JPS60201737A - Data processing system - Google Patents

Abstract

PURPOSE:To attain 5-6 bits code conversion with high accuracy by selecting and storing previously 2<5> pieces of 6-bit signal having MSB and K set at ''1'' and >=2, respectively, and reading out the 6-bit signal in response to a 5-bit input signal. CONSTITUTION:When a 5-bit signal is code-converted into a 6-bit signal, the MSB is set at ''1'' with the number K of continuous 0 bits set at >=2 respectively. Thus 2<5>(=32) pieces of 6-bit signals are selected and stored previously to a ROM102 as the highly accurate data in response to the number of 5-bit input signals. Then the corresponding 6-bit signal is read out to a register 103 every time the 5-bit input signal is supplied to a register 100. In such a way, the data code conversion with high accuracy is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for encoding or decoding binary data to convert a binary data sequence into a binary code sequence suitable for data processing in electronic devices 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 n1 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 6. This converted code is NR
The ZI-converted pattern becomes the recording waveform pattern. In other words, the recording waveform pattern corresponds to code bit "1" with inversion and code bit "0" with no inversion.Here, inversion means that the recording waveform changes from High Level to Low.
to Level or from Low Level to High
It refers to a transition to Level.

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

k; Maximum number of pins 0" that can fit between pins 1"T; Data bit interval (sec) Tmin -' (d+1) T; Minimum inversion interval T
max = −(k+1) T ; Maximum reversal interval Tw
= m-T ; Detection window width (demodulation phase margin) An important point to note about the encoding method is that Tm1n is large in order to not include high frequency components and to be less susceptible to band limitations. 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, Tn]a
x is made as small as possible to reduce low frequency components and include a large amount of clock frequency components. Therefore, T
It is better to reduce the difference between min and Tmax to facilitate synchronization.

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

FM MFM Tmin = 0.5 T Tm1n == TTma
x = TTmax = 2 TTw = 0.5
T' Tw = 0.5 TPM Tmin = 1.5 T Tmax := 6 T Tw20,5T 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 structural block diagram of an electronic device that performs digital modulation of magnetic disks, optical disks, electronic files, and the like. 1 is an information source or its input part, and 2 is an information source naturalization part for suppressing redundancy of information in the information source 1.

Note that band compression compresses the transmission frequency band in an analog manner, and high-efficiency encoding attempts to reduce the average number of bits per pixel (sample value) digitally. is close to amplitude compression. 3 is a channel encoding unit for communication paths, transmission paths, etc., which includes error correction, digital modulation, etc. 4 is a recording/reproducing system for the above-mentioned magnetic disk, optical disk, etc. 5 and 6 are the above-mentioned encoding units This is a decoding section for decoding the data encoded by sections 2 and 3. Reference numeral 7 is an output section that outputs the information obtained by 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, the two point images that are located mm for tracking signal detection during reproduction are the ±1st-order diffracted light of the grating 11, and the remaining one is the non-diffracted light (
zero-order light). Due to the setting of the diffraction efficiency by the grating 11, no signal is recorded in these two point images.
It is easy to record a signal using a point image of only undiffracted light.

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 2'0 is turned off.

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 undergoes modulation of the plane of polarization due to the Kerr effect, and is detected by a system of the light splitting optical element 13 and the analyzer 21.
The light enters 17, 19, and 20 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 a 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 7 Alladay single rotation element is as follows.

The polarization direction of the light reflected 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, R, Bahl
, Block Codes for a C1asso
f Con5trained NoiselessCh
information and
Control.

Vol, 17, 1970. According to P436, it is proven that the number of limited codes of length n bits, that is, codes where d=0 and k is a finite value, is divided by the following Nk(n).

Nk (n) = 2n (0<n=k) □■i=1 The results calculated using the formulas ■ and ■ above are shown in Table 1. Based on this Table 1, n = 10 and = 2 ( It can be seen that there are U304 codes such that 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. 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 274 lθ bit codes shown in FIG. Therefore, from among the 274 codes, we randomly selected 256 codes and converted them into 2
It can be seen that (m, n1dlk)=(81101012) code can be realized by making one-to-one correspondence with 56 pieces of 8-bit data. The same applies to other bit numbers.

When converting data every 5 bits into a 6-bit code, for example, if =5, for 32 = 5-bit data, 32 out of 41 6-bit codes are converted as shown in Table 2 below. All you have to do is match the signs.

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

In FIG. 5, the data series is input from @. This data series is input to 100 5-bit shift registers. OK is the input terminal of the clock that drives the 100 shift registers. This ptsu signal is 10 at the same time.
It is also input to the counter No. 1. The counter 101 generates a pulse every time it counts five crosses, and this pulse is input to the chip select (08) terminal. When a pulse is input to the chip select (O8) terminal, 102 ROMs
loads the data in the shift register 100, thereby specifying the ROM address corresponding to the data. R.O.
Addresses 0 to 31 of M are 32 arbitrarily selected from Table 2.
When a ROM address corresponding to data is specified, the 6-bit code stored at that address is input to the shift register 105 and output from the code 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 to the above.
This is a code in which the number of "bit additions inserted between" is limited by a minimum of 0 and a maximum of S@, iB, and this limitation has the effect of not being broken even by concatenation of 6-bit codes.

Therefore, Tm1n=0.85T Tmax=5.55T TV interval 0.85T. As a result, compared to the conventional FM method, this method has a large T win and 'rw and a small decoding I@b rate, and has fewer low frequency components in the recording waveform (MF
M and 3PM also have the advantage of being easy to synchronize. 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] Ding III Loco/ 14QIIA (b)
10 goe ■ ``mouth 10 g18 (C) 10] engineering ■ro 100 44a total 2747a

Claims (1)

[Claims] (1) Encoding that converts every 5 bits of a binary data series into a code consisting of 6 bits, and/or converting every 6 bits of a binary concatenation series into data consisting of 5 bits. In decoding, 5-bit data and a predetermined 6
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 5-bit data correspond to the predetermined 6-bit code.