medium and clock marks arranged at equal intervals for extracting a clock when reproducing the information and a synchronization mark for detecting a bit slip, the clock mark includes a reproduction signal. It is a data string composed of a combination of the first level data that is the largest and the second level data that the reproduction signal is the smallest, and the synchronization mark is arranged before and after the data line of the clock mark. An information recording method that is a data string formed by adding the data.
[0007]
Further, the position of the clock mark in the synchronization mark and the position of the other clock mark may be recorded at equal intervals.
Furthermore, data may be further recorded on both sides of the clock mark so that two or more data of the same level follow at the beginning and end of the clock mark.
In addition, the first and second types of error correction codes are used to correct errors, information is recorded in the direction of error correction using the first error correction code, and the synchronization mark is set to the second error correction code. You may record in the part which hits the head.
[0008]
Furthermore, there is provided an information reproducing method for reproducing a recording medium recorded by the information recording method as described above, wherein the bit slip is detected based on the synchronization mark and the clock synchronization is also detected. To do.
Further, in an information recording apparatus for recording information on a recording medium and clock marks arranged at equal intervals for extracting a clock when reproducing the information and a synchronization mark for detecting a bit slip, the clock mark includes: Means for recording with a data string comprising a combination of first level data with the largest reproduction signal and second level data with the smallest reproduction signal, and the synchronization mark as the data string of the clock mark. There is provided an information recording apparatus provided with means for recording in a data string in which the first level data is added before and after.
[0009]
Furthermore, an information reproducing apparatus for reproducing a recording medium recorded by the above-described information recording apparatus, information reproducing having means also performs synchronization detection of the clock and detects the bits slip based on the synchronization mark Providing equipment.
Further , a means for separately providing a window for detecting the bit slip and a window for detecting the synchronization of the clock may be provided .
Additionally, to provide information computer-readable recording medium on which data is recorded with a structure having upper Symbol clock mark and the synchronization mark by the recording method as described above.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be specifically described below with reference to the drawings.
FIG. 2 is a diagram showing an example of a reproduction waveform of multilevel recording.
(A) of the figure shows the ideal value of the 8-level reproduction waveform, and (b) of the figure shows the waveform of the ideal reproduction clock.
The voltage of the reproduction waveform changes to a rectangular wave at the rise of the reproduction clock, and the level can be determined stably at the fall of the clock.
(C) of the figure shows an actual reproduction waveform.
[0011]
FIG. 3 is a block diagram showing a configuration of an optical disc apparatus according to an embodiment of the present invention. In the figure, parts related to the present invention are mainly shown, and a minimum configuration necessary for carrying out the present invention is shown.
When the interface controller 8 receives a command from an external device (for example, a personal computer), the optical disk device (optical disk drive) reports to the controller 7 that the command has been received.
The controller 7 is realized by a microcomputer including a CPU, a ROM, a RAM, and the like. The controller 7 controls the entire optical disc apparatus, interprets the command, performs an operation requested by the command, and sends a report through the interface controller 8. To external equipment. Also, control processing of the information recording method and the information reproducing method according to the present invention is executed.
[0012]
The optical disc 10 is a computer-readable recording medium such as a CD-R disc, a CD-RW disc, a DVD + R disc, a DVD + RW disc having the data structure according to the present invention.
First, when recording information on the optical disk 10, information (data to be recorded on the optical disk 10) sent from an external device is temporarily stored in the buffer memory 5 via the interface controller 8 via the digital circuit 6.
The digital circuit 6 performs operations such as attaching an error correction code to the information stored in the buffer memory 5, adding a synchronization signal, and converting the information into a modulation code to a multilevel level.
The address written on the optical disk (optical information medium, recording medium) 10 records information at an address indicated by reading an address written in advance on the optical disk 10.
[0013]
Next, the current is controlled so that the semiconductor laser light source LD on the pickup (PU) 2 (not shown since it is well known) emits light so that the analog circuit 3 records it on the optical disk 10, and the above information is recorded at a multilevel level. To do.
In addition, the pickup 2 receives the reflected light from the optical disk 10 and receives the reflected light by a light receiving element PD (not shown in the drawings) and processes it by the analog circuit 3 to generate a focus error signal, a tracking error signal, and the like. The servo circuit 4 controls the position of the pickup 2 and the position of the lens (not shown because it is known). At that time, the optical disk 10 usually has a spiral groove or data array. Therefore, it moves from the inner circumference to the outer circumference with the passage of time (for example, from the outer circumference to the inner circumference), and exceeds the range where tracking control is possible. Therefore, a control called a caliper is performed so that the entire PU 2 is moved from the tracking servo signal so that the lens position can always be maintained in a neutral state.
[0014]
Next, when reproducing the information recorded on the optical disc 10, the output of the pickup 2 is quantized by the analog circuit 3 and extracted by using a PLL or the like, and the digital circuit 6 performs synchronization detection, demodulation, error correction, etc. And stored in the buffer memory 5. Thereafter, the information is transferred to the external device through the interface controller 8.
[0015]
FIG. 4 is a diagram showing an example of a general format of an arrangement of information to be recorded on the optical disc as the basis of the present invention. As information, clock marks and data are alternately arranged.
When recording a multi-value on an optical disc, unlike the binary value, the edge portion of the reproduction signal cannot be correctly extracted, so that the clock cannot be extracted from the edge portion.
Therefore, a clock is extracted using a special mark called a clock mark (Clock Mark) separately from an information part for recording data (Data).
The length of the data of the clock mark (data length) is set so that the amount of clock fluctuation caused by knitting or the like is within the allowable value of the system. In addition, the clock mark must use a pattern that is not affected by intersymbol interference from the data before and after the clock mark, and it is necessary to prevent erroneous synchronization even if the position varies.
[0016]
FIG. 5 is a diagram showing an example of a clock mark according to the present invention.
As shown in FIG. 5A, this clock mark is a data string “00700” in which, for example, when information is recorded with eight values, the larger reflected light amount is 0, and the lower light amount is 7. There is a reproduction waveform of a reproduction signal at the time of reproduction shown in FIG. Further, (c) in the figure shows a differentiated waveform obtained by differentiating the reproduction signal, and the synchronization position can be detected at the zero cross. A clock can be generated by inputting the synchronization position to a commonly used PLL phase comparator.
[0017]
FIG. 1 is a diagram showing an example of a synchronization mark according to the present invention.
As shown in FIG. 5B, this synchronization mark is similar to the clock mark, for example, when information is recorded with eight values, when the amount of reflected light is 0, and when the amount of light is 7, it is set to 7. Is a data string “00000710”, and FIG. 8B shows a reproduction waveform of a reproduction signal at the time of reproduction. This synchronization mark has the same pattern as the clock mark in the portion surrounded by a broken line in the drawing.
Further, (c) in the figure shows a differentiated waveform obtained by differentiating the reproduction signal, and the synchronization position can be detected at the zero cross. The reason why the synchronization mark is longer than the clock mark is that a fluctuation for recovering a bit slip caused by a defect or the like is larger than the clock mark, so that a larger window is required.
[0018]
FIG. 6 is a diagram showing a format example when information recorded on an optical disk which is a reference of the present invention includes a synchronization mark together with a clock mark.
In this case, clock marks are arranged at equal intervals, and data and synchronization marks are arranged therebetween.
[0019]
Next, information recording processing in this optical disc apparatus will be described.
The controller 7 or the like functions as means for recording the clock mark shown in FIG. 5 and the synchronization mark shown in FIG. 1 in the information, and extracts the information from the optical disk 10 and the clock when reproducing the information. The clock mark and the synchronization mark for detecting the bit slip are recorded so that a part of the synchronization mark is the same as the clock mark pattern. The detailed processing may be performed at each level in the same manner as normal data recording.
[0020]
The clock mark and the synchronization mark are shared by using the clock mark as shown in FIG. 5 and the synchronization mark pattern as shown in FIG.
That is, by making a part of the synchronization mark have the same pattern as the clock mark, the synchronization mark can be given the function of the clock mark.
Therefore, the redundancy of data can be reduced, and the capacity that can be recorded on the optical disk can be increased.
[0021]
Further, the controller 7 and the like also record so that the position of the clock mark in the synchronization mark and the position of the other clock mark are equally spaced during the recording process.
FIG. 7 is a diagram showing a format example according to the present invention when information recorded on an optical disc includes a synchronization mark together with a clock mark.
As shown in the figure, the clock generation can be simplified by arranging the clock mark portion in the synchronization mark and the other clock marks so that the positional relationship between them is equal.
[0022]
Further, the controller 7 or the like records the information as multi-value information during the recording process, and the clock mark is a combination of the first level at which the reproduction signal is the largest and the second level at which the reproduction signal is the smallest. And record.
As shown in FIG. 5, the position of the level “7” where the amplitude is maximum can be set as the clock position by using the portion “070” of the clock mark.
[0023]
In addition, the controller 7 or the like records so that two or more clock marks begin and end at the same level during the above recording process.
As shown in FIG. 5, in order to avoid the reproduction signal from being changed due to intersymbol interference between the values on both sides of the “070” portion of the clock mark, “0” is set on both sides of “070” (each at the beginning and at the end). “0”) is provided, and the data string is set to “00700”.
In this way, it is possible to avoid the reproduction signal from being changed due to intersymbol interference by continuing the same level before and after.
[0024]
Further, when the reproduction signal is interrupted due to a defect or the like, the clock cannot be detected, and the clock is in a free-running state. If the defect becomes longer, a bit slip occurs. If a bit slip occurs, subsequent data cannot be reproduced.
Therefore, in order to recover from the bit slip using the synchronization mark, the controller 7 or the like corrects the error using the first and second types of error correction codes during the above recording process, and the first error Information is recorded in the direction of error correction by the correction code, and a synchronization mark is recorded in a portion corresponding to the head of the second error correction code.
[0025]
FIG. 8 is an explanatory diagram of a normal error correction example which is a reference of the present invention.
FIG. 9 is an explanatory diagram of an example of error correction according to the present invention.
As shown in FIG. 8, the first error correction code is added in the horizontal direction (right side of “data” in the figure), and the second error correction code is added in the vertical direction (below “data” in the figure). Data (information) is sequentially recorded in the horizontal direction (right direction in the figure) from the upper left corner in the figure.
Here, when a defect or the like occurs, errors continuously occur in the horizontal direction, but the errors are corrected by the second error correction code in the vertical direction. For this error correction, a technique called erasure correction is used. At that time, correction is performed using flags, but correction cannot be performed if there are many flags. Therefore, as shown in FIG. 9, a synchronization mark is arranged at a portion (leading portion) corresponding to the beginning of the second error correction code in the horizontal direction of the data.
In this way, by arranging the synchronization mark at the head portion in the horizontal direction of error correction, the flag can be prevented from standing unnecessarily.
[0026]
Next, information reproduction processing in this optical disc apparatus will be described.
The controller 7 or the like reproduces the optical disk on which information is recorded by the information recording process as described above, and when reproducing the optical disk on which the clock mark and the synchronization mark are recorded in the information, It functions as means for detecting slip and detecting clock synchronization, and means for separately providing a window for detecting bit slip and a window for detecting clock synchronization during the reproduction process.
[0027]
Then, the controller 7 or the like has a clock mark for extracting a clock when reproducing the information and a synchronization mark for detecting a bit slip so that a part of the synchronization mark is the same as the pattern of the clock mark. The information is reproduced from the recorded optical disk based on the synchronization mark and the clock mark, and the clock mark window for detecting the bit slip and the synchronization mark window for detecting the clock synchronization are provided separately. The bit slip is detected by the synchronization mark and the clock synchronization is also detected.
[0028]
FIG. 10 is a block diagram showing a detailed configuration related to information reproduction in the optical disc apparatus of FIG.
As shown in the figure, a reproduction signal (reproduction waveform) is input and input to the clock mark detection unit 22 and the synchronization mark detection unit 21 respectively. However, in order to prevent erroneous synchronization during the data period, respective windows are created and supplied from the counter and the sequencer 24. That is, a counter generates a synchronization mark window and supplies it to the synchronization mark detection unit 21, and a sequencer generates a clock mark window and supplies it to the clock mark detection unit 22.
After the clock is detected by the clock mark detector 22, a phase-locked loop circuit (PLL) 23 generates a clock for each cell and compares the phases. When the synchronization mark detection unit 21 detects synchronization, the counter value is set to a specified value. Further, the clock for each cell created by the PLL 23 is output to the counter.
[0029]
In addition, since the clock mark is “00700”, there is a possibility that erroneous synchronization will occur depending on what both sides are. The worst value is “700” behind “007” before.
FIG. 11 is a timing chart of the output of the clock mark window and the synchronization mark window.
As shown in (c) of the figure, erroneous synchronization can be prevented by multiplying the clock mark window for three cells around the clock mark “7” and back and forth.
Similarly, as shown in FIG. 4D, the synchronization mark window is set for 5 cells.
In this way, mis-synchronization can be prevented by setting windows separately for the synchronization mark and the clock mark.
[0030]
Next, an optical disc recorded by the above information recording method will be described.
The optical disc 10 is recorded with data having a structure including the information, the clock mark, and the synchronization mark by the information recording method as described above.
By recording data as described above, the reliability of the data is increased. In particular, recovery after a defect occurs can be performed.
Thus, by forming a part of the synchronization mark in the same pattern as the clock mark, the synchronization mark can be provided with a clock mark function to reduce the redundancy and provide a recording medium with high data reliability.
[0031]
In the above embodiment, the optical disk has been described as the recording medium. However, the information recording method, information reproducing method, information recording apparatus, and information reproducing apparatus of the present invention do not depend on the recording method of the recording medium. That is, the present invention can be similarly applied to a magneto-optical recording medium, a write-once recording medium, and a rewritable recording medium, and the same effect as described above can be obtained.
[0032]
【The invention's effect】
As described above, according to the information recording method, the information recording apparatus, and the computer-readable recording medium of the present invention, a bit slip can be performed with one mark by making a part of the synchronization mark the same shape as the clock mark. Detection and clock detection can be performed simultaneously. Also, according to the information reproducing method and information reproducing apparatus of the present invention, redundancy can be lowered by simultaneously performing bit slip detection and clock detection with one mark.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of a synchronization mark in this embodiment.
FIG. 2 is a diagram showing an example of a reproduction waveform of multilevel recording.
FIG. 3 is a block diagram showing a configuration of an optical disc apparatus according to an embodiment of the present invention.
FIG. 4 is a diagram showing a typical format example of an array of information to be recorded on an optical disc as a basis of the present invention.
FIG. 5 is a diagram showing an example of a clock mark in this embodiment.
FIG. 6 is a diagram showing a format example when information recorded on an optical disc which is a reference of the present invention includes a clock mark and a synchronization mark.
FIG. 7 is a diagram showing a format example when information recorded on an optical disc in this embodiment includes a synchronization mark together with a clock mark.
FIG. 8 is an explanatory diagram of a normal error correction example which is a reference of the present invention.
FIG. 9 is an explanatory diagram of an example of error correction in this embodiment.
10 is a block diagram showing a detailed configuration relating to information reproduction in the optical disc apparatus shown in FIG. 3. FIG.
FIG. 11 is a timing chart of output of a clock mark window and a synchronization mark window in this embodiment.
[Explanation of symbols]
1: Spindle motor 2: Pickup 3: Analog circuit 4: Servo circuit 5: Buffer memory 6: Digital circuit 7: Controller 8: Interface controller 10: Optical disk 21: Synchronization mark detector 22: Clock mark detector 23: PLL 24: Counter and sequencer

Claims (9)

In an information recording method for recording information on a recording medium and clock marks arranged at equal intervals for extracting a clock when reproducing the information and a synchronization mark for detecting bit slip,
The clock mark is a data string composed of a combination of the first level data with the largest reproduction signal and the second level data with the smallest reproduction signal, and the synchronization mark is the data string of the clock mark. An information recording method characterized by being a data string formed by adding the first level data before and after.   2. The information recording method according to claim 1, wherein recording is performed so that a position of a clock mark in the synchronization mark and a position of another clock mark are equally spaced. 3. The information recording method according to claim 1 , wherein data is further recorded on both sides of the clock mark so that two or more data of the same level continue at the beginning and end of the clock mark . An error is corrected using the first and second types of error correction codes, information is recorded in the direction of error correction by the first error correction code, and the synchronization mark is placed at the head of the second error correction code. 4. The information recording method according to claim 1, wherein the information is recorded in a portion. An information reproduction method for reproducing a recording medium recorded by the information recording method according to any one of claims 1 to 4,
Information reproducing method characterized in that also performs synchronization detection of said clock and detects the bits slip based on the synchronization mark. In an information recording apparatus for recording information on a recording medium and clock marks arranged at regular intervals for extracting a clock when reproducing the information and a synchronization mark for detecting a bit slip,
Means for recording the clock mark with a data string composed of a combination of first level data with the largest reproduction signal and second level data with the smallest reproduction signal; and the synchronization mark with the clock mark An information recording apparatus comprising: means for recording in a data string formed by adding the first level data before and after the mark data string. An information reproducing apparatus for reproducing a recording medium recorded by the information recording apparatus according to claim 6 ,
Information reproducing apparatus characterized by comprising means for performing even synchronization detection clock and detects the bits slip based on the synchronization mark. 8. The information reproducing apparatus according to claim 7, further comprising means for separately providing a window for detecting the bit slip and a window for detecting the synchronization of the clock. The clock mark and a computer-readable recording medium on which data is recorded with said synchronization consists mark structure the information recording method according to any one of claims 1 to 4.

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