SU758241A1 - Method of isolating information of reproduced signal - Google Patents

Description

The invention relates to computing and can be used in storage devices on magnetic disks, drums and tape.

A known method of extracting information from a reproduced signal, in which a signal is corrected in amplitude, differentiated, eliminates a decrease in signal amplitudes in intervals that are not less than two periods of sync pulses [1].

The disadvantage of this method of extracting information is that <it does not provide reliable reproduction when using multi-frequency signals.

The closest in technical essence to the proposed method is a method for extracting information from a reproduced signal, which consists in correcting the signal in amplitude, differentiating, eliminating a drop in signal amplitudes in intervals of at least two periods of sync pulses, symmetrically limiting in amplitude, using the resulting sequence pulses form a sequence of clock pulses, and

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The initial information sequence is obtained from an undifferentiated signal by the method of amplitude detection by means of a sequence of pulses following each other through a single period of sync pulses [23.

The disadvantage of this method is the implementation of the amplitude detection operation, which requires the use of automatic gain control, which complicates the process of extracting information. However, in this case the method does not provide sufficient noise immunity in the absence of a sequence of units in the information signal.

The purpose of the invention is the improvement of the reliability of information extraction of the reproduced signal.

This goal is achieved by the fact that, in the method consisting in that the signal is corrected in amplitude, differentiated, the amplitudes decrease in the signal in intervals of at least two periods of sync pulses, symmetrically limited in amplitude, using the resulting pulse sequence is formed after 4

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“the accuracy of the sync pulses, and the initial information sequentially is obtained from the transformed reproduced signal with the exception of pulses following each other through one period of sync pulses, after the amplitude correction of the opera; The elimination of the amplitude decay in intervals of at least two periods of clock pulses is carried out for undifferentiated and differentiated reproduced signals, after which they are compared after equivalence to equivalence from the signal received. as a result of the comparison, direct and reverse codes are formed, and the operation

'Exceptions carry out the signal obtained as a result of the comparison, by the formation of prohibiting rectangular pulses, the leading front of which form the second every

......... of the pulse following one synchronization period in the received

'sequences of direct code, and the falling edge of each second pulse, following one synchronization period, in the resulting sequence of the reverse code.

FIG. 1 gives time diagrams of information extraction; in fig. 2shema device that implements this method

FIG. 1a shows the input information sequence; FIG. 1b gives the recording current in accordance with the recording method, at which inserts are made from the signal with a frequency twice as large as

'‘' 'Ch'ans'Tot' sync pulses if a large sequence is encountered

'zeros. Playback signal trample amplitude corrector for

alignment amplitude. signal and reduce phase distortion (figure 1 - &) and differentiate. Undifferentiated and differentiated signals (Fig. 1 in I. 1 (e) are adjusted in form to eliminate the amplitude decay in sections 2T (T-period of clock pulses) and more. The amplitude decay is due to

'that the playback channel, turn on ..... the material head does not skip

‘. the constant component of the sig / nal / spectrum spectrum When the playback signal is processed by the information extractor, at the 'amplitude decay points', false information pulses can occur.

..... but limit for receiving rectangular signals. From the differential "'/ p ^ zironayOgo of a rectangular signal (fig.1e), along the front edge, they form pulses (fig, 1l), which are fed to the synchronization input of the sync pulse generator. For. information highlights use two

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series of pulses shifted relative to each other by 0.5T (Fig. 1m, n). Differentiated (Fig. 1h) and undifferentiated (Fig. 1e) rectangular signals are compared by equi valency.

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The resulting comparison signals (Fig. 1 and, k) are gated by a sync series (Fig. 1H).

From the signals received after Ί0 gating (Fig. 1s, p), exclude pulses, the distance between which is T. For this, from the sequence of pulses (Fig. 1o) with Triggers made according to the scheme of three

. „Triggers, form a direct and inverse codes (Fig. 1 p, c), shift the forward code pulses by 0.5 T, select. Every second pulse from a sequence of pulses (Fig. 1p) following with an interval of T (Fig. 1t)

The 20–5–5 trigger, which is cocked by the second pulses and reset by the pulses of the return code, generates an exception signal (Fig. 1y) from the information sequence of 25 pulses, the 'distance' between which is T (Fig. 1f).

To exclude pulses that follow with an interval T from the signal shown in Fig. 1n, the same sequence of operations is used 30 as for the signal shown in Fig. 1o

FIG. 1x, n are output. information sequence

32 and synchro-escort.

The device consists of an amplifier

1 playback, amplitude corrector 2, differentiator 3, corrector 4 waveforms, symmetrical limiter 5 shaper 6

40 pulses, generator 7 sync pulses, second equalizer 8 of the Nahl sig form, second symmetric limiter 9, comparison circuit 10 for equivalence, elements 11 AND, Τς-trigger 45 12, built according to the scheme of three triggers; 8-5 flip-flops 13, ^ -triggers 14 and 15, built according to the scheme of three triggers without communication with the inverse output of the second 8-5-flip-flop on

50 8-input of the third 8-5-flip-flop, elements 16 and 17 And, T _£ -trigger 18, built according to the scheme of three triggers, 8-5-flip-flop 19, TC, - triggers 20, 21, built according to the scheme

„- three triggers without communication from the inverse output of the second 8-5-flip-flop to the 8-input of the third 8-5-flip-flop, element 22 AND, element 23 OR.

The operation of the device is understandable and its consideration of the timing diagrams shown in FIG. one,

Instead of amplitude detection, in this method, peak detection was applied, which is less sensitive to amplitude ^: signal oscillations and 5

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interference pulses. Therefore, the proposed method provides improved reliability of products.

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Claims (1)

Claim The method of extracting information from the reproduced signal, which consists in correcting the signal in amplitude, differentiating, eliminating the decline in signal amplitudes in "intervals of at least two periods of clock pulses, symmetrically limiting in amplitude, forming a sequence of clock pulses using the resulting pulse sequence the sequence is obtained from the transformed reproduced signal with the exception of pulses following each other through one period inhroimpulsov, characterized in that, in order to increase the reliability of reproduction after correction operation to eliminate the amplitude of the amplitude decay at intervals lasting at least two clock periods osusche- 25 cTvlyaet for undifferentiated and differentiated reproduced signals, then the resulting sequences are compared to equivalence, from the signal obtained 5 'as a result of the comparison, direct and reverse codes are formed, and the exclusion operation is performed by the signal obtained as a result of the comparison, whose leading edge forms their every second pulse, following one synchronization period in the resulting Direct Code sequence, and The second front forms the second each second pulse, which follows after one synchronization period in the received sequence of the reverse code.