DE1936051B2 - METHOD FOR RECORDING LINE DRAWINGS ON THE SCREEN OF AN ELECTRON BEAM TUBE AND CIRCUIT ARRANGEMENT FOR PERFORMING THE METHOD - Google Patents

Description

The invention relates to a method for recording line drawings on the screen of a Electron beam tube, the coordinates of individual points on the lines of the drawing with different large distances are given and with straight connecting lines between the points Lines are produced which approximate the line drawings and where from the Differences in the coordinates of neighboring points can be derived from differential voltages.

An electron beam is often used to display information calculated by computers used. Mostly it concerns with the representationei a limited number of symbols, the sim Numbers, letters and characters, their record data in an electronic memory on the recording device or in the computer. The data consists of binary numbers de

3 4

Coordinates for positioning on the image- Desired, as little data and storage space as possible

screen and made up of binary-coded numbers as an indication of the claim.

Lengths of the individual lines from which the An important requirement is not met. the

Symbols are constructed. Each section of the line is made up of the line width must cover the entire length of the line

be uniform over a whole multiple of a small piece, so that it is a satisfactory one

built whose size looks at the limit of perception. In achieving this uniformity

of the eye. The symbols have raster - there is a very great difficulty, namely,

structure. The data of the symbols are partly due to the very large differences in length

th addresses stored in memories. You do not control the sections or the recording times

When this address is called up by the computer, the illumination is uniform and therefore not the same

drawing the icons on the screen. Line width is reached. Two errors occur.

Often - one not only uses symbols, but also Firstly, the speed and brightness of the image, so-called "line drawings" are to be recorded, these are not constant between the line points, of lines of the same line width and any The line segments then appear like commas after Form existing drawings. Take 15 thickened one side as an example. Second is also the brightness a weather map, which apart from the symbols and the entire line of lines through the different meteorological signs also different lines, basic brightness of the individual line segments not one Contains shapes such as coastline and iso-lines. uniform. The visual impression of the line is Devices that record weather maps are so bad.

called "plotter". It is already known in the case of scientific Com- 20 This is also known in the case of the representation

Computer calculations often result in functions of characters consisting of vectors and in

which are expediently written with the help of the plotter at the same time, an automatic one

recorded as curves and the intensity of the electron beam must be controlled.

can be fixed photographically for evaluation. men. Due to the fact that when distracting by means of digital /

Such curves are represented on analog converters known simply from the difference co-ordinates of currents, by forming rows of points that are recorded closely next to each other on critically damped deflections, so that the coils are switched closed line signals the progression of an increasing function. This perceives. This type of recording has, however, signal is then differentiated, amplified and has the disadvantage that a large number of points must be recorded 30 pulse shaper to the control grid of the cathode ray. Each point must be fed through an X and tube, thereby defining a substantially equal y coordinate which is generated in many single-shaped intensities. This method is calculated and possibly saved by the circuitry effort relatively simple, must be. the accuracy achieved in the constancy of the

In order to reduce this large amount of data, 35 brightness is used but for purposes where an exact

In an improved recording method, one involves recording line drawings on film material

Instead of dots, small lines with fixed lengths. is made, by far not sufficient.

A certain number of line units is laid down. The present invention therefore has for its object

with different angles of inclination. Based on a method for the intensity control of the

to indicate rows of many of these lines of corresponding electron beam, through which a constant

Inclination in any order and amount is approximation- brightness of the electron beam is achieved while

tion to the specified curve. the time to deflect the beam from a point to

But here one is forced to a compromise. is equal to others.

If the line is drawn with a few line units, the invention achieves this by recording the difference of greater length, so you need 45 reference voltages ( Δ χ and Iy) sawtooth generators little information and storage space, but you get control, which during the same time intervals in an angular, jagged and unsightly lines. Correct axis affiliation with sawtooth currents If, however, the lines are small enough to provide this post-horizontal and vertical deflection, the proportion of which is improved, then the steepness of the slope increases proportionally to the differential voltages, the amount of data that is to be created, to be addressed that at the same time the amounts of the difference voltages must be saved and saved. gen squared, the results added, the sum

A favorable recording method consists in root extraction and, after passing one of the points, the smallest possible number of points on the linearity between control voltage, beam current and line drawing in differently sized and expediently brightness-compensating correction elements for selected distances, and these points serve to control the intensity of the electron beam ,
to connect with each other by straight lines. An advantageous further development of the invention thus results in a polygonal curve through which the nominal value is such that the sum and the difference of the curve are approximated. In order to achieve the best possible approximation differential stresses (Jx and Δγ) and to achieve with ration, each curve segment must be multiplied by a factor (r and r ₂ ) so that small radii of curvature add many points close to one another be present, in curved pieces with and after passing a correction element to the large radius of curvature fewer points are required to compensate for the nonlinearity of the electron, and in straight pieces they only need to be present at the beginning and end of the beam pipe to control the intensity of the beam. That serve so.

The line drawings made work despite the very 65 Furthermore, it is particularly advantageous that the different point spacings in the lines sum and the amount of the difference in the difference smooth. They satisfy the stresses (Δχ and Δγ) formed with a few points, each with a requirement for accuracy and satisfy the factor (r _r and K ₁ ) multiplied and a totalizer

that the amount of the difference between the F i g. 3 graphical explanations for an approximation

Differential voltages and those with another to carry out the process,

Factor (Z) multiplied sum of the differential voltage F i g. 4 a circuit arrangement for implementing

voltages are subtracted from each other and the thereby tion of this approximation,

resulting difference with a further factor [K ₂ ) 5 F i g. 5 graphic explanations for one more

multiplied and unipolar to further inputs of the approximation for carrying out the invention,

Summing is performed and that the output F i g. 6 a circuit arrangement for implementing

the total voltage occurring after this extended approximation.

Passing the correction element to compensate for the recording of any representations

Nonlinearity of the cathode ray tube to the inten- io the screen of a cathode ray tube happens

sität control of the beam is used. in a conventional way by adding one to a point

It can preferably be provided that one electron beam is bundled in two orthogonal

Distances between neighboring points on the line string coordinate directions, preferably

evaluating circuit when crossing a horizontal (x-direction) and vertical (y-direction)

or several specified step values the voltage), deflected and thereby more or less bright

voltage values J.ν and Δγ is keyed by one or more or also dark. By specifying a

Factors reduced and the time intervals for the coordinate pairs χ and γ is the position of a

Deflection of the electron beam by the same factor point on the screen and determined by

enlarged, so that in all positions of the circuit deflection currents or voltages, which this coordinate

Line segments of the same brightness are recorded, assigned to ao nata, controllable.

A circuit arrangement for carrying out the target a certain point on the screen procedure is characterized by a common clock for the sawtooth generators controlled by a computer or a memory, this is done by the numerical values of the function coordinates χ indicated by the differential voltages and γ of the point, which are offered in binary amplifiers to square the difference voltage. The number of digits in these binary amounts, through one to the outputs of the function numbers, depends on the resolution, the more strongly connected adders and through one of the electron beam points on the screen connected to the output of the adder, which should be enough. As a practical example, the following output signal of the adder may apply square roots. The usable screen diameter be functional amplifier, which through the non-linearity 30 carries about 210 mm, so that a square field of the electron beam tube compensating correction with the side lengths of 150 mm can be used. The gate member with an intensity control electrode of the electron beam point has a diameter of electron beam tube is connected. 0.05 mm. In each coordinate direction are then

Another advantageous embodiment of the Er- 3000 positions possible, in the entire field 9 · 10 ⁶ . To the

finding can consist of the sawtooth 35 specification of the position or the data technology

generators by means of a common clock generator, the usual expression for “addressing” a

and can be switched off that one of the difference points in the field is a 12-digit each for χ and γ

Voltages a sum signal forming adder and binary number required.

one of the differential voltages a differential signal The F i g.l represents any curve,

(IJJf-JKj) forming the first subtracter, which a 40 is to be recorded on the screen.

Rectifier is connected downstream, with the input Lir. get by with as little tax data as possible,

terminals of an adder are connected, whose are a few points P ₁ , P .. ..P _n on the curve

Output via which the nonlinearities of the electron selected. The distances are very different

Beam compensating correction element with one and so chosen that straight connecting pieces

Control electrode of the electron beam tube connected »5 between adjacent points (shown in dashed lines)

that is. the closest possible approximation to the target curve

This embodiment can preferably still be used.

The curve piece P ₁ -P ₁ is defined by the coordinates x _u

gears (C, C _n ), which are determined by blocking diodes on from y, for point P ₁ and X ₂ , y ₄ for point P ₂ . Around

further subtracters and voltage dividers 50 the connecting line P ₁ -P _{1 to be} visible,

standing correction elements are connected by the electron beam has to make the way from P ₁ to P ₂

the abstractors each have a first input with a finite speed and a

wetsen, going through the unipolar with the difference signal matched brightness.

(jJ X— JKj) of the first subtracter can be acted upon. The path that the ray should take is the

is, and by adding the subtractors each a negative 55 hypotenuse of the right triangle with the

Have input that is connected to voltage divider catheters J χ and Jy, where Jx = X ₈ -X ₁ and

sen, whose voltage values from correction factors is Jv = '/ t -' / x .

/ _ ZA ₁₁ ,,,, - .... »J.- If the connecting lines between neighboring

(Z, .- ^ L) and the nut the add, erer ver ^^ _{in immcr} ¹ year ^ _n ^^ _{! ΑάψζιάάίαεΧ}

are bound. 60, this has the consequence that the recording

The invention is very different in the following on the basis of the speed and that the Drawings explained in more detail; it shows the brightness of the point of light or the intensity of the F i g. 1 a polygon that has to be regulated to a curve on the electron beam so that all

is approximated, line pieces equal or approximated glc-oh hay on-

F i g. 2 a circuit arrangement for recording 65 can be drawn. The beam current fs is therefore from

of line pieces of different lengths in the same depending on the deflection speed

Times and at a controlled speed and

regulated jet current, f) Is = E- \ Jx ² f Jy ^s · / n ».

7 8

Here £ is a setting constant and / »η is a radio straight line 71 through the point Δ χ - Δ γ = 1,

tion to correct the nonlinearities between them intersects the ordinate at 0.68.

Control voltage and beam current as well as between the straight line 71 can be determined by adding the straight lines 72

Beam current and point brightness on the screen. and 73 are won. The straight line 72 is through

The simulation of the function f) becomes with the help of 5 the equation
the structure according to FIG. 2 made possible. The differential voltages Δ χ and ZIy are h) A = r _x (Δχ + Δγ)
applied to terminals 1 and 2 and access

the functional amplifiers 53 and 54, which are shown in FIG. ₁ , where T 1 = 0.5, and the straight line 73

Form squares Δ χ ² and Δ y ² . The result span by the equation
Connections on lines 55 and 56 are made with the aid

of the adder 57 is added, and the sum is given by i) B = r ₂ \ Δχ-Δγ \,
the functional amplifier 59 square root, so that at the output of the line 60 one of the magnitude \ Δχ ^λ + Δ) ^Λ pro, where r _{2 is} equal to that on the ordinate through the proportional voltage. _{This voltage should correspond to the amount r 2} enclosed by the 15 straight lines 71 and 72, namely the beam current of the electron beam tube 22 and thus Hch ~ 0.18.

the brightness of the point of light to be recorded The electronic implementation of the addition of the

steer. So that the proportionality is maintained, both equations h) and i) show the circuit diagram

the control voltage is built up via the correction element according to FIG. 4th

61 = fii "pre-distorted in such a way that the non-linear 20 to the inputs 1 and 2 are the voltages Δ χ

Distortion applied between control voltage and beam and Ay . Δ χ is sent simultaneously to the adder

current as well as beam current and luminous intensity of the 74, the subtracter 75 and the sawtooth generator 63

Rohres are compensated. This pre-distorted span- passed for the horizontal deflection and Δ γ to the

voltage reaches the control electrode, second inputs of 74 and 75, as well as the saw

of the pipe. ² 5 tooth generator 64 for vertical deflection. By doing

Simultaneously with the functional amplifiers 53 and 54 functional element 74, a simple adder, is

the sawtooth generators 63 are formed by Δ χ and Ay, the sum Zi x + Zly and via line 76

and 64 controlled. The slope steepness of the dem. Summing 77 supplied. In the functional

Lines 67 and 68 supplied sawtooth currents are stronger 75 the DiEfCrCnZZIjC-Jy is formed, the

proportional to the voltages Zl χ and Zl y. The clock 30 via the line 78, the rectifier 79 and the

Generator 65 simultaneously delivers via line 66 to line 80 to the second input of summer 77

both sawtooth generators start and stop pulses. The rectifier 79 has the task of

with always the same intervals. While each inter-difference Αχ-Δγ take effect according to their amount

valls will leave a line segment between two neighboring ones.

Points written. The deflection currents for the basic 35 Correction of the non-linearity between control positions voltage and brightness of the electron beam tube are added to lines 67 and 68 added up. happens, as already described, with the help of the

This proposed solution just described can lead to correction amplifier 61. The sawtooth generators 63 in borderline cases lead to technical difficulties. and 64 supply via the lines 67 and 68 the jet speed is very large, so it is, as in the description of FIG. 2 already difficult to simulate the function f) explained with sufficient detail, uniformly rising (or falling) currents. When electronically squaring their rate of change d // dr proportional and with the subsequent square root, however, Ax or A γ can be. The clock generator 65 still supplies residual errors, especially in the case of small 45 via the line 66 to the deflection amplifier, start beam speeds and stop pulses with always the same intervals.

The following suggestion avoids this computation. During each interval there is a line segment between

operations are written using an approximation of two adjacent points,

method. If only additive is used, it offers the approximation achieved with the straight line 71

Arithmetic operations with a lower electronic 50 suffice in many cases because you accordingly have the

Effort sufficiently satisfactory results. FoI- holiness of the electron beam is controlled and

lowing considerations lead to the new solution: the eye for density and width fluctuations dei

recorded lines is not very sensitive.

g) It should be V ~ F-] Δχ ¹ + Ay *. Nevertheless, a demand for better access

55 approach to the target curve 70 can be met. Start dei

The constant F is used to normalize the straight line 71 becomes a line of two or more

The value-1 is included. With constant Ay Wei, great pieces produced, which are

^^} 2 ^{6 The} polygon of the target curve fits the better

grow Ax from 0 to ZIx = Zl γ. V then has the in the greater the number of pieces.

F i g. 3 curve shown by curve 70. 60 F i e. Figure 5 shows the improvement using voi

See, HeinsKr W _OT * J, J, "0.7 Ay at J ₁ - 0. ™> ™ g-jj * ^

its greatest Ay at Δχ = Δ γ. The curve 70 applies to, for example, ZIx = 0.5 ZIy.

any sizes of Jx and Jy, where ZIx and Jy The line is 81/82, as shown in the drawing

are interchangeable. 65 can be seen by adding the straight lines 72, 8-

A straight line 71 is drawn through curve 70, and 85 is obtained, although the negative As

in such a way that the closest possible approximation to that of the straight line 85 (shown in dotted lines) is suppressed

Curve 70 is reached. For example, it'll be a must. The addition of the straight lines 72 and %

ίο

SsSi ^

For equation h) the factor T ₁ remains = 0.5, for _{g6, which forms the factor} £ 1 ± L , the corresponding factor is obtained

the equation
C.

partitioned off
the straight line is 85.

= K Mv-2 JxI

_{g ()} ^ _{Differe annung} μ _Χ _Λ y |

^ ^ ^ J ^^^ _an ^ _{itmg 89} ^ nn posi-

^{be tive or} negative. But only the positive value should be used corresponding to the positive one on the left

For them it is to be demanded that their values of K ₂ = 0.12 branch of the straight line 85 in F i g. 5. Use the Sperrbei Tx = 0 ^ rnkste writeln J χ decrease until at diode 90, the negative voltage is disabled. The Tx = 05 Δγ the value zero is reached. If the voltage continues to be positive, the line 91 leads to increasing Jx values, and the sign changes until i ₅ adder 77 Um for straight line 85 the correct b TlTx- 1 becomes the value C = -K ₂ . To obtain this negative slope, this voltage is evaluated at the input of the adder 77 or previously with the factor K ₂ , as has also happened with the factors r _x and r ₂ or K ₁ . The sum voltage 20 on the line 60 finally passes through the correction element 61 and controls in known manner the beam current of the electron tube 22. The deflection of the beam by means of the deflection device 21 occurs in always equal times by the sawing

where Z is an auxiliary variable for determining the straight line 25 tooth generators 63 and 64, as already described. 85 is with the interchangeability of Δ χ and Δγ an extension of the circuit to even bigger ones

Any degree of accuracy can be achieved. With every kink around which the traverse ₁ j grows, the number of aggregates increases so,

Z = - = Vs- 3 ° 88 and 90 by one each. The factors Κ _Λ ... Κ _η and

1 V furthermore the values for Z ₁ ... _{Z n} are advantageous

to be determined graphically. For this purpose, a drawing must be made that is opposite to the F 1 g. 5 must consequently be expanded. The individual sections of the polygon are extended to the point of intersection with the uer ordinate. The lengths divided on the ordinate result in the values K ... on a corresponding scale. The projections of the breakpoints au. the abscissa provides the values for determining Z. Di Fk k

b TlTx 1 the value C ₂ g,

The dotted branch should not be used. ^P never G-4d- 8 * -! Thus avoids at A χ = 0.5 J y the GA over "d" this "m point lies the kink

The corner point is given by the equation: ^H \ λ_λ \

y \ Z = - -,

Δχ + Δγ

h It η becomes
In the case of our example it should be at Δ χ = V ₂ J γ,

₁ _ y j

1 + Va

For the practical implementation of the operation with electronic means, it is advisable to use the equation) to be transformed into:

1) \ Δχ — Δγ \ - Ζ (Αχ + Αγ) = 0,

where we use the equation of a straight line intersecting the zero line at the inflection point A _{x =} ii Δγ

get the for the realization of the straight line 85 ver

40 The factors Z can be used by inserting the through positive branch lying halfway along the zero line, the relations obtained in the projection between J.v

The slope of the straight line is chosen so that it is obtained by and Λγ in equation k).

the point Jv = O and C = Κ, Αγ goes. The not one modification should be mentioned. If the

required right branch with negative values will become too large if the points are spaced, it is useful-

the electronic implementation by diodes 45 moderately, the setting variables, namely the recording

eesTjerrt ^ζε ' ^{1 un (} ^ ^the beam current, corresponding to the switching

"Fig. 6 shows an electronic circuit layout 2 d 6 i

construction, which is based on the F i g. 5 explained

improved alinearproximation process implemented.

The adders 74, 75 ^ of the rectifier 79, furthermore the adder 77 'and the correction element 61 are shown in FIG. 4 is known. The equations for the sum A + B which is formed in the summer 77 are known

to add further straight lines, from which the polygon and the ray

gonzug the approximation curve exists. These are C. 55 not going to be too big. For this purpose, the voltage C .C _n . For now we are content with C; the values Δ χ and Jy at the input terminals 1 and 2 id F i 5 hd

desired, optionally reduced by further factors. By the same factor that will be due the generator 65 supplied clock intervals increased.

m to switch over according to the Sc lines 2 and 6 in adapted stages; The input voltages are the criteria for this switchover. 1 .v and Λγ.

When the distance limit is exceeded, the changeover causes the intervals between start and stop pulses of the clock generator 65 to become larger, so that the writing time is not disproportionately short and the beam current ih ll ß i when the point distances are large

C .C _n . gg ;

means one of the F i g. 5 corresponding approximation with only one break point. That of the drawing (F i g 5) extracted and calculated factors

T ₁ = 0.5; K ₁ = 0.1 ; K ₁ = 0.12 and Z = Vs-

For this purpose 2 sheets of drawings

Claims (7)

Patent claims: 1. A method for recording line drawings on the screen of an electron beam tube, the coordinates of individual points on the lines of the drawing are given with differently large distances, with straight connecting lines between the points of the line drawings produced approximately the same lines and from the Differences in the coordinates of neighboring points differential voltages are derived, characterized in that the differential voltages (J χ unu Δ γ) control sawtooth generators, which deliver sawtooth currents for horizontal and vertical deflection during the same time intervals with correct axis affiliation, the steepness of which is proportional to the differential voltages, that at the same time the The magnitudes of the differential voltages are squared, the results are added, the sum is square rooted and, after passing a correction element (61) that compensates for the non-linearities between control voltage, beam current and brightness, results in I. Intensity control of the electron beam is used. 2. Approximation method in the intensity control for the method according to claim 1, characterized in that the sum and the difference of the differential voltages (J χ and J γ) are formed and multiplied by a factor (r _r and T ₂ ) that the amounts Both result voltages are added and, after passing a correction element, are used to compensate for the non-linearity of the electron beam tube to control the intensity of the beam. 3. The method according to claim 2, characterized in that the sum and the amount of the difference between the differential voltages (J χ and Δ γ) are formed, multiplied by a factor (r and K ₁ ) and fed to a summer (77), that the amount of the difference between the differential voltages and the sum of the differential voltages multiplied by a further factor (Z) are subtracted from each other and the resulting difference is multiplied by a further factor (K ₂ ) and fed unipolarly to further inputs of the adder (77) and that the total voltage occurring at the output of the adder (77) after passing the correction element (61) is used to compensate for the non-linearity of the electron beam tube to control the intensity of the beam. 4. The method according to claim 1 to 3, characterized in that a the distances between adjacent points on the line evaluating circuit when one or more predetermined step values are exceeded, the voltage values J χ and J γ reduces by one or more factors and the time intervals for the deflection of the electron beam is enlarged by the same factor, so that line pieces of the same brightness are recorded in all positions of the circuit. 5. Circuit arrangement for carrying out the method according to claim 1 with sawtooth generators controlled by the differential voltages for the X deflection and / or deflection, characterized by a common clock generator (65) for the sawtooth generators (63, 64), by functional amplifiers (53) controlled by the differential voltages , 54) to square the difference voltages, by an adder (57) connected to the outputs of the functional amplifiers (53, 54) and by a further functional amplifier (59) connected to the output of the adder (57) and squareing the output signal of the adder (57) ), which is connected to an intensity control electrode of the electron beam tube through the correction element (61) which compensates for the non-linearity of the electron beam tube. 6. Circuit arrangement for performing the method according to claim 2 with sawtooth generators controlled by the differential voltages for the X and F deflection, characterized in that the sawtooth generators (63), 64) can be switched on and off by a common clock generator (65), that an adder (74) which forms a sum signal from the difference voltages and a ^{first subtractor (75) which forms a difference signal (| JA r} - J Y \ ) and which is followed by a rectifier (79) with the input terminals of an adder (77), the output of which is connected to a control electrode of the electron beam tube via the correction element (61) which compensates for the nonlinearities of the electron beam 7. Circuit arrangement according to claim 6 for carrying out the method according to claim 3, characterized in that the adder (77) has further inputs (C, C _n ) which are connected via blocking diodes to further subtractors (88, 88 ″) and voltage dividers (86 , 86 ") existing correction elements are connected, that the subtractors (88, 88") each have a first input to which the difference signal fljjr-J y |) of the first subtractor (75) can be applied in a unipolar manner, and that the subtractors (88 , 88 n) each have a negative input which is connected to voltage dividers (86, 86 ″), the voltage divider values of which consist of correction factors - ^ l) and which are connected to the adder 74 are connected.