SU1451764A1 - Method of magnetic recording and playback of digital information - Google Patents

Abstract

The invention relates to a magnetic recording technique, allows an increase in recording density and reliability of synchronization and decoding during playback and can be used in digital recording and processing equipment. Recording according to this method is performed by re-magnetizing the magnetic recording medium at the boundaries of digital positions, with the same clock intervals of the recording signals 1 and O, while in the recording signal of one of the binary bits 1 or O a predistortion pulse is formed, symmetrical about the middle of the clock interval with the duration 2-30% of the duration of the clock interval recording. A predistortion pulse reduces the magnetization in the middle of the interval when the corresponding bit is written, which during playback causes a change in the steepness of the voltage of the reproducibility of the signal, which creates a physical difference when recording and playing bits 1 and O. During playback, the signal is amplified, twice differentiated the level of the result of the first differentiation form the sync signals and decode the signals of one of the information bits 1 or O through three zero-crossing oh level of the result of the second differentiation in the interval between two adjacent clock signals. The playback signal is self-synchronous, single-slot, each period of this signal carries two bits of information, which increases the recording density. Improving the reliability of synchronization and decoding is ensured by the fact that for decoding information, ancillary synchronization is not required, and it is realized by the difference in the number of zero crossings between the two times of the differentiated reproduced signal in the interval between the sync signals. 3 il. F cl h

Description

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

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The purpose of the invention is to increase the recording density and increase the reliability of synchronization and decoding during playback.

Fig. 1 shows plots of recording and reproducing signals by the proposed method; in fig. 2 and 3 are stream diagrams, respectively, of recording and reproducing devices for performing the operations of the proposed method.

The method is carried out as follows.

In the process of recording, the magnetic recording medium is re-magnetized from one saturation state to another at the boundaries of the digital positions of the information signal, with the same time interval of the sigpal records for information 1 and O. In the clock interval of the recording signal one of the binary information bits 1 or O forms the predisciption (pa of figs, 1 this pulse is formed for signals 1), symmetrical about the middle of the clock interval, with duration. 2-30% of the duration of the clock recording interval (signals and Xg in Fig. 1), the predistortion pulse produces a short-term reversal of the carrier in the opposite direction in the middle of the interval, and thus the carrier is demagnetized, as a result of the magnetization of the magnetic carrier for The two information signals 1, Opi O, recorded with predistortion, are smaller than those of the other, which, when reproduced, results in a difference in the slope of the change in the signal voltage in the middle of the interval (signal X in FIG. 1) than Physical difference between signals 1 and O is recorded during recording and playback,

In the process of reproducing the signal from the carrier, the magnetic shadow is amplified, differentiated and, at the moments of transition through the zero level, the result of this first differentiation (signal Xd in FIG. 1) generates sync signals (X,), performs the second differentiation (signal Hu) ,

Due to the fact that the difference in the magnetization of the carrier when recording 1 and O is reproduced, these signals are reproduced with a different steepness of the voltage variation in the middle of the interval and the result of the second differentiation (signal Xd) crosses the zero level (in the interval between two adjacent sync signals X / p) three times for those informational signals (in this case, signals 1), which were recorded with a predistortion pulse, and once, if such predistortion was absent (in Fig. 1 for informational O signals). This allows decoding information signals 1 or O by the number of transitions through the zero level of the result of the second dl1) fermentation in the intervals between two adjacent clock signals, namely, signal 1, over three such transitions.

A recording device that implements the operations of the recording process according to the proposed method can be performed according to the flowchart in FIG. 2 and contains a clock pulse generator 1 connected to the counting input of trigger 2, the forward and inverse outputs of which are connected respectively to the counting input of trigger 3 and c the first input of the first element IS-HE 4, the second input of which is connected with the output of the generator 1, and the third input - with the source of input information (not shown in FIG. 2). The output of the first element AND-NOT A is connected to a shaper of 5 pulses, an output connected directly and through an inverter 6, respectively, to the second inputs of the second 7 and third 8 elements I-Sh, the first inputs of which are connected, respectively, to the direct and inverse outputs of trigger 3, The outputs of the elements AND-HE 7 and 8 are connected to the inputs of the fourth element AND-HE 9, the output of which through the recording amplifier 10 is connected to the magnetic recording head 11.

The operation of the recording device is illustrated by the signal plots Xf-X in FIG. 1.

Playback device; implementing the operations of the reproduction process of the proposed method can be performed by structural

Scheme np FIG. 3 and contains serially connected magnetic reproducing head 12, amplifier 13, first 14 and second 15 differentiators, to the outputs of which the first 16 and second 17 limiters are connected, respectively, connected to the first 18 and second 19 pulse shapers, the output of the first shaper The 18 pulses is the output of the device's sync signals and is also connected to the inputs of the installation in O of the first 20 and second 21 flip-flops connected in series. In this case, the output of the first trigger 20 is associated with the output of the second limiter 19, and the output of the second trigger 21 is the information output of the device (the output of the information signals 1). The operation of the playback device is explained in plots of the Hu-X / 3 signals in FIG. 1. The pulse sequence X, formed by zero transitions of the signal X d (the result of the second differentiation) is fed to the counter input on the flip-flops 20 and 21, which are periodically set to O with each clock signal X, (,. the counter receives three pulses, and the O signal only

one, therefore, the signal at the output of the trigger 21, the information output of the device, appears only during playback 1 (the signal in figure 1).

The recording density of the proposed method can be doubled, since each period of a single-interval playback signal carries two bits of information, while the playback signals have self-synchronization, and the decoding of information is reliably performed by the difference in the number of transitions

through the zero level of the result of the in-time differentiation of the reproduced signal for the informational signals 1 (three transitions) and O (one transition) in the interval between two adjacent sync signals, and this does not require the formation of auxiliary sync series, which synchronizes the reliability.

Claims (1)

Invention Formula The method of magnetic recording and reproducing digital information, in which magnetic magnetic record carrier at the boundaries of digital positions is remagnegated during the recording, with the same time interval of the data recording signals 1 and O, and pulse predistortion is introduced in the time interval of the recording signal one of the binary bits of informational 1 or O, and during playback they amplify, differentiate the reproduced signals and generate pulse signals at the moments of transitions of differentiated signals through zero It is characterized by the fact that, in order to increase recording density and increase the reliability of synchronization and decoding, the predistortion pulse during recording is formed symmetrical about the middle of the clock interval with a duration of 2-30% of the duration of the recording signal clock interval, and during playback, sync signals are generated at the moments of transition through the zero level of the result of the threshold differentiation and decodes the signals of one of the information bits 1 or O at three zero-level transitions in the interval between two adjacent sync signals of the second differentiation. r J T I 1 0 rm 0 g П П n П П П П П П П П П П П / L1 GP rn n n n  fP I Ir s n nTL 6 PP n I n i  Chag / I I I IIIL 4 i I 1 M I IIIIII I ..L  "NJlJlJlJnJlJbJ J-ln 1 SI Compiled by A.Lukanin Editor E.Kopcha Tehred.Didyk Proofreader A.Obruchar Order 7085/50 Circulation 558 BHHHroi State Committee on Inventions and Discoveries at the State Committee on Science and Technology of the USSR 113035, Moscow, Zh-35, 4/5 Raushsk nab.  ...."at - ,-. - -. “- - - - - Production and printing company, Uzhgorod, st. Project, 4 Tszig. Subscription