SU813498A1 - Device for displaying information on crt screen - Google Patents

Description

(54) DEVICE FOR DISPLAYING INFORMATION ON SCREEN OF ELECTRON BREAD TUBE

The invention relates to computing and can be used in the design of devices for displaying information. According to the main author. St. No. 618768 a device is known for displaying information on the screen of a cathode ray tube (CRT), containing a data input unit, a digital code converter in a time interval, a clock generator, a beam scanner, a cathode beam receiver, a control panel, a television sensor, the first OR element, a discriminator, Generator and image storage unit .- :, The drawbacks of the known device are that there are dark gaps, especially well visible, in the two adjacent lines of the image raster on the EDT screen at a short distance from the screen, which occurs when inputting and outputting information from a CRT screen using a pen, cursor, etc., degrades the image quality, the height of which is determined by the selected number of lines of image decomposition along the by increasing the number of lines to the television will lead to a change in the television standard and an increase in the band of transmitted frequencies (a decrease in the number of television channels), and for television-type display devices it will increase the amount of information in the image frame and image frame playback speed. The purpose of the invention is to improve the display accuracy by increasing the resolution of the vertical capacity by two times while maintaining the playback time of the image frame and the amount of the original information (transmitted frequency band) in the image frame:. The goal is achieved by the fact that the first switch, one of which is connected to the output of the controlled generator, the other to the output of the clock generator, and the inverter, the other input of which is connected to the output of the clock generator, and the output to the other input of the block are entered into the device. the image memory and the third input of the dynamic memory unit, serially connected to the second switch, the input of which is connected to the output of the synchronizing generator, and a controlled amplifier, the second input of which connected to the output of the second OR gate, the third to the output of the discriminator and the output of the controllable amplifier is connected to the cathode rubki .vtoromu entry. The drawing shows a block diagram of the device. The device for displaying information on the screen of a cathode ray tube contains a block of data input 1, a digital code converter 2 in a time interval, a synchronous generator 3, a beam sweep, an electron beam tube 5, a remote control, a television sensor 7, the first element OR 8, a block 9 of dynamic memory TI, the second element OR 10, the disc minator 11, the controlled oscillator 12, the image memory block 13, the first switch 14, the inverter pulse generator 15, the second switch 16, the controlled amplifier 17, the communication link 1 from the digital calculator A car, a communication bus 19 to a digital computing machine, a manual input bus 20, an external video source bus 21, for example, a detected radio signal of a television broadcast, an external clock 22, for example a detected clock broadcast television signal 23, a reference voltage, a bus 24 26, input and 27 - output unit, 9 dynamic memory, bus 28.29 input and 30 output of the first switch 14, bus 31-33 input and 34 -. output controlled amplifier 17, bus 35 input and 31 - output of the second switch 16. When building a device for displaying information on the screen of a CRT 5, it is advisable to focus on the standard television broadcasting standard, so the clock generator 3 can generate sync series in standalone mode or in mode relaying (slave) from a variety of television signal sources (e.g., broadcasting on bus 23). Informatschi CRT 5, the beam of which the beam scanner 4, synchronized by the synchronous generator 5, is deployed line by line and frame in accordance with the television standard, is outputted either directly from the digital computer over the bus 28, or from the control panel as commands from the jfdish , a light pen, a cursor sensor, either from a television sensor 7, or from a blank of 1 image memory: (, letters; symbols, scale formulas), or from an external video source (television broadcast). The task of data entry block 1 is to provide a conjugation of two opposing information flows - input on bus 18 and output on bus 19, delimiting them by type, intermediate memorization, forming interrupt commands, coordinating television sweep parameters With the pace of operation of a digital computer. The data input unit 1 generates image codes from which the corresponding image and the codes of reproduced values are read from the image memory 13, which, as a result of the dynamic compensation by the sweep function in the digital code converter, are converted into modulation pulses in time interval 2. The discriminator 11 of the beam sweep unit 4 receives a voltage proportional to the rate of current change in the horizontal deflection system. This voltage, equal to U aJ "di / dt, can be removed, for example, from the collector of the horizontal sweep output transistor / where L is the inductance in the horizontal deflection system; di / dt is the rate of change of current in the horizontal deflection of the system, or from the branches of the horizontal transformer, or from the additional winding of the horizontal transformer. In a linear sweep, the derivative di / dt is equal to the constant voltage, and the voltage at the output of the discriminator 11 is either zero or the required initial value of the control voltage. The voltage from the output of the discriminator 11 controls the frequency of the controlled oscillator 12, which may include a jet lamp, a varicap, etc. From the output of the controlled generator 12, the read pulses through the switch 14 and the pulse shaper 15 are fed to the inputs of the image memory unit 13 and the dynamic memory unit 9. During the forward run of the horizontal sweep, the switch 14 does not change the parameters (frequency and duration) of the pulses from the output of the controlled oscillator 12. The order of reading the information from the imaging unit 15 from the image memory unit 13 and the dynamic memory unit 9 to the first one also does not change the time (the beginning of the line) reads the first word, the second - the second, ..., at the last time (end of the line) the last word is read. The imaging unit 15 may be, for example, reversible by the sync generator 3 plus or minus the counting unit, the address counters of the image memory blocks 13 and the dynamic code 9.

Pulse modulated contours of reproduced images read from the image memory block 13 via an OR 10 element, controlled amplifier 17 are fed to a modulator of a cathode ray tube 5. The gain of the controlled amplifier ly during the forward sweep stroke is equal to a predetermined value and changes in small limits relative to the specified value. Switch 16 turns off one or more stages of controllable amplifier 17 in order to obtain the required 1st gain factor during forward running.

The nonlinearity coefficient of the sweep per line is determined from the formula

6 Chah Um1p SLjMa,

max where 4 and Vuin respectively maxiFlUI rnlrf

the minimum and minimum rate of change of the current di / dt in the horizontal deflection coils. With a constant modulation frequency of the expanded line, the nonlinearity coefficient of the reproduced image 6 Hj is also equal.

The length t of the image element of the string is equal to

e - ..

where t is the playback time of this element.

If, as the speed of movement of the CRT 5 beam changes, the playback time of the element varies accordingly: an increase in speed, a decrease in time, a decrease in speed — an increase in time, then a nonlinear scan on the screen of the cathode ray tube 5 forms a linear image.

Thus, the nonlinearity coefficient of the controlled generator 12

"G Ugmok ypMin.

with in fMOX

where V {and - respectively maxim. and the minimum rate of change of the frequency df / dt of the controlled oscillator 12 must be equal in magnitude to the nonlinearity coefficient of the sweep, which is realized by the discriminator 11 and controlled by the generator 12.

For linearization of the reproduced image with external sources of video signals (television broadcasting, cable television - bus 21 digital code converter in time interval 2, television sensor 7), the frequency of which in the places of their formation is not possible, the block 9 of dynamic memory is used, on which

video signals are received through the element OR 8.

The video signal is recorded linearly in block 9 of a dynamic Ps1m, and information read by a clock controlled generator 12 is non-linear in accordance with the nonlinearity of horizontal scanning as mentioned above.

Thus, the image is reproduced by linearizing the video signals transmitted through the element OR 10 and the controlled amplifier 17 to the modulator of the electron-beam tube 5.

The brightness of the reproduced image element in a row on the screen of the electron-beam tube 5 is proportional to the amplitude of the modulating pulses and inversely proportional to the speed of movement of the CRT beam 5.

To preserve the ratio of the brightness gradations of the reproduced image elements readable at varying speeds during the linearization process of the image, the amplitude of the modulating pulses per CRT modulator 5 is increased according to the voltage from the output of the discriminator 11 and the amplitude of the modulating pulses increases. pulses, the amplitude of the modulating pulses is reduced.

During the reverse run of the sweep, the switch increases the frequency and reduces the duration of the readout pulses from the output of the controlled oscillator 12 by as many times as the forward stroke duration is greater than the reverse stroke duration.

Shaper J.5 reverses the order of reading information from block 13 of the image memory and block 9 of the dynamic block to reverse, t; e. at the first moment of time (the beginning of the reverse sweep) the last word is read out, at the second - the last but one word ... at the last moment of time (the end of the reverse sweep stroke) is the first word.

Linearization of the image reproduced during the reverse run of the sweep. It is carried out completely analogous to the linearization of the discriminator 11 to the generator 12 being controlled during the forward stroke.

The switch 16 switches the control of the dual amplifier 17 to the reverse sweep time so that the gain of the controlled amplifier 17 increases by as many times as the forward stroke duration is greater than the reverse pulse duration. Small changes with respect to the nominal gain factor of the gain amplifier of the controlled amplifier 17 during the return stroke are carried out completely analogous to the changes in the gain during the forward stroke.

Usually the distance between; two adjacent lines of the 5 raster displayed on the CRT screen are less than the line height. In the proposed device, the pasaepTkH playback on the reverse path fills the gap with the melody with two adjacent lines. The image becomes splinter jular, even with a short distance, the raster structure is not visible. It occurs with: a kind of interpolation of the modulation of image elements between two adjacent lines, since it can be considered that between two adjacent lines the image elements do not change in an essential way. The last statement does not belong to the smallest elements of the image with a height of one line f, but such elements occur very rarely. For such elements, the vertical definition decreases as the height of the above elements has increased.

Claims (1)

1. USSR author's certificate No. 618768, cl. G 06 K 15/20, 1976.