JPH10134525A - Magnetic recording and reproducing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a magnetic recording and reproducing apparatus in which the number of memory elements is reduced and in which a circuit scale is reduced. SOLUTION: A third memory element 9 temporarily stores (delays) error- corrected and coded digital data from an error-correcting and coding circuit/ error-correcting and decoding circuit 1 so as to be supplied to the input terminal A of a waveform comparison circuit 17. A waveform equalization circuit 13 changes a reproduced signal from a reproducing means into a digital signal so as to be supplied to the input terminal B of the waveform comparison circuit 17. The waveform comparison circuit 17 compares both inputs so as to output 1, 0 or -0. An error judgment circuit 19 judges that an error exists in the reproduced signal when 1 or -1 is input even in one bit. At this time, the error-correcting and coding circuit/error-correcting and decoding circuit 1 fetches the same digital data againg.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus for backing up data of a computer, for example.

[0002]

2. Description of the Related Art Conventionally, in a magnetic recording / reproducing apparatus for signals using a magnetic disk or a magnetic tape, a magnetic medium is run at a certain speed for magnetic recording, and the magnetic medium is brought into contact with a magnetic head in a state close to the contact. A signal was recorded on a magnetic medium by changing the magnetic flux density while applying magnetism.

However, the gap of the magnetic head is very narrow in recent years due to the necessity of recording a high frequency. Usually, the signal is reduced or lost.

[0004] As in the case of recording an analog signal, there may be a case where a loss is present at the time of reproduction, which can be approximately complemented. However, in the case of recording / reproduction of digital data, even a loss of 1 bit is a serious problem. Become.

Therefore, generally, in order to recover the error of the data, a code for recovery is added in advance at the time of recording, and when the loss of the reproduced data is found, the code is used to recover the data. ing.

Further, if the data cannot be restored, new necessary data may be recorded again.
In this case, a means has been conceived in which data can be surely recorded without taking time by checking whether or not the original data can be reproduced by reproducing while recording.

[0007] In order to use the correction function for confirming by reproducing while recording, it is necessary that the recording processing means and the reproduction processing means move simultaneously and independently.

The principle of error correction will be described with reference to the data arrangement diagram of FIG.

In general, digital data is corrected by arranging data in a fixed row and column, and adding a sign (data) of the operation result of the row and column on each matrix to each matrix in advance. This can be done by referring to the code at the time of reproduction.

For example, the data xi, j in FIG. 5 refers to the data ai of the operation results of all the i rows and the data bi of the operation results of all the j columns to determine whether the data at the time of reproduction is incorrect.

FIG. 4 shows the configuration of a conventional magnetic recording / reproducing apparatus.

The error correction coding circuit 101 converts the input digital data into the first storage element 1 according to the arrangement shown in FIG.
03 is stored. The error correction encoding circuit 101
The digital data is read out from the storage element 103, error-correction-coded, and stored in the second storage element 105 in accordance with the arrangement shown in FIG. The error correction encoding circuit 105 reads the error correction encoded digital data (FIG. 7) from the second storage element 105 and supplies the digital data to the recording unit 107.

The recording means 107 is a recording medium (not shown)
The digital data (FIG. 7) which has been subjected to the error correction coding is recorded in the first row.

The reproducing means 109 reproduces the digital data recorded from the recording medium and supplies it to the digitizing circuit 111. The digitizing circuit 111 converts the reproduction signal into a digital signal.

The error correction decoding circuit 113 stores the output of the digitizing circuit 111 in the third storage element 115 in the arrangement shown in FIG. The error correction decoding circuit 113
The digital data stored in the third storage element 115 is read out, error-corrected decoded, and stored in the fourth storage element 117 in the arrangement shown in FIG. Error correction decoding circuit 11
Reference numeral 3 reads and outputs the error-corrected decoded digital data from the fourth storage element 117.

The comparison circuit 119 compares the input digital data with the output digital data bit by bit. The error determination circuit 121 determines whether or not the reproduced output digital data is the same as the input digital data based on the output from the comparison circuit 119.

If even one bit in the reproduced digital data is different from the input digital data, the same digital data is taken into the error correction encoding circuit 101 again, and
The above operation is repeated.

[0018]

The above-mentioned conventional magnetic recording / reproducing apparatus requires four storage elements and requires a large circuit scale.

Accordingly, an object of the present invention is to provide a magnetic recording / reproducing apparatus having a small circuit scale.

[0020]

An additional means for adding a digital code for correction to digital data, a recording means for recording the output of the additional means as a magnetic signal, and a reproduction for reproducing the recorded signal Means, digitizing means for converting a reproduced signal from the reproducing means into a digital signal, and decoding means for restoring digital data using a digital code for correction in the digital signal from the digitizing means, In a magnetic recording / reproducing apparatus for restoring data while reproducing the digital data simultaneously with the storage, a storage means for storing an output of the adding means, and a waveform equalizing means for performing waveform equalization on a reproduced signal from the reproducing means. And a waveform comparing means for comparing the waveform of the output of the war record storage means with the output of the waveform equalizing means.

[0021]

FIG. 1 shows the configuration of an embodiment of a magnetic recording / reproducing apparatus according to the present invention.

The error correction encoding circuit / error correction decoding circuit 1 stores the input digital data in the first storage element 3 according to the arrangement shown in FIG. The error correction coding circuit / error correction decoding circuit 1 reads digital data from the first storage element 3, performs error correction coding, and stores it in the second storage element 5 according to the arrangement shown in FIG. The error correction coding circuit / error correction decoding circuit 1 reads out the error correction coded digital data (FIG. 7) from the second storage element 5 and supplies it to the recording means 7.

The recording means 7 includes a recording medium (not shown)
The error correction encoded digital data (FIG. 7) is stored.

The reproducing means 11 reproduces the digital data stored from the recording medium as a waveform signal. The waveform of the reproduction signal is different from that at the time of recording due to the characteristic peculiar to magnetic recording and reproduction.

The output from the error correction encoding / decoding circuit 1 is supplied to the third storage element 9.
The third storage element 9 temporarily stores the output from the error correction encoding circuit / error correction decoding circuit 1. In the case of the helical scan method, the third storage element 9 has a capacity of at most one track. good. The third storage element 9 has a function of delaying the input of the third storage element 9 so as to temporally match with the reproduction signal from the reproduction unit 11.

The output of the third storage element 9 is supplied to the A input terminal of the waveform comparison circuit 17.

The reproduced signal from the reproducing means 11 is supplied to the waveform equalizing means 13. The waveform equalizer 13 has characteristics (1 / Z) such as complementing the characteristics (Z) included in the electromagnetic conversion system during recording and reproduction, the recording circuit and the reproduction circuit, and converts the reproduction signal into a digital signal. I do. The output of the waveform equalizing means 13 is supplied to the B input terminal of the waveform comparing circuit 17.

FIG. 2 shows a first configuration example of the waveform comparison circuit 17. The subtracter 21 subtracts the digital signal from the B input terminal from the digital signal from the A input terminal. The output of the subtracter 21 is supplied to a low-pass filter 23 and integrated. The output of the low-pass filter 23 is 1 or 0 or -1.
Is one of

FIG. 3 shows a second configuration example of the waveform comparison circuit 17. The subtracter 21 subtracts the digital signal from the B input terminal from the digital signal from the A input terminal. The output of the subtracter 21 is supplied to a latch circuit 25. The latch circuit 25 latches an input according to a clock synchronized with data input to the subtractor 21. The output of the latch circuit 25 is either 1 or 0 or -1.

The output of the waveform comparison circuit 17 is supplied to an error judgment circuit 19. When 0 is input, the error determination circuit 19 determines that there is no error in the reproduction signal. The error judging means 19 judges that there is an error (error) in the reproduced signal when 1 or -1 is input even for one bit, and outputs the signal. At this time, the error correction encoding circuit / error correction decoding circuit 1 fetches the same digital data again, and repeats the above-described operation.

The reproduced signal from the reproducing means 11 is supplied to a digitizing circuit 15. The digitizing circuit 15 converts the reproduction signal into digital data.

The error correction encoding circuit / error correction decoding circuit 1 stores the output of the digitizing circuit 15 in the first storage element 3 in the arrangement shown in FIG. The error correction coding circuit / error correction decoding circuit 1 reads the digital data stored in the first storage element 3, performs error correction decoding, and stores the data in the second storage element 5 in the arrangement shown in FIG. The error correction encoding circuit / error correction decoding circuit 1
And reads and outputs the error-corrected decoded digital data from the storage element 5.

[0033]

As described above, according to the present invention, it is possible to provide a magnetic recording / reproducing apparatus having a small circuit scale, substantially requiring only two storage elements.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a magnetic recording / reproducing apparatus of the present invention.

FIG. 2 is a block diagram showing a first configuration of a waveform comparison circuit 17 of FIG.

FIG. 3 is a block diagram showing a second configuration of the waveform comparison circuit 17 of FIG. 1;

FIG. 4 is a block diagram showing a configuration of a conventional magnetic recording / reproducing apparatus.

FIG. 5 is a data array diagram for explaining the principle of error correction.

6 is an array diagram of input digital data stored in a first storage element 1 of FIG.

7 is an arrangement diagram of digital data stored in a second storage element 5 after being subjected to error correction coding in FIG. 1; FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Error correction encoding circuit / error correction decoding circuit, 3 ... First storage element, 5 ... Second storage element, 7 ... Recording means, 9 ... Third Storage element, 11
... Reproduction means, 13 ... Waveform equalization circuit, 15 ...
Digitizing circuit, 17 ... Waveform comparison circuit, 19 ...
Error judgment circuit.

Claims (3)

[Claims] An adding unit for adding a digital code for correction to the digital data; a recording unit for recording an output of the adding unit as a magnetic signal; a reproducing unit for reproducing the recorded signal; Digitizing means for converting a reproduced signal from the reproducing means into a digital signal, and decoding means for restoring digital data using a digital code for correction in the digital signal from the digitizing means, A magnetic recording and reproducing apparatus for restoring data while reproducing at the same time as storing; a storage means for storing an output of the adding means; a waveform equalizing means for performing waveform equalization on a reproduced signal from the reproducing means; And a waveform comparing means for comparing the waveform of the output of the means with the output of the waveform equalizing means. 2. The magnetic recording / reproducing apparatus according to claim 1, wherein a characteristic of the waveform equalizing means is a characteristic opposite to a characteristic from the recording signal to the reproduction signal. 3. The magnetic recording / reproducing apparatus according to claim 1, further comprising a judging means for judging the quality of the reproduced signal based on an output of the comparing means.