SU1278935A2 - Method of digital recording and reproducing from magnetic record medium - Google Patents

Abstract

This invention relates to magnetic recording. The purpose of the invention is to improve the fidelity of the recording-reproduction of information. To do this, when recording, the interval of pause between recording "1 and" About information that is formed into code groups before recording is carried out by simultaneously changing the magnetization of the magnetic recording medium with polarity determined by the value of the recorded information before the pause and the period of change of the carrier magnetization, two times larger than the period of change of magnetization when recording "1" and "On the code group of the recorded information. 1 il.

Description

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The invention relates to magnetic recording, in particular to methods of digital recording and reproducing on magnetic recording media, and is an improvement of the method according to the author. St. No. 1081651.

The purpose of the invention is to improve the fidelity of the recording-reproduction of information.

The drawing shows time diagrams, the essence of the proposed method.

Diagram a shows a recorded sequence of digital information, diagrams of bivs show a change in the carrier magnetization on parallel tracks, diagrams g and d show sequences of pulses formed from playback signals, and diagram e represents a voltage corresponding to the product of the reproduced pulse sequences by diagram g - a sequence of pulses, corresponding to, and to every second pulse of a pair of pulses parallel to the tracks or to the pulse of one of the tracks and the absence of a pulse of another track, in the diagram and - the pulses delayed by half the clock period, in the diagram k - the potential of the pause between code groups, in the diagram l - the strobirovannye delayed pulses and in the diagram m - the sequence of reproduced information.

The method is carried out as follows.

When recording "About information, the magnetization of the carrier on parallel tracks during the clock period of the recording is in an antiphase position, and when recording" 1 information, the magnetization of the carrier on both tracks during the clock period is in the in-phase state (diagrams a, b and c). When recording the active pause signal, the magnetization of the carrier on parallel tracks changes simultaneously with a period twice as long as the clock period of the recording, the end of the pause signal is recorded as a change in the magnetization of the carrier with a clock period of recording (diagrams a, b, and c during the time corresponding to pause signal). The introduction of an additional change in the magnetization of the carrier at the end of the pause signal is necessary so that after the pause signal any value of the binary code can be recorded without using other time intervals between the magnetization reversals other than the clock and double clock periods. This significantly narrows the energy spectrum of the recording signals, which in the proposed method is concentrated around two harmonics. The reproduction of the waveform thus produced is carried out by forming two reproduced pulse sequences corresponding to the maximum values of the signal, taking into account its

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polarities (digrams g, and g}. Then, from these sequences, a voltage is formed that corresponds to the product of the polarities of both pulse sequences (diagram e). This voltage is used to gate another pulse sequence, which is obtained by selecting each second of a pair of pulses by parallel tracks (temporal misalignment of pulses recorded simultaneously on parallel tracks is caused by the effects of the recording-reproduction path noise) or one of horns in the absence of a pulse of another track (diagram g), and a time delay of half a clock

the period of recording the information of the pulse sequence obtained in this way (diagram u}. At the same time, the time interval between the pairs of parallel pulses is checked and the potential of the pause signal is calculated when this time interval exceeds one and a half of the recording clock period, and the potential of the pause signal ends when the the interval is less than one and a half of the clock period (dia 5 frame). Output code pulses are generated in the absence of the potential of the pause signal by gating a delayed pulse sequence by a voltage corresponding to the product of the polarities of both reproduced pulses

0 sequences (diagrams e, and, k). The output impulse “1 information is given with a positive sign of the gate voltage, and the impulse“ About information is output with a negative sign of the gate voltage.

Claims (1)

Invention Formula The method of digital recording and playback on magnetic recording media according to the author. St. No. 1081651, characterized in that, with the purpose of increasing the fidelity of recording-reproducing information, when recording, the interval of pause between recording "1 and "About the information that is formed into code groups before recording is carried out by simultaneously changing the magnetization of the magnetic carrier recording with the polarity determined by the value of the recorded information before the pause, and the period of change of the magnetization of the magnetic recording carrier, twice as long as the period of change of the magnetization during the recording of "1 and" On the code group of the recorded information, while simultaneously generating a signal for the end of the pause the magnetization of the magnetic recording medium twice, and during playback, the pause interval and the pause end signal are determined by measuring the duration of the interval between the corresponding pulse sequences of two pulses reproduced. Lp; / and I, I and I l n