JPS60201735A - Data processing system - Google Patents

Abstract

PURPOSE:To attain code conversion with high accuracy by storing previously the 14-bit signals having MSB and K set at ''1'' and >=2 respectively after dividing them into plural groups and reading out a specific 14-bit signal of a specific group in response to the states of an 8-bit input signal and code. CONSTITUTION:When an 8-bit signal is code-converted into a 14-bit signal, the 13-bit signals having the MSB set at ''1'' with the number K of continuous 0 bits set at >=2 respectively are divided into groups and stored to Tables 1-4 of a ROM. Then the Table number is selected in response to the states of ''1'' and ''0'' of the lower bits of the preceding input signal when the 8-bit input signal is supplied to a register 100. The 13-bit signal corresponding to the input signal in the Table is read out for code conversion.

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 6. 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 code pid 1'' with inversion and code pid 0' with no inversion.Here, with inversion, the recording waveform changes from High Level to Low Le.
to vel or from Low Level to High L
It means to transition to evel.

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 i maximum inversion interval Tw
= 'T; Detection window width (demodulation phase margin) An important point to mention about the encoding method is that Tm1n is set to a larger value in order to not include high frequency components and to be less susceptible to band limitations. is good. 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
The clock frequency component should be as small as possible, the low frequency component should be reduced, and the clock frequency component should be large. Therefore, Tm
It is better to make synchronization easier by reducing the difference between 1n and Tmax.

Typical conventional encoding methods include pM and MFM.
, aPM, etc. Although the details are omitted, (+n,
12M is (1, 2, 0, 1) and MFM is (1, 2, 1,
3) 3PM is (3, 6, 2, 11). Therefore, T+n i n Tmax Tw is as follows.

1i”M MFM Tmin = 0.5 T Tm1n = TT+na
x = TTmax = 2 TTw = 0.5
TTw = 0.5 TPM Tmin = 1.5 T Tmax = 6 T Tw = 0.5T 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 Rin encoding and/or decoding method.

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

':iSi diagram is a block diagram of the configuration of electronic equipment that performs digital modulation of magnetic disks, optical disks, electronic files, etc. 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 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 faith source 8, and the light source 9 is brought 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, grating 11,
The light beam transmitted through the polarizing plate 12 and the optical element 13 forms three point images on the recording medium by the objective lens 14. 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.

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.

In addition, as a means for adjusting the light N between recording and reproduction, a skewer having a Faraday rotary element inserted between the optical element 13 and the recording medium 15 can be used.

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 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, the electronic device described is a video disk, but it is not limited to this at all, and can also be applied to data processing in a network constructed 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 for a C1ass
of Con5trained NoiselessC
information an
dControl.

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

Nk(n)=2° (0kn≦k)-■i=1 The results calculated using the above 0.0 formula are shown in Table 1. According to this Table 1, n-10 = 2 (d,,,o)
It can be seen that there are 504 codes. 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 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 "o1 rorororororo 1" or "010 rororororo 10".

Consider separating data into 8-bit units and converting them into lo-bit codes. Then, the 8-bit data becomes 2
There are 62,256 codes, which is smaller than the 274 10-bit codes shown in FIG. Therefore, by selecting 256 codes out of 274 codes and making them correspond 1:1 to 256 8-bit data, we can obtain (
It is possible to realize m, n, d, k) = (8, 10 + 0.2) code. When converting data every 8 bits into a 14-bit code for other bit numbers, if the last bit of the previous code is 41'' for 8-bit data 2B==256 pieces, the second Make a one-to-one correspondence with the 275 14-bit codes in the table, and if the last 2 bits of the previous code are ``10'', any 256 of the 426 14-bit codes in Table 3 If the last 3 bits of the previous code are 1100'', then ? It is only necessary to make a one-to-one correspondence between any 256 14-bit codes among the 376 14-bit codes in the 44 table. Note that in the initial state when a code starts, the previous code does not exist, but at this time, the last two bits of the previous code are "1" or the last two bits are "1".
It is assumed that encoding is performed by specifying either ``0'' or the last 3 bits being ``100''.

FIG. 5 is a block diagram of the encoding structure of the present invention. In FIG. 5, a data sequence is inputted.

This data series is input to 100 8-bit shift registers. O]1 This is an input terminal for the clock that drives the shift register of the CFi 100. This clock signal is also input to the counter 101 at the same time. counter 1
01, a pulse is generated every time eight clocks are counted, and this pulse is input (aS) to the logic circuit 104. 1
The last 5 bits of the 4-bit code are monitored, and when the last 1 bit C-14 is 11", Table 1 of the ROM 102 is
Turn on the chip select terminal os1 to select
When the last two bits 0-13 and 0-14 are 110#, turn on the chip select terminal as2 for selecting Table 2, and set the last three bits 0-12.0
-13. When 0-14 is 1100'', the chip select terminal cs3 for selecting Table 3 is turned ON.However, the timing of turning ON is when a pulse is input from the counter 101 to the logic circuit 104.

It is obvious that such a logic circuit 104 can be easily realized.

As above, create Table 1 or Table 2
In one case, 'rabxe 5 is selected, and at that time, the 8-bit shift register 10008-bit data is stored in ROM 10.
It is pushed into 2. and a Table corresponding to the data
The address within is specified. 256 14-bit codes arbitrarily selected from Table 2 are written in Table 2, and 256 14-bit codes arbitrarily selected from Table 3 are written in Table 2. Ash, Tab
le 3 contains 256 1's arbitrarily selected from Table 4.
A 4-bit code is written. When the address in 'I'abxe corresponding to the data is specified, the 14-bit code stored at that address is transferred to the shift register 10.
3, and is outputted from the sign output terminal 3. At this time, the last 3 bits of the 14-bit code are J) O-12, C
-16 and C-14 are monitored by the logic circuit 104 to determine the next Table to be selected. 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, 14
, 14) In the encoding method: bshi, Twin = 1.1
4 T Tmax = 2.8 6 T TW = Q, 57. Accordingly, in this method, Tw is MFM or 5P.
M is larger (Tmax is smaller than 3PM, it is a method with a small IJI decoding error rate, and there are some low frequency components (it has the effect of being easier to synchronize than 3PM. Therefore,
An electronic device capable of high-density and high-precision recording and/or reproduction can be provided.

[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 and 103 are shift registers,
is the data input terminal, ■ is the sign output terminal. (α) 10 gocho ■mouth] / 14 Q a(t))
70I [1 mouth 10 818 (C) 10 two]] Ko 100 44m @+ 274a

Claims (1)

[Claims] (1) Encoding that converts data every 8 bits of a binary data series into a code consisting of 14 bits and/or converting a code every 14 bits of a binary concatenation series into data consisting of 8 bits. In decoding, 8-bit data is associated with a predetermined 14-bit code depending on the code state,
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 14-bit code.