SU1223295A1 - Magnetic video recording device - Google Patents

Abstract

The invention relates to instrumentation and can be used in devices that have carried out line-by-line recording of information, in particular in video recorders. The purpose of the invention is to expand the functionality. The device contains a magnetic head drive control unit 6, a magnetic playback head displacement drive 7, a demodulator 8., a frequency amplitude signal envelope detector 9, an auto-tracking unit 11, triggers 12, 14 and 25, a single vibrator 13, controlled keys 15, 16 , 22 and 23, adder 17, comparators 18, 19, digital-to-analog converter 20, part-time amplifier 21, OR circuit 24, AND circuit 26, pulse generator 27, counter 28 and reference voltage source 29 interconnected with each other and defined device elements the way that bespechivaet record-playback additional information signal with an arbitrary frequency spectrum. 2 Il.

Description

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The invention relates to instrumentation and can be used in devices, having carried out line-by-line recording of information, in particular, video recorders.

The purpose of the invention is to expand the functional possibilities by ensuring the recording and reproduction of additional information signals with an arbitrary low frequency spectrum.

FIG. 1 shows a structural diagram of a magnetic video recorder; in fig. 2 - voltage plots that show the operation of the device ..

A magnetic video recording device (Fig. O contains a recording head 1, an offset actuator 2, a control unit 3. driving a magnetic recording HEAD, a device input 4, a magnetic reproduction head 5, a magnetic reproducing head drive control unit 6, a reproducing magnetic displacement actuator 7, demodulator 8, detector 9 of the frequency-modulated signal envelope, block 6 includes a bus Turning on auto-tracking 10, node 11 auto-tracking, first trigger 12 and one-shot 13, second trigger 14, first control key 15, second control key 16, adder 17, first and second comparators 18 and 19, digital-to-analog converter 20, inverting amplifier 21, third control key 22, fourth control key 23, OR circuit 24, third trigger 25, AND circuit 26, generator 27 pulses, counter .28, voltage source 29.

The device works as follows.

In the device, the type of modulation of the additional information signals can be Any. Suppose unit 3 is a frequency modulator. Then, depending on the level of the information signal, the frequency of the output oscillations of block 3 changes.

(Fig. 2a) and. and, excites the actuator bias magnetic recording head 2, which begins to oscillate

a constant amplitude with a variable frequency in accordance with the control voltage applied to the input of the unit 2 J. The forming lines turn out to be modulated according to the signal of the additional information, as

295

depicted in FIG. Sv (in Fig. 3c, the recording line conventionally occupies a horizontal position). The additional information encoded with the help of the signal U (can be reproduced only if the magnetic head 5 is displaced by the value L 8 "a (. - O„ "(dotted line in Fig. Sv) and occupies position II In this case, the width of line a becomes variable and dependent on voltage Uj, and the FM signal and / reproduced by head 5 has an envelope U, in which additional 5 information is encoded (fig.3g) enters block 9 - an envelope detector, In the simplest case, a diode loaded on a low-pass filter is the output of which contains a signal and. (t), proportional to U, (t), in which additional information is encoded. Further, the signal UQ (t) goes to the demodulator (with the selected modulation method at 5. frequency), where the information is decoded. When generating control voltage to the 7 i Offset mechanism that moves the head 5 by the value of US; "aKc michs, the proposed 0 device works as follows. The voltage of the command 10 switches on the auto tracking, then the block 11 starts wives . A command voltage of 10, which jumps in a sudden manner (for example, from a positive value to O), sets trigger 12 to O, with the result that at its output Q 0 there is a zero potential falling to the control ; and the input of the control key 15, which opens, and the output voltage of the auto-tracking unit, acting on the displacement drive unit 45, places the head 5 in position I (Fig. 3). The voltage difference of the tire commander 10 is delayed by the single-vibrator 13 for the time required to move the head 5 from the arbitrary position to the position I

(fig. Sv), after which the counter 28 is zeroed, the trigger 14 is transferred to the state S by input S and through the AND circuit 26 to the counter 28 the pulses from the oscillator 27 begin. At the output of the digital-to-analog converter 20, bitwise tied with counter 28 appears stepwise

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the increasing voltage that is applied to one of the inputs of the comparator 18, and also after the inverting amplifier 21 to one of the inputs of the comparator 19, where it falls relative to the zero level. The voltage at the output of autotracking unit 11 may be positive or negative. If it is positive, then if its level coincides with the level of increasing step voltage, a voltage jump occurs at the output of the comparator 18, and if it is negative, then a similar signal occurs at the output of the comparator 19 The output voltage of the comparator 18 or 19, the passage through the OR circuit 24, sets the trigger 14 to the state O, the flow of pulses from the generator 27 to the counter 28 is stopped, and at the output of the digital-to-analog converter At 20, there is a voltage equal in magnitude (with a slight error) to the voltage at the output of the device of the auto-tracking unit 11. To generate a voltage to D / A converter 20 equal to the output voltage of the auto-tracking unit not only in amplitude but also in sign, a trigger 25 is used. If a voltage jump appears at the output of the comparator 19, the trigger 25 is set to position I on its output Q appears zero potential controlled key. opens and the input of the adder 17 receives a signal from the output of the digital-to-analog converter 20.

If the information signal appears at the output of the comparator 19, then the trigger 25 is set to the O position, the control key 22 is closed, and the signal from the output of the inverting amplifier 21 arrives at the input of the adder 17. voltage from the outputs of the block 20 or 21, the output signal of the OR circuit 24 is fed to the S input of the trigger 12, which is set to state 1, the control key 15 is closed, the control key 16 is opened and the control drive of the displacement head 5 is supplied right s output from the adder 17. It is the sum of voltages and .d and u ,, wherein UijA - voltage equal to the output voltage ustroyst

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autotracking, and U is the output voltage of source 29. If U (, then head 5 is in position I in Fig. Sv, therefore U is chosen 5 so that the total control voltage Uu (+ Uy supplied to the playback head drive, provides translation of the head to position II (fig. Sv) and reproduction of additional information.

The modulation of the recording lines with additional information signals practically does not degrade the quality indicators of a television image, since frequency modulation is used to record the video signal and before the arrival of the FM image signal to the frequency demodulator

Claims (1)

lizatsi the magnitude of this signal. Invention Formula A magnetic video recorder that contains the drives of the magnetic and H6IX recording and playback heads, control units for these drives, the playback drive control unit contains an auto-tracking unit, whose input is connected to the bus. Auto-tracking tracking, a detector of the frequency-modulated signal, connected to the magnetic reproduction head, characterized in that, in order to extend the functionality by providing recording-reproduction of additional information, mation with the pro- by an arbitrary low-frequency spectrum, a demodulator was inserted into it, the control unit for driving the displacement of the magnetic recording head was made in the form of a modulator, the input of which is the information input of the device, and The control unit for the drive of displacement of the magnetic reproduction head additionally introduced the first and second comparators, the first, second, three tiy and fourth controlled keys, first, second and third triggers, adder, reference voltage sources, one-shot, pulse generator, AND, OR circuits, counter, digital a log converter and an inverting amplifier, while the output of the envelope detector of the frequency-modulated signal is connected to the input of the modulator, bus Enable autotracking is connected to the R-input of the first trigger directly, and with the S-input of the second trigger through a single-oscillator, the code Q of the first trigger is connected to the control input of the first control key connecting the first output of the node autotracking with the input of the bias drive of the magnetic playback head, output Q of the first trigger is connected to the control input of the second control key connecting the output of the adder to the bias drive input of the magnetic playback head, the second output of the auto unit Reckingen yervym connected to the inputs of the first and second comparators, the second input of the first comparator. with the output of digital-to-analog converters, the input of an inverting amplifier and through a third controllable key - with the first input of the adder, the second input of the second comparator is connected to the output of the inverting 232954 the 4th amplifier and via the fourth controlled key to the second input of the adder, the third input of which is connected to the output of the source of the reference voltage, 5, the output of the first comparator is connected to the first input of the circuit OR n input S of the third trigger, the output of the second comparator is connected to the second - open the input of the OR circuit and the input R of the third trigger, the output Q of which is connected to the control input of the third controlled key, and output Q to the control input of the fourth control key, the output of the circuit OR connection to the input R of the second trigger and input S lane second trigger, output Q of the second trigger is connected to the first input of the AND circuit, the second input of which is connected to the output of the generator named lV ° about the counting input of the counter, which is associated with the inputs of the D / A converter, the installation input of the counter is connected to the –input second trigger. Eyes Lx t  . I G; G: - °° T „e..r ... Subscription 1720/55 circulation 543 VNISh State Committee of the USSR 11 cp; inventions and openings of Raushsk nab. 4/5 Branch PPP Patent, Uzhgorod, r npoeK il yT Roshko Subscription the USSR