JPS60201731A - Data processing system - Google Patents

Abstract

PURPOSE:To attain 3-5 bits data code conversion with high accuracy by selecting and storing previously 2<3> pieces of 5-bit signals having MSB and K set at ''1'' and <=2, respectively, then reading out the 5-bit signal in response to a 3-bit input signal. CONSTITUTION:When a 3-bit signal is code-converted into a 5-bit signal, the MSB is set at ''1'' with the number K of continuous 0 bits set at <=2 respectively. Thus 2<3> (=8) pieces of 5-bit signals are selected previously as the highly accurate data in response to the number of 3-bit input signals. These selected 5-bit signals are stored to a ROM102. Then the corresponding 5-bit signal is read out to a register 103 every time the 3-bit input signal is stored to a register 100. Thus the data code conversion is made possible with high accuracy.

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 where the number of bits ``0'' between adjacent pids 1'' is limited to a minimum of 6 bits and a maximum of 0 bits. code NRZI
The converted pattern becomes the recorded 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, "with inversion" means that the recording waveform is from High Level to Low L.
to evel or from Low Level to High
It refers to a transition to Level.

The encoding method is general K (m + n r d + k
) is expressed by four parameters. 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 (see) Tmin = ' (d+1) T; Minimum inversion interval Tmax = -(k+t)T; Maximum inversion interval Tw
='T; Detection window width (demodulation phase margin) Regarding the encoding method, an important point to note is that Trnrn is large so that Tm1n does not include high frequency components and is less susceptible to band limitation. It's better. Further, Tw is preferably larger so as not to make it difficult to distinguish between pulses and to lower the decoding error rate. Also, Tmax
should be as small as possible, reduce low frequency components, and include large clock frequency components. Therefore, Tm
It is better to make synchronization easier by reducing the difference between 1n and Tmax.

Typical conventional encoding methods are FM and MFM.
, 3PM, etc. Although the details are omitted, (m, n, d
, k), the FM is (1, 2,
0,1) MFM is (1,2,1,3)3PM is (3,6
, 2, 11). Therefore Tm1n Tmax
Tw is as follows.

FM MFM Tmin = 0.5 T Tm1n = TTmax
= T Tmax = 2 TTw = 0.5 T
Tw20, 5T PM Tmin = 1.5T 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 section 2.3 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 and detection during reproduction are the ±1st-order diffracted light of the grating 11, and the remaining one is the undiffracted light (
zero-order light). By setting the diffraction efficiency of 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 section 5.6 described in FIG. 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.
Detector 1 is a system of light splitting optical element 13 and analyzer 21.
On 7.19.20, 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.

Also, the signals of the detectors 19 and 20 are differentiated by the differential AMP 22.1. Using this signal, the objective lens is swung left and right 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.

Faraday rotating elements are, for example, YIG, IJ
It is made of glass doped with rare earth elements (e.g. iron, iron, garnet) and can rotate the plane of polarization of the 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 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, RlBahl,”
Block Codes (or a C1ass o
f Con5trained NoiselessCh
information and
Control tVol, 17. 1970, P.
According to 436, the limit code for length n bits is d=0.
It has been proven that the number of codes for which k is a finite value is divided by 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=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 restriction of =2 will not be violated even if the codes are concatenated.

In other words, in FIG. 4(a), the first bit is always a code, the last bit is 1, and the middle 8 bits are limited to 20. 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 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 10-bit codes (274) in FIG. Therefore, we randomly select 256 codes from 274 codes and convert them into 256 codes.
By making one-to-one correspondence with 8-bit data, (m*n, d, k) = (8, 10
+0,2) sign can be realized. The same applies to other bit numbers.

When converting 3-bit data into 5-bit codes, for example, if k = above, 8 5-bit codes correspond to 23 = 8 pieces of 3-bit data as shown in Table 2 below. Table 2 FIG. 5 is a block diagram of the encoding configuration of the present invention.

In FIG. 5, data series are input as many times as ■. This data series is input to a 10003-bit shift register. This is an input terminal of a clock that drives the shift register of CK#'11OO.

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

Chip Select) When a pulse is input to the (C8) terminal, the ROM 102 loads the data in the shift register 100, thereby specifying the address It01't4 corresponding to the data. ) Eight 5-bit codes arbitrarily selected from Table 2 are stored at addresses O to 7 of tOM, and when the ROM address corresponding to data is specified, the data is stored at that address. The 5-bit code is transferred to shift register 10.
3 and output from the sign output terminal (■).

This completes the conversion and encoding from one data to a code. Note that during the above encoding, etc., a CPU (not shown) may control registers and the like.

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 5-pit 4-to code shown in Table 2 is a code in which the number of bits 90'' that can be inserted between contiguous pits and ``l'' is limited to a minimum of 0 and a maximum of 1, This restriction has the advantage that it cannot be broken even by the concatenation of 5-pit codes. Therefore, Tm1n = o, 6 T Tmax = 1.27 Tw = 0.6T. Compared to the FM method, this method has larger Tm1a and Tw and lower decoding error rate, and has fewer low frequency components of the p and ntM waveforms (M
This method has the advantage of being easier to synchronize than 3PM and 3PM. Therefore, it is possible to provide an electronic device capable of recording and/or reproducing at high density and with high accuracy.

[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. Figure 5 is a block diagram of the encoding configuration, '102 is a ROM, 100,1
03 is a shift register, ■ is a data input terminal, and ■ is a sign output terminal.

Claims (1)

[Claims] (1) Encoding that converts data every 3 bits of a binary data series into a code consisting of 5 bits, and/or converting every 5 bits of data of a binary code series into data consisting of 3 bits. In decoding, 3-bit data and predetermined 5
A binary data processing method characterized by performing encoding and/or decoding in correspondence with bit codes. (2. A binary data processing method according to claim 1, characterized in that a conversion table is used to make the 3-bit data correspond to the predetermined 5-bit code.