SU1381589A1 - Device for extracting data in reproduction of information on magnetic medium - Google Patents

Abstract

The invention relates to the field of information accumulation. The purpose of the invention is to reduce the error in the allocation of data by increasing the synchronization stability. By analyzing the position of the input data relative to the center of the time window, the frequency of the controlled oscillator is automatically adjusted by changing the delay value. In the absence of input data, the reversible counter retains its previous state, with the result that the controlled oscillator does not change its frequency until the input data is received. 2 Il.

Description

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The invention relates to the accumulation of information and can be used in accumulators on a movable magnetic carrier for separating clock signals from reproduction data, as well as in other systems of phase-locked loop.

The purpose of the invention is to reduce the error in the allocation of data by increasing the synchronization stability.

FIG. 1 shows a diagram of the device; in fig. 2 - diagrams of the device.

The device includes a connected input input 1, output bus 2, first 3, second 4 and third 5 D-triggers, first 6 and second 7 counters, comparison block 8, AND-HE element 9, first 10 and second 11 delay lines, multiplexer 12, reversible counter 13, element I 14, driver 15 pulses, divider 16 frequencies, decoder 17, controlled oscillator 18.

D-flip-flop 3, counter 7 and comparator block 8 are used to analyze the position of the input data relative to the center of the time window and to issue a control signal for changing the frequency of the controlled oscillator 18.

The AND-HE element 9, the delay line 11, made in the form of a multi-tap delay line, multiplexer 12 and reversible counter 13 are a controlled oscillator 18 designed to learn 1x sync series coinciding in frequency and phase with the input data. Counter 6, D-flip-flop 4, element 14 and shaper 15 serve to generate a pulse of frequency correction of the controlled oscillator 18 and to eliminate spurious surge during switching of the reversible counter 13 and multiplexer 12. D-flip-flop 5 serves for the initial start of the controlled oscillator 18. The decoder 17, intended for the IFF recording method, extracts information from the input data.

In general, the counter size and the number of outputs of the delay line 11 are determined by the task of tracking the frequency and phase. As an example of device powering, the width of the reversible counter 13 is chosen equal to 4, which allows control of the 16-input multiplexer and use the multi-tap delay line 11 to 16 outputs; switching of the reversible counter is performed after averaging analysis of the position of 16 pulses relative to the center of the time window, which determines the width of the counters 6 and 7, equal to 4.

The input of the initial installation of the reversible counter 13 receives a signal indicating the beginning of the arrival of the input data. By this signal, the counter 6 is reset to the zero state and the reversible counter 13 is set to the state equal to half of its capacity. In this case, the multiplexer 12 switches the eighth tap of the delay line 11, which corresponds to the output of the doubled frequency controlled by the generator 18 relative to the frequency of the input data.

The first data pulse arriving at the input bus 1 sets the trigger 5 to one state, which will allow the generator 18 to be generated synchronously with the input data. The doubled frequency is fed to the D input of the D-flip-flop 3,

5 on the synchronous input which receives input data. The trigger analyzes the position of the data pulses relative to the double frequency pulses, the positive edge of which determines the center of the time window. (Counter 7 reads data pulses when there is a high level at the output of D-flip-flop 3, counter 7 reads data and is ahead of the center of the time window. At the same time, counter 6 counts all data pulses and after 15

5 cycles gives the transfer signal. On this signal, D-flip-flop 4 is charged, which spreads a pulse through the element I 14 to the counting input of the reversible counter 13. A short PM pulse is generated on the front frame 1T of the counting pulse from the output of the for0-I 15 pulse. During the arrival of the counting pulse output control. 1 em1 o generator 18 is present "1 and the impulse from the imaging unit 15 overlaps with the operation of the generator 18, i.e. on his way out

5 forcibly appears "1. Since generator 18 also generates 1 at this time, such an effect on the generator does not affect its operation. This eliminates a false outlier in the generator 18 during the operation of the reversal1 of the counter 13 and the multiplexer 12.

When the counting impulse arrives at the input of the reversible counter 13, a direct or reverse count signal is present at the input of the counting direction

5 - block 8 comparison. If a high level is present at the output of the comparison block 8, then this means that the value of the counter 7 is larger than eight, and the data is delayed relative to the center of the time window. The controlled oscillator 18 needs to be adjusted in the direction of decreasing the frequency, for which the counter 13 has to increase its value, as a result, a large amount of the delay in the feedback circuit is controlled by the controlled generator 18. If the output is b, lock 8

comparison is present at a low level, this means that the value of counter 7 is less than eight, and the data is ahead of

The center of the temporary window. The controlled oscillator 18 is corrected in the direction of increasing the frequency, for which the counter 13 decreases its value, as a result a smaller delay is chosen. On a temporary aperture. FIG. Figure 2 shows the position of the data, in which the frequency of the controlled oscillator 18 decreases. After the passage of the first 1 st pulses, the shaper 15 generates a pulse, resetting the counters 6 and 7 to the initial state.

Thus, by analyzing the number of input data relative to the center of the time window, automatic control of the frequency of the controlled oscillator 18 occurs due to a change in the delay value. In the absence of input data, the reversible counter 13 retains its previous state, as a result of which the generator 18 does not change its frequency until the input data is received.

Formula and lopra shadows

A device for extracting data when reproducing information on a mobile magic. HocHre.:ie, containing a series-connected adjustable oscillator, a frequency divider and a decoder, the output of which is connected to the output njnne, the first delay line connected between the input 1NO and the other input of the decoder, Comparison unit, lemma And, characterized in that, in order to reduce the effectiveness of the allocation of data by increasing the synchronization stability, the first one, BTopoii and t |} and its D-triggers, nerv1 and the second counters, the former

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The pulses, the univalent oscillator is made in the form of a series-connected AND-NOT element, a second delay line and a multiplexer, as well as a reversible counter connected by outputs to other relevant inputs of the multiplexer, the forward output of which is the output of the control oscillator and connected q D-in - the house of the first D-flip-flop, with the first input of the NAND element directly and through the AND element with the counting input of the reversing counter and with the input of the pulse former, the output of which is connected to the reset inputs of the first and second counters and to the gate input of the multi-loop 5, connected by the inverse output through the second D-flip-flop to the second input of the I element, the input of the initial installation of the reversible counter connected to the installation input of the first counter and through the third D-flip-flop to the second input of the I - NOT, the input input is connected to the synchronous inputs of the first and third D-flip-flops, the first and second counters, the input of the resolution of the latter is connected to the output of the first D-flip-flop, and the outputs of the second counter are connected to the control input audio mladschie down counter data inputs of which are connected to logical zero, which bits are connected mladnshe second input element and comparing the first counter data inputs, an inverted output connected to the D-input of the second D-flip-flop ,. the senior information input of the reversible counter is connected to a logical unit, which is connected to the D-BXO of the third D-flip-flop and to the higher bit of the second inputs of the reference element.

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Claims (1)

Claim A data extraction device for reproducing information on a movable magnetic medium, comprising a serially connected controlled oscillator, a frequency divider and a decoder, the output of which is connected to the output bus, a first delay line connected between the input bus and the other input of the decoder, a comparison unit, AND element, characterized in that, in order to reduce the error in the selection of data by increasing the stability of synchronization, the first, second and third D-flip-flops, the first and second counters, the importer are introduced into it of pulses, the controlled generator is made in the form of series-connected AND-NOT element, a second delay line and a multiplexer, as well as a reversible counter connected by outputs to other corresponding inputs of the multiplexer, the direct output of which is the output of the control generator and connected to the D-input of the first D-trigger , with the first input of the AND element — NOT directly and through the AND element with the counting input of the reversible counter and with the input of the pulse shaper whose output is connected to the reset inputs of the first and second counts sensors and to the gating input of the multiplexer connected by the inverse output through the second D-trigger with the second input of the And element, while the input of the initial installation of the reverse counter is connected to the installation input of the first counter and through the third D-trigger with the second input of the element AND is NOT, the input the bus is connected to the sync inputs of the first and third D-flip-flops, the first and second counters, the last counter enable input is connected to the output of the first D-flip-flop, and the outputs of the second counter are connected to the control input of the roar through the comparison unit a dividing counter, the lower information inputs of which are connected to logic zero, to which the lower bits of the second inputs of the comparison element and the information inputs of the first counter are connected, by the inverse output of the second D-trigger connected to the D-input, the senior information input of the reversing counter is connected to a logical unit, which is connected to the D-input of the third D-trigger and to the senior bit of the second inputs of the comparison element. fie2