JPS60201734A - Data processing 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 relates to binary data encoding or decoding that converts a binary data sequence into a binary code sequence suitable for data processing in electronic equipment such as magnetic disks and optical disks. Concerning a hexadecimal data processing method.

2. Description of the Related Art Conventionally, various encoding methods (also called digital modulation methods) have been proposed in order to improve the recording density when recording binary data on a recording medium such as a magnetic disk or an optical disk. Encoding generally involves converting m bits of data into an n-bit code in which the number of bits ``0'' between adjacent bits ``1'' is limited to a minimum of 6 and a maximum of 0. This converted code is converted to NRZ
The I-converted pattern becomes the recording waveform pattern. In other words, the recording waveform pattern corresponds to the sign bit "1" with inversion and the sign bit "O" with no inversion. Here, "with inversion" means that the recording waveform is from 14high level to low.
to Level or from Low Level to High
It means to transition to h Level.

The encoding method is generally expressed by four parameters (m, n, d, k). First, important parameters will be defined for the following explanation.

k: Maximum number of bits "0" that can be inserted between bits "1" T: Data bit interval (sec) Tm+n - (d+1) T ; Minimum inversion interval 1] Tmax = -(k+1) T ; Maximum inversion Interval T
w = -ili-T, detection window width (reverse FA phase margin)
The important thing to note about the encoding method is that Tm
Regarding in, Tm1n should be larger so that it does not include high frequency components and is less susceptible to band limitations. Further, Tw is preferably larger so as not to make it difficult to distinguish between pulses and to lower the decoding error rate. Further, it is better to set Tmax to be as small as possible, to reduce low frequency components, and to include a large clock frequency component, thereby reducing the difference between Tmin and Tmax to facilitate synchronization.

Typical conventional encoding methods are FM and MFM.
, 3PM, etc. Either omit the details or (m r n
When expressed by the parameter r d r k ), F
M is (1, 2, 0, 1) MFM is (1, 2, 1, 3)
'3PM is (3, 6, 2, 11). Therefore, Tm1n Tmax Tw is as follows.

F″M MFM Tmin = 0.5 T Tm1n = TTmax
= T Tmax = 2 TTw = 0.5 T
' Tw = 0.5 TPM Tmin = 1.5 T Tmax = 6 T Tw = Q, 5'l' Since Tw is as small as 0.5T in this encoding method,
This method has the disadvantage that the decoding error rate increases as data density increases.

From the above explanation, it is an object of the present invention to provide a data processing method that eliminates the above-mentioned drawbacks, has fewer low-frequency components in the recording waveform, and performs easy self-clock encoding and/or decoding. , an object of the present invention is to provide an electronic device that employs the encoding and/or decoding method.

The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram of the configuration of electronic equipment that performs digital modulation of magnetic disks, optical disks, electronic files, and the like. 1 is an information source or its input unit, and 2 is an information source encoding unit for suppressing redundancy of information in the information source l.

Bandwidth compression compresses the transmission frequency band in an analog way, and high-efficiency coding digitally attempts to reduce the average number of bits per pixel (sample value). is close to amplitude compression. 3 is a channel encoding unit for communication paths, transmission paths, etc., which includes 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 data encoded by the encoding units 2 and 3.

7 is an output unit that outputs the information obtained through the above processing.

FIG. 2 is a block diagram showing an example of the recording/reproducing system 4, and is a diagram showing a head section of a video disc or the like.

First, let's talk about the signal recording system. Based on the input data, a drive signal from a signal source 8 causes a light source 9, for example, a semiconductor laser, to blink and emit light. Note that one signal source 8 includes the encoding units 2 and 3 shown in FIG. The light beam emitted by the light source 9 becomes a parallel light beam by the collimator lens 10,
The light passes through a grating 11, a polarizing plate 12, and an optical element 13 whose transmission reflectance is polarization dependent. A point image is created 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.

The grating 11 separates the beam angle in order to focus a sub-spot for tracking detection onto the perpendicular magnetic recording medium 15 using the objective lens 14.

At this time, three point images are formed on the recording medium 15 due to the action of the grating 11. Of these three point images, two point images used for tracking signal detection during reproduction are ±1st-order diffracted light of the grating 11, and the remaining one is undiffracted light (zero-order light). By setting the diffraction efficiency by the grating 11, it is easy to record a signal using only the point image of the undiffracted light without performing signal recording 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 a signal distributor 18, one of which is used as an autofocus signal, and the other is used for outputting and monitoring recording signals. Note that this output is sent to the decoding units 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, three point images are formed on the recording medium. The light beam from the recording medium 15 has its plane of polarization modulated by the Kerr effect, and is detected by a detector x7 in a system of a light splitting optical element 13 and an analyzer 21.
．． The light enters 1c+ and 2o in a bright and dark modulated state. The signal from the detector 17 is distributed into two systems, one system serving as an autofocus signal and the other system serving 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 13, a bright and dark pattern with high contrast can be detected in the reproduction system.

Note that a Faraday rotary element can be inserted between the optical element 13 and the recording medium 15 as a means for adjusting the amount of light between recording and reproduction.

The Faraday rotation element is made of, for example, YIG (yttrium-iron-garnet) crystal or glass doped with rare earth elements, and can rotate the plane of polarization of a light beam by applying a magnetic field. The reason for using this Faraday rotating 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 13, and the amount of light transmitted through the analyzer 21 is different.

Furthermore, 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 light i1i that passes through the analyzer 21 to differ between recording and reproduction. different.

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

The Faraday rotating element applies an appropriate magnetic field during recording and rotates the polarization plane of the recording light beam, thereby adjusting the amount of light entering the detector 17 using the combination of the optical element 13 and the analyzer 21, thereby solving the above problem. It is.

In this example, a video disk was described as the electronic device, but there is no need to limit it to this, and the present invention can also be applied to data processing in a network constructed from workstations, printers/host computers, disk devices, etc.

Next, the encoding method will be explained.

D, T, Tang and L, RoBahl;
” Block Codes for a C1ass
of Con5trained NoiselessC
information an
dControl.

Vol, 17.1970. According to P436, it has been proven that the number of restricted codes of length n bits, where d=0 and k is a finite value, is the following Nk(n).

Nk (n) = 2"(0<n≦k) - ■i=1 The results calculated using the above formulas ■ and ■ are shown in Table 1. According to this Table 1, at n-10, = It can be seen that there are 504 codes with 2 (d=0).However, when these codes are concatenated, there is a restriction of =2 at the junction between codes, as shown in Figure 3. However, if a 10-bit code can be constructed as shown in FIG. 4, the restriction of =2 will not be violated even if the codes are concatenated.

In other words, FIG. 4(a) is a code in which the first bit is always 1, the last bit is 1, and the middle 8 bits are restricted to 2. According to Table 1, there are 149 of these.

FIG. 4(b) is a code in which the first bit is always 1, the last two bits are 10, and the middle seven bits are limited to 1 to 22. According to Table 1, there are 81 such items.

FIG. 4(C) is a code in which the last bit is always 1, and the last 3 bits are 100, and the middle 6 bits are limited to 2. According to Table 1, there are 44 of these.

From the above, there are 274 restriction codes that do not violate the restriction of =2 even if they are connected as shown in FIG. In addition to the above, the code may be "010 rororororo 1" or "010 rororororo 10".

Consider separating data into 8-bit units and converting this into a 10-bit code. Then, the 8-bit data becomes 2
' = 256 codes exist, which is smaller than the number of 1O bit codes (274) in FIG. Therefore, we randomly select 256 codes out of 274 codes and convert them into 256 codes.
(m, nld, k): (8110
1012) code can be realized. The same applies to other bit numbers.

When converting data for every 8 pits into a 13-bit code, for 8-bit data 2' = 256 bits, if the last bit of the previous code is 11'', use the 256 13-bit codes in Table 2. If the last two pits of the previous code are "10", the 402 1's in Table 3
The last 3 bits of the previous code are @
100'', there is a one-to-one correspondence with any 256 13-bit codes among the 375 13-bit codes in Table 4, and the last 4 bits of the previous code are 11000''.
In this case, it is sufficient to make one-to-one correspondence with any 256 13-bit codes among the 333 13-bit codes in Table 5. Note that in the initial state when a code starts, the previous code does not exist, but in this case, the last bit of the previous code is 1'' or the last two bits are 10.
Encoding is performed by specifying one of the following: ", the last 3 bits are ioo", or the last 4 bits are 1000.

FIG. 5 is a block diagram showing the configuration of encoding according to the present invention. In FIG. 5, a large number of data sequences are input. This data series is manually input to a 10,008-pit shift register. CKt'il This is the input terminal of the clock that drives the shift register of OO.

This clock signal is also input to the counter 101 at the same time. The color/receiver 101 generates a pulse every eight clocks, and this pulse is input manually to the logic circuit 104.

The last 4 bits of the 13-bit code are monitored, and when the last 1 pit C-13 is '1', the Table of ROM 102 is
l f: Chip select terminal 081 for selecting
Turn on and the last two pits C-12 and C-13 are 10"
When the chip select terminal C82 for selecting Table 2 is turned on, the last 3 bits C-11, C
-12, C-13 is 1100” Table 3
Turn on the chip select terminal C83 for tl-select and set the last 4 bits C-10 to C-13 to 100”
At this time, the chip select terminal C84 for selecting Table 4 is turned ON. However, the timing to turn it on is when a pulse is manually applied to the logic circuit 104 from the counter 101. It is obvious that such a logic circuit 104 can be easily realized.

As above, create Table 1 and Table 2.
, Table 3 or Table 4 is selected,
At this time, the 8-bit data in the 8-bit shift register 100 is written into the ROM 102. Then, the address in the Table corresponding to the data is specified. Table l
256 13-bit codes arbitrarily selected from Table 2 are written in Table 2, and 256 13-bit codes arbitrarily selected from Table 3 are written in Table 2. ) Table 3 contains 256 13-pit codes arbitrarily selected from Table 4.
In ble 4, 256 13-bit codes arbitrarily selected from Table 5 are written.

When an address in the table corresponding to data is designated, the 13-bit code stored at that address is manually input to the shift register 103 and output from the code output terminal (2). At this time, the last 4 bits of the 13-bit code are C-
10, C-11, C-11, 4° C-12, C-13 are monitored by the logic circuit 104, and the next Table to be selected is
f is determined. This completes the conversion and encoding from data to code. The code-to-data conversion and decoding performed on the reproduction side may be performed by performing the reverse conversion to that described above.

As explained above, the encoding method of the present invention is (8, 13
, 1, 5) encoding method: Tm1n = 1.23 T Tmax = 3.69 T Tw = 0.62 T. Accordingly, in this method, Tw is MFM or 3
is larger than PM, Tm1n is p larger than MFM, and T
This is a method in which max is smaller than 3PM and the decoding error rate is small, and there are fewer low frequency components, making it easier to synchronize than 3PM. Therefore, it is possible to provide an electronic device capable of high-density and high-precision recording and/or reproduction.

[Brief explanation of the drawing]

Figure 1 is a block diagram of the configuration of an electronic device, Figure 2 is a configuration diagram showing an example of a recording/reproducing system, Figure 3 is an explanatory diagram of connections between codes, and Figure 4 is an explanation of codes in a 10-bit configuration. 5 is a block diagram of the encoding configuration, 102 is a ROM, 100 and 103 are shift registers,
■ is a data input terminal, ■ is a sign output terminal. Applicant Canon Co., Ltd. (α) 10 Goe I [mouth] / 74 Q 1m (b)
10go ■■ [mouth 10 1JI (C)10]]]ko100 44m horsefly 274a

Claims (1)

[Claims] (1) Encoding that converts every 8 bits of the binary data series into a code consisting of 13 bits, and/or converting the code every 13 bits of the 2 Brigadier series into data consisting of 8 bits. In decoding, 8-bit data is associated with a predetermined 13-bit code depending on the state of the code,
A binary data processing method characterized by performing the encoding and/or decoding. (2. A binary data processing method according to claim 1, characterized in that a conversion table is used to make the 8-bit data correspond to the predetermined 13-bit code.