SU987852A1 - Video signal oscillogram reproduction device - Google Patents

Description

(54) DEVICE FOR PLAYING Oscillograms of video signals

one

The invention relates to television technology, in particular, to means for monitoring and measuring parameters of a television signal, as well as displaying waveforms of signals on a video monitoring device screen. HaodpeteHHe can be used in industries of industry and research where visual inspection or analysis of the objects and processes under investigation is necessary. So, for example, the device can be used in the instrumentation of television centers to monitor and measure the parameters of a television video signal.

A device for playing video signal waveforms is known, comprising a synchronizer, a grid generator, a mixer, a television microtransmitter, an adapter device and parallel video channels according to the number of output waveforms, each of which includes K level memories, where K is the number of active rows in the raster , variable frequency clock and comparator. The output of the clock generator is connected to the recording control inputs To the level storage units, to the information input of each of which an input video signal is supplied. The output of each memory unit is connected to the first input of the comparator, to the second

The 5 input of which is supplied with a saw-tooth voltage of the horizontal frequency from the synchronization of the torus. H-and the read-out control inputs of the memory blocks are fed by horizontal sync pulses also from the synchronizer 10 tor. The outputs of the comparators of each video channel through a serially connected mixer, television microtransmitter and adapter device are connected to the output bus of the device 1.

The disadvantages of this device are 15 s, firstly, the low quality of reproduction of high-frequency signals, due to the point nature of the reproduction of the oscillograms, and secondly, the inconvenient character of the representation,

2Q signals, since the time axis is vertically directed.

A device for reproducing oscillograms of video signals is known, which contains an analog-to-digital converter, the output of which is connected to the first input of the code comparison block, to the second input of which the output of the row counter, also available in the device, is connected. The output of the code comparison unit through the mixer is connected to the input of the video monitor. The outputs of the blocks for forming horizontal and vertical lines of the coordinate grid are connected to the second and third inputs of the mixer. The operation of the analog-to-digital converter, shift register, row counter, and blocks of the grid lines is performed using synchronizer 2.

The disadvantage of this device is also the low quality of reproduction of high-frequency signals due to the dotted representation of the waveforms of the signals, due to which the connectivity between the individual samples of signals is lost, and the resulting waveforms do not give a sufficient idea of the waveform.

The closest in technical essence and the achieved result to the proposed is a device for reproducing oscillograms of video signals, containing sequentially connected analog-to-digital converter, switch, memory block, code comparison unit and video control block. It also includes a synchronizer and a display position selection unit. The first output of the synchronizer is connected simultaneously to the control inputs of the analog-digital converter and the storage unit, the second output to the control input of the switch, and the third output to the input of the unit for selecting the position of the display area. The output of the display position selection unit is connected to the second input of the code comparison unit. The output of the memory unit is connected to the second information input of the switch. The analog-to-digital converter input is connected simultaneously to the synchronizer input and the input video signal bar. The video signal of the selected image line is converted into digital form and recorded into a memory block, which can be made in the form of parallel shift registers, the number of which is determined by code width, and the length of each register is determined by the number of raster elements in the video signal line. In one frame, one sample (raster element) of the video signal is converted and stored. In the playback mode, one of the inputs of the code comparison block receives the code of the current line from the output of the display zone start selection block, and the other - video signal codes from the memory block, and during the time during which the code of one line stands, the memory block goes through all codes written to it. At the moment the codes coincide, a pulse is generated that is output to the screen of the video control unit. Thus, a certain raster line number is associated with each value of the video signal, and an oscillogram of the signal is drawn on the screen of the video control unit. Wherein

the time axis is directed horizontally. A disadvantage of the known device is the poor quality of displaying high-frequency signals of greater magnitude, since in this case the curve is formed from far-apart points, and the observer loses the ability to integrate it. Despite the fact that these samples are located at the correct positions, the quality of visualization of high-frequency signals is low.

The purpose of the invention is to increase the display quality by allocating the area limited by the waveform and increasing the number of possible reproduction modes.

The goal is achieved by the fact that

0 to a device containing a synchronizer connected in series, an analog-to-digital converter, whose information input is connected simultaneously to the synchronizer input and is the device input, the first switch, the control input of which is connected to the second output of the synchronizer, the memory block whose control input is connected to the first output of the synchronizer, and the output to another information input of the first

0 of the switch, and the code comparison unit, as well as the unit for selecting the position of the display zone, whose input is connected to the third output of the synchronizer, and the output to the second input of the code comparison unit, and the video monitoring unit, are entered sequentially connected selection of the position of the display area, the trigger, the reset input of which is connected to the fourth output of the synchronizer about the block, as well as the shift register, the output of which is connected to the second input of the AND element, and the information, clock and reset

5 inputs are connected respectively to the output of the OR element, the first and fourth outputs of the synchronizer.

In addition, the OR element is connected to the input of the video monitoring unit through an input serially connected inverter and a second switch, the control input of which is connected to the output of the input control unit, and the second and third information inputs are respectively to the outputs of the OR element and the code comparison unit.

FIG. 1 shows a block diagram of the device; in fig. 2 - the same, the embodiment; in fig. 3 - timing diagrams of the original video signal (a) and its displays obtained in two modes of operation (b, c). The device contains a video monitor unit 1, serially connected synchronizer 2, analog-digital converter 3, first switch 4, memory block 5 and code comparison block 6, display zone position selection block 7, decoder 8, trigger 9, AND element 10, OR element 11, the inverter 12, the second switch 13, the control unit 14 and the shift register 15. The device operates as follows. In the recording mode, digitized video samples of the selected image line (Fig. 3a) from the output of the analog-digital converter 3 through the first switch 4 are recorded in memory block 5, which is organized as m parallel shift registers, where m is the number of bits Binary codes show each video sample count. The number of bits in each register is equal to the number of samples (raster elements) in the video signal line. One frame of video signal is written to registers in one frame. Upon completion of the recording process, the codes of all the raster video elements of the selected display line are recorded in registers. Thus, the recording process is organized in the same way as in the device prototype. In the playback mode, a signal from the output of the memory block 5 is fed to the first input of the code comparison unit 6, to the second input of which a signal is output from the output block of the position display region 7. The code at the output of the block 7 for selecting the position of the display zone varies with the frequency of the lines and takes values from zero to N, where N is the number of gradations the video signal is quantized. During each row, all information recorded in memory block 5 is output to the first input of block 6 comparing codes with the frequency of raster elements, and through the first switch 4, closing the registers of memory block 5 into the ring, is again recorded in memory block 5. If any of the codes recorded in the memory block 5 is equal to the code set at the output of the display zone position selection block 7, a signal appears at the output of the code comparison block 6. If this signal is fed directly to the video monitoring unit 1, then the waveform of the video signal will be reproduced in the same form as in the device-prototype (Fig. 3, b). Such a mode in the proposed device is also possible if, using the control unit 14, a signal from its third input is connected to the output of the second switch 13. Signals from the output of block B code comparison through the OR 11 element are also fed to the information input of the shift register 15, the number of bits in which is equal to the number of raster elements in the video signal line, and recorded in it. This register through the elements AND 10 and OR 11 is closed in a ring and, in addition, its output signal through the element OR AND the second switch 13 with the corresponding control signal at the output of control block 14, determining the second playback mode, is fed to the input of the video monitor If the image is scanned from top to bottom, then during playback all the raster elements located below the waveform of the video signal appear "highlighted, because in the corresponding positions of the lines there will be signals from the output shift The new register is 15. Thus, the waveform of the video signal appears as the border of two contrastingly colored areas, as shown in FIG. 3, c. This makes it more likely for the observer to see the form of the video signal if there are areas with large amplitudes in the latter. Since the waveform is displayed on the video monitoring unit 1 simultaneously with the image, it may be more convenient for the observer to highlight the upper part of the shadow graph, i.e. invert it. This mode is also provided in the device, if the input of the video monitor unit 1, using the control unit 14, sends a signal from the first input of the second switch 13, where it in turn comes from the output of the OR element 11 through the inverter 12. After the scanning area has finished The code at the output of the display position selection block 7 is equal to N, the decoder 8 generates a signal that flips trigger 9. The output signal of trigger 9 prevents the shift register 15 from passing through element 10 of the signal. So that after scanning the display area, all the remaining lines of the frame are not highlighted, which would place the image observation. The frame sync pulses from the fourth output of the synchronizer 2 in each frame reset the trigger 9 and zero the bits of the shift register 15. The display zone position selection unit 7 entering the device and the control unit 14 can be executed as follows. Block 7 includes an adder, one of the inputs of which receives the code of the current image line from synchronizer 2, the second input is a code that determines the position of the display area on the video monitoring unit 1. This code is set using a set of switches, also included block 7. The difference of the indicated codes is the output signal of block 7. The control block 14 may be

configured as a set of switches with which a binary code is established, needed for controlling the second switch 13.

Thus, the introduction of new blocks and connections eliminates the poor quality of the visualization of high-frequency signals due to disruption of the perception fusion of the reading points, since the video signal is displayed in the form of a shadow graph, i.e. the boundary between two contrasting colored areas.

In addition, the possibility of switching the playback modes is provided: “Shadow graph — inversion of the shadow graph — a line that is not in the prototype device.

A sufficiently new, widely used for similar purposes, television oscilloscope with a line selection unit C9-1 was chosen as the base object. In relation to the known, the proposed device has a greater accuracy of reproduction, due to the possibility of choosing the required number of quantization levels, it has smaller dimensions, weight, two times less power consumption. At the same time, the quality of visualization of a video signal is high; it is possible, depending on the nature of the signal, to present it in the most convenient form for observation. In addition, the proposed device allows displaying a video signal waveform on a single screen with an observed image, which reduces the number of measuring equipment, greatly simplifies and makes the process of photo registration in scientific studies more conspicuous. Less power consumption, greater efficiency and ease of operation, reducing the complexity of the photo registration process when using the proposed device allow to obtain a significant economic effect.

Claims (3)

1. A device for reproducing oscillograms of video signals containing a serially connected synchronizer, an analog-to-digital converter, whose information input is connected simultaneously to the synchronizer input and is the device input, the first switch, the control input of which is connected to the second synchronizer output, memory block, the control input of which is connected to the first output of the synchronizer, and the output to the other information input of the first switch, and the code comparison unit, as well as the selection block by The display zone, the input of which is connected to the third output of the synchronizer, and the output to the second input of the code comparison unit, and the video monitoring unit, are characterized in that, in order to improve the quality of the display by allocating the area limited by the waveform, the sequentially connected decoder is input which is connected to the output of the unit for selecting the position of the display zone, a trigger, the reset input of which is connected to the fourth output of the synchronizer, the element AND and the element OR, the second input of which is connected to the output b comparing the eye codes and output - to the input of the video control unit, and a shift register whose output is connected to the second input of the AND gate, and the data, clock and effluent inputs respectively connected to the output of the OR gate, the first and fourth outputs of the synchronizer. 2. The device according to claim 1, characterized in that, in order to increase the number of possible playback modes, the OR element is connected to the input of the video monitoring unit through an input serially connected inverter and a second switch, the control input of which is connected to the output of the input control unit, and the second and the third information inputs, respectively, to the outputs of the OR element and the code comparison block. Sources of information taken into account in the examination 1. US patent number 4058826, H 04 N 9/62, cl. 358-10, 1977. 2. For the name of Germany No. 2728457, cl. G 06 K 15/20 1979. 3. Forward Germany No. 2655133, cl. H 04 N 7/02, 1978 (prototype). and F 1 / 2.3 fl, 3.