JP3276700B2 - Disc data recording method and disc data recording / reproducing 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 disk data recording method and a data recording / reproducing method.

[0002]

2. Description of the Related Art An ISO standard that defines standard functions of a magneto-optical disk and a magneto-optical disk drive includes:
As a modulation method at the time of data recording, 2-7 RLL (Run
(Length Limited) modulation method.

There are various selection criteria for this modulation method. Basically, a modulation method that can increase the data recording density and minimize the effect of data errors during data reproduction is adopted. You.

[0004]

However, in the simple 2-7 RLL modulation method, it is necessary to take measures such as inserting a resynchronization signal into a user data recording area in order to suppress the influence of data error propagation. In some cases, the data recording density cannot be improved.

[0005] For example, as reported in "Magneto-optical overwrite medium recording method (Izumi, Taguchi, Moriji; 1992 IEICE Spring Conference 4-408p)", 2-7 RLL modulation is used. There is also a report that the data error rate is improved when the data recording operation is performed by inverting the mark bit after performing the above operation.

The present invention has been made in view of the above circumstances, and has as its object to provide a data recording method for a disc and a data recording / reproducing method for a disc.

[0007]

SUMMARY OF THE INVENTION According to the present invention, in a data recording method for a disk, which modulates recording data by a predetermined modulation method, when recording data is recorded on a disk, a mark bit is set. Data is recorded in the non-inverted state and the data error when the recorded data is reproduced is detected as a non-inverted data error, and the data is recorded with the mark bit inverted and the recorded data is recorded. A data error at the time of reproduction is detected as an inverted data error, and when the non-inverted data error is smaller than the inverted data error, data is recorded with the mark bit non-inverted while the non-inverted data error is When the error is larger than the inverted data error, the data is recorded with the mark bit inverted. Further, the predetermined modulation method is as follows:
It is preferable to use a modulation method in which the NRZI modulation method is applied to the 7RLL modulation method.

[0008] Further, after the recording data is modulated by a predetermined modulation method, the recording data is recorded on a disk, and the recording data is recorded / reproduced on a disk in which a synchronizing signal for bit synchronization is arranged at a head portion. In the method, when recording data, when recording the recording data on the disk, the data error is detected as a non-inverted data error when the data is recorded with the mark bit non-inverted and the recorded data is reproduced at that time. When the data is recorded in a state where the mark bit is inverted and the data recorded at that time is reproduced, a data error when the data is reproduced is detected as an inverted data error, and when the non-inverted data error is smaller than the inverted data error, While the data is recorded with the mark bit non-inverted, the non-inverted data error is greater than the inverted data error. When the data is recorded, the data is recorded with the mark bit inverted, and at the time of data reproduction, the recorded data is non-inverted data or inverted data based on the number of detection marks of the synchronization signal included in the head of the recorded data. It is preferable to determine whether there is any data, and when it is detected that the recording data is inverted data, the mark bit detection output is inverted to reproduce the data. The predetermined modulation method may be a modulation method in which an NRZ modulation method is applied to a 2-7 RLL modulation method.

[0009]

Therefore, since data is recorded on the disk by a data recording method with a smaller data error rate, data errors during data reproduction can be reduced, and the reliability of data recording on the disk can be improved.

[0010]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 shows a magneto-optical disk according to one embodiment of the present invention.

A large number of recording tracks are formed concentrically on the magneto-optical disk 1, and each recording track is divided into m sectors as shown in FIG. 2 (a). As shown in FIG. 3B, each sector has a header section HD in which a synchronization signal and the address of the sector (track address and sector address) are recorded, and a recording section DD in which user data can be recorded. Consists of

As shown in FIG. 1C, the recording section DD includes a synchronization signal VFO composed of a predetermined bit pattern for establishing bit synchronization of a reproduction system and a predetermined signal for establishing byte synchronization of reproduction data. A synchronization signal SYN composed of a bit pattern, a data area DA in which a predetermined number of bytes of user data are arranged, and an error correction area EA in which an error correction code ECC for error-correcting user data in the data area DA is arranged. Become. Also, the synchronization signal VFO
The synchronization signal SYN is recorded together with the user data at the time of data recording.

In this embodiment, the data recorded in the data area DA is NRZ modulated by the 2-7 RLL modulation method.
(Non Return to Zero) modulation method is applied. In the 2-7 RLL modulation method, a bit pattern of a data sequence is converted into a signal of a recording sequence according to the rule shown in FIG.

Therefore, for example, the data “10001101111” shown in FIG. 4A is changed to “010000001000001” as shown in FIG.
0001000 ", and the portion where each recording signal becomes data" 1 "is recorded as a mark as shown in FIG.

Now, referring to the above-mentioned "Magneto-optical overwrite medium recording method (Izumi, Taguchi, Morinji; Proceedings of the 1992 IEICE Spring Conference 4-408p)" (hereinafter referred to as reference data), If the mark sequence shown in FIG. 4C is inverted to form the inverted mark sequence shown in FIG. 4D, there is a possibility that data errors will be reduced.

Therefore, in this embodiment, the magneto-optical disk 1
When data is recorded on a non-inverted mark, the non-inverted mark is recorded and the recorded data is reproduced, and the inverted mark is recorded and the recorded data is reproduced. When the error is smaller, a non-inverted mark is used as the recording data. Conversely, when the data error when the inverted mark is reproduced is smaller, the inverted mark is used as the recording data. To

As a result, the rate of occurrence of data errors when reproducing data recorded on the magneto-optical disk 1 can be suppressed, and the reliability of data recorded on the magneto-optical disk 1 can be improved. In general, the data error rate of the magneto-optical disk 1 is higher than that of a magnetic disk or the like, and thus improving the reliability of recorded data is very effective.

At the time of data reproduction, it can be determined whether the recorded data is a mark in a non-inverted state or a mark in an inverted state as follows.

As the synchronization signal VFO arranged at the head of the data area DA, the original data uses a repeating pattern of "101010..." As shown in FIG. When the repetition pattern of “101010...” Is subjected to 2-7 RLL modulation, a recording signal of a repetition pattern of “010001000100...” Is obtained as shown in FIG.

When this recording signal is recorded on the magneto-optical disk 1 in a non-inverted state, as shown in FIG.
. 0001000100... (Data “1” is a mark) and is recorded on the magneto-optical disk 1 in an inverted state, as shown in FIG. A recording pattern (data "1" is a mark) is recorded.

As described above, the frequency of appearance of data 1 (mark) in the synchronization signal VFO when recorded in the non-inverted state is lower than the frequency of appearance of data 0 (non-mark) and recorded in the inverted state. Synchronization signal VFO
Is higher than the appearance frequency of data 0.

Therefore, at the time of data reproduction, the synchronization signal V
If the count value of data 1 is smaller than the count value of data 0 when FO is detected by a predetermined number of bits, it can be determined that the user data at that time is recorded in a non-inverted state, and Is larger than the count value of data 0, it can be determined that the user data at that time is recorded in an inverted state.

FIG. 6 shows a main part of a data recording / reproducing system of the magneto-optical disk drive according to the present embodiment.

In FIG. 1, a control unit 11 controls the operation of each unit of the magneto-optical disk drive and the data recording / writing.
The host interface circuit 12 controls the reproducing operation. The host interface circuit 12 connects the magneto-optical disk drive to a host device used as an external recording device, and performs recording / reproducing data and various data with the host device. It is for exchanging control data.

The error correction coding unit 13 converts the recording data WD output from the control unit 11 at the time of data recording into recording data WDc to which a predetermined error correction code has been added. Is the modulation circuit 14
Has been added to

The modulation circuit 14 converts the recording data WDc into 2-
The modulation is performed by the 7RLL modulation method, and the output signal is applied to one input terminal of the exclusive OR 15 as the modulation record data WDw.

An inverted signal SS output from the control unit 11 is applied to the other input terminal of the exclusive OR circuit 15, and the output signal is applied to the recording circuit 16 as modulated recording data WDw '. ing. Therefore, when the inversion signal SS is set to data “1” (logic H level), the exclusive OR circuit 15 outputs the modulation recording data WDw ′ in a state where the modulation recording data WDw is inverted, and outputs the inverted data. When the signal SS is set to data “0” (logic L level), the exclusive OR circuit 15 outputs the modulation recording data WDw ′ in a state where the modulation recording data WDw ′ is not inverted.

The recording circuit 16 stores the modulated recording data WDw '.
, The recording signal WS output to the optical pickup device 17 is changed. Thereby, the optical pickup device 1
7 records data (marks) on the magneto-optical disk 1 according to the recording signal WS.

The signal SD detected by the optical pickup device 17 from the magneto-optical disk 1 is transmitted to a signal reproducing circuit 18.
Is output to The signal reproducing circuit 18 reproduces a recording signal recorded on the magneto-optical disk 1 based on the signal SD, and its output is applied to the recording data reproducing circuit 19 as a reproduction signal RD.

The recording data reproducing circuit 19 outputs a reproduced signal RD
The reproduction data RDa reproduced from the magneto-optical disk 1 is reproduced based on the reproduction data RDa.
Are output to the demodulation circuit 20. The recording data reproducing circuit 19 determines whether the reproduction signal RD is data recorded in an inverted state or the reproduction signal RD
Is the data recorded in the non-inverted state, and the corresponding reproduced data RDa is formed.

The demodulation circuit 20 converts the reproduced data RDa into 2-
The demodulation process of the 7RLL modulation method is executed to obtain the original data R
This data RDc is output to the error correction decoding unit 21.

The error correction decoding section 21 detects and corrects a data error contained in the data RDc, and the data after the error correction is added to the control section 11 as reproduction data RDd. . In addition, the error correction decoding unit 21 forms error detection data EC indicating the number of detected data errors, and outputs the error detection data EC to the control unit 11.

FIG. 7 shows an example of the recording data reproducing circuit 19.

In the figure, a reproduced signal RD is a PLL
(Phase-locked loop) are applied to the input terminal of the circuit 25, the data input terminal of the D flip-flop circuit 26, and the input terminal of the counter 27. Further, the reproduction signal RD is inverted by the inverter 28, and thereafter, the inverted reproduction signal RD ′
At the input end of the counter 29.

The PLL circuit 25 includes a clock signal CK for sampling data appearing in the reproduction signal RD.
Is generated, and the timing of the clock signal CK is controlled so as to be in phase synchronization with the level change point of the reproduction signal RD.
D flip-flop circuit 26, a counter 27 and a clock input terminal of counter 29,
The reproduced data RDa is output to the next-stage circuit as a sampling clock.

The D flip-flop circuit 26 samples the level of the reproduced signal RD at the rising timing of the clock signal CK. The output of the D flip-flop circuit 26 is applied to one input terminal of the exclusive OR circuit 30 as reproduced data RDe. Have been.

The counter 27 outputs a reset signal RST output from the control unit 11 and applied to a reset input terminal.
Is at the logical L level, and the clock signal CK
The level of the reproduction signal RD applied to the data input terminal at the rising timing of
When the level is at the level, the internal count value is incremented, and the count value is used as the count value CD1 of the data “1” included in the reproduction signal RD at one input terminal of the comparator 31. A has been added.

The counter 28 outputs a reset signal RST output from the control unit 11 and applied to a reset input terminal.
Is at the logical L level, and the clock signal CK
At the rising edge of the signal, the level of the inverted reproduction signal RD 'applied to the data input terminal is detected, and when the level is at the logical H level, the internal count value is incremented. The value of the comparator 31 is the data “1” included in the inverted reproduction signal RD ′, that is, the count value CD0 of the data “0” included in the reproduction signal RD.
Is applied to one input terminal B.

The comparator 31 calculates the count value CD1 applied to the input terminal A by the count value CD1 applied to the input terminal B.
To detect that it is greater than 0,
The detection signal LL is applied to the data input terminal of the D flip-flop circuit 32.

The D flip-flop circuit 32 includes the control unit 1
The detection signal LL is sampled at the rising edge of the detection clock signal CKi output from 1 and applied to the clock input terminal. The output signal of the detection signal LL is used as an inverted signal RV of the other of the exclusive OR circuit 30. It is added to the input end.

When the inverted signal RV is at the logical H level, the exclusive OR circuit 30 outputs the reproduced data RDe.
Is formed, and when the inverted signal RV is at the logical L level, the reproduced data RDe is formed as non-inverted data, and the output data is used as the reproduced data RDa. It is output to the next stage circuit.

With the above configuration, when data is reproduced from the magneto-optical disk 1, the control unit 11 performs the following operation for each sector.

First, when the detection of the header portion HD of the sector is completed, as shown in FIG. 8A, the recording portion DD of the sector is reproduced, the synchronization signal VFO of the head portion is input, and the PLL circuit 25 is inputted. Synchronizes the phase of the clock signal CK with the synchronization signal VFO.

When the timing of completion of the phase synchronization of the PLL circuit 25 is reached after the termination of the header section HD, the control section 11 lowers the reset signal RST to the logic L level and holds this state for a predetermined time Tc. Immediately before the termination of the synchronization signal VFO, the reset signal RST is raised to a logic H level. At the same time, the control unit 11 outputs the detection clock signal CKi immediately before the reset signal VFO rises to the logic H level.

As a result, the counters 27 and 29 are ready to count, and the counter 27 outputs the synchronization signal VF.
The data "1" appearing in O is counted, and a counter 29 is counted.
Counts data “0” appearing in the synchronization signal VFO.

Here, when the sector detected at that time is recorded in a non-inverted state, the synchronization signal V
Data “0” occurs in the FO at a frequency greater than that of data “1”. Therefore, when the counting operation of the counter 27 and the counter 29 has progressed to some extent, the count value CD1 of the counter 29 is larger than the count value CD1 of the counter 27.
0 is larger. As a result, the detection signal LL output from the comparator 31 goes to the logic L level.

For this reason, when the detection clock signal CKi is output, the data input terminal of the D flip-flop circuit 32 is at the logical L level, so that the inverted signal RV output from the D flip-flop circuit 32 is output. Logical L
Become a level.

Therefore, after this, when the signal of the user data DA recorded in the non-inverted state is input, the reproduced data RDe output from the D flip-flop circuit 26 is output by the exclusive OR circuit 30 to the non-inverted state. It is inverted and output as reproduction data RDa.

The sector detected at that time is:
When the data is recorded in the inverted state, the data “1” occurs more frequently in the synchronization signal VFO than the data “0”. Therefore, the counter 27 and the counter 29
In a state where the counting operation has progressed to some extent, the count value CD1 of the counter 27 becomes larger than the count value CD0 of the counter 29. As a result, the detection signal LL output from the comparator 31 goes to the logic H level.

For this reason, when the detection clock signal CKi is output, the data input terminal of the D flip-flop circuit 32 is at the logic H level, so that the inverted signal RV output from the D flip-flop circuit 32 is output. Logical H
Become a level.

Therefore, after that, when the signal of the user data DA recorded in the non-inverted state is input, the reproduced data RDe output from the D flip-flop circuit 26 is inverted by the exclusive OR circuit 30. And output as reproduction data RDa.

Thus, the recording data reproducing circuit 19
Inverts the logical relationship of the data reproduced from the reproduction signal SD in accordance with the recording state of the detected sector so that appropriate reproduction data RDa can be formed.

FIG. 9 shows a processing example of the control unit 11 when recording data for one sector on the magneto-optical disk 1.

First, the control unit 11 executes a data recording operation for one sector with the data "1" set in the inversion signal SS (process 101) (process 102). In this data recording operation, the recording data WD output by the control unit 11 is
Is converted by the error correction encoding unit 13 into recording data WDc to which a predetermined error correction code is added, and the recording data WDc is converted by the modulation circuit 14 into 2-7 RLL.
The data is modulated by the modulation method and output to the exclusive OR 15 as the modulation record data WDw. At this time, since the inverted signal SS applied to the exclusive OR circuit 15 is at the logic H level, the modulated record data WDw is inverted by the exclusive OR circuit 15 and the modulated record data WDw ′.
Is output to the recording circuit 16. In this way,
At this time, the data recording operation in the inverted state is performed.

Next, the control section 11 reproduces data from the sector recorded at that time (step 103). In this data reproduction operation, a reproduction signal RD is output from the signal reproduction circuit 18 in accordance with the detection signal SD output from the optical pickup device 17, and this reproduction signal RD is output from the recording data reproduction circuit 19 as described above. Are converted to corresponding reproduction data RDa and output to the demodulation circuit 20. The demodulation circuit 20 demodulates the reproduction data RDa,
Dc is output to the error correction decoding unit 21. Thereby, the error correction decoding unit 21 performs the error correction decoding process on the reproduction data RDc, and obtains the reproduction data RD obtained as a result.
d to the control unit 11 and the reproduced data RDc
Is output to the control unit 11 as error detection data EC.

The control section 11 inputs the error detection data EC output from the error correction decoding section 21 at this time, and substitutes the value into a variable ECa (step 104). As a result, the number of data errors when data is recorded in the inverted state is set in the variable ECa.

Next, the control unit 11 executes a data recording operation for one sector (process 106) with the data "0" set in the inversion signal SS (process 105). In this data recording operation, the recording data WD output by the control unit 11 is
Is converted by the error correction encoding unit 13 into recording data WDc to which a predetermined error correction code is added, and the recording data WDc is converted by the modulation circuit 14 into 2-7 RLL.
The data is modulated by the modulation method and output to the exclusive OR 15 as the modulation record data WDw. At this time, since the inverted signal SS applied to the exclusive OR circuit 15 is at the logical L level, the modulated recording data WDw is non-inverted by the exclusive OR circuit 15 and the modulated recording data WD
It is output to the recording circuit 16 as w ′. Thus, at this time, the data recording operation in the non-inverted state is performed.

Next, the control section 11 reproduces data from the sector recorded at that time (process 107). In this data reproduction operation, a reproduction signal RD is output from the signal reproduction circuit 18 in accordance with the detection signal SD output from the optical pickup device 17, and this reproduction signal RD is output from the recording data reproduction circuit 19 as described above. Are converted to corresponding reproduction data RDa and output to the demodulation circuit 20. The demodulation circuit 20 demodulates the reproduction data RDa,
Dc is output to the error correction decoding unit 21. Thereby, the error correction decoding unit 21 performs the error correction decoding process on the reproduction data RDc, and obtains the reproduction data RD obtained as a result.
d to the control unit 11 and the reproduced data RDc
Is output to the control unit 11 as error detection data EC.

The control unit 11 inputs the error detection data EC output from the error correction decoding unit 21 at this time, and substitutes the value into a variable ECb (process 108). As a result, the number of data errors when data is recorded in the inverted state is set in the variable ECb.

Next, the control unit 11 determines that the value of the variable ECa is
It is checked whether the value is equal to or more than the value of the variable ECb (decision 109). When the result of the determination 109 is YES, the data error rate in the data recording operation in the non-inverted state executed later is small, and this recording operation is ended as it is.

When the result of the determination 109 is NO, since the data error rate in the data recording operation in the inverted state executed earlier is small, the data recording operation in the inverted state is executed again (steps 110 and 111). ), This recording operation ends.

As described above, in this embodiment, the number of data errors when data is recorded in the inverted state and the number of data errors when data is recorded in the non-inverted state are determined for each sector as a data recording unit. In comparison, since data recording is performed in a data recording operation in which the number of data errors is smaller, the reliability of data recorded on the magneto-optical disk 1 is improved.

FIG. 10 shows another example of the recording data reproducing circuit 19. Note that, in FIG. 7, the same parts as those in FIG. 7 and corresponding parts are denoted by the same reference numerals.

In the figure, a count value CD 1 of a counter 27 for counting data “1” of a reproduced signal RD is applied to an input terminal A of a comparator 31.
Has a constant C corresponding to of the number of bits corresponding to the period Tc during which the counting operation of the counter 27 is performed.
A has been added.

When the count value CD1 applied to the input terminal A is larger than the constant CA applied to the input terminal B, the comparator 31 outputs the output detection signal LL to the logical H level. Get up to level.

Here, when reproducing a sector in which data is recorded in an inverted state, during the period Tc, the synchronization signal V
Since the number of data “1” included in the FO is larger than の of the total number of bits, the detection signal LL output from the comparator 31 becomes a logical H level.

When a sector in which data is recorded in a non-inverted state is reproduced, during the period Tc, the synchronization signal V
Since the number of data “1” included in the FO is smaller than の of the total number of bits, the detection signal LL output from the comparator 31 becomes a logical L level.

Thus, the circuit of FIG. 10 does not require the counter 29 as compared with the circuit of FIG. 7, so that the cost can be reduced.

In the above-described embodiment, a combination of the 2-7 RLL modulation method and the NRZ modulation method is used as a data recording modulation method. Modulation method and NR
A combination of the ZI modulation methods can be used.

In the modulation method combining the 2-7 RLL modulation method and the NRZI modulation method, for example, FIG.
The data “10001101111” shown in (a) is “0100000010” as shown in FIG.
000010001000 ", where each recording signal becomes data" 1 ".
The recording state is reversed as shown in FIG. Therefore, in this case, when the data recording operation is performed in the inverted state, a signal as shown in FIG.

Further, in this modulation method, at the time of data reproduction, reproduced data can be obtained by detecting the position where the polarity of the reproduced signal is inverted and determining that position as the position where data "1" is generated. As in the above-described embodiment, the mechanism for detecting the inversion state of the mark of the reproduction data is:
May be unnecessary.

In the above-described embodiment, it is determined whether data is recorded in the non-inverted state or the inverted state.
Although the determination is performed in sector units, the determination can be performed in larger data units.

The data modulation method is the same as that of the above-described 2-
The present invention can be similarly applied to a case where a method other than the 7RLL modulation method is used.

[0075]

As described above, according to the present invention,
Since data is recorded on the disc by a data recording method with a smaller data error rate, data errors at the time of data reproduction can be reduced, and the reliability of data recording on the disc can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of a magneto-optical disk.

FIG. 2 is a schematic diagram showing an example of a sector format of a magneto-optical disk.

FIG. 3 is a schematic diagram showing a conversion rule from a symbol sequence to a recording data sequence in the 2-7 RLL modulation method.

FIG. 4 is a schematic diagram for explaining a data recording method according to one embodiment of the present invention.

FIG. 5 is a schematic diagram for explaining a principle of determining a data recording state.

FIG. 6 is a block diagram showing a magneto-optical disk drive according to one embodiment of the present invention.

FIG. 7 is a block diagram showing an example of a recording data reproducing circuit.

FIG. 8 is an operation waveform diagram for explaining the operation of the recording data reproduction circuit.

FIG. 9 is a flowchart illustrating a processing example at the time of data recording.

FIG. 10 is a block diagram showing another example of the recording data reproducing circuit.

FIG. 11 is a schematic diagram for explaining a data recording method according to another embodiment of the present invention.

Claims (4)

(57) [Claims] 1. A method of recording data on a disk after recording data is modulated by a predetermined modulation method, wherein the data is recorded in a state where mark bits are not inverted when recording data is recorded on the disk. The data error when the recorded data is reproduced is detected as a non-inverted data error, and the data error when the recorded data is reproduced with the mark bit inverted and the recorded data reproduced is inverted. Detected as a data error, when the non-inverted data error is smaller than the inverted data error, the data is recorded with the mark bit non-inverted, while when the non-inverted data error is larger than the inverted data error, A data recording method for a disk, wherein data is recorded with mark bits inverted. 2. The disk recording method according to claim 1, wherein the predetermined modulation method is a modulation method in which an NRZI modulation method is applied to a 2-7 RLL modulation method. 3. The recording data is modulated by a predetermined modulation method and then recorded on a disk, and the recording data is recorded / reproduced on / from a disk in which a synchronization signal for bit synchronization is arranged at the beginning. In the method, when recording data, when recording data on a disk, the data is recorded with the mark bit non-inverted and the data error when the recorded data is reproduced is detected as a non-inverted data error. When the data is recorded with the mark bit inverted and the data recorded at that time is reproduced, a data error when the recorded data is reproduced is detected as an inverted data error, and when the non-inverted data error is smaller than the inverted data error, While data is recorded with the mark bit non-inverted, the non-inverted data error is larger than the inverted data error. When the data is recorded, the data is recorded with the mark bit inverted, and at the time of data reproduction, the recorded data is non-inverted data or inverted data based on the number of detection marks of the synchronization signal included in the head of the recorded data. Is determined, and when it is detected that the recording data is inverted data,
A data recording / reproducing method for a disk, wherein data is reproduced by inverting a mark bit detection output. 4. The data recording / reproducing method according to claim 3, wherein the predetermined modulation method is a modulation method in which an NRZ modulation method is applied to a 2-7 RLL modulation method.