SU834738A1 - Device for displaying information on crt screen - Google Patents

Description

(54) THE DEVICE FOR DISPLAYING INFORMATION ON THE SCREEN OF THE ELECTRON-BEAM TUBE is not connected with the output of the second digital-to-analog converter, and the output of the communicator is connected to the second input of the second comparator. The drawing shows a block diagram of a device for displaying information. The device contains a control, laziness block 1, a beam deflection block 2, a video amplifier 3, a cathode ray tube 4, a frequency generator 5, a count b, the first digital-to-analog converter 7, the first comparator 8, the voltage driver 9, the second digital-analog converter 10, the switch 11 , the second comparator 12 element OR 13, the bus 14 of the input information of the Command, data), the bus 15 of the output information. The proposed device. About works as follows. The input information about the image reproduced on the screen of the electron-beam tube 4 enters the control unit 1 via the input information bus 14. The control unit 1 cuts the beam deflection unit 2 expands the reproduced image on the screen of the cathode ray tube 4 in accordance with the television standard. The divisions of the measuring scales superimposed on the reproduced image are formed at the time of comparison at the input of the first comparator 8 voltages from the outputs of the first digital-to-analog converter 7 and the driver 9 of the voltages. The pulses generated by the first comparator 8 arrive at the modulator of the electron-beam tube 4 through the element OR 13 and the video amplifier 3. The voltage former 9 generates a voltage proportional to the horizontal deflecting current, and may be a resistor connected in series with the horizontal deflecting coil of the unit 2 beam deflection. The resistance value of the resistor is chosen to be much smaller than the inherent resistance of the horizontal deflection coil, so as not to distort the current form in the horizontal deflection coil, and if necessary, the voltage drop across the terminals of the specified resistor is additionally amplified in the voltage driver 9. The frequency generator 5 is synchronized by the control unit 1 once during each line of the horizontal sync pulse. The frequency of the oscillations of the generator 5 of the frequency is selected in accordance with the minimum distance between two adjacent doors and is therefore much higher than the frequency of horizontal sync pulses, i.e. the frequency generator 5 operates in the frequency multiplication mode. The counter 6 divides the initial sequence of pulses from the output of the frequency generator 5 in accordance with the code of the division factor entered at the input of counter b from the output of control unit 1, and the code of the coefficient of division can be equal to one. Dividing the original pulse sequence allows the distance between adjacent divisions of the scale to be varied. The new digital-to-analog converter 7 forms a step voltage at its output, the absolute value of which is proportional to the scale division number, and the value of each step is proportional to the interval of divisions. The comparison of the voltage from the output of the voltage driver 9 with the voltage from the output of the first digital-analog converter 7 in the first comparator 8, regardless of the linearity of the voltage at the output of the voltage driver 9, occurs only when the specified voltage changes by the voltage step from the output digital-to-analog converter 7. The voltage from the output of the first digital-to-analog converter 7 is a reference, reference (for example, commercially available hybrid eight-digit digit analog converter has K2PD521 type, accuracy on the order of 0.1 - 0.2%). The voltage change at the output of the voltage driver 9 by the magnitude of a single step occurs at unequal intervals in connection with the nonlinearity of this voltage. However, the linear intervals between divisions of the scale reproduced on the screen of the cathode ray tube 4 are maintained with the reference accuracy given by the first digital-to-analog converter 7. Digital values of the coordinates of the generated image points from the output of the control unit 1 are poked to the input of the second digital-analog converter 10, which through the switch 11 is connected to the switch 12. Analog values of the coordinates of points from the output of the control unit 1 through the switch 11 are also connected to the input of the second comparator 12. Control switch 11 is carried out the control unit 1, connected to the input of the second comparator 12 or the output of the second digital to analog converter 10 or the analog circuit unit 1 control signal. The pulses formed through the OR 13 and 13 elements: the video amplifier 3 are fed to the modulator of the electron-tube 4, generated at the moments of coincidence of the voltages from the outputs of the imaging unit 9 to the voltage and the switch 11.

Information about the reproduced image from the output of the control unit 1, if necessary, is transmitted via bus 15 to external devices.

Since the voltage of the scale at the input of the first comparator 8 and the voltage of the elements at the input of the second comparator 12 are balanced by the same voltage from the output of the voltage former 9 proportional to the horizontal deflection current, always regardless of the linearity and changes of the scale are always strictly connected with a reproducible image, i.e. The measurement accuracy of the elements of the reproduced image remains unchanged. i

As an obvious analogy, let us consider the reflection of an object with a ruler superimposed on it in a curved mirror. Since the object and the ruler superimposed on it are distorted equally by the curved mirror, the measurement accuracy of the distorted mirror image of the ruler of the distorted object mirror image remains unchanged for the external observer operating with the mirror image. It should be noted that in the device according to the invention, compared with the above-mentioned inverse analogy, the distances between the scale divisions for any non-linearity of the deflecting current remain the same and the same.

The stability of the frequency generator 5 in the proposed device does not place particularly high demands (in the known devices, the division generators are usually stabilized with quartz or other known frequency stabilization measures are used).

The use of new elements of the frequency generator, the first and second digital-to-analog converters, the first and second comparators, the voltage driver, the switch) favorably distinguishes the proposed device for displaying information from the known ones, since the control parameter of the reproduced image is controlled by an electronic scale that improves image accuracy regardless of linearity horizontal deflection current while reducing the requirements for frequency stability of the generator Sprymerno 3-4 p and compared with the oscillator quartz stabilized). In this case, both digital and analog information are monitored and reproduced uniformly.

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Claims (2)

1. Forward Germany No. 2540766, cl. G About K 15/20, 1977. 2. USSR author's certificate 0 No. 529469, cl. G 06 K 15/20, 1976 ((prototype). 72 one)