SU1084874A1 - Process for generating binary code signals reproduced from magnetic medium - Google Patents

Description

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The invention relates to instrumentation and can be used in digital magnetic recording apparatus.

There is a known method for processing and demodulating Binary code signals recorded on magnetic media using the " no return to zero (BVNM) method. When using this method, pulse signals of “code units” are formed when the signals from a carrier exceed a certain threshold level 1.

A known method for processing and demodulating reproducible signals recorded by the BNHM method at the extreme points of reproducible signals 2.

The closest to the proposed one is the method of processing and demodulating the signals reproduced from the carrier by their extreme points 3.

However, when using the known methods, the parasitic displacement of the moments of the formation of pulses corresponding to extreme points limits the increase in the recording density of binary signals recorded on the medium by the BNHM method.

The aim of the invention is to increase the fidelity of the reproduction, and hence the recording density of the signals of the binary code.

This goal is achieved by the fact that, according to the method of generating binary code signals reproduced from a magnetic carrier, based on the generation of pulses from extreme values of a reproduced signal, pulses are generated at zero intersections of the reproduced signal, form a signal of the following two different units of a binary code by selecting from pulse sequence at zero intersection of the reproduced signal of the pulse following the pulse at the extreme value through the interval from IT to about 1.5 T, where T is the duration of the clock interval, while excluding the pulse that comes after the selected pulse by the extreme value of the reproduced signal, and from the remaining pulses by the extreme values, form the next next units and zero of the binary code.

FIG. One of the possible structural schemes of the device for carrying out the proposed method is given; in fig. 2 - diagrams of electrical signals, explaining the operation of this device.

An input 1 of the device for a signal reproduced from a magnetic carrier is connected to the former of 2 extreme points and to the former of 3 null intersections. The output of the driver 2 is connected to the start input from the one-shot 4. The start blocking input of the one-shot 4 is connected to the output of the one-shot 5. Output

the driver 3 is connected to the start inputs of one-shot 5 and 6, and the blocking inputs of these one-shot are connected to the output of the one-shot 4, to which the start input of the one-shot 7 is connected, the start-up input of which is connected to the output of the one-shot 6, to which the pulse shaper 8 is also connected to the rear to the front of a one-shot pulse 6. To the output of the one-shot 7 a shaper 9 of the pulse is connected along the trailing edge of the one-shot 7.

The device works as follows. The input 1 of the device receives signals reproduced from a magnetic carrier and recorded on it by the BNHM method (diagrams, Fig. 2, a). From these signals, shaper 2 generates pulses (Fig. 26), corresponding to the extremums of the reproduced signals, and Shaped by telephony 3 - pulses, corresponding to zero signal intersection (Fig. 2, #). The pulse coming from the output of the shaper 2 starts the one-shot 4 (Fig. 2, g). In the event that a signal is reproduced from the carrier corresponding to two drops of magnetization following a single clock interval (combination "II"), a pulse corresponding to zero-crossing of the signal is formed at the output of the imaging unit 3 before it generates

Q one-shot 4, which at the time of generation gives permission to start one-shot 5 and 6, one-shot starts (Fig. 2, e to f). The one-shot pulse 6 blocks the one-shot 7, which does not start from the trailing edge of the one-shot 4 (Fig. 2, g), and the shaper 9 is not shaped, and a pulse is sent to the trailing edge of the one-shot 7. This indicates that no combination "10.

After the one-shot 6 is generated, the driver 8 will generate a pulse along its falling edge (Fig. 2, i), indicating that the combination “11

5 The pulse duration of the one-shot 5 is chosen slightly longer than the time interval between zero-crossing and the second extremum in the signal corresponding to the combination of "11, so that from the second extremum of the start signal of the listed single-shot one-shot.

In the event that a single magnetization differential on magnetic carrier 2 is followed by a second after more than one clock interval, then a pulse corresponding to zero-intersection of the signal is generated by shaper 3 after it generates a single vibrator 4, and the launch of single vibrators 5 and 6 does not occur . Therefore, from the trailing edge of the one-shot 4, a one-shot 7 is started, which serves to equalize the time shifts arising from zero-crossing decoding. The shaper 9 generates an impulse on the trailing edge of the one-shot 7 impulse, indicating that the combination “10.

The proposed processing method allows to reduce phase distortions and increase the recording density of digital information by the BNM module, by 20-30%. This is achieved due to the fact that combinations limiting the recording density ("units surrounded by" zero ") are not processed by extreme points, and null-intersections, which in this case have greater temporal stability.

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FIG. 2

Claims (1)

57) METHOD FOR FORMING BINARY CODE SIGNALS PLAYABLE FROM MAGNETIC CARRIER, based on the generation of pulses from the extreme values of the reproduced signal, characterized in that, in order to increase the fidelity of reproduction, the pulses are formed at the zero intersections of the reproduced signal, “form a signal of the following two successive signals in a row,” units ”of the binary code by extracting from a sequence of pulses at zero intersections the reproduced signal of the pulse following the pulse at the extreme value of black in the interval from 1T to 1.5 T, where T is the duration of the clock interval, the pulse closest to the pulse after the selected pulse is excluded from the extreme value of the reproduced signal, and from the other pulses from the extreme pulses the signals of the following binary “zero” and “zero” are formed code.