SU890435A1 - Graphic unformation displaying device - Google Patents

Description

I

The invention relates to computing and can be used in the design of display devices for graphic information, including parabolas.

Graphic information display devices are known that contain serially connected registers, digital-to-analog converters and deviation amplifiers connected to CRT 1.

The closest in technical essence to the invention is a device for displaying graphic information, comprising serially connected control unit, registers, digital-to-analog converters and first drivers connected to video control unit 2.

A disadvantage of the known devices is the inability to reproduce second-order curves, for example, parabolas.

The purpose of the invention is to expand the field of application of the device due to the possibility of building parabolas. The goal is achieved by the fact that the device contains a code converter connected to the control unit and other register inputs, and second drivers connected to the video control unit and the first drivers.

FIG. 1 shows a block diagram of the device; in fig. 2 shows timing diagrams of the formation of a CRT beam sweep signal; in fig. 3 - diagram of the imager; in fig. —the transducer characteristics of the shaper; in FIG. S construction of the segment of a parabola; in fig. 6 is an example of building an image.

The device contains a converter of codes 1, a control unit 2, registers 3 and, digital-analog converters 5 and 6, drivers 7, 8, 9 and 10 and a video control unit. The device works as follows, In response to readiness signals (GT) produced in the control unit 2, from the buffer storage device {BZU) or computer, the image array words containing digital coordinate codes of the end points of the lines 5, the operation code — COP (straight line or PC terminal), comes to the device, accompanied by synchronization signals (CC), prize A beam illumination indicator with / and (shine or not shine), a CPC and a beam illumination indicator accompanied by a CC are fed to the control unit 2, controlling the operation of the device and receiving the image's words. Coordinate codes accompanied by CCs are fed to code converter I., where they are converted to the corresponding forward and inverse paraphase codes, which go to registers 3 and C. Coordinate codes are written to registers 3 and i by CCj coming from block 2. Writing the coordinate codes in a phase-wise manner allows you to avoid a pre-flush reset in O registers 3 and, which is necessary to save the previous values of the coordinate codes prior to the next operation and, therefore, dispense with additional buffer p and significantly reduce the distortion of the waveforms of the o-tilt of the beam, which are caused by the switching processes in D / A converters 5 and 6, with a preliminary reset to O of registers 3 and 4 before recording in them new coordinate codes, which It is important to accurately build a parabola. Coordinate codes stored in registers 3 and A are sent to the corresponding DACs 5 and 6, where they are converted into step-shaped analog signals (Fig. 26, and). In this case, the amplitudes of the analog signals at the outputs of the DACs are proportional to the corresponding digital coordinate codes. The signals from the D / A outputs come to the corresponding drivers (F) 7 and 8, built on the basis of delay lines with water, in accordance with the circuit shown in FIG. 3. These shapers have the properties of zero order fixers and have transfer functions of the type Schr () r-g. where T is the time of establishing the front of the transient response equal to the delay time of the lines. The transient response of such a driver is shown in FIG. at. When a step voltage (fig. Ta) is applied to the ejTO input on the load resistor R, as a result of the summation of the currents flowing through the outgoing resistors R, a step-increasing voltage occurs (fig. 4b). With an increase in the number of taps, the shape of the voltage at the outlets of the shaper approaches that shown in FIG. Av, The rise time of the signals at the outputs of the formers is thus constant, regardless of amplitude, and equal to T. The output of the delay line is loaded on the matching wall R-, whose magnitude is equal to the characteristic impedance of the delay line R. The linearly varying voltages from the outputs of the blocks 7 and 8 (Fig. 2c, e) are fed to the inputs of the formers 9 and 10, made, for example, as well as the formers 7 and 8 in accordance with the scheme shown in FIG. 3. The shapers 9 and 10 have the same parameters as the shapers 7 and 8. Thus, in each coordinate channel there is a sequential connection of two identical shapers with the properties of zero order fixers. Transition 1 to the characteristic and output waveform of a series connection of two identical formers when the first driver 7 or 8 is fed to the input is a step signal (Fig. 2a) shown in FIG. 2g. The front of the transient response of such a series is piecewise parabolic, i.e. consists of two segments of parabolas, smoothly passing into each other. Due to this, at the outputs of the formers 9 and 10, the signals of the scanning beam of the CRT along X and y are created, varying in speMeHk according to the parabolic law (Fig. 2 g, g). This is explained as follows. The signal at the output of the latch is of the zero order, and hence the formers 75 8, 9 And: 10, given as. the function fgbix is the arrival at its input of a signal specified as a function f0j ((t), determined from the following expression |; ti (t) .J: .f ", (t) Outputs which, after having been written) J / “(N, 8) -. dt, (where fi is the sequence number of the cycle for changing the coordinate codes in registers 3 and it; offset within the cycle. Derived from the output signal, for example, the former, i.e. linearly varying voltage, is defined as j D x "-, (2) where dx" .x-Xi, x is the output signal of the digital-to-analog converter during the n-th cycle. In expression (2) the &sign; means the first difference. Derived from the output signal of the imager 9 according to with expressions (1) and (2) is defined as С1Хвых СУ,) (Г), dt n-2te () .. Д% .е + дХ The output signal of the former 9 is defined as to BS) () .- / + A and-ae + C, where C is determined from the continuity condition of the output signal Xg, (n + 1,0) Xgj ,, (n, l) as follows Xn-2 + CP -H Thus, .2 Xft-gt-Xn ВИИ and-г Г Г + After substitution of values Д in this expression we receive) +. Fx -у VF + yg. , t + 2 In a similar way, we obtain the expression for the output signals of a 10 yv, -4 -.- yn-J body.

Oops

+ (UI-O.) - e

+ From expressions (3) and (A) it can be seen that the signals at the outputs of the formers 9 and 10 vary according to a parabolic law. It is known that with such a parametric specification of the coordinates of a line on the xy plane, it is a parabola. . (

  Woo-G1 +, Woo-a

2 2. , which is one of the features of this method of constructing parabolas. Segment Parab, Oly enters. Gz / la with the top of RI To the level of 0.75 h,

Claims (2)

& P "-. Pr.-a. where h is the height of the triangle {omitted from the vertex P „. The signals from the outputs of the formers 9 and 10 are fed to the CRT block 11, consisting of a CRT, a beam brightness control unit, a deflecting system and x and y coordinate amplifiers. Under the influence of two parametric deflection signals on x and y, varying in time according to a parabolic law, the beam on the CRT screen moves along a parabola (or in a particular case along a straight line). If the deviation signals in x and y are identical in time in shape, then the beam moves on the screen of the CRT along a straight line. This is provided by changing the coordinate codes in X and Y in registers 3 and with a period of 21 equal to the sum of the time of formation of linearly varying voltages by blocks and the time for establishing the transient characteristic of shapers 9 and 10, which are the same and equal to T. If the deviation signals in X and y not identical in time in shape, the beam moves on the CRT screen along a parabola. This is provided by changing the coordinate codes x and y in registers 3 and with a period T. Changing the coordinate codes in registers 3 and is carried out by the NW signals (Fig. 2a), the period of which, as well as the GT signals, changes in block 2 depending on the CPC and when building straight lines, it is 2, and the parabola is T. To build a parabola in accordance with the expression (3) and Ci, it is necessary to specify the coordinates of the three reference points f, Pf,, RP-SL lying on one straight line in the xy plane with coordinate, dinata Hu, y, - x. , y; x ,, y, (cf.). The length of the parabola fits into the angle formed by the straight lines passing through the adjacent support points of the RP. The length of the parabola passes through the midpoints of these lines at intermediate points of the Roux, and with the coordinates Ui + YH-J Hu Another important feature of this method of construction straight lines and parabolas is also the fact that when drawing fragments of the image on the CRT screen, a smooth transition of the parabolic segments into straight lines or other parabolic segments is provided, which allows to improve the quality of the image. The indicated features follow from the analysis of expressions (3) and (4). So at the moment n at О you) xc- + yn-a 2 y (t) yyy- + yn-y. output 2 i. by the time of the beginning of the new clock of changing the coordinate codes in registers 3 and i, the functions x, (n) and ygy (n) are proportional to the half sums of the values of the input functions x (n) and y (n) for the two previous intervals. This ensures that the parabola segment passes through the middle of the straight line connecting the adjacent reference points specified in the words of the image array. In addition, since for the derived output (output (.b) Dnn 3Xgt ,, 3Xgyj (ns.) A € .5. Coincides with the slope of the straight line connecting the adjacent reference points, the parabola (x) is tangent to this straight line in its middle. This condition of continuity of the first derivative of the output signals of the formers 9 and 10 ensures a smooth transition of the parabolic segments into the straight lines or other parabolic segments when the fragments of the image are built on the CRT screen. can be constructed by setting the coordinate codes of the vertex point points correctly About the described polygon. Thus, at four vertices of the described polygon, the construction error is circumferentially TI-definable as -LK | I (where R is the radius of the gun) is 6, and at six%, the illumination of the beam is controlled by modified signals with The CRT unit 11 is received from block 2, where they are produced in accordance with the backlight feature and operation code. An example of constructing a fragment of an image based on the specified method of constructing straight lines and parabolas is shown in FIG. 6. At the same time, the formation of scanning signals of a CRT beam is carried out in accordance with the timing diagram shown in FIG. 2. Thus, the use of a direct code converter in the forward and backward and formers made on delay lines and having the properties of latches zero order, provides for the construction on the screen of a CRT along with straight lines and parabolas and thereby expands the functionality of the known device. An apparatus for displaying graphical information containing serially connected control unit, registers, digital-analog converters and first drivers, the control unit being connected to a video monitoring unit, characterized in that, in order to expand the field of application of the device due to the possibility of building parabolas, it contains a code converter connected to the control unit and other inputs of registers, and second drivers connected to the video control unit and the first and formers. Sources of information taken into account during the examination 1. USSR author's certificate No. 63125, cl. On K 15/20, 1971 2. US patent W, cl. , 19b9 (prototype). sz but about g 2T ZT ifT 5G 6T 7T 8G 5MM. d w / i (one) e Well F jr (//г.2