SU1103283A1 - Device for reproducing digital information from magnetic record medium - Google Patents

Abstract

A DEVICE FOR PLAYING DIGITAL INFORMATION FROM A MEDIA MAGNET RECORDING, containing a reproducing head connected through a reproduction amplifier to the input of the driver of zero pulses, a sync block, the first output of which is connected to the counting input of the counter and the synchronizing controller of the shifter of the one of the settings of the controller and the controller of the register of the shader of the one of the settings of the controller and the register of the controller of the shader of the one of the settings of the controller and of the controller of the shader of the one of the settings of the one of the settings of the controller and of the controller of the shader of the one of the settings of the shader of a registry of the controller of the shift of the registry of the shader of a wipy and one. output through the first element OR - with the synchronizing input of the static register and with zero setting input of the counter, the first and second outputs of which are connected respectively the first and second address inputs of the memory element, the trigger, two inputs of which are connected respectively to the two address outputs of the memory element, and the output to the second input of the first OR element and the first input of the sync block, the third output of which is connected to the synchronization input of the recorder, the remaining inputs of the latter are connected respectively to all address outputs of the memory element, the address inputs of which are connected via a static register to the address output of the shift register, characterized in that, in order to reduce error of the result of reproducing digital information from a magnetic recording medium, the connected between the output of the playback amplifier and the second input of the sync block are connected in series to the rectifier, the pulse shaper by extremum, the first element AND, the second element OR, and the demodulator, the second output of which is connected the information input of the shift register, as well as the second element I and sequentially connected to the output by the rectifier Schmidt trigger, the third element I, the first summing up three (L ger, the fourth element And, the second summing trigger and multiplier, the output of which is connected to the second input of the second element OR, and the second input to the fourth output of the sync block and the second input of the demodulator, the second output of the Schmidt trigger connected to the second element And the second input of the first summing trigger, the second inputs of the second and third elements I are connected to the output of a shaped pulse body at the extremum, the second output Yu of the first summing trigger is connected 00 to the second input of the second summing trigs g pa, and the output of the pulse shaper of zero .sv coupled to the second input of the fourth element I.

Description

The invention relates to magnetic recording, in particular, to devices for reproducing digital information from a magnetic recording medium. A device for reproducing digital information from a magnetic recording medium is known. containing a reproducing head connected through a playback amplifier to the input of the pulse generator, the output of which is connected to the first of the sync block inputs and to the information input of the shift register connected by a synchronization input to the output of the sync block connected to the input of the register unit, the other inputs of which are connected to the memory element trigger, binary counter and the element OR C. The known device allows the reproduction of digital information recorded with a relatively high density, however, has a significant discrepancy in the result of reproducing digital information from a magnetic recording medium. The closest in technical essence to the present invention is a device for reproducing digital information from a magnetic recording medium, comprising a reproducing head connected through a reproduction amplifier to the input of the pulse former by zero, a sync block, the first output of which is connected to the counter's counting input and synchronizing the inputs of the shift register and the memory element, and the second output through the first element OR - with the synchronizing input of the static register and with the zero installation input of the counter a, the first and second outputs of which are connected respectively to the first and second address inputs of the memory element, the trigger, two inputs of which are connected respectively to the two address outputs of the memory element, and the output to the second input of the first OR element and the first input of the sync block, the third output Kogorogb associated with the synchronization input of the recorder, and the remaining inputs of the latter are connected respectively to all the address outputs of the memory element, the address inputs of which are connected via a static register with the address output e memory elements whose address inputs are connected via a static register to the address outputs of the shift register 2. The remote device also allows for the reproduction of digital information recorded with relatively high density, but has a significant inconsistency of the reproduction result, as there are no protection measures digital information from errors resulting from a decrease in the amplitude of the reproduced signal due to parasitic amplitude modulation or the period of the information following nnyh symbols due to knocking in the mechanism of movement of the magnetic carrier. The purpose of the invention is to reduce the fissure of the result of reproducing digital information from magnetic recording media. This goal is achieved in that a device for reproducing digital information from a magnetic recording medium, comprising a reproduction head connected through a reproduction amplifier c. the input of the pulse driver is zero, the sync block, the first output of which is connected with the counting input of the counter and the clock inputs of the shift register and the memory element, and the second output through the first OR element - with the clock input of the static register and zero setting input of the counter, the first and the second outputs of which are connected respectively to the first and second address inputs of the memory element, the trigger, two inputs of which are connected respectively to the two address outputs of the memory element, and the output to the second input The first OR element and the first sync block input, the third output of which is connected to the synchronization input of the recorder, the remaining inputs of the last one are connected respectively to all address outputs of the memory element, the KOTopqro address inputs are connected via a static register with the shift register output output, entered between the output the playback amplifier and the second input of the sync block in series connected rectifier, pulse shaper according to the extremum, first AND element, second OR element and demo a puller, the second output of which is connected with the information input of the shift register, as well as the second element I and the Schmidt trigger sequentially connected to the output, the third element I, the first summing trigger, the fourth element I, the second summing trigger and the multiplier whose output is connected to the second input of the second element OR, and the second input to the fourth output of the sync block and the second input of the demodulator; the second output of the Schmidt trigger is connected through the second element AND to the second input of the first summing trigger and, the second inputs of the second and third elements and connected to the output of the pulse shaper to an extremum, the second output of the first adder latch coupled to a second input of the second summing trigger a pulse shaper on the output coupled to a second input of the fourth item I. In FIG. 1 shows a functional diagram of the device; on fng. 2 - timing charts of the device. The device comprises a reproducing head 1 connected through a reproduction amplifier 2 to the input of the imaging unit 3

pulses on zero, sync block 4, shift register 5, connected by a synchronization input to the output of sync block 4, connected by a second output to block 6 of the register, other inputs of which are connected to memory element 7, trigger 8, binary counter 9, element 10 and static register 11, the information inputs of which are connected to the outputs of the shift register 5, and the outputs to the address inputs of the memory element 7 connected by other address inputs to the outputs of the binary counter 9, the inverse control input to the first output of the syn block 4 connected by the third output to the input of the element OR 10, another input of which is connected to the output of the trigger 8 connected to the second input of the sync block 4. Moreover, in the device the output of the element OR 10 is connected to the sync input of the five-bit static register 11 and to the zero setting input binary counter 9, the counting input of which is connected to the first output of the sync block 4, the trigger inputs and connected to the outputs of the memory element 7. The device includes playbacks connected between the output of amplifier 2 and the first input of the sync block 4, serially connected rectifier 12, pulse shaper 13 by extremum, first element 14, second element 15 and demodulator 16, the second output of which is connected to the shift register information input. 5, the Schmidt trigger 17 connected to the output of the rectifier 12, the outputs of which are connected respectively via the second and third elements AND 18 and 19 to the inputs of the first summing trigger 20, the output of which through the fourth element 21 and 21 The second summing trigger 22, the doubled frequency shaping unit 23 is connected to the second input of the first element OR 15. In the device, the second inputs of the second and third elements And 18 and 19 are connected to the output of the generator of 13 pulses according to the extremum, the second output of the first summing trigger 20 is connected to the second input of the second summing trigger 22, the fourth output of the sync block 4 is connected. to the second inputs of the demodulator 16 and the double frequency shaping unit 23, the second input of the fourth element I 21 is connected with the output of the imager 3 pulse in at zero.

The device works as follows.

The signal reproduced by the magnetic head 1 (Fig. 2a) after amplifier 2 is converted into three sequences of pulses, namely, the second and third element I 18 and 19 receive the signal formed by the extremum from the former 13 pulses (Fig. 2b), on the fourth: fifth element 21; - formed by shaper 3 pulses by zero (Fig. 26), the third pulse sequence after rectifier 12 receives processing in

Schmidt's trigger 17 (Fig. 2d, 9). These pulse sequences are used to obtain a pulse corresponding to the fallout mode (Fig. 2e). The formation of the beginning and end of the fallout region (the region with reduced amplitudes of the reproduced signal) is carried out using the second and third elements AND 18 and 19 and the first summing trigger 20.

And already in the second trigger 22, a pulse corresponding to the fallout mode is formed into a replacement pulse (Fig. 2g). In the device, the sync block 4 (which is a controlled generator, two dividers and a driver) converts the sync pulses received from the output of the demodulator 16 (Fig. 2h) into a high-frequency pulse sequence (Fig. 2a), the follow-up period of which carries information about the detonation in the movement mechanism magnetic carrier; This high-frequency sequence of pulses goes to one of the dividers, which performs the function of matching the frequency with a discrete change in the speed of the tape drive mechanism, from the output of which it goes to the demodulator 16 and the double frequency shaping unit 23, from which the replaced sequence in the drop zone (Fig. 2k) is summed up from the information on the second element OR 15 and then goes to the demodulator 16 (Fig. 2n). In the demodulator 16, using the high-frequency pulse sequence, selection is made according to the duration of the synchronization pulses (Fig. 2h) and information symbols (Fig. 2m). The sync block 4, in addition to the high-frequency pulse sequence, produces three sequences of synchronizing pulses: uniform clock (Fig. 2n), uniform, group (Fig. 2o) and output gating (Fig. 2n). From the second output of the demodulator 16, the information symbols are fed to the information input of the five-bit shifting register 5, which forms the time-shifted pulses supplied to the information inputs of the five-bit static register I. Signals from the outputs of the five-bit static register 11 arrive at the address inputs of the element the memory forming the pulses supplied to the registration unit 6 (Fig. 2c,, y, f, x), the trigger trigger 8 is generated. reset pulse (Fig. 2p) to the initial state.

The base object does not provide for measures to replace the signal in the dropout area. Although the detection of synchronization pulses and binary symbols in digital technology to a certain extent does not depend on detonation, however, if there are depositions in the reproduced signal and no special measures are taken, the detonation value will significantly change the reliability of both synchronization pulses and binary symbols. In the proposed device, the elements 1223 and the sync block 4 provide reliable detection of synchronization pulses and binary symbols from the reproduced signal subjected to detonation of the tape drive mechanism. The period of the output signal of the controlled oscillator included in the sync block 4 is proportional to the detonation value, therefore approximately the same number of high-frequency sequence pulses will be placed in one period of the reproduced pulses. Under conditions of varying the amplitude of the reproduced cigal, the device generates a fallout and substitution pulses, and the output of the double-frequency shaping unit 23 produces replacement pulses, during which time changes are made that are proportional to the detonation value. Due to this, the permissible value of the duration of the fallout of the reproduced signal is significantly enhanced while maintaining the normal operation of the demodulator 16. Thus, the proposed device, as compared with the base object, allows reducing the inconsistency of the playback result by 20-30% arising from detonation in the mechanism (movement to increase the order of detection of synchronization pulses and information symbols by experimentally testing a prototype device It is proved that the proposed device allows decreasing the amplitude of the reproduced signal due to parasitic amplitude modulation or the period of following information symbols due to detonation in the mechanism for moving the magnetic media to reduce the uncertainty of the result of reproducing digital information and increase the accuracy detection of synchronization pulses and information symbols.

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Claims (1)

DEVICE FOR PLAYING DIGITAL INFORMATION FROM A MAGNETIC RECORDING MEDIA, comprising a reproducing head connected through a playback amplifier to the input of a pulse shaper to zero, a sync block, the first output of which is connected to the counting input of the counter and to the synchronizing inputs of the shift register and the memory element, and the second OR element - with the synchronizing input of the static register and with the zero installation input of the counter, the first and second outputs of which are connected respectively to the first mu and the second address inputs of the memory element, a trigger, the two inputs of which are connected respectively to the two address outputs of the memory element, and the output - with the second input of the first OR element and the first input of the sync block, the third output of which is connected with the synchronizing input of the recorder, the rest of the inputs of the last respectively connected to all address outputs of the memory element, the address inputs of which are connected through a static register to the address output of the shift register, characterized in that, in order to reduce the error the result of reproducing digital information from a magnetic recording medium, it is connected to the rectifier, an impulse generator at an extremum, a first AND element, a second OR element, and a demodulator, the second output of which is connected to the information input of the shift register, connected between the output of the playback amplifier and the second input of the sync block , as well as the second element And and connected in series with the output of the rectifier Schmidt trigger, the third element And, the first summing trigger, the fourth ele ment And, the second summing trigger and multiplier, the output of which is connected to the second input of the second OR element, and the second input - to the fourth output of the sync block and the second input of the demodulator, while the second output of the Schmidt trigger is connected through the second element And to the second input of the first summing trigger, the second inputs of the second and third elements And are connected to the output of the pulse shaper at the extremum, the second output of the first summing trigger is connected to the second input of the second summing trigger, and the output of the pulse shaper in zero connected with the second input of the fourth element I.