JPH05300024A - Information conversion system and magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To record a pilot signal for tracking control by making a 10-bit code word whose CDS is 0 or 10-bit code words whose CDS is + or -2 corresponding in pairs to one information word and using a selected pair for the coding. CONSTITUTION:When a pilot area signal inputted to an FF 18 is zero, 8-bit data are inputted to a coder 3, in which the data are converted into a 10-bit code word based on a code selection signal Q' from an FF 12 and the code word is outputted to a P/S converter 13. Furthermore, the coder 3 outputs a selection signal Q to a selector 11, a selector 16 selects '110' from a pilot area signal received from the FF 18, a load value to a counter 14 is '0110', and the counter 14 outputs a load CLK at a 1CLK width to the P/S converter 13 every time a CH-CLK is counted for ten times. The converter 13 converts an inputted 10-bit parallel code word into a serial code and the result is outputted to an NRZI modulator 17. The modulator 17 applies NRZI modulation to the inputted serial code word and the result is outputted as recording data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information conversion system for recording and encoding a plurality of information and a magnetic recording / reproducing apparatus for recording / reproducing on / from a medium such as a magnetic tape at a high density.

[0002]

2. Description of the Related Art As an information conversion method in a conventional magnetic recording / reproducing apparatus, for example, "THEDATA CONNECT" is used.
Some used the 8/10 modulation method shown in "RENCE STANDARD" (issued in June 1987).
The modulation method is an information conversion method that divides digital data into 8-bit information words and converts them into 10-bit code words. FIG. 11 is a circuit configuration diagram for explaining the operation, and FIG.
Is an information conversion table. In FIG. 11, 1 is 8-bit digital data and 1-bit table selection signal (Q ').
, An encoder that outputs a total of 11 bits of a signal (Q) that selects a 10-bit codeword and the next codeword table, and 2 is for delaying the codeword table selection signal by one information word. It is a flip-flop. Note that the contents of the information conversion table shown in FIG.
It is stored in (Read Only Memory) etc., and for 256 information words from “00” to “FF” in hexadecimal notation,
The code word of CDS = 0 is associated with the information word on a one-to-one basis, and
For the code word of S ≠ 0, the CDS is associated with one information word with the code words of +2 and −2 as a pair. The table Q ′ = − 1 has CDS = + 2 and the table Q ′ = + 1.
Is composed of a code word of CDS = -2. Also,
The signal (Q) for selecting a table is for performing CDS (table) selection in the direction of suppressing charge divergence in the code word string.

Next, the operation will be described. In FIG. 11, first, in the 8-bit information word “FF” input to the encoder 1, the table selection signal (Q ′) is −1,
CDS = + 2 corresponding to “FF” of Q ′ = − 1 “1”
A 10-bit codeword of 111101010 "is output. At the same time, a signal Q for selecting the next codeword table is output as -1. The 10-bit parallel signal was converted to a serial signal. After that, NRZI modulation is performed, and as a result, the DSV value at the end of the code word becomes +2. When "00" is next input to the encoder 1, the output of the code word is the same as the Q output immediately before. -1 is symbol-delayed, and CDS = 0 corresponding to "00" of Q '=-1 becomes "0".
The 10-bit signal "1010101101" and Q are output as 1. As a result, the DSV value at the end of the code word after NRZI modulation remains +2.
When "1" is input, the output of the encoder 1 is "1" with Q '= 1.
10-bit signal of CDS = -2 corresponding to 1 "and Q is -1
Is output with. As a result, the DSV value at the end of the codeword after NRZI modulation becomes 0. Hereinafter, by the same means, the 8-bit information word input to the encoder 1 is either Q ′ = − 1 or Q ′ = 1 corresponding to each information word based on the table selection signal output immediately before. The code word of that table is selected and output. As a result, the DSV value at the end of each codeword after NRZI modulation is 0 or ± 2.
Limited to the value of. This indicates that the divergence of DSV is suppressed, and as a result, DC-free information conversion containing no DC component is realized.

FIG. 14 shows the format of DAT, which is a magnetic recording device using the 8-10 modulation method. As shown in the figure, in this format, an ATF area is provided for performing tracking control, and a pilot signal for tracking control is recorded in this area.

FIG. 15 shows the format of the digital VTR disclosed in Japanese Patent Laid-Open No. 3-217179.
Here, it is divided into a video data area, an audio data area, a servo pilot area, and a subcode area, and the pilot signal is recorded only in the servo pilot area.

[0006]

Since the conventional magnetic recording / reproducing apparatus is configured as described above, the DSV cannot be controlled arbitrarily, and a portion for recording the pilot signal for tracking control is separately provided. Therefore, it is difficult to perform high-density recording because the amount of data increases and the recording rate increases in order to perform accurate tracking.

The present invention has been made in order to solve the above problems, and can generate a pilot signal for tracking control. Further, since the recording rate hardly increases, high density recording is possible. It is an object of the present invention to obtain an information conversion system and a magnetic recording / reproducing device which are as follows.

[0008]

A magnetic recording / reproducing apparatus according to the present invention comprises means for recording a plurality of information by area division,
When recording and encoding at least one piece of information of the plurality of pieces of information, each code word composed of a 10-bit code word of CDS = 0 and a pair of code words of CDS = + 2 and −2 is used. Means for associating with each information word of 8 bits and selectively using those code words, and means for recording and encoding at least one other piece of information, each of the 10-bit code Add 1 bit to a word and add CDS = ±
It is characterized in that it has a code word of 1 and has means for performing coding by selectively using those code words.

[0009]

In the magnetic recording / reproducing apparatus according to the present invention, when recording and coding at least one or more information among a plurality of area-divided information, a CDS consisting of 10 bits for one information word is used. One codeword of 0 or CDS is +
By associating two code words of 2 and -2 with a pair and encoding them by selectively using those code words, DC
When a free code is formed and at least one other piece of information is recorded and coded, 1 bit is added to each of the 10-bit code words to make a code word of CDS = ± 1. By encoding by selectively using code words,
A code is configured such that the DSV has the same value in every constant cycle.

[0010]

EXAMPLES Example 1. An embodiment of the present invention will be described below. Now, it is assumed that one bit is added to the code having the information word length = 8 and the code word length = 10 to form a code having Tmax / Tmin = 4. At this time, d (that is, the minimum number of “0s” between any “1” and the next “1”) = 0, k (that is, between any “1” and the next “1”) Maximum number of "0") =
Set to 3. However, the code uses the NRZI (F) rule.
Therefore, in order to satisfy K = 3 in each code word, the number of consecutive “0” s in the code word is set to a maximum of 3 in the code word, and 1 bit is added at the joint of the code words.
The maximum is 1 at the B end and the LSB end side. Where DC
In order to form a free code, 256 pairs of code words having different CDS polarities may be set. At this time, the number of codewords satisfying the above condition is that the CDS is 0
There are 163, +2 for 140 and -2 for 95. Therefore, DSV divergence can be suppressed, that is, DC-free modulation can be performed using 163 codewords having 0 CDS and 93 pairs of codewords having +2 and -2 CDS. The code conversion tables configured in this way are shown in FIGS. The data in FIGS. 3 to 8 represent binary digital signals in hexadecimal notation. For 8-bit input data (information word), a 10-bit code (code word) and a code word are NRZI modulated. 12 bits are output in total, including 1 bit of the inversion number information of the code word after the above (hereinafter referred to as Q) and CDS (1 bit of 0 or not) of the code word.

FIG. 1 is a diagram showing an example of a circuit configuration for realizing the present invention. Reference numeral 3 denotes 8-bit digital data (information word) and the 12-bit digital data shown in FIGS. Encoder for converting to data, 4 and 6 are NOT gates, 5, 7, 8 and 9 are EX-OR gates, 10, 12 and 18 are flip-flops, 11 and 16 are selectors, 13 is 10-bit or 11-bit P to convert parallel data to serial data string
An / S converter, 14 is a counter, 15 is a 4-input NAND gate, and 17 is an NRZI modulator which processes the code word converted into serial data so as to repeat inversion every "1" level. FIG. 2 is a code selection table for determining the code to be selected by the value of the immediately preceding and current DSV control signals, the CDS value of the code word selected immediately before, and the previous Q'signal. Figure 3
8 is the above-mentioned code conversion table, FIG. 9 is a view showing the code conversion and the DSV value according to one embodiment of the present invention, in which FIG. 8A shows a pilot area signal (written with “1”), (B) is a DSV control signal (“1” is + direction),
(C) is the input data (12 bits), (d) is the code selection signal Q ', (e) is the selected code word, (f) is the signal waveform to be recorded, and (g) is at the end of the code word. The respective DSV values are shown. FIG. 10 is a diagram showing the recording format of the magnetic recording / reproducing apparatus in one embodiment of the present invention. In the figure, sub-code signals and the like are stored in the sub-data areas (SUB1 and SUB2) and the main data area (MAI).
In N), video signals, audio signals, etc. are recorded. In addition, pilot signals are generated in the sub data areas (SUB1 and SUB2).

The operation of the circuit in one embodiment will be described below with reference to FIG. First, when the pilot area signal output from the flip-flop 18 is "0", that is, when recording and encoding information other than the sub-data area, 8-bit data is input to the encoder 3 and
The code selection signal Q ′ output from 12 and the 8-bit data are converted into a 10-bit code word (parallel), and P /
Output to the S converter 5. Further, the Q signal is output to the selector 11. In the selector 16, "110" is selected by the input pilot area signal "0", the load value of the counter 14 becomes "0110", and the load CLK of 1 CLK width is converted to P / S every time CH-CLK is counted 10 times. Output to the container 13. The P / S converter 5 converts the input 10-bit parallel code word to serial, and the NRZI modulator 6
Output to. At this time, the output of the NOT gate 4, that is, the LSB is input to the P / S converter 13, but CH-CL
Since the load CLK is input every K10 times, this LSB
Is not output. The NRZI modulator 17 NRZI modulates the input serial codeword and outputs it. Further, the Q signal output from the encoder 3 is input to the selector 11 and selected by the pilot area signal, and the flip-flop 12
Entered in. Next, when the pilot area signal output from the flip-flop 18 is "1", that is, when the information in the sub-data area is recorded and coded, 8-bit data is input to the encoder 3 and output from the flip-flop 12. From the selected code selection signal Q'and the 8-bit data
It is converted into a 10-bit codeword (parallel) and output to the P / S converter 5. In addition, the Q signal is sent to the selector 11 and NOT.
It is output to the gate 4 and the CDS signal is output to the EX-OR gate 5. In the selector 16, "101" is selected by the input pilot area signal "1", and the counter 14
Becomes 0101, and every time CH-CLK is counted 11 times, the load CLK of 1 CLK width is converted into P / S converter 13
Output to. The P / S converter 5 converts the input 10-bit parallel code word and LSB into serial,
Output to the RZI converter 6. The NRZI modulator 17 NRZI modulates the input serial codeword and outputs it. Further, the DSV control signal is the flip-flop 10 and the EX-O.
It is input to the R gate 9, and the output of the flip-flop 10 is input to the other input of the EX-OR 9. EX-OR
The output of the gate 9, that is, the current DSV control signal and the previous DV
The exclusive OR of the SV control signals is applied to one input of the EX-OR gate 8. The EX-OR gate 5 takes the exclusive OR of the CDS signal and the Q ′ signal output from the encoder 3, is inverted by the NOT gate 6 and sends it to one input of the EX-OR gate 7. The EX-OR gate 7 takes the exclusive OR of the output of the NOT gate 6 and the Q'signal and sends it to the other input of the EX-OR gate 8. The EX-OR gate 8 takes the exclusive OR of the EX-OR gates 7 and 9 and sends it to one input of the selector 11. In this way, the signal according to the code word selection table shown in FIG. 2 is output as the Q "signal. This Q" signal is selected by the pilot area signal and sent to the flip-flop 12 for the next encoding. It becomes the code selection signal Q '.

For example, as shown in FIG. 9A, when the pilot area signal is "0", the input data is "7".
F ", the previous polarity is" 0 ", and the Q'signal is" 0 ",
The 10-bit codeword output from the encoder 3 is “1110
010101 ", CDS becomes +2, and DSV also becomes +2. Then, the Q signal" 1 "is output. Next, when the data" 00 "is input, the Q'signal, that is, the previous Q signal is" 1 ". Therefore, the code word “0100010001” is selected, the CDS is 0, and the DSV is +2. Next, when the pilot area signal is “1” and the DSV control signal is also “1”, the data “51” is When input, since the Q'signal is 0, the codeword "1010010011", the Q signal "0", and the CDS signal "1" are output, CDS is -2, and DSV is 0. Data "15" Is input, the Q'signal is "0", so the codeword "010110"
1001 ”is selected, LSB becomes“ 0 ”, CD
Both S and DSV become +1. Next, the data “8C”
Is input, the code word “11101” is generated due to Q ′ = “1”.
"00011" is selected, the LSB becomes "1", and the CD
S becomes +1 and DSV becomes +2. Similarly, a modulation method can be realized in which the DSV fluctuates in the cycle of the DSV control signal in the area where the pilot area signal is "1", that is, in the sub data area.

Using the modulation method as described above, 1
Pilot signals for tracking servo are generated at two locations in the track. Therefore, the sub data area (S
In UB1 and SUB2), as described above, 1 bit is added to the LSB of the 10-bit codeword to perform modulation including the pilot signal as the 11-bit codeword, and the 10-bit codeword is used in other areas. The modulation used as it is.

Example 2. In Figure 10, the sub data area is 1
Although the pilot signal is written in two places in the track and the pilot signal is written in this part, three or more areas for writing the pilot signal may be provided in one track in order to accurately follow the narrow track. You can write it in.

[0016]

As described above, according to the present invention, when an 8-bit information word is converted into a 10-bit code word, as a code word, after NRZI modulation, the same level of continuity is 1 to 4 The following is the case. Since the CDS is coded while controlling the CDS value in order to suppress the divergence of the DSV by using the code words with 0 and ± 2, it is possible to realize the DC-free modulation method. Furthermore, in the area where the pilot signal is written, by adding 1 bit to the 10-bit code word, the CDS is used as a code word of ± 1,
Since the modulation is performed so that the DSV fluctuates in synchronization with the V control signal and the pilot signal for tracking control can be obtained, it is not necessary to provide an ATF area, that is, an area for recording only the tracking control signal. Further, since one area is added to the code word and the area for writing the pilot signal is made a part, it is not necessary to increase the recording rate so much, and high density recording is possible. Moreover, since the area where the pilot signal is written and the other areas are basically the same modulation method, the circuit scale hardly increases.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram according to an embodiment of the present invention.

FIG. 2 shows a DSV control signal according to an embodiment of the present invention.
10 is a code selection table that determines a Q ″ signal that selects the next code word from the CDS value of the code selection signal Q ′ / selected code word.

FIG. 3 is a code conversion table according to an embodiment of the present invention.

FIG. 4 is a code conversion table according to an embodiment of the present invention.

FIG. 5 is a code conversion table according to an embodiment of the present invention.

FIG. 6 is a code conversion table according to an embodiment of the present invention.

FIG. 7 is a code conversion table according to an embodiment of the present invention.

FIG. 8 is a code conversion table according to an embodiment of the present invention.

FIG. 9 is a code conversion and DSV according to an embodiment of the present invention.
It is the figure which showed the value.

FIG. 10 is a diagram showing a recording format of a magnetic recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 11 is a circuit configuration diagram of a conventional information conversion device.

FIG. 12 is a code conversion table by a conventional information conversion device.

FIG. 13: Code conversion and D by a conventional information conversion device
It is the figure which showed the SV value.

FIG. 14 is a diagram showing a recording format of DAT which is a conventional magnetic recording / reproducing apparatus.

FIG. 15 is a diagram showing a recording format of a conventional digital VTR.

[Explanation of symbols]

 3 Encoder 4, 6 Code Selector 5, 7, 8, 9 EX-OR Gate 10, 12, 18 Flip-Flop 11, 16 Selector 13 P / S Converter 14 Counter 15 4 Input NAND 17 NRZI Modulator

Claims (3)

[Claims] 1. When the digital data is separated into 8 bits (information word) and converted into a code word of 10 bits, each code word has a bit "0" between bits "1" and "1". Is limited to 3 or less within a codeword and 2 or less between codewords, and CDS (Codewo
A code word whose rd Digital Sum) is 0 is directly associated with the 8-bit data, and the CDS is +2 or −.
For a code word of 2, the two code words having different CDS are paired to correspond to the 8-bit data, and the polarity signal of each code word is used to selectively use the two code words to obtain the DSV. An information conversion method characterized by suppressing the divergence of (Digital Sum Variation). 2. When the digital data is separated into 8 bits (information word) and converted into a code word of 11 bits, the information conversion method according to claim 1 is used.
By adding 1 bit to the LSB of a 10-bit codeword, the CDS is used as a pair of codewords of +1 and -1, and a bit "0" between bits "1" and "1" in a code string is used. The number is set to 3 or less, one of the pair of code words is selectively used according to the control signal of DSV, and the DSV varies in synchronization with the control signal of the DSV. Characterizing information conversion method. 3. A magnetic recording / reproducing apparatus for recording a plurality of pieces of information in an area-divided manner. When converting digital data into a recording code, in one or more areas in one track, the scope of claim 2 The magnetic recording / reproducing apparatus is characterized in that the information conversion method described in claim 1 is used in other areas, and the information conversion method described in claim 1 is used in other areas.