SU1520586A1 - Device for reproducing information from magnetic carrier - Google Patents

Abstract

The invention relates to the accumulation of information and can be used in magnetic storage devices. The purpose of the invention is to increase the accuracy of reproduction of information. This is achieved by eliminating false pulses caused by exposure to additive noise and various kinds of interference. Contains serially connected magnetic head 1, amplifier 2, amplifier-corrector 3, differentiator 4, detector 5 zero levels, delay block 6, element 7 and output bus 10, while the second input of element 7 7 is connected via a strobe generator 8 and amplitude corrector 9 with an amplifier-corrector 3 output. In the strobe generator 8, the reference voltages for comparators 11 and 12 are set symmetrically using a potentiometer 13. Amplitude detection logic signals are generated at transitions by the reproduced signal through the level the reference voltage for the positive region by the comparator 11, for the negative, respectively by the comparator 12. The logical signals generated by the comparators 11 and 12 are delayed by delay lines 17 and 18, followed by multiplying the source and delayed signals, respectively, at elements 19, 20. At the output element 16, an amplitude detection signal is generated. 2 Il.

Description

The invention relates to the field of information storage and can be used in magnetic storage devices.

The aim of the invention is to increase the accuracy of the reproduction of information.

Fig. 1 shows a block diagram of a device for reproducing information from a magnetic carrier; Fig. 2 shows diagrams of time diagrams explaining the operation of the device,

The device contains serially connected magnetic head 1, reproduction amplifier 2, amplifier-corrector 3, differentiator 4, zero-crossing detector 5, delay unit 6, the output of which is connected to the first input of the And 7 element, the second input of the strobe connected through the generator 8 and the amplitude corrector 9 With the output of the amplifier-corrector 3, the output bus 10 connected to the output element And 7b. The strobe generator 8 contains two comparators 11 and 12 whose non-inverting inputs are the generator inputs B of the strobe and the inverting inputs You are connected to the middle lead of the potentiometer 13 connected between the common bus 14 and the bus 15 of the reference voltage, the OR element 16, the output of which is the output of the strobe generator 8, two delay lines 17 and 18, two elements 19 and 20 whose outputs are connected The inputs of the OR element are 16o. In this case, the output of the comparator 11 is connected to the first input directly and through the delay line 17 to the second input of the AND 19 element, the first input of the And 20 element is connected to the output of the comparator 12 and through the delay line 18 to the second input of the AND 20 element.

The device works as follows.

The signals reproduced by the magnetic head 1 are amplified and corrected by the amplifier 2 and the amplifier-corrector 3 (FIG. 2a). Then the differentiator 4 differentiates the signal (in fig.2d). The pulses corresponding to the peak values of the reproduced signal are formed when the differential signal crosses the zero level in the detector 5 zero crossings (Figure 2d).

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One of the main reasons for generating false pulses when reproducing information by means of peak detection is the effect of additive noise and various kinds of interference on the reproduced signal. False impulses during reproduction usually occur in places of sagging of the shelves of the differential signal caused by overcorrection of the reproduced signal . Dp reduce the likelihood of the formation of spurious pulses, the reproduced signal is aligned in amplitude using amplitude corrector 9 and subjected to amplitude detection at the intersection levels symmetrically set for the positive and negative regions of the reproduced signal in the strobe generator 8. (figure 2). In the strobe generator 8, the reference voltages for the comparators 11 and 12 are set symmetrically using a potentiometer. 13 The amplitude detection logic signals are developed at transitions by the reproduced signal through the reference voltage level respectively for the positive reproduced signal region by the comparator 11, for the negative reproduced signal region by the comparator 12

As a result of amplitude titration, logical signals are formed for the positive and negative levels of intersection (Fig. 2e, g).

The switching times in the amplitude detection signals correspond to the intersection points of the reproduced signal threshold levels o

Since the threshold levels for the reproduced signal are usually set based on the overlap of the average noise value, individual noise components can exceed the threshold detection levels, which leads to the emission of spurious noise in the sagging areas of the differential signal shelves. In order to eliminate these pulses, the logical signals obtained with amplitude detection are subjected to a time delay by delay lines 17 and 18 by the amount of time t (Fig. 2e, and). followed by a logical definition of the source and

B 152 delayed signals, respectively, for positive and negative levels of intersection by elements AND 19, 20 (Fig. 2g, k). The signals obtained after a logical multiplication of the original and delayed signals for positive and negative levels of intersection summarize

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holding in series connected magnetic head, reproduction amplifier, amplifier-corrector, differentiator, zero crossings detector, delay unit whose output is connected to the first input of the And element, the second input connected through the strobe generator and the amplitude

OR 16, obtaining a total signal corrector with an amplifier-corrector output, an output bus connected to the output of the AND element, while the strobe generator is made in the form of two comparators, the non-inverting inputs of which are the strobe generator inputs, and the inverting inputs are connected to the middle The input of the potentiometer connected between the common bus and the reference voltage bus and the OR element, the output of which is the output of the strobe generator, is characterized in that, in order to increase the fidelity of reproduction, in the strobe generator, enter There are two delay lines and two AND elements whose outputs are connected to the inputs of the OR element, the output of the first comparator is connected to the first input directly and through the first delay line to the second input of the first And element, the first input of the second And element is connected to the output of the second comparator and through the second delay line with the second input of the second element I.

nap amplitude detection (Fig 2l). In order for the peak detection pulses to be in the center of the positive shelves of the total amplitude detection signal, they are delayed by the delay block 6 (FIG. 2m). Information and reproduced signal are extracted by gating the total amplitude detection signal by the pulses of the peak detection. FIG. 2n) „

Claims (1)

The total amplitude detection signal allows for the removal of information from the reproduced signal by spurious pulses caused by the effects of additive noise and various kinds of interference. Due to this, for a given reproduction method, the fidelity of reproducing information is greatly improved. A device for reproducing information from a magnetic carrier, a corrector with an amplifier-corrector output, an output bus connected to the output of the element I, the strobe generator being made in the form of two comparators whose non-inverting inputs are the inputs of the strobe generator and the inverting inputs are connected to the middle An input of a potentiometer connected between a common bus and a reference voltage bus, and an OR element whose output is an output of a strobe generator, characterized in that, in order to increase the fidelity of the reproduction In the strobe generator, two delay lines and two AND elements are entered, the outputs of which are connected to the inputs of the OR element, and the output of the first comparator is connected to the first input directly and through the first delay line to the second input of the first element And, the first input of the second element AND is connected with the release of the second comparator and through the second delay line with the second input of the second element I. g 11 I III in I III I I 111 III11 I I m I I g 11 t tl | ui-JTJTJbJl "Jir e JTLJTUiJruri jniui-JirL Well JbrL-JLJLJLJ gjTLJUULJUJl- 3 .., L.-LL-GY1L n..JljrL-JlJT lJl ..- rL -.- n П П П П П n n П П n p n fi / -Jgrsh JshshshlshglJl-J -JSh-lshshshllJSh  I I MM M II 11 I I n I I in I I I I I I I I I I I I I I I I III I It I I I I t n I 11