JPS60201727A - Binary data encoding method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an electronic device such as a magnetic disk, an optical disk, etc., when recording binary data on a recording medium or reproducing it from a recording medium. Encoding method of binary data to be converted into code sequence and/or
Or it relates to an electronic device having the encoding method.

BACKGROUND ART Conventionally, in electronic devices such as magnetic disks and optical disks, it has been necessary to record large amounts of information, and when recording binary data on a recording medium, it has been essential to improve the recording density.

In general, the encoding method converts m-bit original data into an n-bit code, and performs NRZ conversion on this code to obtain a recording waveform pattern. The recording waveform no turn corresponds to the inversion of the tb sign bit "" and the correspondence of the sign bit ""0" to no inversion. The encoding method is generally (m, n, l
, IC).

Next, terms using the above parameters will be explained.

T: Data bit interval T'min == -(d+1) T: Minimum inversion interval Tmax = -(k+1) T: Maximum inversion interval Tw=-T: Detection window width (demodulation phase margin) DBV (Digital
ital 8nm Variation, cumulative charge variation): Hlg of the recording waveform pattern whose sign has been converted to NRZI
When hlevel is +I Low 1eve1 is -1, it is 9 (F) Integral value based on the recorded waveform pattern.

When DBV can increase without limit, its sign has a DC component. When the variation range of DBV is finite, DO7 Lee is established.

OD8 (Oodeword Digital Rum)
+ 1 DBV0 from the beginning to the end of the symbol Note that the above symbols will be used in the following explanation.

Also, it has traditionally been a typical encoding method.

(1) A, M, Patθ11'''jcnaoaer
and I) Ecoaer for! L Byte-
Or 1entea (0+5)e/900dJ
”+M Technical J) isalogu
rjs Bulletin, Vol, 18. No, I
June 1975 (p248) (2) A. M. Patel, “Oharge-Oon
strained Byte -0rientea (
0,3) Code”, more M Technical Di
Closure Bulletin, Vol. 19.
No, 7. December 19716 (p2715) is mentioned. (1) is an (a, p, o, 3) encoding method = (2) #1 After concatenating two (8,?, 0.3) codes of (1), the connected bits are 2 bits. It is a DC-free code by adding the characters, and as a result, DC
It becomes a free (a, 1o, o, g) code and becomes h.

In method (1), Tm1n W −T = 0.139
TTmax = -X4 T = 5.56 T(2
), Tm1n == -T = 0.8 T0 Tmaz = -X 4 T = 5.2 TD and DO7 Lee. However, this method concatenates two codes, and after 9, t] 18 bits, and DO
DE because the connection bit for freeing cannot be added.
Although the variation range of IV is limited, it becomes large.

Regarding the encoding method, the important thing to mention is that T
Regarding m1n 4C, it is better for Tm1n to be thicker i so that it does not include high frequency components and is less susceptible to band limitation. Also, the larger Tw is, the better the fish will be so as not to make it difficult to distinguish between pulses.

Also, Tmax should be as small as possible, and Tm1n and rma
In order to reduce the difference in x to facilitate synchronization and to reduce low frequency components, it is better to have a smaller Tmax.

From the above explanation, the present invention has k=12, which is smaller than the conventional technology, is extremely easy to synchronize, and has few low frequency components (both Twin and Tw have large values of 0.8T).
Provides an encoding method and a DO7RI encoding method using the same, and further provides a magnetic disk having the above encoding method,
Its purpose is to provide electronic devices such as optical discs.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a block diagram illustrating the configuration of an electronic device that performs a gauge/tal modulation method for magnetic disks, optical disks, etc. ,1
is an information source or its input unit, and 2 is an information source encoder for suppressing redundancy of information in the information source 1. In addition,
Bandwidth compression #'i compresses the transmission frequency band in an analog manner, and high-efficiency encoding digitally attempts to reduce the average number of bits per pixel (sample value).
In that sense, it is similar to amplitude compression. The s#i communication path and transmission path channel encoding section include error correction, digital modulation, etc. Reference numeral 4 denotes a recording/reproducing system for the magnetic disk, optical disk, etc. described above. Further, 5 and 6 are decoding units for decoding the encoded data in the encoding units 2 and 5. 7#: is an output unit that outputs the information obtained through the above processing.

Figure jI2 is a block diagram showing an example of the recording/reproducing system 4, and is an example applied to a video disc.

First, let's talk about the signal recording system. Based on input data, a drive signal is sent from a signal source 8, and a light source 9, such as a semiconductor laser, emits blinking light. Note that the signal source aVi includes the encoding units 2 and 3 in FIG. The light beam emitted by the light source 9 is converted into a parallel light beam by the collimator lens 10,
The light passes through a grating 11, a polarizing plate 12, and an optical probe 13 whose transmission reflectance is polarization dependent. A point image is formed on the perpendicular magnetic recording medium 15 by the objective lens 14 . Although the semiconductor laser light is approximately P-polarized with respect to the optical element 13, the polarizing plate 12 is also installed with the polarization direction in the P direction.

An objective lens 14 performs angular separation of a beam of light so that sub-spots for tracking detection of 11 gratings are focused on a perpendicular magnetic recording medium 15.

At this time, five point images are formed on the recording medium 15 due to the action of the grating 110. Of these three point images, two point images used for tracking signal detection during reproduction are the ±1st-order diffracted light of the grating 11, and the remaining one is the undiffracted light (zero-order light). Depending on the setting of the diffraction efficiency of the grating 11, it is easy to record signals using only the point images of undiffracted light without recording signals using these two point images.

The combination of the cylindrical lens 16 and the 4-split detector 17 is
This is to obtain an autofocus signal for adjusting the position of the objective lens 14 in order to focus the point image correctly.

The signal from the 4-split detector 17 is divided into two systems by the signal splitter 18, one for the autofocus signal and one for the #
– is used for recording signal output and monitoring. Note that this output if m is the decoding unit 5, 6 . It includes an information output section 7.

Also, during recording, a tracking signal detection detector 19.
The differential signal from 20 is in the OFF state.

Next, the signal reproduction system will be described.

A signal of a constant level is applied from the signal source 8 to bring the light source 9 into a state of emitting a constant amount of light. Further, the amount of light at this time is adjusted to such an amount that the recorded magnetic domain pattern is not reversed, as described above. The light beam transmitted through the collimator 10, grating 11, polarizing plate 12, and optical element 13 is sent to the objective lens 1.
4. Focus three point images on the recording medium. The light flux from the recording medium 15 undergoes modulation of the plane of polarization due to the Kerr effect, and is then transmitted to a detector 17 by a system of a light splitting optical element 13 and an analyzer 21.
．． At 19.20, the light enters a modulated state of brightness and darkness. The signal from the detector 17 is divided into two systems: one system is used as an autofocus signal, and the other system is used as a reproduction signal.

Further, the signals from the detectors 19 and 20 are differentiated by the differential AMP 22, and the objective lens is swung left and right using the signal to perform tracking.

Note that due to the action of the optical element 15, a bright and dark pattern with high contrast can be detected in the reproduction system.

Note that a 772-day one-rotation element can be inserted between the optical element 13 and the recording medium 15 as a light amount adjustment means between recording and reproduction.

7 Alladay one-turn zero is made of, for example, Y-G (yttrium, iron, garnet) crystal or glass doped with rare elements, and when a magnetic field is applied, the plane of polarization of the light beam changes. can be rotated. The reason for using this 7 Alladay single rotation element is as follows.

The polarization direction of the reflected light from the recording medium 15 during recording is different from the polarization direction of the reflected light subjected to Kerr rotation during reproduction. Therefore, the reflected light beam is separated from the incident light beam by the light splitting optical element 151C, and the amount of light transmitted through the analyzer 21 is different.

First, during reproduction, the amount of light emitted by the light source must be lower than during recording to prevent the recorded magnetic domain pattern from reversing, so this factor also causes the amount of light that passes through the analyzer 21 to differ between recording and reproduction. different.

If the amount of light guided through the cylindrical lens 16 to the four-split detector 17 for detecting the alignment signal and the autofocus signal is significantly different, it is necessary to switch the sensitivity of the detector 17 between recording and playback. Gender arises.

7. The Alladay one-rotation element rotates the polarization plane of the recording beam by applying an appropriate magnetic field during recording), optical element 13
The amount of light entering the detector 17 is adjusted by the combination of the detector 17 and the analyzer 21, thereby solving the above problem.

In addition, in this example, we will talk about video discs.
There is no need to limit it to this at all, and workstations 7 wn,
The printer, the host computer, and the encoding system of the present invention (corresponding to 1 and 2.3 in FIG. 1) will be explained next.

D, T, Tang and L, R, Bahl, @Bl
ock 0otlea for aolass of
0onstrainecl No1seless Ch
annelg”.

Engineering format aM 0ontro1. Vo
l, 17, 1970. According to p456, it is proven that the number of limited codes of length n bits, that is, codes where Ja=0 and k is a finite value, is the following Nk (n).

Nk (n) = 2” (0<n≦k) Table 1 shows the results calculated using this formula.

Table 1 From Table 1, it can be seen that there are 504 codes where n=10 and =2 (n=o). However, when these codes are concatenated, the restriction of =2 may be violated at the junction between the codes, as shown in FIG. However, if a 10-bit code can be constructed as shown in FIG. 4, the Mi2 restriction will not be violated even if the codes are concatenated.

Figure 4 (,) is a code in which the first bit is always 1, the last bit is 1, and the middle 8 bits are limited to 20. There are 149 of these in Table 1. Figure 4 (
b) is a code whose first bit is always 1, and the last 2
If the number of bits is 10, the middle 7 bits = 20, which is the limit code. There are 981 of these in Table 1. Figure 4(c)
is a code in which the last bit is always 1, the last 3 bits are 100, and the middle 6 bits are limited to 20. There are 44 of these in Table 1.

As described above, there are 274 restriction codes that do not violate the restriction of 1 (= 2) even if the connection is configured as shown in FIG.

Consider separating data into 8-bit units and converting this into a 10-bit code. Then, the 8-bit data becomes 2
There are 256 codes, which is smaller than the 274 10-bit codes in FIG. Therefore, by appropriately selecting 256 codes from the 27411m codes and making them correspond one-to-one with the 256 8-bit data, (
It can be seen that the code m+”+dyk) = (8, 1o, o, z) can be realized. Next, in Fig. 4 (a) + (1)), (
An example of specific creation of each code of 0) will be described. This may be done according to the state transition diagram shown in FIG. Here 81, 82.8
5 is the three states and 81 is the initial state. ≠ indicates the DFi data bit, and O indicates the sign bit. Figure 6 shows how to create a restriction code for 6 bits 1 (=20) in Figure 4 (Q). The same applies to Figure i4 (!L) (b). Figure 6 will be explained in detail. First, 6-bit data (
D,...n6) are prepared. (D,...D,)Fi
(0...O), (o...1)t(0...10)・
... and arrange them in increasing order by 1. 6-bit code (
Represented by a,...a, ). First (D,...D, )
The case when =(0...0) will be described. According to the state transition diagram of FIG. 5, JD=Q generates C3=1. Next, C at D2;0
7=1 is generated, and in the same manner, D6=0 and 06=1 are generated, thereby completing the creation of the first code. The same goes for the following, but when (D, . . . D, ) = (oooll), the last bit is 1 and goes to 8top. This is (000111
) means that a code cannot be created.

The codes are created in the same way, and this operation is repeated 9 times until 44 codes are created. and (D, ~D6)=(
110110) and (a,...a, )==(0010
01) and all 44 items are extracted. Figure 4 (
a) In the case of (b), the data are (D, ・
・・D, ) (D, ・・D8) and sign (a, ・
. .C,) (O, . . a, ) can be created.

Of the 274 codes extracted in the above manner that do not break the restriction, 256 codes are randomly selected, and 256 codes are
The (8, 10, 0, 2) encoding system can be realized by making one-to-one correspondence with 8-bit data. As mentioned above, Cm+ "T d+ k) = (8H1
0T Ow 2 ). The selected 256 codes may be written into the ROM and made to correspond to data using a lookup tab le method.

Next, an operation is performed to make DC free for each code and every 10 bits, and DBV (Digita11
3um Variation).
DO7 has a great effect of suppressing DC fluctuations! We will explain how to create the J-code. Figure 7 is a block diagram of the encoding configuration.
It is a block diagram of the structure of the part corresponding to 1, 2.3 in the figure. First, the encoding algorithm performed in the above block diagram will be explained below.

s'rgp1: Set D8V==o, p=o 5TJliP2: Set 8 by the above-mentioned encoding method.
The bit data is converted into a 10-bit code (named W, and the first bit of W (always 1) is named W).

8TJ! tP3: Calculate ODS.

5rJl! p4: (1) If PeQ -1) Sig
nDBV! 111gn0Da &RabaW, is set as inverted sass D8V=DBV-ODB.

(11) If p=Q or slgn DBV Jy 81
If gn0DI3, then W, is non-inversion TeDlff, = D8
Set V+ODB.

Qii) If P=i':) sign DSV =
If 51gn0DE, then W, is non-inversion TeD8V = D13
Set it to V-ODE.

QV) If p=1 sign DBV + 54gn
0DS Suraba W, reverse sasse D8V = DEIV +
Set with ODS.

The code W after the operation of 5TEP4 is completed is named T.

Note that P is 72g, which is 0 if the number of 1w is even, and 1 if it is odd. In addition, Hlgh 1evel (1) of the binary signal obtained by HRZX-converting the sign W is set to +1, and Low
1 level (0) is set as -1, and the value obtained by taking the sum of the values is ODS (Oodewora Digital 8u
m). However, it is assumed that W is converted to NRZ and the binary signal starts from Low 1 level. Also s
ign Indicates the polarity of ODS (+or-) However, OD
When S is 0, 51gnCD8 is 10.

s'rips: p=po(y)p) However, ■ indicates exclusive OR.

Output W' as a sign.

BTHP6 + STJ for next encoding! ! Jump to P2.

Based on the above description of the algorithm, the input in FIG.
Read the corresponding 10-bit code from ROM 51 3
2 shift registers in parallel (5TfliP5 in the above algorithm).

This 10-bit code is simultaneously input to 35 77 registers. The 10-bit code loaded in 33 is passed through 34 NRZ converters.

Converted to NRZ engineering. The number of @1's in this NRZ
The number of O''m is divided into 36 OD8 kakuntas B), and the respective values are stored in 37 and 5B register A register B.
(Albo!J, (A) BTBPS
). 5417) The NRZI converter is configured as shown in FIG.
@ in FIG. 8 indicates that the input terminal 59 is 1 for the exclusive OR circuit 40.
The output terminal of the bit delay element is shown. 0D13 is calculated by subtracting the contents of register B 38 from the contents of register A 37 by subtracter 4 in FIG. 7, and this result is stored in register 42 CD8.

Next, E of the above algorithm? Tj! Although it is iP4 (
1) The case of ~ dynamic is (1) Jin≠ p (OqΦaq) = 1 (+1) #->P (OqΦaq) = 1 (iii)
<==> To P C (f) A-q) = 1Qψ) => It is equivalent to P (Oq■dq) = 1, and this judgment is performed by the logic circuit 43. However, P is the value shown in FIG. 744 and is either 1 or 0. Oq is MEiB of 42 ODE registers, (lq is MEiB of 45 DSV registers)
It is IB. Since the contents of the register are expressed in two's complement, it is negative when MBB is 1, and a positive number when it is 0, so the comparison of the polarities of DSV and CD8 can only be made by comparing cq and aq. ■ indicates exclusive OR. Based on the above four flag signals, the logic circuit of 1c43 inverts the bit of W of 46 if 72 of 1) is turned on.
= DSV - ODS is performed by 47 adders and subtracters, and the result of the operation is stored in 45 D8V registers. FIG. 9 shows a specific example of a circuit for generating the four flag signals mentioned above. The details are omitted. As described above, 8T]P4 ends. Next, 87ffP5 outputs the code W' from the shift register 52 and outputs it from the output terminal of 48, and also identifies whether the number of 1's in W' is even or odd at the P7 lip 70 of 48. . When the number of tabs 1 is the number, 48 is 0), and when it is an odd number, it is 1. This is done by setting the initial value of 48 7 lip 70 lip to 0 and 1
All you have to do is invert it every time . This content is 4
It can be stored for 90 baths. Then, the contents of the buffer 49 and P44 are exclusively ORed by the exclusive OR circuit section 50, and the result is stored in P44. That's 5
When TAP5 ends, the process returns to 8THP2 and the same process is repeated.

As detailed above, the method of the present invention (8°10.0
．． 2) According to the sign, Tm1n =-= 0.8 T, Tmax =-(
2+1) Tm2.4 T10 10 Tw = -T = 0.87, and in the conventional method, typical 0 (L?+0+3), Tm1n = -Tm0.89 T, Tmax = -
(5+1)=3.569 Tw=-Tm0.89 For example, if you compare this method and this method, with this method, TmaX can be significantly reduced with a slight decrease in Tm1n +Tw, and synchronization is possible. This has the advantage that it is easy to use and has a low frequency component. Note that the same holds true when compared with other methods. Also, (8
There are nine DC-free codes realized using e10eO+2) codes. In addition, when selecting 256 codes from the 274 codes shown in Figure 2, code 1 in Wg4 diagram (a)
By selecting 26 out of 94 codes, 81 codes in Fig. 4(1)), and 26 codes from Fig. 4(c), the number of cases where the limit is violated at the concatenated part of the codes can be minimized. This has the effect of enabling efficient encoding.

Furthermore, since this method is created based on the (8, 10, 0, 2) code, there is a possibility that =2 will be broken only at the concatenated portion of the 10-bit code. Therefore, compared to the conventional method, it is possible to create a DO7 code with less low frequency components and easier synchronization.

This method uses DO7! for every code and every 1θ bit! J
- (inversion or no inversion of the first bit W of the sign), D8'V (Digi
This has the effect of creating a DC Cree code that has a small variation range (tal, Sum Variation) and is highly effective in suppressing DC variation. Note that the present invention is not limited to encoding from 8 bits to 10 bits, but can be similarly applied to encoding or decoding from 5 bits, or other bits other than the above, such as from 3 bits to X bits. . Further, as explained above, according to the present invention, it is possible to provide an electronic device that can handle data with extremely high efficiency and high precision.

[Brief explanation of drawings]

Figure #11 is a block diagram of the configuration of the electronic device, Figure FG2 is a configuration diagram showing an example of a recording/reproducing system, Figure 3 is an explanatory diagram of the connections between codes, and Figure 4 is an explanatory diagram of codes with a 10-bit configuration. , a diagram showing a method for creating a restriction code, FIG. 7 is a block diagram of the configuration of encoding, FIG. 8 is a block diagram of the configuration of an exclusive OR circuit, and FIG. 9 is a diagram showing a specific example of a flag signal generation circuit. . 1... Information source 2... Information source encoding 3... Channel encoding 31... ROM table 54... NRZ engineering converter 32,! +3...Shift register 35.36...CD8 counter applicant Canon Co., Ltd.=4 (α)! Rococo]]]]kof 14Qacb>F[
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Claims (1)

[Claims] 10 data patterns for every 8 bits of binary data series
When converting to a code made up of bits, the first bit of a 10-bit code always starts with 1, and in the remaining 9 bits, there is a code in which there are at most two 0s between 1 and 1. A binary data encoding method characterized by converting into .