SU512487A1 - Device for reading signals from a magnetic storage unit - Google Patents

Description

The main inputs of registers 2-4 are connected to the output of the delay element 38, and the outputs to the inputs of the corresponding elements “AND the first three groups, the outputs of which are connected to the inputs of the same name elements“ OR 8, AND and 14, the outputs of which are connected respectively to the inputs of the elements “OR 30 and 31, elements “And 28 and 29, and an additional delay element 24, and elements“ And 26–27. The remaining connections of the elements of the device are shown in FIG. one.

FIG. 2 shows the pulses 40 at the gate inputs of the elements “AND 5-10, 12, 13, 18 and 23; impulses 41-43 respectively at the outputs of the elements “OR 11, 14, 8; impulses 44-46 respectively at the outputs of the elements “And 28, 27, 26; pulses 47, 48 at the outputs of the elements “OR 30 and 33, respectively.

From the analysis of the reproduced differentiated signal (not shown in Figs. 1 and 2), it follows that the half-wave of the signal, which is significantly different in duration from the neighboring half-waves, is subjected to the greatest distortions. The results of measuring the half-wave durations of the signal allow us to conclude: if the half-wave length is equal to or more than 35 relative units (40 relative units, for example, 0.5 ms), then we are dealing with a half-wave 2T (where T is the period of a continuous sequence of zero information) a duration of 24 units and less is a half-wave T, if the duration of 31-33 units is a half-wave 1.5T; If 26-29 units, then 1.5T or T, depending on the duration of the adjacent half-waves. If the duration is 26-29 units, and the duration of the adjacent half-wave is 2T, then this is the half-wave T, if the duration is 26-29 units, and the duration of the adjacent half-waves is T or 1.5T (not 2T), then this is the half-wave 1.5T.

When reviewing the operation of the proposed device, it should be taken into account that the pulses 40 shown in FIG. 2, generate pulses of the extracted information, corresponding to the previous differential of the reproduced signal.

The device works as follows.

The counting code 49 counter 1 serves pulses, the frequency of which is much more than the frequency of the reproduced information signal. The pulses at the input 49 can be obtained, for example, by multiplying the frequency of the clock pulses reproduced from the special track of the magnetic carrier. At the input 50 of the counter 1, pulses are applied, which are generated at the moments of intersection of the x-axis by a differentiated reproducible signal. The counting state 1 is not every successively reset, is written to register 2, register 2 is written to register 3, and register 3 is written to register 4. The pulses at the output of the OR 8 element appear if the contents of register 3 is 35-41 relative units, and

This means that the duration of the corresponding half-wave of the reproduced signal is 35 to 41 units. The appearance of a pulse from the output of the element “OR 8 indicates that the half-wave duration is 2T.

One of the elements “And 9, 10 gives an impulse if the register contains and the duration of the corresponding r ol-wave is equal to T. At the output of one of the elements“ And 12, 13

a pulse appears if the content of register 3 and the duration of the corresponding half-wave of the reproduced signal are 30-33 units. The impulse at the output of the element OR 17 is in the case when the contents of register 3 and the duration of the corresponding half-wave of the signal are 26-29 units.

Blocks 19 and 20, if registers 2 and 4 are equal to or greater than 35

units, give not impulse, but the permissive level. This level goes through the element "OR 21 to one of the inputs of the element" AND 18 and through the element "NOT 22 to the input of the element" And 23. The element "And 18 gives an impulse if register 3 contains 26-29 units, and one of registers 2 or 4 is not less than 35 units, i.e. the duration of a half-wolf is equal to T. Element I 23 gives an impulse if register 3 contains 26-29 units,

and registers 2 and 4 contain no more than 33 units. The output impulses of the element “And 23 go through the element“ OR 14 to the inputs of the elements “And 26 and 27 and through the delay element 24 to the input of the trigger 25. Output

The pulses of the element “And 18 arrive through the element“ OR II at the inputs of the elements “And 28 and 29.

I.Mnulse from the output of the element "OR 8, corresponding to the duration of 2T, appears

at the output of the element “OR 30 (zero of the selected information) and after the time determined by the delay element 32, at the output of the element“ OR 33 (a unit of the selected information). Pulses from the output element

"OR 11 (corresponding to the duration T) passes through the element" And 28 (units of the selected information) or through the element "And 29 (the zeros of the selected information). The pulses from the output of the element “OR 14 (corresponding to a duration of 1.5T) are transmitted through the delay element 24 to the input of the trigger 25 and through the element“ AND 27 (the zero of the selected information) to the input of the element “OR 30. The difference of the reproduced signal 1.5T is zero, if before him was a unit of information. If before it there was a zero, then the drop of the reproduced signal 1.5T corresponds to information 01. In this case, the impulse from the output of the element “OR 14 goes through the delay element 24 to the input of the trigger 25 and through the element“ AND 26 to the inputs "OR 30 and 31. At the output of the element" OR 30, an impulse corresponding to zero information appears, and after a time,

determined by the delay element 32, - impulse at the output of the element “OR 33, which corresponds to the information unit.

Claims (1)

Invention Formula A device for reading signals from a magnetic memory block containing a driver, the input of which is connected to the output of the playback amplifier, and the output to the inputs of the delay elements, a generator, three groups of AND and OR elements, characterized in that, in order to increase the reliability and device speed, it contains the fourth group of AND and OR elements, an additional delay element, registers and a counter, the inputs of which are connected to the outputs of the generator and one of the delay elements, and the outputs to the bit inputs of the first istra, The discharge the inputs of each subsequent register are connected to the bit outputs of the previous register register, the control inputs of the registers are connected to the output of another delay element, and the outputs are connected to the inputs of the corresponding elements “And the first three groups, the outputs of which are connected to the inputs of the same name“ OR, the outputs are connected to the inputs of the corresponding elements “AND and“ OR of the fourth group and input additional delay element. four/ 2 3  5 S 47 48 O01 Fi.g