SU754468A1 - Method and device for magnetic recording of marker pulse - Google Patents

Description

The invention relates to the field of instrumentation and can be applied in any field of technology for recording digital information on magnetic media.

There is a method of magnetic recording of digital information, according to which, to increase the reliability of the recorded information, a recording of a special pulse, modulated in width, determines the beginning of a group of binary characters. However, they use two separate tracks on magnetic media for recording one code symbol by one, and the other for synchronization pulses, which increases the consumption of magnetic media. In addition, the use of modulation of the pulse pulse width does not allow identifying it at high recording densities due to the limited resolution of the carrier [1].

The closest in technical essence is a method of magnetic recording of a marker pulse, consisting in the fact that the carrier is reversal in opposite directions.

However, writing a marker in this way at high densities is impossible, so

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as the upper cutoff frequency, this is the frequency of the sync pulses and ever higher frequencies are not reproduced (3].

It is also known an apparatus for detecting ₅ osuschest recording method comprising recording a sync channel, a serial bus, an inverter, a counting trigger circuit 2I-OR-NO element, a magnetic recording apparatus and the playback in the channel generator, coincidence circuit, inver.10 Torr , two consecutive one-shot.

However, this device has a low noise immunity code on a single track, as the failure of a single clock leads to a distortion of all information [2].

The aim of the invention is to improve noise immunity at high longitudinal recording density information.

The goal is achieved by the fact that when recording, one sync pulse is passed at the moment of the beginning of the marker pulse, and during playback the marker pulse is selected by comparing the intervals between the reproduced signals with the synchronization interval. To do this in the device.

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implements the proposed method and contains a synchronous generator, a serial code bus, an inverter, a counting trigger, a 2I — OR — NOT circuit and a magnetic recording apparatus in the recording channel, and a driver, coincidence circuits, an inverter, two series-connected single-oscillator, in the recording channel two inputs of the counting trigger are combined and connected to the input bus of the marker pulse, and two additional single-oscillators and two OR circuits are introduced in the playback channel, with three inputs of one of them connected to the outputs of two x main and one additional series-connected one-shot, and the output to the input of another additional one-shot, the output of which is connected to the output bus of the marker pulse and to the input of another OR circuit, the other input of which is connected to the output of the first main one-shot, and the output of the output clock of the sync pulse .

FIG. 1 is a block diagram of a recording-playback device implementing a method; in fig. 2 - timing charts of the device.

The device for recording and reproducing a marker pulse contains a generator of clock pulses 1, the output of which is connected to inverter 2 and the input of one-oscillator 3, the output of one-oscillator 4, whose input is connected to the output of inverter 2, is connected to AND - the input of the 1st element AND 2I — OR — NOT 5, another And - the input is connected to the input bus of the serial code 6, and And - the inputs of the second element And the circuit 5 is connected to the output of the one-shot 3. The output of the circuit 5 is connected to the counting input of the trigger 7, and the control inputs of the trigger VI and K are combined and connection with the input bus of the marker pulse 8, and the output of the trigger 7 is connected to the input of the recording amplifier of the magnetic recording apparatus 9, the output of the playback amplifier of which is connected to the input of the former 10. The output of the former 10 is connected to the input of two coincidence circuits 11 and 12, while the output of the circuit 11 connected to the input of the single selector 13, and the output of the latter to the input of the single vibrator 14, the output of which is connected to the input of the single vibrator 15. The second input of the Circuit 11 is connected to the output of the inverter 16, the input of which is connected to the output of the single vibrator 14, and the second input The matches are 12'- directly to the output of the one-shot 14. The outputs of the one-shot 13, 14 and 15 are connected to the inputs of the OR circuit 17, and its output is to the input of the one-shot 18, the output of which is connected to the input of another OR 19 circuit, the second input of which is connected to the output of the one-shot 13, and the output is with the output bus of the clock pulses 20. The output bus of the marker pulse 21 is connected to the output of the one-shot 18, and the output bus of the code pulses 22 - with

output of the coincidence circuit 12.

The device works as follows. From the synchronous generator 1, the clock pulses in the form of meanders are sent to start the one-shot 3 and simultaneously to the inverter 2, from the output of which the one-shot 4 is started. The output pulses of the one-shot 3 and 4 are shifted in this way by half the period of the clock frequency . The pulses from the one-shot 3 output to the combined I - inputs of the circuit 5 are constantly present at its output, while the output pulses of the one-shot 4 pass to the output of the circuit 5 only if there is a unit of serial code on the input bus 6 in this synchronization period. Circuit 5 a mixture of synchronization and code pulses is fed to the counting input of the trigger 7, which at the output generates synchronizing ramps and code drops in the interval between the clock pulses. The output sequence of drops of the trigger 7 is fed to the input of the recording amplifier of a single-channel tape recorder 9, which forms the corresponding sequence of differences on the tape carrier. When applying to the combined I and K inputs of a blocking marker pulse that coincides with one of the sync pulses, it is prohibited to switch the trigger 7 with this sync pulse, i.e. there is no synchronizing difference on the magnetic carrier, which is a sign of the marker (Fig. 2 a-e) .

When playing information comes from the output of the linear amplifier of the tape recorder 9 to the input of the shaper 10. The task of which is to generate pulses of the same polarity from bipolar differences in the carrier magnetization (Fig. 2, g). From the output of the shaper 10 pulses arrive at the input of the circuit And 11, which is open in its original state. The first pulse, coming from the output of the circuit 11, triggers the one-shot 13, the pulse duration of which is about a quarter of the synchronization period. The one-shot 14 starts with a falling edge of the one-shot impulse 13, its pulse duration is about half of the synchronization period, and the falling edge is used to start the one-shot 15. Moreover, the one-shot 14 impulse arriving at the input of the coincidence circuit 12 allows the code pulses to pass to the output bus 22 located in the middle of the synchronization period, and at the same time the inverted pulse of the one-shot 14 prohibits the passage to the output of the circuit 11 code pulses. Output pulses of one-shot 13, 14, 15 run after 5

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Consequently, they go to three inputs of the OR circuit 17, and the sum of the pulse durations of the three single vibrators is slightly longer than the duration of the synchronization period. Therefore, in the presence of sync pulses, the overlapping pulses of the single vibrators form a constant potential at the output of the circuit 17. At. In the absence of a single clock pulse, the potential at the output of the circuit 17 drops to zero, and this voltage drop triggers the one-shot 18, the output pulse of which serves as a marker and goes to the output bus of the marker 21, as well as to the input of the circuit OR 19, where it is added to the pulses sync pulses supplied from the output of circuit 19 to the output bus of sync pulses 20.

Recording a marker pulse allows to increase the noise immunity of a digital recording of a sequential code at high densities by using a marker as a sign of the boundary of a group of th binary symbols. Since the method does not involve the introduction of additional differences or changes in the distance between edges of recording token, but only eliminates one of the differentials, the longitudinal recording density ₂ NOSTA not limited conditions marker and reproducing can be increased to the limit value. A simple single-channel tape recorder can be used to record and play digital information. thirty

Claims (2)

Claim 1. The method of magnetic recording of the marker pulse, which consists in the fact that the carrier is re-magnetized in opposite ³⁵ directions, characterized in that, in order to increase the noise immunity when a high longitudinal information recording density, when recording, they skip a single sync pulse at the moment the marker pulse starts, and during playback, the marker pulse is extracted by comparing ₅ intervals between the reproduced signals with a synchronization interval. 2. A device for implementing the method of π. 1, which contains a synchronous generator, a serial code bus, an inverter, a counting trigger, a 2I — OR — NOT circuit, a magnetic recording apparatus in the recording channel, and a driver, coincidence circuit, inverter, two series-connected single-oscillator in the playback channel, in order to increase reliability, two inputs of the counting trigger in the recording channel are combined and connected to the input bus of the marker pulse, and two additional single-oscillators and two OR circuits are introduced in the playback channel, with three inputs of one of them connected There are two main and one additional one-vibrators in series with the outputs, and the output is with the input of another additional one-vibrator, the output of which is connected to the output bus of the marker pulse and the input of another OR circuit, the other input of which is connected to the output of the first main one-vibrator and the output with bus clock output.