SU510742A1 - Device for reproducing digital information from magnetic media - Google Patents

Description

one

The invention relates to automation and computer technology and is intended for use in memory devices with a moving magnetic carrier.

Devices for reproducing digital information from magnetic media are known, comprising a sync pulse generator and an amplifier-driver and an OR element connected to the input and output of the device.

The described device is characterized in that it has a shift register, a counter, an adder, triggers and elements "And, the first inputs of the elements" And are connected to single inputs of triggers, the zero output of one of the triggers is connected to the second input of the second element "And, zero output another trigger is connected to the second input of the first element “AND, and the single outputs of the triggers are connected to the second inputs of the third and fourth elements“ AND, the outputs of which through the adder are connected to the clock generator, and the output of the third About the element “AND is connected through a sequentially connected counter and shift register with the inputs of the element“ OR.

The drawing shows a functional diagram of the described device.

It consists of amplifier-formaker 1, elements "And 2 and 3, triggers 4 and 5. elements" And 6 and 7, adder 8, a clock generator formed by resonant filter 9, phase-shifting circuits RiCt and RzCz, differential amplifiers 10 and 11, elements “AND 12-15, counter 16, shift register 17 formed by elements“ Pi 18 and 19, trigger 20, elements “And 21 and 22, trigger 23, elements“ And 24 and 25, and element “OR 26.

The device receives an information signal corresponding to the method of recording by modified phase modulation (IMF), from which amplifier 1 generates pulses of a duration of 0.25 period in places where the signal passes through the zero axis. These pulses go further to the elements And 2 and 3, in which the phases of informational and synchronizing pulses are compared, coming in two feedback loops from the generator outputs (from the outputs of the differential amplifier 10). In order for the device to function correctly, several "units of a further order must be recorded at the beginning of the information sequence.

In the initial state, the sync pulse generator generates the signal “Allowed to the input of the element“ And 2, and the sequence “units through the elements“ And 2 and 6 and the adder 8

enters the resonant filter 9 of the generator. A sinusoidal oscillation occurs in the resonant filter, which is fed through the RtCi phase-shifting circuit to the input of the differential amplifier 10. A paraphasal rectangular signal from the outputs of amplifier 10, supplied to the inputs of the “I 2 and 3” elements, provides for the separation of the “one” and “eu” pulses and the shape of the pion signal; according to their phase.

For reliable strobing in the "And 2 p 3" elements, triggers 4 and 5 are introduced, which allow movement of the leading edge of information pulses within the positive component of the sync pulses. To ensure that the duration of the pulses coming through the adder 8 to the resonant filter 9 does not change when the gating conditions change, enter the elements "And

6 and 7, in which the single outputs of the flip-flops 4 and 5 are polled by the input information signal. From the outputs of the elements "And 6 and

7, pulses that are stable in duration are output, which makes it possible to obtain a constant signal amplitude from a resonant filter.

The correct temporal relationship between the information signal and the feedback signal at the inputs of the And 2 and 3 elements is provided by the RiCi circuit; the circuit provides a shift in the 0.25 period of the output signals of the differential amplifiers 10 and 11. Using the four signals from the outputs of the amplifiers 10 and 11 allows you to form two two-phase signals: one - generated by the elements “And 12 and 13 — to reset the triggers 4 and 5; the other, formed by elements "And 14 and 15, is to control the shift register.

The combination of the phases of the selected pulses and sync pulses is performed by a logic circuit consisting of a counter 16,

shift register 17, performed on elements 18-25, and the element "OR 26.

The output of the element “AND 6” is connected to the input of the counter 16, which provides for the gating of the information signal by the clock pulses in the elements “AND 18 and 19 so that the minimum interval for the gating is equal to one clock cycle. Using the shift register 17 and the element

"OR 26 is provided to restore the sequence of" units from the potential signal of counter 16, while the output of the element "OR signal coincides in phase with the tracking sync series (from the output of element" AND 15), and there are no phase distortions in the letters.

Claims (1)

Invention Formula Device for playing digital information from a magnetic driver, containing a clock generator and connected to the input and output of the device, an amplifier-driver and an “OR” element, characterized in that the purpose of improving the reliability of the device, it sets the shift register, counter,. adder, triggers and elements “And, with the first inputs of elements“ And connected to single inputs of triggers, zero output of one of the triggers connected to the second input of the second element “And zero output of another trigger connected to the second input of the first element“ And, and single outputs flip-flops are connected to the second inputs of the third and fourth elements “And, the outputs of which through the adder are connected to the clock generator, the output of the third element“ And connected via a succession of the counter and shift register with inputs of the element “OR.