JPS60201739A - Data processing system - 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 methods for encoding or decoding binary data to convert a binary data sequence into a binary negative sequence suitable for data processing in electronic equipment such as magnetic disks and optical disks. It relates to a binary data processing method.

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 data 01 bit 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 6. This converted code is N
The RZI-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 "0" with no inversion. Here, tomorrow's reversal means that the recording waveform will change from High Level to Low level.
w To Level or from Low Level to I-
It means to transition to High 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; Data bit interval (sec) Tmin = ' (d+1) T ; Minimum inversion interval Tmax = "(k+1)T; Maximum inversion interval Tw =
'T: Detection window width (demodulation phase margin) An important point to mention about the encoding method is that Tm1n should be larger so that it does not include high frequency components and is less susceptible to band limitations. good. Furthermore, the TW is preferably larger so as not to make it difficult to distinguish between pulses and to lower the decoding error rate. Further, Tmax is made as small as possible to reduce low frequency components and include a large clock frequency component. Therefore, Tm1n
It is better to make synchronization easier by reducing the difference between and Tmax.

Typical conventional encoding methods are FM and MFM.
,,3PM, etc. Although the details are omitted, (+n
, n, d, k), FM is (1,2,0,1) and MFM is (1,2,
1, 3) 3PM is (3, 6, 2, 11).

Therefore, Tm1n Tmax Tw is as follows.

I”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 = 0.5 T 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. Reference numeral 1 indicates an information source or its input unit, and 2 indicates an information source encoding unit for suppressing redundancy of information in the information source 1.

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 the 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. Collimator 10. The light beam transmitted through the grating 11, the polarizing plate 12, and the optical element 13 is transmitted through the objective lens 1.
4, three point images are formed on the recording medium. The light flux from the recording medium 15 has its plane of polarization modulated by the Kerr effect, and is transmitted to the detector 17 by the thread between the light splitting optical element 13 and the analyzer 21.
．． At 19.20, it enters a light 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 1.3, 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 amount of light that passes through the analyzer 21 to differ between recording and reproduction. .

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

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 disc is used 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 established from a workstation, a printer/host computer, a disk device, etc.

Next, the encoding method will be explained.

D, T, Tang and L, RoBahl,”
Block Codes (or a C1ass o
f Con5trained NoiselessCh
information and
('ontrol.

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) = 2n (0 < n = k) - ■i = 1 Table 1 shows the results calculated using the above formulas ① and ②.

Table 1 From Table 1, it can be seen that there are 504 codes where n=10 and d=2 (d=0). 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 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 2 bits are 10, and the middle 7 bits are limited to 2. 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 1 or = 2, so the limit code is 4. According to Table 1, there are 44 of these.

From the above, even if the connection is configured as shown in FIG. 4, there are 274 restriction codes that do not violate the restriction of =2.

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 pit data is 2
There are 8=256 codes, which is smaller than the number of 10-bit codes (274) in FIG. Therefore, we randomly select 256 codes from 274 codes and convert them into 256 codes.
It can be seen that (m, n, d, k) = (8, 10 + 0, 2) code can be realized by making one-to-one correspondence with 8-bit data. The same applies to other bit numbers.

When converting data for every 6 bits into a 7-bit code, when k = 3, for 26 = 64 pieces of 6-bit data, 64 of the 7-bit codes shown in Table 2 below are converted. Just make the signs correspond.

Table 2, FIG. 5 is a block diagram of the encoding structure of the present invention.

In FIG. 5, the data series is input as shown in ``■''. This data series is input to a 10006-pit shift register. CK is an input terminal of a clock that drives 100 shift registers.

This clock signal is also input to the counter 101 at the same time. The counter 101 generates a pulse every time it counts six chips, and this pulse is input to the chip select (CS) terminal.

When a pulse is input to the chip select (CS) terminal, it becomes 1.
The ROM 02 stores the data of the shift register 100, and the ROM address corresponding to the data is designated. ROM addresses 00 to 63 store 64 7-bit codes arbitrarily selected from Table 2. When the ROM address corresponding to data is specified, the 7-bit code stored at that address is stored. is input to the shift register 103 and outputted from the sign output terminal (2).

This completes the conversion and encoding from data to code.

The code-to-data conversion and decoding performed on the playback side can be performed by performing the reverse conversion as described above.

-As explained above, the fbit code shown in Table 1 is the bit ``'0'' that falls between the adjacent bits ``11!1''.
(This is a code whose number is limited to a minimum of 0 and a maximum of 3), and this restriction has the effect of not being broken even by concatenation of 7-bit codes.

Therefore, 'l'min = 0.867 Tmax = 3.437 1'w = 0.867. As a result, this method has a large Tm1n and Tw and a small decoding film sheet compared to the conventional FM method, and has fewer low frequency components in the recorded waveform (MFM and
There is also an effect of the ψ method of synchronization. Therefore, it is possible to provide an electronic device capable of high-density and high-precision recording and/or reproduction.

[Brief explanation of drawings]

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. Figure 5 is a block diagram of the encoding configuration, 102 is a ROM, 100 and 103 are shift registers,
is the data input terminal, ■ is the sign output terminal. (α) 10] Ee ■ Loco / 14QItA (b) 10
GoTchoUro10 81a (C) 1r100 44m 1! it 2'/4a

Claims (1)

[Claims] (1) Encoding that converts every 6 bits of the binary data series into a code consisting of 7 bits, and/or converting the code every 7 bits of the 2 brigadier series into data consisting of 6 bits. In decoding, 6-bit data and a predetermined 7
A binary data processing method characterized in that the encoding and/or decoding is performed in correspondence with a bit code. (2. A binary data processing method according to claim 1, characterized in that a conversion table is used to make the 6-bit data correspond to the predetermined 7-bit code.