JP4107098B2 - Information recording apparatus, information reproducing apparatus, information recording / reproducing apparatus, and recording pulse modulation method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an information recording apparatus, an information reproducing apparatus, an information recording / reproducing apparatus, and a recording pulse modulation method, and more particularly to an information recording apparatus and an information reproducing apparatus for generating a recording pulse signal corresponding to recording information and recording the recording pulse signal. And an information recording / reproducing apparatus and a recording pulse modulation method.
[0002]
[Prior art]
In the optical disk, the recording information is recorded after being modulated into recording pulses having a pulse width 3T to 11T that is 3 to 11 times the reference clock T. At this time, for example, in the case of a CD (compact disc), the reference clock T is about 231 nsec. In the case of a DVD (digital versatile disc), the reference clock T is about 38 nsec.
[0003]
FIG. 9 is a diagram showing evaluation of 100,000 pits recorded based on the CD standard, and FIG. 10 is a diagram showing pulse widths of pits recorded based on the CD standard.
[0004]
As shown in FIGS. 9 and 10, in the conventional CD standard, the interval of 3T to 11T is set to be the reference clock T (= 231 nsec) (for example, see Non-Patent Document 1).
[0005]
[Non-Patent Document 1]
Heitaro Nakajima and Hiroshi Ogawa, “The Illustrated Compact Disc Reader (Revised 3rd Edition)”, Ohmsha, May 1996, p. 156-161
[0006]
[Problems to be solved by the invention]
However, the recording pulse 3T having the smallest amplitude in any of the standards of CD and DVD cannot obtain the full amplitude when it is reproduced after being recorded on the disk due to the relationship between the spot diameter and the pulse width. For this reason, as compared with a recording pulse of 4T or more, there is a problem that jitter is deteriorated, deviation is shifted, and an error is easily generated. Further, as shown in FIG. 7, 3T has a high appearance frequency and has a problem that it becomes a first factor of error.
[0007]
The present invention has been made in view of the above points, and an object thereof is to provide an information recording apparatus, an information reproducing apparatus, an information recording / reproducing apparatus, and a recording pulse modulation method that can accurately reproduce recorded information.
[0008]
[Means for Solving the Problems]
The present invention adjusts the difference between the pulse widths of recording pulses modulated to recording pulses (3T to 11T) that are integral multiples of the reference clock (T) to different times (1.2T, 0.9T) according to the recording information. It is characterized by doing.
[0009]
According to the present invention, by adjusting the pulse width of a recording pulse to a recording time set in advance to a different recording time for each pulse width according to the pulse width, jitter and the like are likely to occur. The recording pulse can be easily discriminated by increasing the interval from the pulse width to be recorded.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a block diagram showing an information recording apparatus according to an embodiment of the present invention.
[0011]
The information recording apparatus 1 of this embodiment is an optical disk drive apparatus such as a CD-R / RW, and includes a turntable 11, a spindle motor 12, an optical pickup 13, a guide rail 14, a thread motor 15, a motor driver 16, and a laser controller 17. , Read amplifier 18, servo control unit 19, ATIP detection unit 20, decoder 21, buffer 22, interface 23, encoder 24, controller 25, and memory 26.
[0012]
For example, a recording medium 10 such as a CD-R / RW disc is inserted into the turntable 11. The turntable 11 is fixed to the rotation shaft of the spindle motor 12 and can be rotated by the rotation of the spindle motor 12.
[0013]
Further, the optical pickup 13 is disposed so as to face the information recording surface of the recording medium 10. The optical pickup 13 is guided by a guide rail 14 and is movable in the radial direction of the recording medium 10 and the arrow A direction.
[0014]
FIG. 2 shows a configuration diagram of the optical pickup 13.
[0015]
The optical pickup 13 includes a light emitting unit 31, an optical system 32, an objective lens 33, a photodetector 34, a tracking actuator 35, a focus actuator 36, a lens holder 37, and an elastic holding member 38.
[0016]
The light emitting unit 31 is configured by a laser diode or the like, and outputs an irradiation light beam to the recording medium 10. The light beam output from the light emitting unit 31 is supplied to the optical system 32. The optical system 32 bends the light beam supplied from the light emitting unit 31 in the direction of the objective lens 33.
[0017]
The objective lens 33 converges the light beam from the optical system 32 onto the recording medium 10. The objective lens 33 is held by a lens holder 37 that is movable in the directions of arrows A and B by a wire 38. The lens holder 37 is provided with a tracking actuator 35 and a focus actuator 36. The tracking actuator 35 moves the lens holder 37 in the direction of arrow A in accordance with the tracking signal supplied from the motor driver 16, and moves the position of the objective lens 33 in the direction of arrow A so that the light beam L follows a desired track. Move. The focus actuator 36 moves the lens holder 37 in the arrow B direction according to the focus signal supplied from the motor driver 16, and moves the position of the objective lens 33 in the arrow B direction so that the light beam L is focused on the recording medium 10. Move to.
[0018]
Information is recorded on the recording medium 10 by the light beam L converged on the recording medium 10. Further, information recorded on the recording medium 10 is reproduced by the reflected light of the light beam L converged on the recording medium 10.
[0019]
Information recording / reproduction is controlled by the power of the light beam applied to the recording medium 10, that is, the power of the light beam output from the light emitting unit 31. The light emitting unit 31 is driven by the laser controller 17, and the power of the light beam output is controlled according to the drive signal level supplied from the laser controller 17.
[0020]
The light beam reflected by the recording medium 10 is supplied to the photodetector 34 through the optical system 32. The photodetector 34 converts the main signal component, tracking error signal component, and focus tracking signal component of the reflected light of the recording medium 10 into electrical signals. The electrical signal converted by the photodetector 34 is supplied to the read amplifier 18.
[0021]
The read amplifier 18 amplifies the electrical signal from the photodetector 34. The electric signal amplified by the read amplifier 18 is supplied to the servo control unit 19.
[0022]
The servo control unit 19 controls the motor driver 16 based on the main signal component, the tracking error signal component, and the focus error signal component. The motor driver 16 uses the spindle motor 12, the thread motor 15, the tracking actuator 35, and the focus actuator 36 to track the desired track while the light beam from the optical pickup 13 focuses on the desired track on the recording medium 10. To control.
[0023]
Further, the main signal component of the electric signal amplified by the read amplifier 18 is supplied to the ATIP detection unit 20 and the decoder 21. The ATIP detector 20 detects an ATIP signal from the main signal component and supplies it to the encoder 24. The decoder 21 decodes reproduction data from the main signal component. At this time, the decoder 21 determines the pulse width in increments of the reference clock 1T and decodes the original data as usual.
[0024]
The reproduction data decoded by the decoder 21 is temporarily stored in the buffer 22 and then transmitted from the interface 23 to a host computer or the like. In recording data, recording data is supplied to the interface 23 from a host computer or the like. The recording data is temporarily stored in the buffer 22.
[0025]
The recording data stored in the buffer 22 is encoded into a recording signal by the encoder 24 at a timing according to the ATIP signal. At this time, the recording signal is output as a pulse signal of “3T” to “11T” having a pulse width 3 to 11 times that of the reference clock, where T is the reference clock. The recording signal output from the encoder 24 is supplied to the laser controller 17. The laser controller 17 controls the light emitting unit 31 built in the optical pickup 13 based on the recording signal supplied from the encoder 24. The light emitting unit 31 controls the intensity of the light beam applied to the recording medium 10 according to the recording signal. Thereby, recording pits corresponding to the recording signal are formed on the recording medium 10.
[0026]
Next, the operation of the encoder 24 will be described.
[0027]
FIG. 3 shows a functional block configuration diagram of the encoder 24.
[0028]
The encoder 24 includes an encoding unit 41, an output unit 42, a count value setting table 43, and a clock generation unit 44.
[0029]
The encoding unit 41 generates a recording pulse based on the recording data from the buffer 22. The recording pulse generated by the encoding unit 41 is supplied to the output unit 42. The output unit 42 refers to the count value setting table 43 according to the recording pulse supplied from the encoding unit 41, sets the count value of the recording pulse, and counts the clock from the clock generation unit 44 by the set count value. Thus, a recording pulse is generated.
[0030]
FIG. 4 shows a data configuration diagram of the count value setting table 43.
[0031]
The count value setting table 43 stores the count values C3 to C11 of the clock for every pulse width 3T to 11T of the recording pulse. T represents the period of the reference clock.
[0032]
The count value C3 is set at time 3T, the count value C4 is longer than time 4T, 4.2T, the count value C5 is longer than time 5T, 5.1T, and the count value C6 is time. The count value C7 is set to 6T, the count value C7 is shorter than the time 7T, 6.9T, the count value C8 is shorter than the time 8T, 7.8T, and the count value C9 is shorter than the time 9T, 8.7T. The count value C10 is preset to 9.6T, which is shorter than the time 10T, and the count value C11 is preset to the time 10.5T, which is shorter than the time 11T. Thus, the time difference between the count value C3 and the count value C4 is + 1.2T, and the time difference between the count values of the count values C4 to C11 is + 0.9T. This increases the time difference between the pulse width 3T and the pulse width 4T, so that the pulse width 3T and the pulse width 4T can be clearly identified during reproduction.
[0033]
Since the formed pits are stable in the pulse widths 4T to 11T, even if the time difference is shortened, the pits can be reliably identified. Therefore, the time difference between the count values C4 to C11 is shortened to 0.9T in the pulse widths 4T to 11T, and the total time is set to be substantially the same as the conventional time in the pulse widths 3T to 11T. . This can prevent the recording density from being reduced.
[0034]
Note that the count value setting table 43 may be provided in the memory 26 and taken into the encoder 24 via the controller 25.
[0035]
Next, the processing of the encoder 24 will be described.
[0036]
FIG. 5 shows a process flowchart of the encoder 24.
[0037]
First, when the encoding unit 41 receives recording data from the buffer 22 in step S1-1, the encoding unit 41 analyzes the recording data and generates a recording pulse pattern in step S1-2. The recording pulse pattern generated by the encoding unit 41 is supplied to the output unit 42. In step S1-3, the output unit 42 refers to the count value setting table 43 and acquires a count value corresponding to the recording pulse pattern.
[0038]
When the recording is started in step S1-4, the output unit 42 sets the count value acquired in step S1-5, and irradiates the recording medium 10 with the recording light beam in step S1-6. The laser controller 17 is controlled, and the count value is down-counted by the clock generated by the clock generator 44. When the count value becomes zero in step S1-7, the output unit 42 stops irradiating the recording medium 10 with the recording light beam in step S1-8. The output unit 42 repeats the processes of steps S1-1 to S1-8 until the recording operation is finished in step S1-9.
[0039]
As described above, pits can be formed on the recording medium 10 with the recording pulse width preset in the count value setting table 43.
[0040]
The recording pulse generated by the output unit 44 as described above is supplied to the laser controller 17. The laser controller 17 causes the light emitting unit 31 built in the optical pickup 13 to emit light according to the recording pulse from the encoder 24. As a result, a pit having a length corresponding to the pulse width of the recording pulse is formed on the recording medium 10.
[0041]
FIG. 6 is a diagram showing an evaluation of 100,000 pits recorded based on the CD standard with the pulse width set according to one embodiment of the present invention, and FIG. 7 is a CD standard with the pulse width set according to one embodiment of the present invention. It is a figure which shows the pulse width of the pit recorded based on this.
[0042]
As shown in FIG. 6 , the 3T pulse width has an average time of 694.16 nsec, which is approximately three times the reference clock T (= 213 nsec).
[0043]
The 4T pulse width has an average time of 971.82 nsec, which is approximately 4.2 times the reference clock T. Further, the 5T pulse width has an average time of 1180.06 nsec, which is approximately 5.1 times the reference clock T, and the 6T pulse width has an average time of 1388.31 nsec, which is approximately 6 times that of the reference clock T. Double, 7T pulse width has an average time of 1596.56 nsec, which is approximately 6.9 times the reference clock T, and 8T pulse width has an average time of 1804.80 nsec, which is an abbreviation of the reference clock T. The pulse width of 7.8 times and 9T has an average time of 2013.05 nsec, which is approximately 8.7 times the reference clock T, and the pulse width of 10T has an average time of 2221.30 nsec. The average time of the pulse width of 9.6 times and 11T is 2429.54 nsec, which is about 10.5 times the reference clock T.
[0044]
Thus, by making the difference between the pulse width of 4T to 4.2T and the pulse width of 3T, where the light beam is not stable, larger than the reference clock T, 4T can be reliably identified even if the jitter deteriorates at 3T. You can
[0045]
In this embodiment, the pulse width difference between 3T and 4T is increased, but the pulse width between 4T and 5T may be made larger than the reference clock T. In short, the light beam is not stable. The difference in pulse width may be set larger than the reference clock T as the pulse width.
[0046]
Further, in this embodiment, the difference in pulse width between 3T and 4T is increased, and the overall recording density is increased by reducing the difference in pulse width so as to compensate for the difference between 4T and 11T. It is devised not to.
[0047]
The count value setting table 43 can change the count value in accordance with an instruction from the outside. For example, the count value setting table 43 is changed by instructing the controller 25 from the interface 23 and accessing the count value setting table 43 of the encoder 24 from the controller 25 to change the count value. Further, in a drive such as a CD-R / RW, the recording pulse width of 3T to 11T can be freely and easily changed by simply changing the strategy, so that it is set by changing the strategy. Also good.
[0048]
Next, the operation of the decoder 21 when decoding the recording pulse encoded as described above and recorded on the recording medium 10 will be described.
[0049]
FIG. 8 shows a processing flowchart of the decoder 21.
[0050]
When the reproduction pulse is supplied in step S2-1, the decoder 21 measures the pulse width of the reproduction pulse in step S2-2. In step S2-3, the decoder 21 determines 3T to 11T based on the measured pulse width.
[0051]
The decoder 21 detects 3T when the edge of the end of the reproduction pulse is around 3T from the start, and 4T when the edge of the end of the reproduction pulse is around 4.2T from the start 5T is detected when the edge of the end of the reproduction pulse is about 5.1T from the start and before and after that, and 6T is detected before and after the end of the reproduction pulse about 6.0T from the start. Detected at a certain time, 7T is detected when the end edge of the reproduction pulse is around 6.9T from the start, and 8T is detected at the end of the reproduction pulse centered at 7.8T from the start. It is detected when it is in the front and back, and 9T is detected when the edge of the end of the reproduction pulse is 8.7T around the start, and 10T is detected when the edge of the end of the reproduction pulse is 9 from the start. Detected when it is in its back and forth around a 6T, end edges of 11T regeneration pulse is detected when it is in its back and forth around a 10.5T from the beginning. At this time, the decoder 21 recognizes the center time for detecting the pulse width based on the count value setting table 43 of the encoder 24.
[0052]
In step S2-4, the decoder 21 decodes the data based on the detected 3T to 11T. The decoder 21 stores the decoded data in the buffer 22 in step S2-5. The decoder 21 repeats the processing of step S2-1 to step S2-5 until the reproduction ends in step S2-6.
[0053]
These settings may also be set by changing the strategy with the controller 25 as in the encoder 24.
[0054]
In this embodiment, an optical disk drive device such as a CD-R / RW has been described, but other optical disk drive devices such as MO (magneto-optical) disks, magnetic recording devices such as hard disk drives, floppy disk drives, etc. It is also applicable to.
[0055]
【The invention's effect】
As described above, according to the present invention, jitter or the like is likely to occur by adjusting the pulse width of the recording pulse to a recording time set in advance to a different recording time for each pulse width according to the pulse width. By increasing the interval between adjacent pulse widths in terms of pulse width, the recording pulse can be easily discriminated.
[Brief description of the drawings]
FIG. 1 is a block diagram of an embodiment of an information recording apparatus of the present invention.
FIG. 2 is a configuration diagram of an optical pickup 13;
FIG. 3 is a functional block configuration diagram of an encoder 24;
4 is a data configuration diagram of a count value setting table 43. FIG.
FIG. 5 is a process flowchart of the encoder 24;
FIG. 6 is a diagram showing an evaluation of 100,000 pits recorded based on a CD standard with a set pulse width according to an embodiment of the present invention.
FIG. 7 is a diagram showing a pulse width of a pit recorded based on a CD standard with a set pulse width according to an embodiment of the present invention.
FIG. 8 is a processing flowchart of the decoder 21;
FIG. 9 is a diagram showing an evaluation of 100,000 pits recorded based on the CD standard.
FIG. 10 is a diagram showing the pulse width of pits recorded based on the CD standard.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Information recording device 10 Recording medium 11 Turntable, 12 Spindle motor, 13 Optical pick-up 14 Guide rail, 15 Thread motor, 16 Motor driver 17 Laser controller, 18 Read amplifier, 19 Servo control part 20 ATIP detection part, 21 Decoder, 22 Buffer 23 Interface, 24 Encoder, 25 Controller 26 Memory 31 Light emitting section, 32 Optical system, 33 Objective lens, 34 Photo detector 35 Tracking actuator, 36 Focus actuator 37 Lens holder, 38 Wire 41 Encoding section, 42 Output section, 43 Count Value setting table 44 Clock generator

Claims (4)

An information recording apparatus for recording a recording pulse corresponding to recording information on a recording medium,
Modulation means for modulating the recording information into recording pulses having a pulse width that is an integral multiple of a reference clock;
When the period of the reference clock is T, the pulse width of the recording pulse 3T is 3T, the pulse width of the recording pulse 4T is 4.2T, the pulse width of the recording pulse 5T is 5.1T, and the pulse width of the recording pulse 6T is 6T. The pulse width of the recording pulse 7T is 6.9T, the pulse width of the recording pulse 8T is 7.8T, the pulse width of the recording pulse 9T is 8.7T, the pulse width of the recording pulse 10T is 9.6T, and the pulse of the recording pulse 11T An information recording apparatus comprising: setting means for setting the width to be recorded at 10.5T . An information reproducing apparatus for reproducing recorded information according to a pulse width of a reproduction pulse,
Pulse width detecting means for detecting a pulse width of the reproduction pulse;
Recognizing the pulse width detected by the pulse width detecting means based on a reference clock, and reproducing means for reproducing the recording information based on the identified pulse width,
The reproduction means reproduces a reproduction pulse having a pulse width of 3T as a reproduction pulse 3T, a reproduction pulse having a pulse width of 4.2T as a reproduction pulse 4T, and a reproduction pulse having a pulse width of 5.1T, where T is the period of the reference clock. Reproduction pulse 6T, reproduction pulse 6T, reproduction pulse 7T, reproduction pulse 7T, reproduction pulse 8T, reproduction pulse 8T, reproduction pulse 8P, and pulse width 8.7T An information reproducing apparatus, wherein a reproduction pulse having a pulse 9T, a pulse width 9.6T is recognized as a reproduction pulse 10T, and a reproduction pulse having a pulse width 10.5T is recognized as a reproduction pulse 11T . An information recording / reproducing apparatus for recording a recording pulse corresponding to recording information on a recording medium and reproducing the recording information based on the recording pulse recorded on the recording medium,
Modulation means for modulating the recording information into recording pulses having a pulse width that is an integral multiple of a reference clock;
Setting means for setting a recording time to the recording medium according to a pulse width of the recording pulse;
Pulse width detecting means for detecting a pulse width of the reproduction pulse;
Recognizing the pulse width detected by the pulse width detecting means based on a reference clock, and reproducing means for reproducing the recording information based on the identified pulse width,
The setting means has a pulse width of the recording pulse 3T of 3T, a pulse width of the recording pulse 4T of 4.2T, a pulse width of the recording pulse 5T of 5.1T, and a recording pulse of 6T, where T is the period of the reference clock. 6T, recording pulse 7T, pulse width 6.9T, recording pulse 8T, pulse width 7.8T, recording pulse 9T, pulse width 8.7T, recording pulse 10T, pulse width 9.6T, Set the pulse width of the recording pulse 11T to be recorded at 10.5T,
The reproduction means reproduces a reproduction pulse having a pulse width of 3T as a reproduction pulse 3T, a reproduction pulse having a pulse width of 4.2T as a reproduction pulse 4T, and a reproduction pulse having a pulse width of 5.1T, where T is the period of the reference clock. Reproduction pulse 6T, reproduction pulse 6T, reproduction pulse 7T, reproduction pulse 7T, reproduction pulse 8T, reproduction pulse 8T, reproduction pulse 8P, and pulse width 8.7T An information recording / reproducing apparatus which recognizes a reproduction pulse having a pulse 9T, a pulse width 9.6T as a reproduction pulse 10T, and a reproduction pulse having a pulse width 10.5T as a reproduction pulse 11T . A recording pulse modulation method for modulating recording information into a recording pulse that is an integral multiple of a reference clock,
The modulated recording pulse has a pulse width of the recording pulse 3T of 3T, a pulse width of the recording pulse 4T of 4.2T, a pulse width of the recording pulse 5T of 5.1T, where T is the period of the reference clock. The pulse width of the recording pulse 6T is 6T, the pulse width of the recording pulse 7T is 6.9T, the pulse width of the recording pulse 8T is 7.8T, the pulse width of the recording pulse 9T is 8.7T, and the pulse width of the recording pulse 10T is 9 A recording pulse modulation method characterized in that the recording pulse is set to be recorded at 6T and the pulse width of the recording pulse 11T at 10.5T .

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