SU1265837A1 - Device for reproducing digital information - Google Patents

Abstract

The invention relates to instrumentation and can be used to improve the quality characteristics of magnetic recording. The purpose of the invention is to increase the accuracy of reproduction of information. The device contains a magnetic head 1 playback, amplifier 2, differentiator 3, low pass filter 4, comparators 5, 6 and 7, multivibrator 8, 9 and 10, elements 11 and 12, element OR 13, counting trigger 14 and bus 15. Introduction New elements and the formation of new connections between the elements of the device allows one to form digital signals by logging (Logical processing of signals from the outputs of Comparators 5, 6 and 7 with different thresholds of operation. 2 Il.

Description

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The invention relates to instrumentation, in particular to a magnetic recording technique, and can be used to improve the quality characteristics of a digital magnetic recording.

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

FIG. 1 bring: w functional diagram of the device; in fig. 2 timing charts of the device.

The device contains a magnetic playback head 1 connected to a series-connected amplifier 2, a differentiator 3 and a low-pass filter 4, three comparators 5-7, whose inputs are connected to the output of the low-pass filter 4, three multivibrators 8-10, the first

11 and Vtorogl 12 elements AND, elements OR 13, counting trigger 14 and output bus 15.

The inputs of the multivibrators 8-10 are connected to the outputs of the corresponding comparators 5-7. The outputs of the multivibrator 8 and the comparator 7 are connected to the first two inputs of the first element I 11. The outputs of the multivibrator 10 and the comparator 5 are connected to the first color inputs of the second element I 12. The third inputs of the two elements 11 and 12 are connected to the output of the multivibrator 9. The outputs of elements 11 and 12 are connected to the inputs of the element 13 or 13 the output of the latter is connected via a coupled trigger 14 with the output bus 15.

The device works as follows.

The signal from the playback head 1, which has the form of opposite-polarity responses to magnetization differences 1FIG. 2a) amplified in an amplifier

2 and is supplied to the differentiator 3, which changes the waveform in such a way that the zero-crossing times correspond to the peaks of the reproduction signal (Fig. 26). Low-pass filter 4 Reduces the noise power at the input to the solver. The threshold levels of the first 5 and third 7 Comparators are selected depending on the levels of additive and multiplicative noise in the recording-reproduction path and can vary within

from 0.3 to 0.5 level of single response at the differentiator output3

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The threshold level of the second comparator 6 is chosen to be zero. With its help, it is possible to more accurately determine the moments of zero crossing. However, in moments of no response, the state of the second comparator 6 is uncertain, as shown in Figure 2d, shaded. The signals at the outputs of the first comparator are used to eliminate uncertainty.

5 and the third comparator 7. At the falling edges of the pulses from the outputs of the first comparator 5 and the third comparator 7, the first 8 are triggered.

and the third 10 multivibrators, producing pulses of duration Td (Fig. 2 e, h). TD - the duration of the clock interval. The second multivibrator 9 operates on both edges of the pulses coming from the second comparator 6 and generates pulses of duration (Fig. 2g). Thus, at the output of the first element 11, a pulse is generated, the back edge of which determines the temporary position of the peak of the reproduced response of positive polarity with a delay of. The pulse at the output of the second element And 12 determines the position of the peaks of the negative polarity responses. From the output of the element OR 13 (Fig. 2i) imgr.1: 1, sy arrive at the input of the counting trigger 14, which is triggered by the falling edge (Fig. 2k), at the output of which a sequence corresponding to the recording current is formed.

Claims (1)

Invention Formula A digital information playback device containing a magnet on a playback head connected to a pos1: successively connected preamplifier, differentiator1 ru and low pass filter, first And element and output bus, characterized in that, in order to improve the fidelity of reproducing information, three comparators are entered into it, the inputs of which are connected to the output of a low-pass filter, three multiplexers, a second element AND, an element OR and a counting trigger, while the inputs of multivibrators plugged in; the outputs of the respective comparators, the outputs of the third multivibrator and the first comparator are connected via the second element AND and the element 312658374 OR with the input of the counting trigger, the sub torus and the first multivibrator, and connected via the OR element and the first third inputs of AND elements are unified element And to the outputs of the third compara- the output of the second multivibrator. Jii LUUHigiia P eleven