SU1282198A2 - Device for reproducing digital information from magnetic medium - Google Patents

Abstract

The invention relates to magnetic recording and reduces the reproduction errors of digital information by increasing the noise immunity of synchronization. The device contains a source of 1 information signals, a threshold driver 2, a source of a clock signal 3, a driver of clock signal 4, elements AND 5, 11, 12, 13, trigger 7, differentiating circuit 8, one-channel 9, 14 and 15, elements OR 16, element 17 delay and generator 18 pulses. The introduction of new elements and the formation of new connections between the elements of the device allows the selection of the duration of the pulses generated by the single vibrator 15, and the phasing of the pulse generator 18 with each clock pulse received from the magnetic carrier, as well as preparing the channel of the clock pulse received from the magnetic carrier for receiving the next clock pulse from the magnetic carrier in the time interval of the probable arrival, or to the recovery of the recovered sync pulse at the end: this interval is silt. (L with

Description

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The invention relates to magnetic recording, in particular, to devices for reproducing digital information from magnetic media and is an improvement of the device according to the main author. No. 1081654.

The purpose of the invention is to reduce the error in reproducing digital information by increasing the noise immunity of synchronization.

The drawing shows a functional diagram of a device for reproducing digital information from magnetic media.

A device for reproducing digital information from magnetic media contains in each channel of Information signals a source 1 of information signals connected to the inputs of threshold form conditioners 2, a source 3 of a sync signal connected to the input of a generator of 4 sync signals, the first And 5 elements whose outputs are connected to output buses 6 information channels, and some of their inputs are connected to single outputs of the flip-flops 7, the zero inputs of which are connected to the output of the differentiating circuit 8. Single-vibrator

9 connected to the output of interconnected input of the differentiating circuit 8 and other inputs of the first elements And 5, as well as to the output bus

10 of the sync signal, and the input of the one-vibrator 9 is connected to the output of the shape of the 4 clock signal body and to one of the inputs of the second elements 11, the other inputs of which are connected to the outputs

threshold drivers 2, and the outputs are connected to the single inputs of the triggers 7. I

In addition, a device for reproducing digital information from a magnetic carrier, n contains in the sync signal channel the first and second additional elements AND 12 and 13, the first and second additional o;;, novibrator 14 and 15, the element OR 16, the delay element i 7 and the generator fS pulses, with the first additional element AND 12 and the element OR 16 connected in series between the output of the synchro shaper 4 and the input of the one-vibrator 9. The second additional element And 13 is connected to the first input through serially connected Leader 17 and 18 pulses generator

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interconnected to the output of the first additional element And 12 and the input of the first additional one-shot 14, connected by output to interconnected to the corresponding input of the first additional element And 12, the output of the second additional one-shot 15 and the second input of the second additional element And 13 connected to the output from interconnected the input of the second additional one-shot 15 and the corresponding input element OR 16.

A device for reproducing digital information from magnetic media operates as follows.

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When the magnetic carrier is played, the first sync pulse from the source 3 of the sync signal is fed to the input of the imaging unit 4, the sync signal generated by the duration and amplitude of the pulse arrives at the first input of the And 12 element, from the output of which it is fed to the input of the one-vibrator 14, and from the output of the last The inputs of the elements 12 and 13 are given by 30; a pulse is formed over the duration of a pulse that closes the elements 12 and 13 for the duration of its duration. The duration of this impulse is chosen from the considerations that the input of the channel is synchronous s shall be closed until until such time interval the probable arrival of the next sync pulse. Due to the non-uniformity of movement of the magnetic carrier, the period of the clock pulses fluctuates within known limits, which determine the time interval of the probable arrival of the clock pulses. The first pulse, as well as all subsequent ones, from the output of element 12 is phase generator 18 pulses, which generates a pulse with a frequency equal to the frequency of the sync pulses recorded on a magnetic carrier, and in amplitude and duration identical to the pulses coming from the synchro generator 4 of the sync signal. From the output of the pulse generator 18, pulses are applied to the input of the delay element 17. The delay time is selected so that the trailing edge of the delayed pulse is at the end of the time interval of the probable arrival of the clock pulse.

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When a magnetic carrier is played, the first sync pulse from the source 3 of the sync signal is fed to the input of the imaging unit 4, the sync signal generated by the duration and amplitude of the pulse arrives at the first input of the And 12 element, from the output of which it is fed to the input of the one-vibrator 14, and from the output of the last The inputs of the elements 12 and 13 are 0 and 0; a pulse is formed over the duration, which closes the elements AND 12 and 13 for the duration of its duration. The duration of this im- pulse is chosen from the considerations that the input of the clock pulse to be closed until until such time interval the probable arrival of the next sync pulse. Due to the non-uniformity of movement of the magnetic carrier, the period of the clock pulses fluctuates within known limits, which determine the time interval of the probable arrival of the clock pulses. The first pulse, as well as all subsequent ones, from the output of element 12 is phase generator 18 pulses, which generates a pulse with a frequency equal to the frequency of the sync pulses recorded on a magnetic carrier, and in amplitude and duration identical to the pulses coming from the synchro generator 4 of the sync signal. From the output of the pulse generator 18, pulses are applied to the input of the delay element 17. The delay time is selected so that the trailing edge of the delayed pulse is at the end of the time interval of the probable arrival of the clock pulse.

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from the magnetic carrier, and is determined by the formula

T - 1/2 T, ", - Tsi,

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where T is the delay time;

That „,. - the time interval of the probability arrival of the sync pulse,

sync pulse duration.

From the output of the delay element 17, a pulse is fed to the input of the element AND 13, however, since the element AND 13 is closed by a pulse from the one-shot 14, it does not pass anymore. The clock pulse from the output of the element And 12 is fed to the first input of the element OR 16, and from its output to the one-shot 9 and in the channels of information signals. Thus, the channel of sync pulses operates in the presence in the time intervals of the probable arrival of sync pulses coming from the magnetic carrier, tel. In the case when the sync pulse from the magnetic carrier is absent in the time interval of the probable arrival, the elements 12 and 13 turn out to be open and the pulse generated by the clock generator 18 and delayed by the delay element 17 is fed to the input of the element 13 and the output is at the second input of the element OR 16. Further, it is used similarly to a sync pulse transmitted from a magnetic carrier. From the output of the element And 13, a pulse is also fed to the input of the one-shot 15, which produces locking pulses for the elements 12 and 13.

The duration of these pulses is determined by the formula

 T

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-1/2 t

6PI;

de T

- duration of one-shot pulses 15,

-the duration of the pulses of the one-shot 14,

- time interval of the probable arrival of clock pulses.

 Such a choice of the pulse duration

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A device for reproducing digital information from a magnetic nozzle by author. St. No. 1081654, characterized in that, in order to reduce the error in reproducing digital information by increasing the noise immunity of synchronization, the first and second additional elements AND, the first and second additional one-vibrators, the OR element, the delay element, and the pulse generator are inserted into the sync channel. The first additional element AND and the OR element are connected between the output of the clock generator and the one-shot input; the second additional element AND is connected to the first input Consequently, a delayed element and a pulse generator are connected to the interconnected output of the first additional element I and the input of the first additional one-vibrator connected by an output to the interconnected corresponding input of the first additional element I, the output of the second additional one-vibrator and the second input of the secondary section and phasing of the generator 18 and the additional element And, co-pulses with each sync pulse, connected with the output

coming from the magnetic carrier, allowing the entrance of the second one to each other to prepare the channel of the sync-impulse one-shot and corresponding to receive the next sync-impulse input of the OR element.

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The carrier is located in the time interval of the probable arrival, or to issue a restored sync pulse at the end of this interval. They have 5 pulses of units of information from the threshold formers 2 are gated on AND elements by 11 short pulses relative to the pulses of units from the OR 16 element , simultaneously a clock pulse, 10 starts a one-shot 9, the pulse duration at the output of which determines the pulse duration at the output data lines 6 and at the output line 10 of the clock signal.

15 A gating clock pulse on the And 11 element sets trigger 7 into one state, allowing pulses from the one-shot 9 to pass through the first And 5 elements on

20 output information busses 6. The falling edge of the one-shot pulse 9 through the differentiating circuit 8 sets the trigger 7B to the zero state.

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Claims (1)

Invention Formula Device for reproducing digital information from magnetic media by author. St. No. 1081654, characterized by the fact that, in order to reduce the reproduction error of digital information by increasing the noise immunity of synchronization, the first and second additional elements AND, the first and second additional one-vibrators, the OR element, the delay element and the pulse generator, which are connected in series, are inserted into the sync channel. the first additional AND element and the OR element are connected between the output of the sync signal generator and the one-shot input; the second additional AND element is connected by the first input Res series connected delay element and a pulse generator connected between a first output of the additional AND gate and to an input of the first additional monostable connected to the output connected between a respective input of the first additional element and the second additional output of monostable multivibrator and a second input of the second