SU853656A1 - Method of digital data recording and reproduction - Google Patents

Description

(54) RECORDING METHOD - REPRODUCING DIGITAL INFORMATION

I

The invention relates to the field of instrumentation and can be used in the construction of digital storage devices on moving magnetic media.

A known method of recording digital information with self-synchronization, according to which the value of a binary unit is determined either by the direction of magnetic reversal of the carrier at the end of a clock or by the distance between two magnetization reversal 1.

However, when recording information in the form of separate groups, the noise immunity is insufficient for the reason that the detection of the reproduced signal is performed according to its amplitude. Therefore, the presence of noise in the yauses between the groups and spurious amplitude modulation of the signal leads to false detections and skips of the signal.

The closest in technical essence is a method of recording-reproducing digital information with self-synchronization, the phase modulation method 2.

However, the reliability of the reproduced information is low.

The aim of the invention is to improve the noise immunity of the device.

The goal is achieved by those. that in the intervals between code groups the signal is recorded with a frequency of less than two times the clock frequency of recording information, and when playing, the beginning and end of the code groups are determined from changes in the frequency of the playback signal.

FIG. 1 shows a block diagram of a recording device according to the proposed method; in fig. 2 is a block diagram of a reproducing apparatus; in fig. 3 - timing charts, explaining the proposed method.

A device for recording a digital signal according to the proposed method (see FIG. 1) contains an input data bus 1, 5 connected via the OR 2 circuit and a recording unit 3 to the recording head 4, the .5 scheme for determining the pause between code groups, And 6 -and generator 7 reference pulses.

Claims (2)

20 A playback device (see FIG. 2) comprises a serially connected playback head 8, a playback amplifier 9, a pulse shaper 10, and a demodulator 11 of a reproduced signal, an output connected to the output bus 12 of the device. In addition, the device comprises a frequency change meter 13 connected between the pulse shaper 10 and the demodulator 11. The proposed method is carried out as follows. The digital code (see Fig. 3, a) to be recorded goes to one input of the OR circuit 2 and the pause detection circuit 5. In the presence of the input code of the recording unit 3, it is recorded on magnetic media, for example, by phase manipulation method (see FIG. 36). After the end of the next code group, the pause determination circuit 5 (see FIG. 3, c) is triggered, the AND 6 circuit is opened and the generator 7 reference pulses arrive at the recording unit 3 (see FIG. 3, b and 0 in the time interval ti -1d). When a new code group arrives, circuit 6 is closed and the code of this group is recorded on the carrier. The reproduced signals by the head 8 are amplified by the amplifier 9 and are formed into shaping pulses by its 10. The output pulses of the former are fed to the inputs of the demodulator 11 and the meter 13, on the output of which the pulses appear at frequency jumps of the reproduced signal corresponding to the clock frequency of the recording and pause signals ( see Fig. 3, d). In this case, the meter 13 blocks. / demodulator 11 with a negative jump in the frequency of the reproduced signal (see Fig. 3, d). Therefore, the demodulator 11 issues a code to the output side of the device 12 only in the time intervals corresponding to the recorded code groups. The use of the proposed method in accumulators of information on moving magnetic media makes it possible to increase the reliability of the data, since the signal is detected not by its amplitude, but by frequency parameters. Claims The method of recording and reproducing digital information with self-synchronization by the phase modulation method, characterized in that, in order to increase noise immunity, in the pauses between ((one groups record a signal with a frequency less than 2, 4 clock information recording frequency, and during playback the beginning and the end of code groups are determined by changes in the frequency of the reproduction signal Sources of information taken into account during the examination 1. B. Kagan, et al., Storage devices of larger capacity, M., Energia, 1968, p. 0 2. USSR author's certificate number 539316, cl. G 11 B 5/09, 1975 (prototype). V. pg I5 5§ t "N