SU682924A1 - Apparatus for displacing graphical data on the screen of a cathode ray tube - Google Patents

Description

a digital-to-analog beam sweep control circuit, which, on the one hand, does not lead to a significant increase in imaging time compared to analog sweep, and, on the other hand, improves reproduction accuracy. For this purpose, a counter, a differentiation unit and a comparison unit are inserted into the known device, connected to the control unit, an increment register for the coordinate and a counter connected to the code register for the Coordinator, the control unit and the differentiating unit connected to the sawtooth generator.

The drawing shows a block diagram of the proposed device.

A device for displaying graphical information on the screen of an electron beam tube (AND (CRT) contains a register / code by x coordinate, operating in counter mode, and | register 2 codes by y coordinate, connected respectively to blocks 3, 4 of the beam sweep along X coordinates, y, register 5 increments along the coordinate l; and register 6 increments along the coordinate y. Register 5 P1ri: rascheniy on coordinate x is connected to the first input of comparison unit 7, another input JKOTOporo is connected to counter 8, and the output is connected to control unit 9 connected with an installation input zero counts 8 and the trigger input of the generator 10 sawtooth voltage. The functional input of the generator 10 is connected to the adder by coordinate y 1,1, and the output is connected to digital-analog converter 12 connected to unit 4 sweep the beam by coordinate y and to differentiating unit - 13. The latter is connected to the inputs of counter 8 and the register / code by coordinate x. The output of the adder by coordinate 11 is also connected to a register of 6 increments along the coordinate y connected to a digital-to-analog converter and a luminance unit 14 connected to block 9 control and CRT.

The device works as follows.

The device forms a halftone on the screen of a CRT | Image: Kenya from rectangular elements of different brightness. In each cycle of circulation, to the device, the codes of the rectangular element: x, y are the coordinates of the initial point of the beam sweep, Dl, Dg / is the size of the sides, / is the brightness for the corresponding registers 1, 2, 5, 6 and the brightness unit 13. Codes X, y from the registers /, 2 codes by x, y coordinates are received respectively in blocks 3, 4 of the beam sweep by coordinates l: and y and determine the position of the starting point of the beam on the CRT screen. The signals of the control unit 9 are set in the "O counter 8, and then the CRT modulator is turned off" and the generator 10 of the sawtooth voltage will be blighted, to the control input of which through the adder // on the y coordinate comes from the register 6 of the increments on the y coordinate, sides Dg / rectangular element. The rate of rise of the output sawtooth voltage of the generator 10 is proportional to the control input voltage, i.e. proportional to the code Dy. Output sawtooth voltage

generator 10 as a reference voltage is applied to the input of a digital-to-analog converter 12. At the output of the latter, a sawtooth voltage is formed with an amplitude, a horoptional code Dg /, which, through the beam sweep unit 4, coordinates the beam on a CRT screen at a constant speed , that is, with a constant given brightness. Thus, with a fixed x-th x abscissa

one vertical line is formed with a starting point (x, y) and an ending point (x, y + y). After the end of the first saw, the voltage of the differentiator unit 13 produces an impulse, which adds

one in the register of 1.code on the X coordinate and the counter 8 and forms the next voltage saw. Thus, on the CRT screen, the second vertical segment is displayed with the starting point (x +, y) and the ending

point (x + 1, y + Ay). In a similar way, all the DL: vertical segments constituting the rectangular picture element are formed. When forming the last segment, the contents of the register 5 increments by

the x coordinate and the counter 8 coincide, and the comparison block 7 generates a signal arriving at the control block 9, completing the next cycle of operation of the device.

The introduction of a counter that differentiates

the block and the block of comparison and the corresponding links allow each rectangular image element to be formed by a discrete displacement along the coordinates within the DG side of the vertical segments obtained by analog scanning of the beam along the y coordinate within the D / f side. As a result, the accuracy of reproduction of the image on the CRT screen is improved compared to the specified prototype.

Claims (2)

1. Author's certificate L 585510, cl. G 06 K 15/20, 1977. 2. For JV 2329662/24, cl. G 06 K 15/20, 1977, according to which the decision was taken to issue an author's certificate. KELT