SU1580433A1 - Method of magnetic recording digital information - Google Patents

Abstract

The invention relates to instrumentation, in particular to a magnetic recording technique, and can be used in digital recording equipment of recording systems and in computing. In order to increase the fidelity of the record-reproduction result by increasing the recording direction for falling out and distorting the reproduction signal, before forming the recording current pulses, the digits of the information and control tetrads are summed over the selected module M, where M = 2,3,4 or 5, and different values of the checksum are assigned to different dipolar pulses with the corresponding fields of the first and second dipulse pulses. 2 Il.

Description

(L

with

The invention relates to instrumentation, in particular to a magnetic recording technique, and can be used in digital magnetic recording equipment of information recording systems and in computing.

The purpose of the invention is to increase the fidelity of the recording-reproduction result by increasing the correcting ability of the recording to fallout and distortion of signals during reproduction.

FIG. 1 shows a block diagram of an apparatus for carrying out the proposed method; in fig. 2 - timing diagrams explaining the essence of the method.

A device for implementing the method contains in the recording channel an input information bus 1, on which the input information sequence signals are received, a delay block 2 and time separation of information tetrads (four-bit groups of the input information sequence), a block 3 for determining the bit sums of four neighboring information tetrads, a block 4 formations of a control tetrad, a shaper of 5 dipulses, a recording unit 6 with an output 7 for recording on magnetic media (not shown), a control unit 8 containing g 9 generator of clock pulses, the control input 10 the recording, reproducing clock generator 11 pulses, the control input 12, and a reproducing channel - reproducing unit 13, the input signal 14 with the magnetic carrier reproducing unit 15 decoding reproduction signal generator 16 information tetrads formiel

00

about

4i

OE 00

ten

15

20

3,

a control tetrad rover 17, a shader of 18 tetrads group size checksum from a playback signal, a signal generator of a distortion of a dipole signal, a delay block 20, time compression and tetrad control, an output 21 of the information sequence from block 20.

In the device, blocks 2 and 3 are connected to the input information bus 1, outputs connected to the first and second inputs of the driver 5 dipoles connected by the third input to the output of the block, and output to the input of the recording block 6 connected by output 7 to the recording bus on carrier. The output of block 2, in addition, is connected to the inputs of blocks 3 and h. The control inputs of the blocks 2 - k and the driver 5 are connected to the control unit 8 and connected to the corresponding generator outputs 9 clock pulses, the control input connected to the bus Record 10. The clock driver 11 is connected by a control input to the bus 12, information input - to one output of playback unit 13 connected with playback bus 14 from a carrier, and output connected with blocks 15 and 20 and connected to control inputs of drivers 16 - 19 connected by information inputs with another output of Ok 13 is played, and the outputs are from the information inputs of the delay unit 20, time compression and control of the tetrads connected by the output to the output bus 21 of the device.

The diagrams (Fig. 2) show: a - a sequence of four-bit information groups to be recorded on the magnetic carrier 25

thirty

40

amounts for the selected module of each tetrad (in the example, the total case of control modulo five is selected); d - n sequence of recording current pulses, in which the shape of each dipulse is determined by the values of four bits of the corresponding tetrad (informational or control) and one of two (if control modulo two) or of three (if there are three counters), or out of four (if control is modulo four), or out of five (if control is modulo five) values of the checksum, those are happy, d is a sequence of playback signals (blackened are marked by distorted pulses of two adjacent dipuls, true field which are marked by a dashed line), e is an information sequence of tetrad signals and their partial checksums, formed from CHI playback signals (incorrectly decoded tetrads are marked with a circular trace), W are signals of control umm Five tetrads, formed from reproduction signals; h - signals of one-bit checksums calculated from tetrads decoded from the playback signals; and - the output information sequence with built-in bitwise checksums (marked with a wavy line) and restored tetrads (marked with a rectangular stroke).

The recording method includes operations that implement special recording modes for digital information signals.

When recording, the initial informational sequence of signals (Fig. 2a) is fed to the input 1 of the device, the inputs of the delay unit 2 and the recordings (the tetrads are grouped into four separable tetrads and block 3

and within each group for convenience are numbered); b - the same sequence, but with the arrangement of the tetrads of the first and second groups with a time interval between the neighboring tetrads 50 of the same group, proportional to the maximum duration of group dropsouts or distortions, and the corresponding calculated discharge digits modulo two CS 55 and CSG The informational and control dipuls of one group are marked with a line), - in - control

0

five

0

five

five

0

40

the sums on the selected module of each tetrad (in the example the total case of modulo five is chosen); d - post-sequence of current recording pulses, in which the shape of each dipulse is determined by the values of four bits of the corresponding tetrad (informational or control) and one of two (if control is two) or out of three (if control is three), or of the four (if the modulo four is control), or of the five (if the modulo five is control) values of the tetrad checksum, g is the sequence of reproduction signals (blackened outlines the pulses of two neighboring dipulses distorted by extended interference, whose position is marked by a dashed line), e is the information sequence of tetrad signals and their bit checksums formed from CHI playbacks (the rectangular outline shows incorrectly decoded tetrads), W are the signals of control minds modulo five tetrads, formed from reproduction signals; h - signals of one-bit checksums calculated from tetrads decoded from the playback signals; and - output information sequence with embedded bitwise checksums (marked with a wavy line) and restored tetrads (marked with a rectangular stroke).

The recording method includes operations that implement special recording modes for digital information signals.

When recording, the initial information sequence of signals (Fig. 2a) is fed to the input 1 of the device, the inputs of the delay block 2, and the determination of bit specific checksums. In block 2, a delay is effected, for example, by

L3MA + t

 BUT

 t3ftA (1,2,3,4, KC,) (1,2,3,4, KCJ

tetra i

tetras

K (5t

one

with (myx

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2 10tc6

MO KS

cf llax 1 ° C «P

where tc5 ax is the maximum extent of the malfunctions to be corrected, accepted

one

five

ZDSS FOR nn.f- GTt,

equal to two periods of recording pulses, i.e.

Bc5. 2t3otn

To the coefficient of proportionality,

Consequently, the delay in this example is 10 recording periods at a selected value of K — which ensures the time separation of five associated dipulses of one group from each other by 1 period of recording dipulses. This means that the most severe failure due to a fallout or distortion can distort no more than one group pulse that is known to be detected and almost always corrected. In block 3, one-by-one checksum is determined modulo two by a group of four tetrads (Fig. 26 - CS, and COP) and in block k - checksums for the selected module of each tetrad.

From the outputs of blocks 2C, the signals of the information notebooks and checksums (control headers) are fed to the inputs of the imaging unit 5 dig. Bar in the order indicated in FIG. 26, c. In the shaper 5, each tetrade is matched with either a polar dipulse with one polarity of the first pulse — at the first value (OOP) of the tetrad checksum on the selected module (for example, the second and seventh dipulses on Fig. 2d), or a different dipolar pulse with a different polarity of the first pulse — with the second value (001) of the tetrad check sum (for example, the value of the sum 001 in any module corresponds to the ninth and tenth dipulses in Fig. 2d) pny dipu with with the same polarity of the first pulse and with an interval of established length (for example, C,) —with the third value (010) of the checksum of the tetrad (for example, the value of the sum 010 modulo three, four, five correspond to the third and tenth dipulses in FIG. 2d), or a multipole dipulse with a different polarity of the first pulse and with an interval of established length — with the fourth value (011) of the checksum of the tetrad (for example, the value of the sum 011 in the mode four and five

CHOMZ6

The fourth and fifth dipulse in FIG. 2d), or a unipolar dipulse with an interval between pulses — with the fifth value (100) of the tetrad checksum (for example, the sum of 100 corresponds to the first and sixth dipuls in FIG. 2c).

JQ The duration of the first (second) pulse (D) of a dipulse is formed by a minima-pulse (С01 h if the first two (last two) bits of the information or control tetrad are 01 (the second pulse of the third, eighth, ninth and the tenth of the dipulses, the first pulse of the fourth and the fifth dipulses), or equal to .0й - -Г, + а Ј2 for

20 software combination, either equal to C10 i t- 2 Јз for a combination of 1C, or equal to Ј „., 4 3 D

25

And for combination 11, where / Cc is chosen to be J Ј (0.1-0.3) x 0. The duration of the interval between

At WH.- "

impulses are chosen equal to

no more

m h n

Formed according to the specified rules; (Fig. 2d) is fed to the input of the recording unit 6, from the output 7 of which they are recorded on a magnetic recording medium.

The sequence of pulses reproduced from the carrier (Fig. 2e) is amplified in the playback unit 13 and served as clock pulses to the imaging unit 11 and to the playback unit 15 of the playback signal decryption,

in which, from the reproduced sequence, the shaper 16 forms the bit signals of each four-bit information group (Fig. 2e), forms the checksum signals of each tetrad by means of the shaper 17 (Fig. 2g), and forms the signal with the shaper 18; control tetrads - bit checksums of the corresponding groups of related tetrads (ninth and tenth tetrads in Fig. 2e) and using shaper 19 form a signal of a sign of distortion of the dipulse signal when the latter are not decoded (for example, in the case of deposition of signals).

The generated signal sequences from the outputs of the formers are fed to the inputs of the delay block 20, time compression and tetrad monitoring, which determine the actual bitwise modal checksum of two related groups of decoded tetrad playback signals (Fig. 2h), temporarily compress the sequences to the original view (Fig. 2a), the accuracy of the information sequence is checked according to the correspondence of the decrypted and actual control - sum of the tetrads and of the random control UMM corrected tetrad distorted by bit-wise modulo two bits undistorted three tetrads group which includes tetrad distortion and bit porazr dnyh checksums of the same group, from the decrypted reproduction signal of additional (control) dipulsa.

Thus, the bpt values of the distorted sixth tetrad (Fig. 2e) are determined by incrementally modulo two bits of the second, fourth, and eighth undistorted tetrads, along with the sixth tetrad and the additional (control) tenth tetrad, constituting a single group, and bits of one-bit checksums, decoded from the reproduction signal of the tenth dipole. The result is re-checked by the checksum of the tetrad decrypted from the distorted dipulse (this is carried out only in the absence of a signal of a sign of the distortion of the dipulse produced by the former 19), and in cases where the checksum modulo five tetrad is 100 (i.e. the original, before recording, the tetrade, all four bits of the unit, as is the case in the sixth tetrad in Fig. 2g), or 000 (i.e., in the original, before recording, the tetrad, all four bits are zero, as is the case in the seventh tetrade in Fig. 2g), re-restore it bits skazhennoy tetrads and compared with the result of the first reduction.

As a result, at the output of block 20 a corrected output sequence is formed with the control tetrad embedded in it (if necessary) to control the reliability of the information tetrads immediately prior to their use (Fig. 2i).

five

0

five

0

five

0

five

Thus, when using the proposed method, the correcting ability and reliability of recording digital information is significantly improved by effectively detecting errors of any multiplicity in the decrypted information groups and their subsequent correction.

Claims (1)

Invention Formula A method of magnetic recording of digital information, in which information signals of the recording current are formed from the signals of the four-bit groups of the initial information sequence of information tetrads, in which the duration of the first and second pulses is set in accordance with the values of the first two and last two bits of the information tetrad, also form additional control dipoles of the recording current, in which the pulse duration is set in accordance with the values of the control signal There are about one modular two checksums of four adjacent informational notebooks, characterized in that, in order to improve the accuracy of the zashis-reproduction result by increasing the correcting ability of the recording to fallout and distortion of signals during playback, prior to the formation of current pulses the records summarize the values of the bits of the corresponding information or control notebooks for the selected module M (where M 2, 3 4 or 5) - the different polarity pulse corresponds to the first value of the obtained checksum with one polarity of the first pulse, the second value - a dipolar dipole with another polarity of the first pulse, the third value - a dipolar dipulse with one polarity of the first pulse and the set time interval between the dipulse pulses, the fourth value - a dipolar dipulse with the other polarity the first pulse and the time interval between the pulses of a dipulse, and to that value - the dipulse of pulses of the same polarity with a time interval between them, with each four information and one control dipulses corresponding to the neighboring information tetrad of the original record with a time interval between information sequence proportional to the maximum signals and their control tetrad, the duration of group fallouts or recorded on a magnetic distortion carrier. To carrier C carriers Exit T 1 M g 1001 wholesale About 000 zG "G" G # G, Gg G3 Ir TWlrVi "G, g, g, g 1111 0000 / 007 0111 E / 00 5 five I -010 I 011 U 1111 roo t 01 1 1 one 000 0111 1111 1001 7 1 10 1 , 0001 2 007 O 000;  The cop Have g, ll Yy About OOP 100 1 0001 0007  0/7 007 1,100 OOOO 011 1 shh 1 007 ; /before 70СГ7 Z 007 5 1110 0001