JP3036240B2 - Information recording and playback control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling the recording / reproduction of information for recording / reproducing on a recording medium, and more particularly to the information recording / reproduction for recording a code string of recording marks thermally with a laser as in an optical disk apparatus. It relates to a control method.

[0002]

2. Description of the Related Art Conventionally, as such an optical recording / reproducing method, as described in JP-A-3-22223,
The recording code sequence of the recording mark is pulsed to form a series of pulse sequences corresponding to the length of the recording code sequence, and the length and amplitude of the pulse sequence are set to the opposite phase length of the recording code sequence immediately before the recording code sequence. In some cases, the recording is performed by controlling the pulse train into three parts and changing the pulse width of each pulse.

[0003]

The above prior art does not take into account the fact that a change in recording sensitivity to the recording medium due to a change in film thickness of the recording medium or a change in environmental temperature occurs, and cannot control recording marks with high accuracy. Therefore, there is a problem that the recording capacity is reduced.

[0004] It is an object of the present invention to minimize the fluctuation of the recording mark due to the fluctuation of the recording sensitivity and to perform the recording mark control with high accuracy.

It is another object of the present invention to improve compatibility between a recording / reproducing apparatus and a recording medium and to suppress fluctuations in recording sensitivity and recording power caused by the recording / reproducing apparatus.

Another object of the present invention is to improve the reliability, storage capacity and information transfer rate of a recording / reproducing apparatus.

[0007]

Means for Solving the Problems In order to achieve the above object, in order to improve compatibility between a recording medium and a device that performs recording, test writing is performed in advance at a predetermined position on the recording medium, and the test writing is performed. The optimum recording power is found from the obtained reproduction signal, and thereafter, the recording of normal information is started.

In addition, the test data and the input data bit sequence of the regular information are converted into a code sequence corresponding to the modulation method of the recording apparatus, and a data sequence for recording the code sequence on a recording medium is generated. By driving a laser light source to form a recording area on a recording medium, accurate recording is performed.

In order to achieve the above-mentioned other object, a recording pulse train and a recording auxiliary pulse corresponding to the recording mark of the input data bit sequence of the test writing data and the normal information are generated, and two light beams for the recording pulse sequence and the recording auxiliary pulse are generated. It is recorded on a recording medium using intensity or two energy levels.

According to another aspect of the present invention, there is provided a recording medium capable of overwriting information by modulating the light intensity of a recording pulse train and a recording auxiliary pulse, the recording medium being applied to a recording power and an erasing power. It is.

Further, when test writing is performed in a predetermined position on the recording medium in advance and recording of regular information is started based on the optimum recording power obtained by the trial writing, the test writing data and the input data of the regular information are written. The bit sequence is used as a code sequence of a device for recording, and a data sequence for recording the code sequence on a recording medium is generated, and a recording waveform is formed by driving a laser light source to form a recording area on the recording medium. The light intensity and the energy level of the recording pulse train and the recording auxiliary pulse corresponding to the mark are controlled.

[0012]

In the test writing, in order to improve the compatibility between the recording medium and the recording apparatus, a change in the thickness of the recording medium due to the exchange of the recording medium, a change in the environmental temperature, etc. In order to detect a change in the recording sensitivity of the recording medium due to a change in the characteristics of the recording apparatus, a strict recording mark to be recorded is written on the recording medium before recording the regular information. further,
In order to find the optimum recording power from the reproduced signal obtained from the recorded test write data, the recording operation is executed by changing the light intensity or energy of the recording waveform for recording. As a result, the optimum recording conditions for the recording medium can be always obtained, so that the information recording malfunction due to the above-mentioned fluctuation in the recording sensitivity is eliminated, and the recording and reproduction with high reliability can be performed.

Further, in order to minimize test writing performed immediately after recording of regular information or by recording / reproducing at a certain period, a recording pulse train and a recording auxiliary pulse corresponding to a recording mark are generated. This is a recording in which the length and width of a recording mark are controlled while keeping the temperature of the recording medium substantially constant using two light intensities or two energy levels with respect to the pulse.

[0014]

Hereinafter, examples of the present invention will be described. FIG.
Shows an embodiment of the apparatus configuration of the present invention. The information recording / reproducing apparatus includes an optical head centered on a laser 1, a recording medium 5 for storing information, a recording processing system centered on a recording pulse generating circuit 12, and a reproduced signal obtained from the optical head. It is composed of a reproduction processing system centered on a reproduction circuit 16 for converting the data into a data. The recording medium 5 includes a recording film and a substrate holding the recording film.

The command and information data from the host computer are decoded by the controller 8 and the recording data are modulated, and converted into a code string corresponding to the modulation method. The synthesizer 9 is an oscillator for generating a reference clock for the entire apparatus. As a technique for increasing the capacity, the reference clock is changed for each zone so that the recording density at the inner and outer peripheries is substantially constant.
(Zones Constant Angular V
In the case of employing a recording method called (e.g., occupancy), it is necessary to change the oscillation frequency of the synthesizer 9 according to the zone.

In the test writing, in order to improve the compatibility between the recording medium and the recording apparatus, a change in the thickness of the recording medium due to the exchange of the recording medium, a change in the environmental temperature, etc. A test writing pattern for detecting a change in the recording sensitivity of the recording medium due to a change in the characteristics of the recording apparatus is written on the recording medium before recording the normal information. This trial writing pattern
The pattern is converted into a code string corresponding to the modulation method, and is generated in the test writing pattern generation circuit 10.

A code string modulated according to regular information data from the controller 8 and a test write pattern generating circuit 1
The code string from 0 is input to the selector 11 and the control
In response to the control signal of the controller 8, the switching is performed in accordance with the test writing process or the normal recording process. The code string from the selector 11 enters the recording pulse generation circuit 12 and is converted into a recording pulse string for controlling the length and width of a recording mark. These recording pulse trains are input to a laser driver 13 and cause the laser 1 to oscillate at a high output by a recording current from the laser driver 13, and the light emitted from the laser 1 becomes parallel light by a lens 12. Then, the light passes through the prism 3 and converges on the recording medium 5 by the lens 24 to record a recording mark corresponding to the code string. The high frequency superimposing circuit 14 is provided to reduce laser noise caused by the laser 1, and is used for recording / erasing.
In some cases, high-frequency superimposition may be suspended due to the life of the device.

At the time of reproduction, the laser 1 oscillates at a low output and enters the recording medium 5. The light reflected from the recording medium 5 is split into an optical path by the prism 3 and is incident on the photodetector 7. After the photoelectric conversion by the photodetector 7, the signal is amplified by the preamplifier 15 and input to the reproducing circuit 16. The reproduction circuit 16 includes a waveform equalization circuit, an automatic gain control circuit, a binarization circuit, and the like.
The input reproduction signal is defined as a binary signal. Reproduction circuit 16
From the PLL for self-clocking
(Phase Locked Loop) circuit 17. The reproduced clock synchronized with the binarized signal and the binarized signal obtained by the PLL 17 are input to a discrimination circuit 18 for data discrimination, and the resulting data discrimination signal is input to the controller 8. And the data is demodulated. In a magneto-optical disk drive for recording, reproducing and erasing information using an externally applied magnetic field, an external magnetic field generator 6 is provided to switch the direction of the magnetic field during recording / erasing and irradiate recording / erasing power. carry out. At the time of reproduction, the reflected light is separated into p-polarized light and s-polarized light by a wave plate (not shown) arranged in front of the photodetector 7 and each of them is differentiated by the photodetector (two divisions) 7. A magneto-optical signal can be obtained.

At the time of the trial writing process, the reproduced signal in the analog signal state is guided from the reproducing circuit 16 to the trial writing pattern center level detecting circuit 19. As a recording pattern used in the test writing process, a combination pattern of the highest frequency dense pattern and the lowest frequency sparse pattern in the apparatus is used, and the center of the dense pattern in the reproduced signal is used. The test writing pattern center level detection circuit 19 detects the level and the center level of the sparse pattern, and the difference between the center levels is represented by A / A.
The data is taken into the controller 8 by the D converter 20, and when the difference becomes 0, the recording power is determined to be the optimum recording power, and the regular recording is performed. In this way, it is possible to record a highly accurate recording mark by always setting the optimum power by trial writing.

FIG. 2 shows an embodiment of a recording method for recording on a recording medium according to the present invention. Here, a case where the (1,7) RLL code is adopted as the modulation method will be described. The code sequence modulated according to the normal information data from the controller 8 described in FIG. 1 and the code sequence from the test writing pattern generation circuit 10, and the output from the selector 11 is the recording code sequence. is there. This recording code string is (1, 7) RLL
Co - Yes 7 ways when 2T _W ~8T _W de, Ma - Kuejji modulated for recording co - NR for inverting the polarity by "1" of the de
ZI (Non Return To Zero Inv
erse) signal. Here, T _W represents the window width, and the reference clock cycle oscillated by the synthesizer 9 is T _W
be equivalent to. Rotation speed of 5 inch optical disk is 3000rpm
If the recording pit length is 0.75 μm, the transfer speed of 2 MB / s on the inner circumference and 4 MB / s on the outer circumference can be realized with the (1,7) RLL code. _W is 40 ns on the inner circumference and 20 ns on the outer circumference.
The recording pulse generation circuit 12 generates a recording pulse train corresponding to the pulse portion of the recording code train. The recording pulse train is different from the first pulse in the length of the second and subsequent pulses.
Top pulse and the pulse width of 3 / 2T _W against the shortest pulse width 2T _W, 1 / 2T _W min shorter. The pulse width after 3T _W is the first pulse 3 / 2T _W and the pulse width after the second 1/2.
It is obtained by adding the combination of T _W and the gap width 1 / 2T _W (the same as the reference clock waveform). These pulses are generated in synchronization with the reference clock. Thereby, control of the pulse width and the pulse interval is improved.

FIG. 3 shows a recording mark shape, a recording current waveform of a laser, and a control signal. The recording current waveform of the laser is constituted by a combination of a recording pulse train and a gap, and a trailing edge of each recording pulse train is provided with a pause period of a time width by a recording auxiliary pulse. By providing a gap portion having a certain time width (for example, T _W ) from the falling position of the recording code train, the heat from the last falling position of the recording pulse train reduces the temperature of the leading rising position of the next recording pulse train. Make little change. The laser power is set at five power levels. The reproduction power Pr at the time of reproduction, and the reproduction power P at the time when the reproduction power is reduced by the modulation degree to suspend the high frequency superposition at the time of recording.
r ′, the recording power by the recording auxiliary pulse is Pph, the recording power of the first pulse is Pw1, and the recording power of the second and subsequent rear pulses is Pw2. In order to realize this power, APC (Au) which keeps reproduction power constant as a current source
current source I from toPower Control
current source Ip for recording auxiliary pulse superimposed on r ', Ir'
h, a current source Iw1 for the leading pulse to be superimposed, and a current source Iwr necessary for generating the rearward pulse are provided, and the recording auxiliary pulse power -Pph is set to Ir '+ Iph.
The first pulse power -Pw1 is Ir '+ Iph + Iw1, and the rear pulse power -Pw2 is Ir' + Iph + Iw1.
By making the laser emit light at + Iw2, a desired recording waveform can be obtained. At the time of reproduction, the reproduction current Ir is realized by adding Ir 'and the current Ihf from the high frequency superimposing circuit. Next, a control signal at the time of recording will be described. WRG
ATE-N is a gate signal indicating a recording state, and is enabled in a recording data area in a normal sector. It is used as an ON / OFF control signal of the high frequency superimposing circuit, and operates so as to be turned on during reproduction and turned off during recording. WRPLS-P corresponds to the recording pulse train, and PH
PLS-P is a signal for generating a recording auxiliary pulse has a rest period T _W for heat rejection at the rear end of the recording pulse train. PEAKPLS-P is a control signal used to increase the power of the rear pulse compared to the head pulse. These control signals are input to an arithmetic circuit 21 in the laser driver shown in FIG. The control signal at the time of erasure in a magneto-optical disk device that cannot be overwritten is W
The RPLS-P, PHPLS-P, and PEAKPLS-P have the same waveform as WRGATE-P (the reverse polarity signal of the WRGATE-N signal) so that data can be erased. In this recording waveform, the power of the first pulse is set lower than the power of the rear pulse. By doing so, the recording mark width by the first pulse and the recording mark width by the rear pulse can be made equal, and the recording mark length can be controlled with high accuracy. This is nothing other than keeping the temperature on the recording medium by the first pulse and the temperature by the rear pulse constant. Since the recording mark width is constant, the reproduced signal amplitude of the data section obtained by reproducing the recording medium is obtained. Can be constant. By slicing directly at the center or at a certain level of the reproduced signal, a binarized signal can be generated. Further, by using the combination of the recording pulse train and the recording auxiliary pulse, the power level of the recording auxiliary pulse is changed to the erasing power and the recording pulse is changed to the erasing power in the overwritable magneto-optical disk using the exchange coupling film described in JP-A-62-175948. The overwriting can be realized by using the recording power as the recording power.

FIG. 4 shows an embodiment of a laser driver for generating a recording waveform of the laser. APC (Auto Power Controller) for keeping the current sources Iw1, Iw2, Iph and reproduction power constant with respect to the recording current waveform, respectively.
ol). Current sources Iw1, I
w2 and Iph must be variable in each zone in accordance with ZCAV, and zone data from the controller 8 is provided in each current source via the data buses DBUS0-7-P. It can be realized by setting the D / A converter. The D / A converter adjusts the output gain so as to have a predetermined power in consideration of the luminous efficiency of the laser and the utilization efficiency of the optical head. The adjustment data is
This can be realized by incorporating the / A converter in, for example, an EEPROM. Each current source is connected to current switches CS1, CS2, CS3 capable of high-speed switching, and can execute high-speed switching by a recording pulse control signal shown in FIG. 3 to obtain a desired recording current waveform. In this circuit, an npn-type transistor capable of high-speed switching is used instead of a pnp-type transistor in order to cope with high-speed switching of a + drive laser. The total current of the D / A converter provided in each current source is supplied to the current source I by a current mirror circuit (not shown), and the current is sucked into the current switch by each current switch. -Take the form of controlling the current flowing through it. -In the case of a driving laser, it can be realized by adding currents from respective current sources. The high frequency superimposing circuit is turned on during reproduction by the control signal WRGATE-P.
Then, it operates to be turned off during recording. The switch used here is a switch described in JP-A-63-90037.
IN diodes are preferred.

In the test writing process, in order to improve the compatibility between the recording medium and the apparatus that performs the recording, a change in the thickness of the recording medium due to the exchange of the recording medium, the environmental temperature, etc. A change in the recording sensitivity due to fluctuations and changes in the characteristics of the recording apparatus, etc., is detected, and an operation of writing on the recording medium before recording normal information is performed in order to always perform recording under optimum conditions. I do. FIG. 5 shows an example of a flowchart of the test writing processing procedure. If the track for trial writing is ZCAV,
Several tracks are installed in each zone. For example, a method is used in which the recording conditions for all the zones are set based on the results of test writing in three zones: inner, middle, and outer. First, the optical head is positioned on the inner circumference test writing track. Here, a predetermined trial writing track is first erased to prepare for trial writing.
It is necessary to set the erasing power at this time to be high in consideration of all environmental temperatures (for example, erasing power at 0 ° C.). Next, the recording start power of test writing is set. The setting power at this time needs to be low, for example, recording power at 50 ° C. When the test write head sector is detected in the track, the test write pattern starts to be recorded.

FIG. 6 shows an example of a test writing pattern and a method of setting recording power. The closest density pattern ((1, 7)) which is the highest frequency in the device as a test writing pattern
In the case of the RLL code, a repetitive pattern of 2T _W ) and the sparsest pattern (8T _W ) which is the lowest frequency is used. In the case of mark edge recording, it is important to control the time axis of the recording mark, and the time axis of each pattern is controlled when the center level of the reproduction signal of the densest pattern is equal to the center level of the reproduced signal of the sparse pattern. Thus, the recording power at this time is set as the optimum power.
As described above, in this embodiment, the time axis fluctuation is detected by the amplitude level fluctuation. The recording power is updated as the recording power is sequentially updated as one condition per sector. In the case of ZCAV, the recording condition must be set in the laser driver from the controller via the data buses DBUS0 to 7-P. In consideration of the setting time, the recording sector is at least every other sector. (FIG. 6). 1
It is sufficient that the number of recording conditions per process is about 5 to 10. If the pit length is 0.75 μm, the number of sectors is about 30 in the case of 1024 B / sector format at the innermost circumference of a 5-inch disk, so one track is required. The recording process ends within. If the repetition cycle in one sector when the densest pattern and the sparsest pattern are set as one set at this time is selected to be higher than the signal fluctuation at the time of reproduction, the test writing pattern signal and the signal fluctuation are changed. Separation is possible, and detection accuracy can be increased. As a signal fluctuation component at the time of reproduction, a frequency component due to the retardation of the disk substrate itself is the mainstream.
It is preferable to select a cycle that is at least twice the main cycle of the operation.

The reproducing operation of the test writing process starts by positioning the optical head on the test writing track. The sectors recorded by changing the power in the above-described recording operation are selectively and sequentially read out. The test write pattern center level detection circuit 19 shown in FIG. 1 detects the center level (V ₁ ) of the densest pattern and the center level (V ₂ ) of the sparse pattern from the reproduced signals of each sector. , The voltage difference ΔV = V ₁ −
Determine the V _2. .DELTA.V is taken into the controller 8 as digital data by the A / D converter 20, and the recording condition of the sector where .DELTA.V = 0, which is the condition for judging the optimum recording power, is found therefrom. In this series of processing, ΔV =
If there is no sector that becomes 0, the magnitude of the recording condition is determined from the positive and negative polarities of ΔV, and the recording start power is again increased accordingly.
Is set, and the trial writing process is executed. If there is no sector where ΔV = 0 even after performing the test writing process two or more times on the same track, the process ends as an apparatus error.
After finding the sector where ΔV = 0, the setting power for this sector is stored in the memory in the controller as the optimum power. The test writing track whose optimum power is determined by the test writing is erased in preparation for the next test writing process. By setting the erasing power at this time to the maximum recording power used for the test writing process, erasing can be performed without erasing. After the trial writing process on the inner circumference is completed, the trial writing process on the middle circumference is executed. Similarly, after finding a sector where .DELTA.V = 0 at the middle circumference, the setting power for this sector is stored in the memory in the controller as the optimum power.
Finally, the same trial writing process is performed on the outer periphery to obtain Δ
After finding the sector where V = 0, the setting power for this sector is stored in the memory in the controller as the optimum power. The trial writing process is completed by calculating the optimum power of each zone by interpolation from the optimum power at the inner, middle, and outer circumferences and storing the calculated power in the memory.
Recording / reproduction of regular information is started. In the test writing track erasing operation at the start of the test writing in the above-described embodiment, an unrecorded sector detection operation is performed instead of the erasing operation, and the recording operation is performed while sequentially changing the recording power to the detected unrecorded sectors. You may. However, the sectors to be recorded are at least every other sector. In the above embodiment,
The test writing process is executed on the outer periphery, but if the recording sensitivity of the recording medium is known in advance, the test writing process is performed only on a certain zone of the test writing track on the disk. However, a similar effect can be obtained.

FIG. 7 shows an example of a reproduced signal obtained in the test writing process and an actual measurement example. In the reproduced signal, the difference ΔV between the center level of the reproduced signal of the densest pattern and the central level of the reproduced signal of the sparsest pattern changes depending on the size of the recording power. Two types of sampling pulses SAMPLE1-P and SAMPLE2-P are issued from the controller 8 in accordance with the cycles of the densest pattern and the sparse pattern, and V ₁ and V are used as the central levels from the respective patterns. Detect ₂ (3). ΔV = V _{1 with} respect to the recording power condition obtained in the test writing process
It shows an actual example of -V _2. It can be seen that the recording power is substantially proportional to ΔV. When there is no recording condition where ΔV = 0, it is possible to calculate the recording condition where ΔV = 0 from the negative recording condition and the positive recording condition which are closest to 0. FIG. 8 shows a first embodiment of the test writing pattern center level detection circuit 19. Here, the envelope is detected by the peak hold circuit 22 and the bottom hold circuit 23 with respect to the reproduction signal from the reproduction circuit 16, and the center level is detected by dividing each of the resistances. Thereafter, V ₁ and V ₂ are detected as the center levels corresponding to the respective patterns by the two sample hold circuits 24 and 25, and ΔV is obtained by the differential amplifier 26, and the result is A / D Input to converter 20. The A / D converter 20 sends ΔV to the controller 8 as digital data.

FIG. 9 shows a second embodiment of the test writing pattern center level detecting circuit 19. Here, a low frequency cutoff circuit (LPF) 2
7 to detect the average level of the reproduced signal,
Thereafter, as in the first embodiment, two sample hold circuits 24 and 25 detect V ₁ and V ₂ as the average level for each pattern, respectively.
Then, ΔV is obtained by 6 and the result is input to the A / D converter 20.

[0028]

According to the present invention, fluctuations in recording sensitivity to a recording medium due to fluctuations in the thickness of the recording medium and fluctuations in environmental temperature and fluctuations in recording sensitivity caused by the recording / reproducing apparatus are suppressed, and compatibility between the recording / reproducing apparatus and the recording medium is reduced. As a result, the recording mark can be controlled with high accuracy, so that the reliability and recording capacity of the recording / reproducing apparatus and the transfer rate of information can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram for explaining a first embodiment of the present invention;

FIG. 2 is an explanatory diagram of a recording code string and a recording pulse string used.

FIG. 3 is an explanatory diagram showing a recording current waveform.

FIG. 4 is a block diagram of a laser driver.

FIG. 5 is an example of a flowchart of a test writing processing procedure;

FIG. 6 is an explanatory diagram of an example of a test writing pattern and a recording power setting method.

FIG. 7 is a reproduction signal obtained in a test writing process and one measurement example.

FIG. 8 shows a first embodiment of a test writing pattern center level detection circuit 19;

FIG. 9 shows a second embodiment of the test writing pattern center level detection circuit 19;

[Explanation of symbols]

8 ... Controller, 10 ... Test writing pattern generation circuit, 12 ... Recording pulse generation circuit, 13 ... Laser driver, 16 ... Reproduction circuit, 17 ... PLL, 18 ... Discrimination circuit .., 19... Trial write pattern center level detection circuit, 20... A / D converter, 22... Peak hold circuit, 23... Bottom hold circuit, 24, 25. Circuit, 26: Differential amplifier, 27: Low frequency cutoff circuit (LPF)

Continuing on the front page (72) Inventor Hiroshi Ide 1-280 Higashi-Koigabo, Kokubunji-shi, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd. (56) reference Patent flat 3-91124 (JP, a) JP flat 3-95734 (JP, a) JP flat 3-171437 (JP, a) (58 ) investigated the field (Int.Cl. ⁷ G11B 7/00-7/013 G11B 7/12-7/22 G11B 11/10-13/06

Claims (9)

(57) [Claims] 1. A recording pattern used in a test writing process while changing optical recording power at a predetermined position on a recording medium.
Down to the record, to use when the recorded trial writing process
A light spot is irradiated on a predetermined area of the recording medium with light from a light source in order to reproduce a recording pattern and record regular information on the recording medium based on information of the optimum recording power obtained from the reproduced signal. This is a recording / reproduction control method for recording information by forming a recording area physically different from an unrecorded portion on a recording medium, and is used during the test writing process.
And <br/> recording patterns use the code sequence pattern based on the modulation method when recording the input data bit sequence of the normal information, auxiliary recording a recording pulse train corresponding to the recording pattern to be used during the trial writing process A pulse is generated, the lengths of the first pulse and the second and subsequent pulses of the recording pulse train are made different, and the recording auxiliary pulse having a pause period is provided on the rear side of each recording pulse train. A method for controlling recording and reproduction of information, comprising driving a light source to provide light intensity or two energy levels. 2. A recording medium which modulates the light intensity of the recording pulse train and the recording auxiliary pulse to enable overwriting of information.
2. The information recording / reproduction according to claim 1, wherein recording of a recording pattern used at the time of test writing processing is performed on the body , and the recording pattern used at the time of the processing is reproduced to set recording power and erasing power. Control method. 3. The test writing process according to claim 1,
Record the recording pattern to be used during the trial writing process.
An information recording / reproduction control method, comprising controlling both or at least one of the level of a recording pulse train and the level of a recording auxiliary pulse of a recording waveform . 4. The input data file of regular information according to claim 1, wherein the recording pattern used at the time of the trial writing process is a recording pattern.
The most dense pattern of the highest frequency and the most sparse pattern of the lowest frequency in the modulation method when recording the bit train are used, and the center level of the most dense pattern and the most sparse pattern in the reproduced signal are used. Characterized in that the recording power is set such that the respective center levels are equal to each other, and normal recording is carried out. 5. The method according to claim 3, wherein the data is used during a trial writing process.
In the recording operation for recording the recording pattern to be used, recording is performed while sequentially changing the recording power for each sector. In the reproducing operation, the closest pattern and the most sparse pattern are sequentially reproduced while the sector is sequentially reproduced.
Recording / reproduction control for performing normal recording with the recording power set in a sector in which the respective levels become equal, that is, the difference becomes 0, as the optimum power. Method. 6. The method according to claim 4, wherein the data is used during a trial writing process.
A method for controlling recording and reproduction of information, wherein a peak hold circuit and a bottom hold circuit are used for detecting the center level of a reproduction signal of a recording pattern to be used. 7. The information recording / reproducing control method according to claim 4, wherein a low-frequency cutoff circuit is used for detecting the center level of the reproduction signal of the recording pattern for test writing. 8. A disk drive according to claim 4, wherein the repetition period of the combination of the densest pattern and the sparse pattern, which is a recording pattern at the time of the test writing process, changes. A method for controlling the recording and reproduction of information, wherein the method is at least twice as long as the cycle of the information. 9. The method according to claim 5, wherein the data is used during a trial writing process.
For the track on which the recording pattern to be used is recorded, at the end of the processing, the recording pattern to be used at the time of the test writing processing is recorded.
A recording / reproducing control method for information, wherein the track is erased by the recorded maximum power.