SU1032476A1 - Device for forming small-size raster - Google Patents

Abstract

A DEVICE FOR FORMING A SMALL FORMAT, containing an element AND whose output is the output of the device and a first input by the device input, a trigger whose output is connected to the second input of the element I, the first counter, the second counter, the outputs of which are connected to the generator inlets of the sawtooth voltage and digital-analog converter, characterized in that, in order to increase the reliability of the device, it contains a decoder, the input of which is connected to the output of the first counter, one of the inputs of which is connected to the first input AND gate and another input coupled to the second counter, the first input of the flip-flop and one of the decoder output, the other output of which is connected to the second input of the flip-flop.

Description

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The invention relates to automation and computing and can be used to display sign information on the screen of a cathode ray tube (CRT).

Devices are known for forming a small format raster for displaying character information on a CRT screen, including a row counter, an element counter in a row, a sawtooth generator, and a D / C converter. However, the disadvantage of the edich devices is the low speed caused by transients in current deviation amplifiers, which do not have time to work out single increments of the step signal of the horizontal deflection sweep and rapid changes in the voltage of the vertical declination during the return path of the beam during the formation of the raster line.

Closest to the present invention, there is a device for selecting and forming on a CRT screen, comprising two triggers, two AND elements, a delay element, two counters, a switch, a sawtooth generator, a backlight unit, and a digital-to-analog converter 2.

A disadvantage of the prior art device is its complexity, which reduces the reliability of the device. The purpose of the invention is to increase the reliability of the device.

The goal is achieved by the fact that the device containing the element AND, the output of which is the output of the device, and the first input is the input of the device, the trigger whose output is connected to the second input of element P, the first counter, the second counter, the outputs of which are connected to inputs to the sawtooth voltage generator and a digital-to-analog converter, a decoder is inputted, the input of which is connected to the output of the first counter, one of the inputs of which is connected to the first input of the AND element, and the other is connected to the input of the second counter, first, input m trigger and one of the decoder output, the other output of which is connected to the second input of the flip-flop.

Figure 1 shows the functional diagram of the device, figure 2 - time diagrams, 1a of his work, fig.Z - diagram of the current sweep.

The device operates element 1, trigger 2, nerve 3 and second 4 counters, sawtooth generator 5, digital-to-analog converter b, and decoder 7,

The device works as follows.

In the initial state, the counters 3 and 4 are set to zero, the trigger 2 is in the zero state, prohibiting the passage of pulses of TOTAL frequency through the element And 1 n; backlight unit (not shown).

Upon receipt at the counter 3 pulses of the clock frequency (Fig. 2, plot A), the counter begins to work, increasing the output information with each clock cycle by one. Through And the clock ticks on the N-output of the decoder 7, which is connected to the single 1 trigger input 2, the signal (Figure 2 plot B) sets the trigger 2 single state (FIG. 2 plot G). At the same time, the clock frequency pulses start enter through the open element I 1 to the illumination unit (Fig. 2, plot D). After litK cycles, where K is the number of dots in the matrix column, the output of the decoder 7 appears, Fig. 2, plot C), which inserts trigger 2 in the zero state; in this case, the supply of needle pulses (Fig. 2 diagrams D) to the illumination unit stops. At the same time, the installation of the counter 3 to the initial state and a change by one in the State of the second counter 4 occurs, which accordingly changes the output voltage of the digital-to-analog converter 6 by one step (Figure 2) and) Next, the process described is repeated. When the state of the counter 4 changes (Fig. 2, plot E), the sign of the sawtooth voltage at the output of the sawtooth generator 5 (Fig, 2, plot g) changes.

Thus, the backlight pulses are formed only after a certain time delay, equal to the time for establishing transients (Fig. 3),

In this case, the transient process caused by the CRT deflection current amplifier by changing the sign of the sweep signal does not distort the displayable sign, since the current in the amplifiers of the pulsed light pulses changes linearly (the transient is completed). At the same time, the rate of change of the sawtooth voltage of the sweep is quite high and ultimately determined by the maximum allowable speed of the beam moving across the CRT screen.

The technical and economic efficiency of the invention is to increase the reliability of the device.

Claims (1)

DEVICE FOR FORMING A MALFORM RASTER, containing the .and element, whose output is устройства the output of the device, and the first input, the input of the device, a trigger whose output is connected to the second input of the AND element, the first counter, the second count! a chic whose outputs are connected to the inputs of a sawtooth voltage generator and a digital-to-analog converter, characterized in that, in order to increase the reliability of the device, it contains a decoder, the input of which is connected to the output of the first counter, one of the inputs of which is connected to the first input of the And element, and the other connected to the input of the second counter, the first input of the trigger and one of the outputs of the decoder, the other output of which is connected to the second input of the trigger. With N3 m o> 1032476,