SU1069189A1 - Device for reproducing video signal - Google Patents

Abstract

A VIDEO DEVICE PLAYBACK DEVICE containing serially connected analog-to-digital converter the input of which is connected to the second output of the synchronizer, and the second output to the control input of the signal switch, and the unit for selecting display zones, outputs Which is connected to the second input of the code comparison unit, the video monitoring unit, which is connected with the fact that, in order to improve the accuracy of reproduction of high-frequency video signals, a phased pulse generator is inputted, the input of which is connected to the first output of the synchronizer, the frequency healer and the switch of the tactics of the pulses connected in series, while the output of the clock switch is connected to the clock inputs of the analog-to-digital converter and the shift register, a switch whose inputs are under They are connected to the intermediate outputs of the frequency divider, and the first element AND connected in series, with the output of the first element AND connected to the second information input of the clock switch, operating mode selection unit, control unit of the position of the label, the second element AND whose first input is connected to the second the output of the line selection block, the second input to the output of the operation mode selector, and the output to the control input of the clock switch, a tag length counter, an account (whose L input is connected to the output of the first element is And, and the reset input is connected to the first output of the synchronizer, the decoder, the trigger, the third element li, the second input of which is connected to the second output of the line selection block, and the mixer connected in series, while the second input of the mixer is connected to the output of the block code comparison, the third input is to the input of an analog-digital converter, the input of which is the input of the test signal, and the output is connected to the input of the video monitoring unit, the counting element of the line whose counting input is connected to the output shares Frequency and reset input - to the first output of the synchronizer, and the marker start shaper are connected in series, the second input of the mark start shaper is connected to the output of the tag position control unit, and the output is connected to the trigger input, the second input of the first And element is connected if trigger output.

Description

The invention relates to means for monitoring and measuring parameters of a television or other video signal, in particular, to means of displaying waveforms on the screen of a video monitoring unit. A device is known that allows the reproduction of oscillograms of video signals on a television screen, which contains successively connected analog-to-digital: rose converter, and the input video signal is fed to the input video signal of the shift register, comparator, mixer, and video monitoring unit. The device also has a synchronizer and a row counter. The synchronizer produces pulses of the frequency of raster elements, lowercase and frame sync pulses. The device contains two channels of forming vertical and horizontal lines of the coordinate grid. Each channel includes a counter and a one-shot, the output of which is connected to the corresponding slot of the mixer C1. : The disadvantage of this device is the insufficient accuracy of the video signal reproduction in the case when it is necessary to analyze individual high-frequency portions of the signal more precisely, since the signal is converted to the digital form and written to the shift register with a constant frequency of raster elements. It is also known a device for reproducing a video signal, comprising a serially connected synchronizer, a row allocation unit, a row addressing unit, a memory unit, and a video monitoring unit. In the device there are also sequentially connected digital-to-analog converter whose input is connected to the second output of the row addressing unit, comparator whose second input is connected to the synchronizer input and at the same time is the device input and the AND element, the second input of which is connected to the second output of the latch and rows, and an output - to the data inputs of the memory block C23 .. The disadvantage of this device is also not high accuracy reproduction video signal caused by lack of opportunities to reproduce high-resolution high-frequency portions of the video signal. The closest in technical essence and effect achieved to the invention is a video signal reproducing device comprising a series-connected analog-to-digital converter, a signal switchboard and a shift register, the output of which is simultaneously connected to the second information input of the signal switch and the video monitoring unit whose input is connected to video input bus, line selection block, second input. which is connected to the second synchronizer, and the second output - to the control input of the signal switch, and the display area selection unit, the output of which is connected to the second input of the code comparison block, and the third output of the synchronizer is connected simultaneously to the clock inputs of the analog-digital converter and the shift register C3i. A disadvantage of the known device is the low accuracy of reproduction of high-frequency sections of the video signal, contours, borders with abrupt differences in brightness, which is caused by a constant sampling frequency equal to the frequency of raster elements. When creating equipment, it becomes necessary to analyze such sections more thoroughly, for example, in nonlinear processing in more broadband helmets, and the known device does not allow such detailed viewing and control of high-frequency video signals. The aim of the invention is to improve the accuracy of reproduction of high-frequency video signals. The goal is achieved by the fact that the device for reproducing a video signal containing serially connected analog-to-digital converter., A signal switch and shift register, the output of which is connected to the second information input of the signal switch and the input of the code comparison unit, are connected in series to the synchronizer whose input is the input video signal, block line selection, the second input of which is connected to the second output of the synchronizer, and the second output - to the control of the input of the commutator s The display area selector unit, the output of which is connected to the second input of the code comparison unit, the video monitoring unit, is entered into a phased pulse generator, whose input is connected to the first output of the synchronizer, a frequency divider and a clock switch for the pulses, connected in series, the output of the clock switch is connected to the clock inputs of the analog-digital converter and the shift register, the switch.

the inputs of which are connected to the intermediate outputs of the frequency divider, and the first And element connected in series, the output of the first And element connected to the second information input of the clock switch, operating mode selection unit, label position control unit, the second element H, the first input of which connected to the second output of the line selection unit, the second input to the output of the operating mode selection unit, and the output to the control input of the clock switch, a tag length counter, the counting input It is connected to the output of the first element I, and the reset input is connected to the first output of the synchronizer, the decoder, the trigger is the third element I, the second input of which is connected to the second output of the line selection block, and the mixer connected in series with the second input of the mixer connected to the output of the block compare the codes, the third input is to the input of the analog-digital converter, the input of which is the input of the signal under study, and the output is connected to the input of the video monitoring unit, the counter of the line elements whose counting input is connected to the output of the deli Frequency, and a reset input to the first output of the SINCULAR, and a label start shaper connected in series / and the second input of the label start shaper is connected to the output of the tag position control unit, and the output is connected to the trigger setup input, and the second input of the first And element is connected to trigger output.

The introduction of these blocks allows in the recording process to discretize individual selected areas of the video signal under investigation with a frequency greater than the frequency of the raster elements, which during subsequent playback allows the video signal to be displayed with high resolution, i.e. improve the accuracy of high-frequency signal reproduction.

FIG. 1 shows the structural electrical circuit of the device / in FIG. 2 - oscillogram of the video signal of the entire line on the screen of the video control unit of the proposed device / in FIG. 3 - oscillogram of the video signal of the selected line segment on the screen of the video control unit of the proposed device.

The device contains analog-to-digital converter 1, switch 2, signal, shift register 3, code comparison block 4, synchronizer 5, row selection block b, block

7 display area selection, video monitoring unit 8, phase 1 first generator 9 and pulses, frequency divider 10, clock pulse switch 11, switch 12, first element And 13, block 14 of operating mode selection, label position control unit 15, second element And 16, counter 17 of the length of the label, the decoder 18, trigger 19, the third element And

20, the mixer 21, the counter 22 line items, the driver 23 of the beginning of the label.

Included in the device block 6 line selection and block 7

The selection of a display zone can be implemented as follows.

Line selection unit 6 may consist of a counter, a line code comparison unit and a set of switches for setting the code of the selected line. The counting and waste inputs of the counter are respectively low-row and frame clock pulses from the first and second

the outputs of the synchronizer 5, the code from the output of the counter is fed to the first input of the code comparison block, to the second input of which the code from the switches is fed. Counter output

is the first output of block 6

selection line forming the code of the current line of the frame.

The second output of the row allocation block 6 is the output of the block

code comparison. This output is connected to the control input of the switch 2 signal. The display zone selection unit 7 can be performed using an adder and a set of switches to set the corresponding binary code. At one input of the adder, the code of the current line is supplied from the first output of block 6 for selecting the line, and the second input is fed to the code,

formed with the help of switches.

 The adder subtracts from the code of the current line the code formed with the help of switches. To do this, the code generated using a set of switches should be inverse to the code that must be subtracted. Let's say

in the frame of M lines; This means that the code of the current line in each frame varies from O to M. Let L be the code that is necessary, i.e. set using switches.

the return code is L. At the output of the adder, the code in ka: where the frame changes from (0-L) to (M-O. As long as the code of the current line is less than -), the output of the transfer of the adder is a signal indicating a negative sign of bore.

This signal is used to prohibit the output to the output of the adder by feeding it to the gate input of the latter. As soon as the code of the current line becomes equal to y, the inhibit signal will disappear, and the code at the output of the adder will change from O to M-ot. In this range there are codes from O to N, corresponding to the display area, and the condition so that the entire display area fits on the screen. The value of N is specified in the device in the analog-to-digital converter 1, this is the number of gradations, which is quantized from the video signal.

The output of the adder is the output of the display zone selection unit 7. By installing a particular code with a set of switches, you can move the display area to a convenient part of the frame. Switch 12 can be performed, for example, using a jack switch for chiolo positions corresponding to the number of intermediate outputs of the frequency divider 10. In the simplest case, the mode selection unit 14 is a toggle switch for generating a one-bit binary code necessary to control the switch 11 clock pulses. The starting stamp generator 23 can be implemented using a code comparison unit, the first input of which is to feed the current code of the line elements from the output of counter 22, and the second input the code from the output of the label position control unit 15.

which can be done with

set of switches. Almost all the digital blocks of the device can be implemented on a chip series 133 (155). So the frequency divider 10, the beginning of the meca shaper 23, the counter 22 line elements can be performed on the chips 133IE5. All comparison blocks, code 4, code comparison block 4, mark start shaper 23, code comparison blocks in the row selection unit 6 to display area selection unit 7) are implemented on the chip 133LP5. The switch 2 signal, the switch 11 clock pulses can be performed on the chip 133LR1, or 133KP5, and the decoder 18 - on the chip 133ID4. The adder in block 7 of the selection of the display zone is implemented with the help of 133HjM3 chips. The 3-shift multi-bit register can be performed using 505IRZ microcircuits.

The device works as follows.

At the moment when the selected video line of the selected video line arrives at the input, the line selection unit 6 generates a signal that switches the signal switch 2 so that the video signal codes of the video line from the analog-digital converter output 1 are recorded in the shift register 3. 2 signals are switched in such a way that the 3 shift register is closed in a ring, and all information recorded in it during each line with a clock frequency equal to the frequency of the raster elements ntov is output as a parallel binary code on the first input of the unit 4 comparing codes. To the second input of the code comparison unit 4, a signal is output from the display zone selection unit 7. In the part of the frame selected for the display, the output signal of the display zone selection unit 7 sequentially, varying with the frequency, the string takes values from O to W, where

N is the number of gradations by which the video signal is quantized. B moments of coincidence of codes from the output of the display zone selection block 7 and from the output of the shift register 3 at the output of the code comparison block 4, a signal is generated which through the mixer 21 is fed to the screen of the video control block 8, forming an oscillogram of the signal under study. Simultaneously with the oscillogram, through the mixer 21, the entire monitored unit is output to the video monitoring unit 8.

the signal that forms the normal television image. In addition to these two signals, the image of the mark 24 is formed on the screen of the video monitoring unit B.

The image formation of the mark 24 is as follows.

At the moment of equality of the counter code, the 22 elements of the line, to the counting input of which the pulses of the SLED elements are received, and the code from the label position control unit 15 at the output of the label start shaper 23, which is a code comparison unit, form a signal that translates trigger 19 unit. The output signal of the trigger 19 is the signal of the mark 24. This signal through the third element AND 20 is output to the first input of the mixer 21 for supplying the video monitor unit 8 to the screen. The duration of the signal of the label 24 is determined by the frequency of the pulses through the switch 12 and the first element 13 served on the counting input of the counter 17 of the length of the label. The output code of this counter supplies1 to the input of the encoder 18, the signal from which triggers trigger 19 to its original state, completing the process of generating the tag 24 signal. Strobbing the output signal of trigger 19 in the third element AND 20 with the signal from the second output of block 6 so that the video signal of the mark 24 is formed only in place of the selected line. The device operates in two modes: unmarked mode and slave mode. You are on the label. In the first case, both writing and reading to the clock inputs of the analog-to-digital converter 1 and the shift register 3 feed the frequency of the raster elements from the output of the divider 10 parts through the switch 11 of the clock pulses. In this case, the video signal is played without a time scale conversion, and on the screen of the video monitoring unit 8 an oscillogram of the full line of the image is formed. The video signal of the mark 24 in this mode is also displayed on the screen. The formation of a tag signal in the untagged mode of operation is performed in the same way as in the tag operation mode. The duration of the signal of the mark 24 and in this case is determined by the frequency of the pulses, which through the switch 12 and the first element And 13 are fed to the counting input of the counter 17 of the mark length. The higher the frequency of these pulses, the shorter the label, because in a shorter time the counter code 17 of the label length reaches the code for which the decoder is set to 18. This code is equal to the number of elements in the string. The modes of operation with and without a label differ only in the organization of the record in register 3, and not in the formation of the signal of the label. If it is necessary to analyze individual parts of the video signal in more detail, then with the help of the tag position control unit 15 and the switch 12, the desired position and duration of the mark are selected, and the unit is switched to the second mode using the mode selector block 14. In this case, during recording, the analog-to-digital converter 1 and the shift register 3 are clocked with higher frequency pulses from the selected intermediate output of the frequency divider 10, which arrive at the clock inputs via switch 12, the first element I 13, and the switch 11 clock pulses. These pulses are received only during the formation of the label, providing a record in the register 3 of the selected line segment. During playback, register 3 is clocked with pulses of raster elements. Thus, the signal of the selected area is extended to the full length of the screen. Enhanced frequency recording and subsequent playback with stretching provide more accurate, more detailed. higher resolution playback of the selected section of the video signal line. Thus, the introduction of new blocks into the device eliminates the disadvantage of the known low fidelity of high-frequency sections of the video signal, as it allows for changes in the time scale, namely the recording of the video signal being studied with an increased frequency and reproduction with the original frequency, which ensures reproduction with great accuracy .

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Claims (1)

DEVICE FOR PLAYING VIDEO, containing a series-connected analog-to-digital converter, a signal switch and a shift register, the output of which is connected to the second information input of the signal switch and the input of the code comparison unit, a synchronizer connected in series, the input of which is a video signal input, a line highlighting unit, and a second input. which is connected to the second output of the synchronizer, and the second output to the control input of the signal switch, and a block for selecting the display zone, the output to Or connected to the second input of the code comparison unit, a video control unit, characterized in that / in order to increase the accuracy of high-frequency video signals, a phased pulse generator is introduced, the input of which is connected to the first output of the synchronizer, a frequency divider and a switch of clock pulses connected in series, while the output of the clock pulse switch is connected to the clock inputs of the analog-to-digital converter and the shift register, switch, input. which is connected to the intermediate outputs of the frequency divider, and the first element And connected in series, while the output of the first element And is connected to the second information input of the clock pulse switch, the mode selection block, the label position control unit, the second element And, the first input of which is connected to the second output of the line selection block, the second input to the output of the operation mode selection block, and the output to the control _ input of the switch of clocking <g pulses, a label length counter, the counting input of which is connected to the output of the first element And, and the reset input is to the first output of the synchronizer, a decoder, a trigger, a third element And, the second input of which is connected to the second output of the line selection unit, and the mixer connected in series, while the second input of the mixer is connected to the output of the unit code comparison, the third input is to the input of an analog-to-digital converter, the input of which is the input of the signal under investigation, and the output is connected to the input of the video control unit, a line element counter, the counting input of which is connected to the output of the divider tons, and the reset input is to the first output of the synchronizer, and the label start generator is connected in series, while the second input of the label start generator is connected to the output of the label position control unit, and the output is connected to the trigger installation input, and the second input of the first AND element is connected to the output trigger. SU., „1069189