SU1015427A2 - Method of digital data reproduction and recording to moving magnetic medium - Google Patents

Abstract

I. METHOD OF DIGITAL RECORDING AND REPRODUCTION OF INFORMATION ON A MOBILE MAGNETIC MEDIA BY the aut. Ev. No. 841033, characterized in that, in order to increase the fidelity of reproducing information by compensating for media transfer, in the pauses between code groups of information, the carrier magnetization is changed simultaneously on both tracks, the end of the pause is recorded as a constant magnetization level without changing its polarity on the first track, and the beginning of a pause in the form of a constant magnetization level on the second track, during playback; count the number of reproduced pulses from one track, with no pulses on the other, determine the difference in the number of pulses corresponding to the number of recovered 1 and О information in the pauses, and change the delay time of the signals reproduced from both tracks in accordance with the sign and value of this difference.

Description

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2. The method according to p. 1, about tl and h ay n. and and with. by the fact that at the beginning of the recording the clock period of the pause signal establishes more possible temporal mismatch of the signals

products, and the recording time of the pause signal with a reduced clock frequency is determined by the required accuracy of the compensation of the effect of carrier transfer;

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This invention relates to instrumentation engineering, in particular, to a technique of magnetic recording and reproducing digital information, and. can be used for digital recording of continuous processes in tape recorders.

On the main auth, sv. 841033 a digital recording and reproducing method is known, according to which binary units are recorded on magnetic media in the form of changes in the carrier magnetization of two parallel tracks shifted by one quarter of the clock cycle depending on the value of the recorded information, and on the value of the binary unit during playback the trial t according to the sign of the time position of each pair of them. EI pulses.

The disadvantage of this method is that the reproducible information is not very correct due to the influence of the magnetic carrier skew, since the magnitude of the time error of the signals does not. parallel tracks due to skewing may exceed a quarter of the clock period, which leads to playback errors. I. -,

The purpose of the invention is to increase the fidelity of the reproduced information by compensating for the effect of carrier skew.

This goal is achieved by the fact that according to the method of digital recording and reproducing information on a movable magnetic carrier in the pauses between code groups of information, the carrier magnetization changes simultaneously on both polarity tracks, the end of the pause is recorded as a constant magnetization level without changing its polarity on the first track, and the beginning of the pause - in the form of a constant level of magnetization in the second track; during playback, count the number of reproducions of their pulses from one track, with utstvii pulses - on the other determined amount difference pulses, the number of recovered sootvetstvuyushaya 1 and G information in the pauses, and varied reproduction delay time on both tracks in accordance yignalrv

with the sign and magnitude of this difference.

At the beginning of the recording, the clock period of the pause signal is set to more than 5 possible temporal mismatch of the playback signal, and the duration of the recording of the pause signal with a reduced clock frequency is determined by the required accuracy of compensation for the influence of carrier skew.

The drawing shows diagrams explaining the proposed method of digital recording and reproducing information on a movable magnetic carrier.

5. Diagrams a and d are given.

changes in the carrier magnetization on the first and second tracks when writing a digital code and pause signals between code groups, on diagram Q me - b - a code group determination signal, Z id - output pulses 1 and O, respectively, and on it change the difference in the number of pulses 1 and O in pauses.

5 The method is carried out as follows.

The pause signal is recorded by simultaneously reversing the carrier on both tracks, the end of the pause is recorded in the form of no reversal of ticks on the first track, and 1 and O are two transversals of the carrier on both tracks, and when recording 1, the change in the reversal in the first track is ahead of the remagnetization

on the second, and when recording O, the change of carrier bite on the first track is delayed by a quarter of the clock relative to the carrier bias on the first track (d and (5). Thus, when recording signals, the magnetization reversal carrier is produced simultaneously,

5 on both tracks is performed at different times, and the directions of the reversal on both tracks coincide a quarter of a tact after each pair of pulses has been recorded. At the same time, a pause is written in the form

the absence of magnetization reversal on the lane, the wake path, and the beginning of the pause - in the form of the absence of magnetization reversal on the second, swarm path.

When playing, the pulses from both tracks of the carrier are distributed into pairs of unipolar pulses, 1 code is determined with the first pulse reproduced from the first track, and O with the first pulse reproduced with a mountain track. The recovery of the recorded code is performed equally in the pauses and code gaps. At the same time, the end of the pause is determined when there is a series of pulses reproduced from the second track, if there are no impulses from the first (diagram c), and the beginning of the pause - if there is a series of pulses in the first track (diagram f.), Media skew during playback of the waveform causes a temporary shift of reproducible parallel tracks, signals (figure 5, dashed line). Therefore, in the pauses, the code value determined by the sign and the skew value will be restored (diagram d and 3K, on which the sequences of the output pulses 1 and O are given, respectively). The difference in the number of these pulses is determined (diagram e), according to the value of which the reproducible signals are delayed, thus compensating for both dynamic and static carrier skew.

Since the magnitude of the time shift of signals due to carrier skews can exceed the clock period at a sufficiently high recording density, to enter the phase, a pause signal is required at the beginning of the signal graph / we

write, with a period, the value of the second one exceeding the possible time shift. At the same time, the duration of such a pause signal is set such that the prescribed accuracy of compensation is ensured.

For digital magnetic recording, there is a lot of noise coming from the playback signal. Therefore, in order to ensure the reliability of recording and playback, the duration of the start and end signals is necessary; set the pauses so that the probability of a signal of such a length falling out is equal to the specified one. Of these, 5 conditions establish the number of clock periods for recording the start and end of the pause signal. Therefore, at shorter durations, false pause and code group signals will not be generated, thus providing noise immunity to suchNoNffixaM.

Thus, the application of the proposed method contributes to increasing the reliability of recording and reproducing digital information by compensating for carrier skew and reducing the effect of the playout signal dropout of a certain duration. The skew compensation is made according to the statistical value of the code reproduced in the pauses. With the aft, there is no need to determine the error signal with the help of measuring devices of small time intervals, which simplifies the technical implementation of compensation for the influence of the skew.

Claims (2)

(54.) 1. METHOD OF DIGITAL RECORDING AND PLAYBACK OF INFORMATION ON MOBILE MAGNETIC CARRIER by ed. St. No. 841033, characterized in that, in order to increase the fidelity of reproducing information by compensating for the influence of media transfer, in the pauses between code groups of information the magnetization of the medium is changed simultaneously on both tracks, the end of the pause is recorded as a constant level of magnetization without changing its polarity on the first track, and the beginning of a pause in the form of a constant level of magnetization on the second track, during playback, the number of reproduced pulses from one track is counted, in the absence of pulses - from another, determine the difference in the number of pulses corresponding to the number of restored 1 and About information in pauses, and change the delay time of the signals reproduced from both tracks in accordance with the sign and value of this difference. e I I e FbF-zFtftRfl innnTLTLT-J S I Jz t, e 2. The method according to π. 1, characterized in that at the beginning of the recording, the pause signal cycle time is set longer than the possible temporal mismatch of the signals of the product, and the duration of the recording of the pause signal with a reduced clock frequency is determined by the required accuracy of compensation for the effect of carrier transfer.