SU1278934A1 - Device for reproducing from magnetic record medium - Google Patents

Abstract

The invention relates to the accumulation of information and reduces the temporal distortion of the reproduction result. The band-pass filter 8 from the sum of the information and reference signals generated by the digital-to-analog converter 6 separates the reference signal supplied to the detector 10 and the pulse shaper 15, which sets the counter 20 to "O" and enables the generation of pulses by the pulse generator 19. Counter 20 starts counting and generates a code received through memory register 21 to a digital-to-analog converter .. 22, which generates a signal controlling 1 pass filter 16. Detector 10 simultaneously generates a signal proportional to the residual time distortion. Since a change in the passband of the filter 16 causes a change in the transit time of the reference signal through it, f then the element 27 is controlled by (L holder and voltage adder 29. 1 or 10 I

Description

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The invention relates to the accumulation of information, namely, devices for reproducing from a magnetic recording medium.

The purpose of the invention is to reduce the temporal distortion of the reproduction result from the magnetic recording medium.

The drawing shows a block diagram of the proposed device for reproducing from a magnetic recording medium.

The device comprises a reference frequency signal generator 1, a frequency multiplier 2, a playback unit 3 and an analog-digital converter 4 connected in series, a buffer memory block 5 and a digital-analog converter 6, the output of which is connected to the input of the low-pass filter 7 and to the input of the band-pass filter 8. The output of the low pass filter 7 is connected to the output bus 9 of information. The output of the band-pass filter 8 is connected to the input of the phase detector 10, which consists of a frequency detector 11 and an integrator 12 connected in series. The input and output of the phase detector 10 coincide with the input of the frequency detector 11 and the integrator 12, respectively.

The device also contains the first counter 13 connected by an input to the output of the generator 1 of the reference frequency signal and connected by an output to the first input of the buffer memory unit 5 and to the first input of the movement control unit 14 of the magnetic recording medium, a driver 15 pulses connected to the output of the bandpass filter 8 , an additional band-pass filter 16 connected between the output of the playback unit 3 and the input of the frequency multiplier 2, and the fall compensation 17 connected in series and the second counter 18. The output of the second counter connected to a first input of an analog-digital converter 4 to the second input of the buffer memory 5 and to the second input of the control movement of a magnetic recording block 14.

In addition, the device contains a pulse generator 19 connected in series, a third counter 20, a memory register 21, and an additional digital-to-analog converter 22, an amplitude detector 23 connected in series, a first additional low-pass filter 24 and a peak detector 25 connected in series by a second additional low-pass filter 26 and a controllable delay element 27 connected by an output to the second input of the analog-to-digital converter 4 and connected in series with the source 28 of the reference voltage and adder 29 voltages. The output of the phase detector 10 is connected to the input of the amplitude detector 23. The output of the pulse generator 15 is connected to the inputs of the pulse generator 19 and the third counter 20. The output of the peak detector 25 is connected to the input of the memory register 21. The output of the additional digital-to-analog converter 22 is connected to the input of the additional band-pass filter 16 and to the input of a voltage capacitor 29 connected by an output to the input of the controlled delay element 27. The output of the frequency multiplier 2 is connected to the first input of the fall compensator 17 connected by a second input to the output of the generator 1 of the reference frequency signal. The output of the playback unit 3 is connected to the input of the second additional low-pass filter 26. Reproduction from a magnetic recording medium by means of the device proposed is as follows.

The information and reference signals reproduced from the magnetic recording medium by the playback unit 3 are fed through the second additional filter 26 lower. These frequencies and the controlled delay element 27 are analog-to-digital converter 4. The sum of the information and reference signals is converted into digital code by analog-digital converter 4 with the frequency of the trigger signal generated by the additional band-pass filter 16, multiplier 2 frequencies and compensator 17 depositions. In this additional band-pass filter 16 produces the selection of the reference signal, the multiplier 2 frequency - multiplying its frequency, and the compensator 17, for replacing the missing pulses with the pulses of the generator 1 signal of the reference frequency. The second and first counters 18 and 13, which are affected by the fallout compensator 17 and the reference frequency signal generator 1, form a control signal supplied to the analog-to-digital converter 4 and the write and read addresses supplied to the buffer memory unit 5. The digital code is recorded in the buffer memory unit 5 at a frequency determined by my personal start signal, and read from it at a frequency determined by the generator 1 of the reference frequency signal. The digital-to-analog converter 6 converts the digital code, read from the buffer memory block 5, into an analog signal, sent to the STRIP filter 8 and the low pass filter 7. In this case, from the low-pass filter 7 to the information output bus 9, a signal is supplied whose temporal distortions are significantly reduced. The second and first counters 18 and 13 also act on the motion control unit 14 of the magnetic recording medium. The latter maintains the speed of movement of the magnetic recording carrier so that the average distance between the cell,

5 to which the recording is made, and the cell from which reading is made, remained constant and equal to half the capacity of the block 5 of the buffer memory.

The bandpass filter 8 from the sum of the information and reference signals generated by the digital-to-analog converter 6 separates the reference signal supplied to the phase detector 10 and to the pulse shaper 15. The latter sets the third counter 20 to the zero state and allows the generation of pulses by the generator of 19 pulses. The third counter 20 starts counting and generates a code received through memory register 21 to the additional digital-to-analog converter 22. Additional digital-to-analog converter 22 generates an analog signal that controls the passband of the additional band-pass filter 16. At the same time, the phase detector 10 is from the reference signal allocated band-pass filter 8, generates a signal proportional to the magnitude of the residual temporal distortion. The amplitude detector 23 and the first additional low pass filter 24 extract an envelope from this signal. At the moment of the minimum of this envelope, the peak detector 25 generates a voltage drop, which records the code of the third counter 20 in the memory register 21. Thereafter, the code value at the output of the register 21 of the memory becomes unchanged and the bandwidth of the additional band-pass filter 8 stops changing. Since when the passband of the additional bandpass filter 16 changes, the time of the reference signal passing through it changes, the controllable delay element 27 is controlled by the voltage adder 29, which is influenced by the reference voltage source 28 and the additional digital-to-analog converter 22.

Claims (1)

Invention Formula A device for reproducing a magnetic recording medium containing a reproducing unit, a reference frequency signal generator, a frequency multiplier, a motion control unit of a magnetic recording medium and an analog-to-digital converter connected in series, a buffer memory block and a digital-analog converter whose output is connected to the filter input a low frequency connected by an output to an information output bus and to an input of a bandpass filter connected by an output to an input of a phase detector, characterized in that, in order to reduce temporal distortions of the playback result, a first counter connected to the output of a reference frequency signal generator is inserted into it and connected output to the first input of the buffer unit memory and to the first input of the control unit of the movement of the magnetic recording medium, a pulse shaper connected by the input with the output of a bandpass filter, an additional bandpass filter connected between the output of the playback unit and the input of the frequency multiplier, connected in series to the fallout compensator and the second counter, the output of which is connected to the first input of the analog-digital converter, to the second input of the buffer memory unit and to the second input of the control unit of the magnetic recording carrier, connected in series by a pulse generator, the third counter , a memory register and an additional digital-to-analog converter, an amplitude detector connected in series, a first additional low-pass filter and a peak detector, sequentially, the second additional low-pass filter and a controlled delay element connected by an output to the second input of the analog-digital a converter, and a reference voltage source and a voltage adder connected in series, the output of the phase detector connected to the input of the amplitude detector, the output of the pulse generator connected to the inputs of the pulse generator and the third counter, the output of the peak detector is connected to the input of the memory register, the output of the additional digital-to-analog converter is connected to the input of the additional band-pass filter and to the input of the adder voltages connected by an output to the input of a controlled delay element, the output of the frequency multiplier is connected to the first input of a fallout compensator connected by a second input to the output of the reference frequency signal generator, and the output the playback unit is connected to the input of the second additional low-pass filter.