SU771711A1 - Device for reproducing phase-modulated signals - Google Patents

Description

54) DEVICE FOR REPRODUCTION OF PHASOMULATED SIGNALS

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The invention relates to magnetic recording and is intended for use in devices for reproducing discrete information from a magnetic tape, B particularly in tape cassette storage devices on magnetic tape and on magnetic flexible boards for subscriber stations.

A device is known for reproducing phase-modulated signals, tO containing serially connected pulse formers and elements AND whose outputs are connected to the inputs of the OR element, and the output of a single element AND connected to the output zero LINE. The output of the pulse generator is connected to a counter whose outputs are connected to the decoder. The device also contains the output unit bus and the second element OR 20

The only disadvantage of this device is unstable operation during fluctuations of the boundaries of signal elements arising in conditions of high magnetic recording density, which is due to. Low noise immunity of this device.

The closest in technical essence to the present invention 30

is a device for reproducing phase-modulated signals, containing an input bus connected to the inputs of two drivers, as well as a generator connected via a counter c. the decoder, and two separate OR elements, a single output terminal and an initial start terminal, the output of the first driver being connected through the first element AND to the zero output terminal, and the output of the second driver is connected to the first input of the second element AND.

The disadvantage of this device is that it is based on processing a phase-modulated signal with a single-mode distribution of the durations of neighboring elements that do not take into account the mutual influence of neighboring magnetized sections of the magnetic carrier within the neighboring signal elements, which inevitably leads to to reduce noise immunity and reliability, since the process of fluctuation of neighboring elements of a phase-modulated signal is real, caused by high density} pisi, is a three-mode.

The aim of the invention is to improve noise immunity at high recording density.

The goal is achieved by the fact that the device is equipped with three single-vibration and shaper correction gates, the first inputs of which are connected to the output of the generator, and the second inputs are connected to the initial start terminal, and are connected in series with the counter by a parallel register, control unit and prohibition circuit, the control unit with its other inputs is connected to the outputs of the first single vibrator, decoder, correction gate driver, to the initial start terminal and the single output terminal connected also with the input of the inhibit circuit, with the third input of the first one-shot and with the output of the first element OR, whose inputs are connected to the outputs of the AND elements, the second output of the control unit and the output of the third one-vibration, also connected to the second input of the first element And, are connected through the second element OR to the second input of the second element AND, and the second output of the first one-shot is connected via the second one-shot to the trigger input of the counter, the remaining inputs of which are connected respectively to the initial start-up terminal and to a separate control unit output.

The drawing shows a block diagram of a device for reproducing phase-modulated signals.

A device for reproducing phase-modulated signals contains pulse shaper 1, elements AND 2, elements OR 3 and 4, prohibition circuit 5, control block b, decoder 7, parallel register 8, first one-shot 9, second one-shot 10, reversible counter 11, third one-shot 12 , generator 13 reference pulses, driver 14 correction gates, single output terminal 15, zero output terminal 16, terminal 17 of the phase-modulated signal input, terminal 18 of the initial start signal.

When the signal arrives at terminal 18, the initial start-up, the first one-shot 9, the second one-shot 10, the third one-shot 12, the control unit 6 and the correction gate generator 14 are reset. In this case, the output of the control block b is signal 1, which through the OR element 3 enters the input of one of the elements AND 2. When a phase-modulated signal arrives at terminal 17, a bit transition pulse appears at the output of one of the pulse shaper 1, which through one of the elements AND 2, the first element OR

4 is fed to the inputs of the one-shot 9, the prohibition circuit 5 and the control block b. The single-oscillator 9 generates a constant delay pulse, the back edge of which launches the one-oscillator 10, also (Normalizing, pulse ps: total delay. During operation of the single-oscillator 1C, the RECORD 1 command is formed in the control block b, according to which information from the counter is written to the parallel register 8 11, the RECORD 2 command, in which 1 bits are recorded in all bits of register 8, and the READ 1 command, in which information is copied from register 8 to counter 11, a bit transition pulse arriving at the input of block 6, translates it into From the trailing edge of a constant delay pulse formed by the one-shot 10, the counter 11 is started, by which the time interval is measured until the next transition pulse arrives by subtracting the pulses at the oscillator frequency 13. With the arrival of the second bit transition pulse, the prohibition circuit 5 generates a pulse the prohibition arriving at the control block b, and the last one prohibiting the execution of the RECORD 2 command. The one-vibration 9 generates a constant delay pulse, during which in the counter 11 the sums occur simulating pulses of the frequency generator 13 so that the expected third pulse of the bit transition is compatible with the middle of the pulse that will be generated by the third one-oscillator 12. During the operation of the one-oscillator 10, information is recorded from counter 11 into register 8 and back by the RECORD 1 and READ 1 commands block b, respectively. From the trailing edge of the pulse generated by the one-shot 10, the counter 11 is started, operating in the mode of summing the pulses of the frequency of the generator 13. The overflow pulse of the counter 11 starts the one-shot 12, which forms the gate-pulse which is fed to the second input of the other element AND 2 and the input of the first element OR 3. Simultaneously with the one-shot 12, the shaper 14 of the correction gates is started, which forms three correction gates-pulses and valid intervals between them, the total duration of which is equal to the duration of an explicit strobe pulse from the leading edge of which, in block b, an READ 2 command is formed, according to which information from register 8 is rewritten into counter 11. In protective intervals between the first and second, second and third strobe pulses, in the block b, the RECORD 3 and RECORD commands are formed 4, READING 3,. READING 4, according to which information from counter 11 5 is written to register 8 and back

respectively. During the strobe-pulse deactivation, the augment quality is corrected by its midpoint relative to the I1pulse of the bit transition that entered it, which consists in measuring the deviation error of the bit transition from the midpoint of the correction strobe by subtracting the oscillator frequency pulses 13 from counter 11 to the moment of arrival of the bit transition pulse and the summation of the pulses after the arrival of the bit transition pulse before the strobe-pulse correction ends. If the bit transition pulse turns out to be in the time domain of the correction strobe pulse, then block 6 forms a zero level at the input of the OR 3 circuit, the AND 2 circuit is controlled by the one-shot strobe 12. At the same time, clock pulses corresponding to positive and the negative edges of the bit transitions, and at terminal 16, information pulses corresponding to the negative edges of the bit transitions are entered.

Thus, in the course of operation, the change in g and the duration of the elements of a phase-modulated signal under conditions of high density magnetic recording is monitored.

Claims (2)

1. USSR Author's Certificate No. 430434, cl. G 11 B 5/00, 1971, 2. USSR author's certificate number 419961, cl. G P In 5/06, 1972 (prototype).