JP3499940B2 - Encoding and decoding method - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates, about the method of encoding and decoding information bits to high-density recording on the information recording medium.

[0002]

2. Description of the Related Art As a first conventional example, Japanese Patent Publication No. 2-313.
There is an optical memory device disclosed in No. 30. In this example, the so-called RLL code is used to convert the information bits into code bits and record the code bits along the track. 12
Shows a well-known (1,7) RLL code conversion table. For example, as shown in FIG. 13, according to this conversion rule, the code bit converted by so-called NRZ recording is serially recorded along the track 101. Recording was similarly performed on the tracks 102 and 103.

As a second conventional example, Japanese Patent Laid-Open No. 2-24783.
There is a multi-beam recording / reproducing device disclosed in Japanese Patent Laid-Open No. In this example, in order to reduce crosstalk from adjacent tracks, the first light beam reproduces the first read signal from the code bit, and the second light beam reproduces the second read from the code bit of the adjacent track. The signal is reproduced and the second read signal is subtracted from the first read signal to reduce the crosstalk.

As a third conventional example, Japanese Patent Laid-Open No. 4-3419
There was an information signal recording and reproducing apparatus disclosed in Japanese Patent Laid-Open No. 74. In this example, the video format signal is divided into video signals of three channels and recording is performed by three multi-beams.

[0005]

However, when recording is performed according to the code rule of the first conventional example, a reproduction error occurs due to crosstalk from the adjacent tracks 102 and 103 as shown in FIG. For example, light spot A
At the position "1" or "record mark", the adjacent tracks 102 and 103 were "0" or "non-mark", so that the crosstalk was zero. In this example, so-called NRZ recording was performed, and "1" was recorded as a "recording mark" and "0" was recorded as a "non-mark". However, in the light spot B, the adjacent track 10
Since the code of 3 is "1" and the code bit of both adjacent tracks 102 and 103 is "1" in the light spot C, crosstalk occurs and a reproduction error occurs.

In order to solve this problem, the second conventional example reduces the crosstalk by the above method. But,
The second light beam inevitably reads the code bit of the adjacent track. Therefore, since the second read signal also has crosstalk from the adjacent track, there is a problem that the crosstalk cannot be sufficiently reduced even if the second read signal is subtracted from the first read signal.

Further, in recent years, as shown in FIGS. 10 and 11, there has been proposed a multi-beam recording / reproducing apparatus capable of high-speed recording / reproducing by performing recording / reproducing with a plurality of light beams. For example, a single beam recording / reproducing apparatus can record / reproduce only one sector at a time, but a multi-beam recording / reproducing apparatus records / reproduces a plurality of sectors at one time.

However, conventionally, recording is performed by the recording method of the first conventional example, and even in the case of a multi-beam recording / reproducing apparatus, one sector of recording or reproducing is required to record or reproduce one sector of data. Playback time was needed. That is, when recording / reproducing sectors equal to or less than the number of beams, it is impossible to increase the speed.
In addition, as a matter of course, at least one byte of recording or reproducing time is required to record or reproduce 1 byte of data. In other words, the same was true when recording / reproducing bytes equal to or less than the beam number.

In the third conventional example, the video signal is divided into three channels and recorded / reproduced with three light beams. However, the division method is not disclosed, and digital data for computers is not disclosed. Was not disclosed at all. Further, since the identification signals are recorded on different time axes of adjacent tracks, it is difficult to speed up the recording / reproducing time of one piece of video information.

[0010]

The present invention solves the above problems.
The encoding and decoding method according to claim 1, wherein
On the first track,Recorded dataThe first encoded
When the sign bit is "1" or "record mark", the first
The first code bit of the second track adjacent to the track.
Adjacent to the truck in the direction perpendicular to the track,Recorded dataTo
The encoded second code bitBased on the encoding rules
It is characterized by being "0" or "non-mark".

Further, as described in claim 2, a first coding rule for obtaining the first code bit in the odd-numbered track and a first coding rule for obtaining the second code bit in the even-numbered track. When the first code bit according to the first coding rule is "1" or "record mark", the second coding rule positions the bit and the track in a direction perpendicular to the track. Set the second bit to "0"
Alternatively, it is characterized as "non-mark".

Then, as described in claim 3, one-dimensional recording data before encoding is an m × n matrix composed of m bits in the direction along the track and n bits in the direction perpendicular to the track. Two-dimensional code bit matrix {C
i, Rj} (i = 1, ..., M, j = 1, ..., N), and when the matrix element {Ci, Rj} corresponds to “1” or “record mark”, {Ci , Rj-1} or {Ci, Rj + 1} is "0".
Alternatively, it is characterized as "non-mark".

Further, as described in claim 4, at least one "0" or "non-mark" is provided between the converted "1" or "recording mark" and the next "1" or "recording mark".
When the first code bit of the first track is "1" or "record mark", the code words having the are arranged at right angles to the track with respect to the position of the first code bit. The second code bit of the second track adjacent in the right direction is set to "0" or "non-mark".

[0014]

[0015]

[0016]

[0017]

[0018]

[0019]

In the encoding and decoding method of the present invention, when the code bit to be read is "1" or "record mark", the code bit adjacent in the direction perpendicular to the position of this code bit is "0". Or set it to "unmarked". Therefore,
Since the sign bit of the adjacent track can be only “non-mark”, even if the light beam reads it, chromatogram of the read signal does not occur.

[0020]

[0021]

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An information recording / reproducing apparatus according to the present invention will be described below by taking an optical recording / reproducing apparatus as an example.

FIG. 22A is a diagram showing an optical recording / reproducing apparatus of the present invention. When information is recorded, information bits (recording data) are input to the encoder 151, encoding is performed over, for example, three tracks, and modulation bits (code words) are temporarily stored in the buffer memory 152. When the light beam is tracked to the first track, the modulation bit to be recorded on the first track is first output from the buffer memory, and when the light beam is tracked to the second track, the modulation bit to be recorded on the second track is recorded on the third track. When tracked, the modulation bits to be recorded on the third track are sequentially output. These modulation bits are sent to the laser driving circuit 153. A drive current is sent from the laser drive circuit 153 to the semiconductor laser 154, a light beam is applied to the optical disc 157 through the beam splitter 155 and the objective lens 156, and modulation bits are sequentially applied to the first track, the second track, and the third track. Will be recorded.

At the time of reproducing information, the reflected light from the recording bit recorded on the optical disk 157 bends the optical path by the beam splitter 155 through the objective lens 156 and guides it to the photodetector 158. The reproduction signal converted into the electric signal is amplified by the amplifier 159 and converted into a digital signal of "1" or "0" by the waveform shaper. In the first track, the reproduction bits from the first track are first stored in the buffer memory 161, then in the second track, the reproduction bits from the second track and in the third track are stored in the order of the reproduction bits from the third track. It The accumulated reproduced bits of the three tracks are demodulated by the decoder 162 into one information bit. In the above description, the case where the number of light beams is one is shown. However, when the number of light beams is three, the first track, the second track and the third track can be recorded / reproduced at a time, so two buffer memories in the figure are used. 152 and 161 are unnecessary.

FIG. 23 is a diagram showing a flow chart at the time of recording information in FIG. 22A. The information bit (recording data) is input to the encoder, is encoded, for example, over the third track, and the modulation bit (code word) is temporarily stored in the buffer memory (step s1). Next, the light beam is moved to the first track (step s2). The modulation bit to be recorded on the first track is output from the buffer memory and is recorded on the optical disc (step s
3). Next, the light beam is moved to the second track (step s4). The modulation bit to be recorded on the second track is output from the buffer memory and recorded on the optical disc (step s5). Next, the light beam is moved to the third track (step s6). From the buffer memory,
The modulation bit to be recorded on the third track is output and recorded on the optical disc (step s7).

FIG. 24 is a diagram showing a flowchart at the time of reproducing information in FIG. 22A. First, the light beam is moved to the first track (step s11). The recording bit recorded on the first track is reproduced and stored in the buffer memory (step s12). The light beam is moved to the second track (step s13). The recording bit recorded on the second track is reproduced and stored in the buffer memory (step s14). The light beam is moved to the third track (step s15). The recording bit recorded on the third track is reproduced and stored in the buffer memory (step s16). The accumulated reproduction bits of the first track, reproduction bits of the second track, and reproduction bits of the third track are input to the decoder to decode the information bits (step s17). In the above flow chart, the case where there is one light beam is shown, but when there are three light beams, the first track, the second track, and the third track can be recorded / reproduced at once, so that each of the light beams can be reproduced. There is no need to move to the track and store in the buffer memory.

The first to fifth embodiments described below are the encoding method of the encoder 151 in FIG. 22A, that is,
This relates to step s1 of the flowchart of FIG. The configuration of the encoder 151 will be described based on FIG. 22B. The encoder 151 includes a code bit converter 171 and an encoding table 172. Sign bit converter 1
Reference numeral 71 converts the information bits into code bits according to the contents of the coding table.

In addition to the configuration of the encoder using the encoding table as described above, the encoder is configured so that the input information bits are directly converted into encoded bits by the logical operation circuit. You can also

The first embodiment will be described below.

FIG. 1 is a code conversion table in the first embodiment of the present invention. This is divided into coding rules for even-numbered tracks and odd-numbered tracks.
This is an example of converting bits into 3 bits of sign bits. That is, on the other hand, the information bit "0" of the even-numbered track is converted into "000", and "1" is converted into "010". On the other hand,
Information bit “0” of odd-numbered track is set to “001”
Then, "1" is converted to "100".

FIG. 2 shows an example in which a code bit is recorded on a track based on this code conversion table. For simplicity of description, the description will be limited to so-called NRZ recording, and “1” and “0” will be used instead of “recording mark” and “non-mark”.

Information bit "0" is added to the even-numbered track 10.
1 "is converted and recorded. Odd numbered tracks 11 and 1
In “2”, “01” and “10” are converted and recorded. Then, as shown in the figure, when the read code bit of the even-numbered track 10 is "1", the code bit of the odd-numbered tracks 11 and 12 adjacent in the direction perpendicular to the position of this code bit is "0". You can Conversely, the same applies to the case of the code bits of the odd-numbered tracks 11 and 12.
Therefore, it is possible to provide a coding method in which crosstalk of read signals does not occur.

The second embodiment will be described below.

FIG. 3 is a code conversion table in the second embodiment of the present invention. Similarly, this is divided into the coding rules for the even-numbered tracks and the odd-numbered tracks, but this time is an example of converting 2 bits of information bits into 4 bits of code bits. Others are the same as those in the first embodiment,
Although detailed description is omitted, when the code bit to be read from the even-numbered track 10 is "1", the even-numbered track 11 adjacent in the direction perpendicular to the position of this code bit is adjacent.
And the 12 sign bits can be "0". In the first and second embodiments, the sign bit “0” may be continuous, so that it is difficult to achieve bit synchronization by the PLL. In this case, if the additional bits shown in FIG. 4 are added, for example, every 1 byte, it is possible to avoid the continuation of "0".

The third embodiment will be described below.

FIG. 5 is a code conversion table in the third embodiment of the present invention. Similarly, this is also divided into coding rules for even-numbered tracks and odd-numbered tracks, and is an example of converting 3 bits of information bits into 8 bits of code bits. Of the 8 sign bits, the last 2 bits are "0"
Is an additional bit for avoiding the continuation of. It should be noted that the conversion of 4 or more information bits other than those in the first to third embodiments can be performed in the same manner as in the first, second, and third embodiments, and thus detailed description will be made. Is omitted.

The fourth embodiment will be described below.

FIG. 6 shows an example of an encoding method according to the fourth embodiment of the present invention. This is a two-dimensional code bit matrix {Ci, Rj, which represents a one-dimensional information bit before encoding by a 3 × 3 matrix configured by three bits in the direction along the trunk and three bits in the direction perpendicular to the track. } (I = 1,
2, 3, j = 1, 2, 3). Further, when the matrix element {Ci, Rj} is "1", {Ci, Rj
At least one of j−1} and {Ci, Rj + 1} is set to “0”. For example, the sign bit matrix 20
"21" on track 21 and "01" on track 22
0 ”, and the track 23 becomes“ 100 ”. Then, as shown in FIG. 7, when the read code bit of the track 22 is "1", the code bits of the tracks 21 and 23 adjacent in the direction perpendicular to the position of the code bit can be set to "0". Conversely, the same applies to the code bits of the tracks 21 and 23. Therefore, it is possible to provide a coding method in which crosstalk of read signals does not occur.

Although FIG. 6 shows one two-dimensional code bit matrix, in order to explain the other matrix in an easy-to-understand manner, "1" and "1" are connected by straight lines 24 and 25, respectively. Considering that a two-dimensional sign bit matrix is represented by a straight line geometric pattern, this is shown in FIG. Note that FIG.
The two-dimensional code bit matrix of is shown at 26 in FIG. It is easy to understand that the patterns of these 30 kinds of two-dimensional code bit matrices are classified as follows by point symmetry or line symmetry.

[0040]

[Table 1]

Due to these geometrical patterns, when the code bit to be read from the track 22 is "1", the track 21 adjacent in the direction perpendicular to the position of this code bit is adjacent.
It can be visually seen that the sign bits of 23 and 23 can be "0".

Now, for example, 16 kinds are selected from these 30 kinds of two-dimensional code bit matrices. Then, it becomes possible to convert one-dimensional information bit of 4 bits into these 16 types of two-dimensional code bit matrix. The remaining two-dimensional code bit matrix can also be used as a bit resynchronization pattern.

In this example, at least one "1" and "0" is included in every track, which is a so-called RLL code. That is, it is possible to realize an encoding method that facilitates bit synchronization in the PLL circuit.

For a two-dimensional code bit matrix of 3 × 3 matrix or more, since the number of code bit matrices is large,
The description is omitted due to space limitations.

The fifth embodiment will be described below.

FIG. 9 is a diagram showing an encoding method in the fifth embodiment of the present invention. This is a method in which after encoding based on the conventional RLL code conversion table shown in FIG. 12, the code bits are arranged in the direction perpendicular to the track, not in the direction along the track. For example, by arranging the information bits in order from the top of the code conversion table, "01101100001"
... ", the sign bit is" 100010101.
000001 ... ". That is, (1,
7) In the RLL code, the code bit is "1" and the next "1".
Since at least one "0" is inserted between the two, the sign bit of the adjacent track must be "0" for the sign bit "1".
It becomes possible to Therefore, it is possible to provide a coding method in which crosstalk of read signals does not occur. The number of tracks in FIG. 9 is 6, which is an integer multiple (1 bit) of the conversion unit (3 bits or 6 bits) of the code bit.
Or 2). In other words, the number of tracks is RLL
If it is determined to be an integer multiple depending on the type of code, it is possible to perform coding with good delimitation.

In the above description, the (1,7) RLL code is taken as an example, but the same applies to other RLL codes.

In the optical recording / reproducing apparatus and the optical recording medium, the code bit interval between adjacent tracks is extremely short (about 1 to 2 μm), which easily causes crosstalk. It is easy to synchronize and arrange next to each other. In other words, the present invention is an encoding method that is particularly effective for optical recording / reproducing devices and optical recording media.

In the first to fifth embodiments, the code bits of adjacent tracks are all synchronized with each other in the direction along the tracks. This enables recording and reproduction particularly easily in a multi-beam recording / reproducing device having a plurality of light beams. That is, since the irradiation positions of a plurality of light beams can be fixed in the multi-beam recording / reproducing apparatus, it is possible to record / reproduce the code bits that are always synchronized.

Further, for simplification of the description, the description has been limited to the NRZ recording, but it is not necessary to limit to this, and in so-called NRZI recording or the like, the code bits to be recorded on the track are "record marks" and "record marks". If it is expressed by "non-mark", it is possible to perform the same encoding.

A multi-beam recording / reproducing apparatus according to the present invention will be described below by taking an optical recording / reproducing apparatus as an example.

FIG. 25 is a diagram showing an optical recording / reproducing apparatus of the present invention. When information is recorded, information bits (recording data) are input to the encoder 213, encoding is performed over, for example, three tracks, and modulation bits (code words) are sent to the distributor 214. The distributor 214 outputs a modulation bit to be recorded on the first track, a modulation bit to be recorded on the second track, and a modulation bit to be recorded on the third track. These modulation bits are sent to three laser drive circuits 2150, 2160, 2170, respectively. Driving currents are sent from the laser driving circuits 2150, 2160, 2170 to the semiconductor lasers 215, 216, 217, and three optical beams are irradiated onto the optical disc 252 via the beam splitter 250 and the objective lens 251, and three distributed modulations are performed. Bits are recorded at the same time.

At the time of reproducing information, the three reflected lights from the recording bits recorded on the optical disc 252 are guided to the three photodetectors 218, 219 and 220 by bending the optical path by the beam splitter 250 through the objective lens 251. The reproduced signals converted into electric signals are respectively amplified by the amplifier 253,
Amplified by 254 and 255, waveform shapers 256 and 25
At 7, 258, it is converted into a digital signal of "1" or "0". The reproduced bits from the first track, the reproduced bits from the second track, and the reproduced bits from the third track are input to the collector 221, and the combined reproduced bits are demodulated into information bits by the decoder 222. . In the above description, the case where the number of light beams is three is shown,
When the number of light beams is one, the first track, the second track, and the third track cannot be recorded / reproduced at one time, and therefore the two buffer memories shown in FIG. 22A are required instead of the distributor 214.

FIG. 26 is a diagram showing a flow chart at the time of recording information in FIG. Information bit (recorded data)
Is input to the encoder and is encoded, for example, over the third track (step s21). Modulation bits are distributed to each track (step s22). Next is the first
The modulation bits to be recorded on the track, the modulation bits to be recorded on the second track, and the modulation bits to be recorded on the third track are respectively recorded on the optical disc by the three light beams (step s23).

FIG. 27 is a diagram showing a flow chart at the time of reproducing information in FIG. The recording bits recorded on the first track, the recording bits recorded on the second track, and the recording bits recorded on the third track are reproduced by the three light beams (step s31). The reproduced bit of the reproduced first track, the reproduced bit of the second track, and the reproduced bit of the third track are collected by the collector (step s32). Next, the reproduced bits collected are decoded into information bits by the decoder (step s3).
3). Although the above flow chart shows the case where the number of the light beams is three, when the number of the light beams is one, the first track, the second track and the third track cannot be recorded / reproduced at a time, and therefore each track of the light beams is It is necessary to move to and to store in the buffer memory.

In the above, by the multi-beam recording device,
Although an example has been shown in which the code bits of adjacent tracks are all synchronized with each other in the direction along the track, the present invention is not limited to this.
It is also possible to synchronize with a single beam, for example, with a well-known sample servo device. This device is a device that reproduces clock pits recorded in advance in a hole shape on a disc, generates a recording clock in synchronization with the clock pits, and records a recording mark based on the recording clock. In this device, since the clock pits of the adjacent tracks of the disc are also recorded in advance, it is possible to synchronize the recording clocks of the adjacent tracks in the direction along the tracks, so that the code bits can be synchronized. .

In the sixth and seventh embodiments below, the encoder 213, the distributor 214 and the collector 221 in FIG.
Mainly related to the decoder 222.

The sixth embodiment will be described below.

FIG. 14 shows an information recording method in the sixth embodiment of the present invention. In this example, three light beam examples are shown. The light beams 201, 202 and 203 move the tracks 207, 208 and 209 in the direction of arrow A, respectively, to record / reproduce the code bit.

FIG. 16 shows a well-known (1,7) RLL code conversion table as an example of the encoding method.
This code bit is recorded in the track shown in FIG. That is, first, the code bit “100” is recorded on the tracks 207, 208, and 209 one bit at a time.

Then, two information bits "01" can be recorded in the time corresponding to one code bit. In other words, recording can be performed with a recording length of 1 bit in the direction along the track. Next, when the code bit "010" is recorded in the tracks 7, 8 and 9 one bit each, the information bit 2 bit "10" can be recorded in the time corresponding to one code bit. Similarly, the sign bit "10
"1" and "000001" can be recorded.
Regeneration can likewise take place in a short time.

Therefore, by dividing one word or one byte into a plurality of recording tracks for recording, high-speed recording / reproducing becomes possible. In this case, the speed can be tripled compared with the conventional one.

In this way, if recording is continued, similarly, the recording time of information for one sector can be shortened in inverse proportion to the number of light beams. In other words, the recording length of one sector along the track can be shortened.

In the above embodiment, the (1, 7) RLL code which is a variable length code is taken as an example. However, the present invention is not limited to this, and in the case of an 8/10 modulation code which is a fixed length code, the number of code bits is 10. Since the number of light beams is 3, if the number of light beams is 3, 30 bits, which is the least common multiple, is recorded as one block, it is possible to perform recording / reproduction with good breaks.

Alternatively, the number of bits that is an integral multiple of 30 bits may be blocked.

FIG. 17 is a diagram showing a part of the optical recording / reproducing apparatus of FIG.

In FIG. 17, at the time of information recording, the recording data is encoded by the encoder 213, the code bit signal b is sent to the distributor 214, and the code bit b is distributed bit by bit to the recording bit signals c1, c2, c3. Information can be recorded on the recording medium by the three light beams d1, d2 and d3 which are respectively sent to the semiconductor lasers 215, 216 and 217. During information reproduction, the transmitted light or reflected light e1, e2, e3 from the recording medium is guided to the photodiodes 218, 219, 220, respectively, and reproduced signals f1, f2,
The f3 is guided to the collector 221, the reproduction bits are collected by a method reverse to that at the time of recording, and the reproduction bit signal g is sent to the decoder to be decoded into reproduction data.

The distributor 21 in FIG. 17 will be described with reference to FIG.
4 will be described in more detail. The shift register 22 in the distributor 214 receives the code bit signal b from the encoder 213.
Enter in 3. The clock ck1 is set to the shift register 223
To the frequency divider 224. The shift register 223 shifts the sign bit signal b at each rising edge of the clock ck1.

The bit signals h1, h2, and h3 are output from the three output terminals of the shift register 223 to the D-FFs 225 and 22.
6, input to the data input terminal D of 227,
The output ck2 of 4 is input to the clock input terminal ck.

The recording bit signals c1, c2, c3 are output from the output terminals out of the D-FFs 225, 226, 227, respectively.

FIG. 19 is a diagram showing the waveform of FIG. The bit signals h1, h2, and h3 shifted by the clock ck1 in the shift register 223 are clocked by the clock ck.
When it is captured at the rising edge of 2, the recording bit signals c1, c2, c3 can be obtained. The recording bit signals c1, c2, and c3 are obtained by converting the serially arranged code bit signals b into parallel bits every 3 bits.

The collector 22 shown in FIG. 17 will be described with reference to FIG.
1 will be described in detail. The reproduction signals f1, f2, f3 are input to the shift registers 228, 229, 230. The clock ck3 is input to the shift register 231 and the frequency divider 232. The output signal ck4 of the frequency divider 232 is input to the shift registers 228, 229, 230 and 231. In the shift registers 228, 229, 230, the clock ck4
Of the reproduced bit signals i1, i2, i for each rising edge of
Shift 3 respectively. The shift register 231 fetches three reproduction bit signals i1, i2, and i3 at one time for each rising edge of the clock ck4, and outputs the clock c
Shift by 1 bit for each rising edge of k3. The reproduced bit signal g is output from the output of the shift register 31.
Is sent to the combiner 222.

FIG. 21 is a diagram showing the waveform of FIG. The shift register 231 fetches three reproduction bit signals i1, i2, and i3 at one time for each rising edge of the clock ck4, and outputs 1 for each rising edge of the clock ck3.
Shift bit by bit. The reproduction bit signal g is a signal in which the reproduction bit signals i1, i2, and i3 arranged in parallel are serially arranged in units of 3 bits.

The seventh embodiment will be described below.

FIG. 15 shows an information recording method in the seventh embodiment of the present invention. Compared to FIG. 14, the light beam 204,
The arrangement directions of 205 and 206 are tracks 210 and 211.
Although not orthogonal to 212 and 212, the other parts are the same and detailed description thereof will be omitted. If a time shift occurs due to the position shift of the light beam, each recording / reproducing time may be adjusted by a delay element or the like by the time shift. Others are the same.

[0076]

According to the present invention, when the code bit to be read is "1" or "record mark", the code bit adjacent in the direction perpendicular to the position of this code bit is "0" or "non-mark". Can be Therefore, since the code bit of the adjacent track can be only “non-mark”, crosstalk of the read signal does not occur even if the light beam reads it, and a coding and decoding method without reproduction error is provided. It becomes possible. Particularly in a multi-beam recording / reproducing apparatus, synchronized code bit recording / reproduction is easy, and excellent effects can be obtained. In addition, similar effects can be obtained by replacing all "1" or "record mark" with "0" or "non-mark" in the above embodiment. Further, the coding method in which crosstalk from both adjacent tracks does not occur is the most effective, but the coding method in which only the crosstalk from one adjacent track is removed can also obtain a great effect.

The present invention is also applicable to an optical recording / reproducing apparatus such as a magneto-optical disk recording / reproducing apparatus, a recording / reproducing apparatus such as a card, a tape or the like, a write-once type or a phase change type optical recording / reproducing apparatus. , The same effect can be obtained.

[0078]

[0079]

[0080]

[0081]

[0082]

[Brief description of drawings]

FIG. 1 is a diagram showing a code conversion table according to a first embodiment of the present invention.

FIG. 2 is a diagram showing code bits recorded by the code conversion table of FIG.

FIG. 3 is a diagram showing a code conversion table according to a second embodiment of the present invention.

FIG. 4 is a diagram showing additional bits of the code conversion tables of FIGS. 1 and 2;

FIG. 5 is a diagram showing a code conversion table according to a third embodiment of the present invention.

FIG. 6 is a diagram showing a two-dimensional code bit matrix according to a fourth embodiment of the present invention.

7 is a diagram showing code bits recorded by the code conversion table of FIG. 6;

FIG. 8 is a diagram showing a geometric pattern of a two-dimensional code bit matrix according to a fourth embodiment of the present invention.

FIG. 9 is a diagram showing a code bit arrangement according to a fifth embodiment of the present invention.

FIG. 10 is an explanatory diagram of reading of a conventional multi-beam recording / reproducing device.

FIG. 11 is an explanatory diagram of reading of a conventional multi-beam recording / reproducing device.

FIG. 12 is a diagram showing a conventional code conversion table.

13 is a diagram showing code bits recorded by the code conversion table of FIG.

FIG. 14 is an explanatory diagram of an information recording method according to a sixth embodiment of the present invention.

FIG. 15 is an explanatory diagram of an information recording method according to a seventh embodiment of the present invention.

FIG. 16 is a diagram showing a conversion table of a (1,7) RLL code which is an example of a code code.

FIG. 17 is a configuration diagram for realizing an information recording method according to a sixth embodiment of the present invention.

FIG. 18 is a detailed explanatory diagram of a distributor in FIG.

19 is a diagram showing a waveform of each part of the distributor in FIG.

20 is a detailed explanatory view of the collector in FIG. 4. FIG.

21 is a diagram showing a waveform of each part of the collector in FIG. 7. FIG.

FIG. 22A is a block diagram of an information recording / reproducing apparatus in a first example of the present invention.

FIG. 22B is a diagram showing the structure of the encoder of the information recording / reproducing apparatus.

FIG. 23 is a flowchart showing an information recording method according to the first embodiment of the present invention.

FIG. 24 is a flowchart showing an information reproducing method according to the first embodiment of the present invention.

FIG. 25 is a block diagram of a multi-beam recording / reproducing apparatus according to a sixth embodiment of the present invention.

FIG. 26 is a flowchart showing an information recording method according to the sixth embodiment of the present invention.

FIG. 27 is a flowchart showing an information reproducing method according to the first embodiment of the present invention.

[Explanation of symbols]

10 even numbered tracks 11, 12 odd numbered tracks 13 additional bits

Claims (4)

(57) [Claims] 1. A recording medium is recorded by an information recording / reproducing apparatus .
When recording, encode the recorded data according to the prescribed rules.
A method of finely decrypt, the first track, the first code bit obtained by encoding recording data is "1" or when the "recording marks", second adjacent tracks of the first A second code bit, which is adjacent to the first code bit of the track in a direction perpendicular to the track and which encodes the recording data, is set to "0" or "non-mark" based on an encoding rule. Encoding and decoding method. 2. The encoding and decoding method according to claim 1, wherein a first encoding rule for obtaining a first code bit in an odd-numbered track and a second encoding rule in an even-numbered track are used. A second coding rule for obtaining a code bit, and when the first code bit according to the first coding rule is "1" or "record mark", the bit according to the second coding rule And a second code bit located in a direction perpendicular to the track is set to "0" or "non-mark". 3. The encoding and decoding method according to claim 1, wherein the one-dimensional recording data before encoding is composed of m bits in a direction along the track and n bits in a direction perpendicular to the track. A two-dimensional code bit matrix {Ci, Rj} (i = 1, ..., M, j = 1, ...,
n), and when the matrix element {Ci, Rj} is "1" or "record mark", {Ci, Rj-1} or {Ci, Rj +
An encoding and decoding method characterized in that at least one of 1} is set to "0" or "non-mark". 4. The encoding and decoding method according to claim 1, wherein at least one "1" or "recording mark" after encoding and at least one "1" or "recording mark" When code words having "0" or "non-mark" are arranged in a direction perpendicular to the track, and the code bit of the first track is "1" or "record mark", the position of the first code bit is relative to the position of the first code bit. And a second code bit of a second track adjacent in a direction perpendicular to the track is set to "0" or "non-mark".