SU674241A1 - Video signal recording-reproducing apparatus - Google Patents

Description

The xy input is connected to the input of the third peak detector | 5a, the input connected to the signal conditioner; the output of the first integrator through the input first peak detector is connected to a different input of the first adder, and another input of the second adder is connected with the input of the selector switch

FIG. Figure 1 shows the electrical structure of a device for recording and reproducing a video signal; in fig. 2 - time diagrams of the process of video signal conversion and recording; in fig. 3 - Temporary Diagrams for the selection of information about the unevenness of the background of the video signal pre-correction in the charging process.

The device contains a selector 1 clock pulses, the first output of which is connected through a driver of clock pulses 2 s enter the pulse-width converter (SHIP) 3, the output of which through the recording amplifier 4 is connected to the input of the storage tube (ZELT) 5, the input of which is connected to the block scan b, the input of which is connected to the inputs of the control unit 7, the amplifier is read by 8 and the second output of the selector 1 from hp pulses, and to the first output of the storage electron-beam storage unit (ZELT) 5 under The inputs of the first integrator 9, the signal conditioner 10 and the low-pass filter 11 are connected, the output of the connection is different with the other input of the read amplifier 8, and the second integrator 12 connected in series to the Btopo output of the storage electron beam tube (ZELT) 5 the second peak detector 13, the first adder 14, the signal processing unit 15, the second adder 16 and the division block 17, the output connected to another input of a pulse-width converter (SHIP) 3, and another input - to the output of the third peak detector 18, the second peak In this case, the output of the first integrator 9 through the switch is connected to another input of the first integrator 14, besides another input of the second adder. 16 is connected to, the input of the 20 clock selector switch 1, the output 21 of the device ... -

The device works as follows.

The video signal to be recorded (Fig. 2a) is fed to the input of the selector 1 and the first input of the second adder 16. In the selector 1 the line and frame sync pulses from the first are extracted from the video signal. the outputs are fed to the control unit 7, the scanner 6 and the second input of the read amplifier 8, and from the second output the washing clock pulses are sent to synchronize the clock pulse generator 2, from which code the clock pulses (Fig. 2e) follow the frequency f J (where according to the sampling theorem f J 2 f c and f in is the upper cut-off frequency of the original signal that is required to be reproduced) is sent to the second input of the CHIP 3, the first input of which receives the video signal through the second adder 16 and the dividing block 17 to be recorded. In GIS 3, the video signal from analog form is converted into a sequence of modulated pulse widths (Fig. 2c).

This sequence of pulses from the output {YIP 3 through the recording amplifier 4 is fed to the control electrode of the ZELT 5 unit.

A special command received at the second input of the recording amplifier 4 from the control unit 7 records the potential relief on the targets of the ZELT 5 block, and due to the integrating properties of the ZELT 5 block, the potential relief takes an analog form proportional to the shape of the original video signal (Fig. 2d ). (The number of charges applied to the target in the process of its switching by electronic, is directly proportional to two quantities - the current of the switching beam and the switching time).

However, the electron beam, the passage through the equalizer (the grid and the grid of the mice, undergo parasitic amplitude modulation due to the irregularity of the permeability of these grids, which leads to a distortion of the shape of the potential relief. , and the functions characterizing the recorded video signal, that is, the duration of the switching pulses.

Also, additional background distortions arise when reading, since the reading beam has a parasitic amplitude, this modulation is similar to that which the beam current had (beam) during recording.

If we denote the irregularity of the permeabilities of the screen grid and the grid of the target through

Yaek (y) bsG1-% with y:.

 4 ybjUj, (x, y),

Claims (1)

where jUgco and Jl | (, -, respectively, the maximum permeability of the screen grid and the target; 1-tes (he)) and (x, y) are respectively the laws describing the relative change in the permeability of the screen grid and the target grid in the raster plane; 1lo is the current of the recording beam, and F (t) is modular) function, and the law of variation of the current of primary electrons falling on a set and determining the shape of the potential relief, as well as the current of the screen grid and the current of the signal electrode taken during recording, have the following form: Ao () (W) acflf - MO zs () - 3d MoVby) I es.) -V Xi-3co "PWJ 9CD-3c (by); 12) Y ". (Fzso-" MO-Yaash / MO (B) If the signal, which is the sum of the currents of the screen grid and the signal electrode, flowing through these chains during recording, has the form 3c, .V) " oPWtl- / r3coO-JiV, oi; of (lJ 3J - / & 3C - 3cofMo H (.IU to clear: it is clear that the second member of the right side of this expression coincides with the second eirme of the right part (1), and since Since the note of a notional relief is an integration process, then, by subjecting the integrating operation to a total signal, one can obtain complete information on the parasitic modulation of the potential relief. The parasitic amplitude modulation of the beam current can be obtained from the signal removed from the signal electrode, njpoor differentiation operation, which eliminates the influence of the components of the field video signal, since the differentiation of information is the amplitude of the pulses, and not the duration, therefore, it is possible to implement a pyopor rationally) arousal of the video signal applied to the SHIP 3, taking into account these distortions. From the first output of the ZELT 5 block, a portion of the current of the recording beam that has received spurious amplitude modulation due to the irregularity of the permeability of cetoK goes to the first integrator 9 and the signal conditioner 10, in which the spectral components of the useful video signal (Fig. Over) and the section are integrated only the amplitude values of the pulses. Differentiated pulses from the output of the signal conditioner 10 are fed to the third peak detector 8 (Fig. 36). In the third peak detector liS, there is an envelope characterizing the parasitic amplitude modulation of the beam current (Fig. Sv), which is fed to the second input of dividing unit 17. With the help of the first integrator 9 and the first peak detector 19, the sigma extraction operation is performed . . The amplitude is proportional to the product of the modulating function F (t) and the function characterizing the parasitic amplitude modulation of the signal taken from the first output of the ZELT 5 block (Fig. 3 g - dashed line). Using the second integrator 12 and the second peak detector 13, a signal is implemented across the signal gap proportional to the product of the modulating function F (t) and the function characterizing the parasitic amplitude) modulation of the signal removed from the second code of the ZELT 5 block (Fig. Zd) line). The signal from the outputs of the first and second piKobbix detectors 19 and 13 are fed to the inputs of the first adder 14, from the output of which syi-. The signal characterizing the amplitude distortion of the recorded potential relief is measured and which, having passed through the signal processing unit 15 (Fig. Ze), is fed to the second input of the second adder 16.i From the output of the second adder 16, the signal represents the sum of the input video signal and the reverse signal the amplitude distortion of the form of the recorded potential relief is fed to the first input of the dividing unit 17, in which it undergoes predictions, back irponop with a fundamental regional amplitude modulation of the beam current (Fig. Zh - dotted It shows video without predistortion - the ideal case). The signal from the codec of the division block 17 is fed to the first input of SHIP 3. After the write cycle ends, the device is switched to the read mode by a command from the control unit 7, while the amplitude-modulated signal is removed from the first output of the ZELT 5 block (Fig. 2d). This signal is fed to the input of the low-pass filter 11, which eliminates the clock components. From the output of the low-pass filter 11 video games. output shilyra lower natioi 11 video1; ig / j. Nal (Fig. 2d) is fed to the first input of the read amplifier 8 and from it to the output 21 of the device. Claims An apparatus for recording and reproducing a video signal comprising a clock selector, the output of which is connected via a pulse clock generator to an input of a pulse width converter, an output of which a recording amplifier is connected to an input of a storage electron tube module, the deviation input of which is connected to scanner, the input of which is connected to the inputs of the control unit, the read amplifier and the second output of the clock selector, characterized in that, in order to reduce nor unevenness of the video signal, to the first output of the storage cathode tube unit, the sub-input inputs of the first integrator, a signal conditioner and a low-pass filter, the output connected to another input of the amplifier, schshit, and the second peak of the memory cathode tube assembly are connected to the second integrator and the second integrator connected detector. the first adder, the signal processing unit, the second adder and the dividing unit, the output connected to another input of an angular-pulse converter, and the other input to the output 8 entered the third peak detector, the input connected to the signal conditioner, while the output of the first integrator through the input of the first peak detector is connected to another input of the pfvy adder, in addition, another input of the second adder is connected to the input of the sync pulse selector. Sources of information taken into account during esupment 1. USSR author's certificate No. 531307, cl. H 04 N 5/76, 1975. . g. . // 1 / | L A / 1 J l op ompppppp. il Hill III lib  AA.-G- -l-71-7GL7 | I lA / TTF- -CG-Tf jr-ir7 ( 7GL7TL71 -,, one L