DE1918372B2 - Arrangement for generating characters on the screen of an electron beam tube - Google Patents

Description

Screen of a cathode ray tube known, with system or a connected memory, on one whose deflection circuit is given a filter-smoothed character selection decoder 21. Im re-tension is fed. output device, the signals are saved, e.g. B. in one

The in French patent 1 501 039 an- circulating memory. In the embodiment of the invention

given solution uses a delay line 5 formation will have a character capacity of 2 ^e = 64 characters

as a pulse shaper circuit. The coded, the individually considered, so that in the character code each codeword is made out

There are 6 bits of a signal indicating dots of a character. However, this capacity can be used in both

gears are changed in ramp-shaped deflection directions by changing the number of bits

signals converted. There will be abrupt signal transitions. The character selection encoder 21 determines each

With the help of the delay line, as suggested, it is one of the 64 characters and excites the selected line.

converted into relatively slowly changing signals, as will be described in more detail later,

whose total rise time is equal to the delay time. First, in connection with FIG. 3 the

the delay line is. Character generation technique described. Every time

The invention is based on the object of assigning a number of elementary segments to an area for the creation of characters on the basis of the 15 steps, called steps, and their number To indicate the screen of a cathode ray tube, with is determined by the shape of the characters, the the help of which the characters shown have an equal length of the individual steps either of the side edge moderate distribution of brightness and no disfiguring or the diagonal of an egg field. Have stylization, but without any special additional information to need borrowed pulse shaper circuits; fine 20 invention are a maximum of 40 steps to generate the Uniform line widths, digital accuracy, the most complex of viewed characters required. Of the uniform brightness and the generation of arbitrary simplicity, the maximum (to generate Waveforms should each of the 64 digits using simple storage of 40 steps and a simple generator for generating chen assigned, although the device is also for the the character control signals may be possible. 25 asynchronous operation can be modified. Each

This object is achieved in that the deflection character is in a matrix of 10 x 6 elementary coils of the magnetic deflection system one to the one generated, which is aimed at achieving a distance Character display used cathode ray tube between the characters in horizontal and vertical directly applied to the step control signals direction in a box of 12-8 elementary fields where the spacing filler step control signals 30 is located. The beam is at the beginning by a coarsely smaller one as the time constant of the deflection system, deflection system (not shown) to an initial value that the deflection control has already set a new position, which is the position for most characters Step control signal is received when the electron beam 00 is in the lower left part of the relevant character end is the box indicated by the previous control signal and that of the home position is the Ablen step end point has not yet reached. 35 equivalent counter.

Advantageous refinements of this arrangement are When creating a character can be used by anyone

described in the subclaims. in the matrix controlled grid point from both

An embodiment of the invention is in the an upward or downward movement (+ Y, - Y) as

Drawings shown and in the following a right or left movement (+ λ ", -X)

explained. It shows 40 as well as combinations thereof in 45 ^r directions.

F i g. 1 the block diagram of an embodiment can be seen. So that means that the ray of

Example of the invention, each grid point from next to one of the eight

F i g. 2 grid points adjacent to a part of a pacer / fixed memory can be controlled,

for a device according to FIG. 1, Therefore 4 bits are used as distraction for each step

Fig. 3 schematically the creation of a character 45 information given (1 bit for each of the four elements

from elementary steps and the resulting mapping movements + X, —X, + Y, -K).

dung of the sign. The illustration of a sign is now created by

First of all, it should be pointed out that the beam on one of the desired characters in an electron beam viewing device, in which the individual approximately corresponding paths are generated step by step from grid characters separately, is controlled in principle point to grid point and thereby hellzip two deflection devices or controls remain keyed, provided that intermediate movements are not required, namely firstly the coarse deflection, which are only used to reposition the beam step by step from character positions to beam, the step control signals continue to move character positions and secondly the fine - Sequential, but given with such a lead, deflection which only causes a character to actually be generated within the position assigned to a character that the beam is not activated on a controlled grid point and which comes to rest, but continues to run uniformly. Only the fine deflection is dealt with in the following, because already before the last activated one is reached, the control information for continuing to run at point, to which the invention also relates, while the coarse is given to the next point. This is achieved given that distraction is common knowledge and can be achieved in the following ways:
therefore is not described at all. The time constant in the exemplary embodiment

For the exemplary embodiment, a magnetic fine deflection system is used is 175 Na-

Distraction system adopted. The noseconds shown, while the control signals for the individual

Principles are of course just as good for an electronic step (vector segments) on average every 125 nanometers

static deflection system applicable. 65 seconds can be generated, which is a ratio of

In the in F i g. 1, signals 1 2 ": 1 correspond to. Thus, the deflection system can select

for the characters to be mapped as digital data from the end of a character generation cycle

a data source, e.g. B. achieve a data processing steady state.

Because of the inertia-afflicted settling properties of a magnetic deflection system, the respective deflection is on the one hand a function of the deflection voltage and on the other hand also the time elapsed after a start in one direction within the current drawing cycle. In Fig. 3 shows the generation of the character B to illustrate the mode of operation of the exemplary embodiment under consideration. When the cycle is initiated, the electron beam is set to position 00; this corresponds in FIG. 3a to point 31. Due to the first applied control signal elementary step, there is initially a deflection of approximately ¹ J ₂ vertical units. The second subsequent control signal elementary step already allows the beam to reach position 1 ¹ I ₄ . The third step adds to the previous two and deflects the beam to 2 '/ ₈ , the fourth approximately to position 3, the fifth to approximately 4 and the sixth to 5. This control signal elementary sequence of steps and the vertical beam positions achieved are in shown in the table below until the beam position 10 is reached. In addition, the table shows the sizes of the individual successive elementary beam deflection steps as well as the respective wake of the beam.

Control signal beam
position Y Beam deflection Beam in
Elementary Elementary
steps Elementary-
steps stepped (vertical (vertical Direction) 0 Direction) Vi _ V ₂ 1 IVi V ₂ • V4 2 2Vs Vt Ve 3 3 Ve 1 4th 4th Vs 1 5 5 1 1 6th 6th 1 1 7th 7th 1 1 8th 8th 1 1 9 9 1 1 10 10 1 1 11th 10 1 0 11-1 0

It can be seen that the beam never has a larger wake than about 1 step. Since the vertical bar of the character B should be 10 units corresponding to the y-beam position 10, 11 control signals are given. If the run-out were not slowed down after the last steps, the beam would continue vertically to point 35 beyond the desired turning point 33 to pivot to the right. Therefore, when the turning point 33 is reached, a negative control signal elementary step -1 is added and the first control signal elementary step for the horizontal articulation is applied at the same time. The fact that the beam deflection can be brought into a quasi-stationary state at certain points with the aid of negative control signal elementary steps. enables the beam to be guided with right-angled or acute-angled kinks. In this way, a curve can be generated approximately as shown in FIG. 3b is shown.

On the basis of FIG. 3 should point this out again be that because of the inertia of the magnetic deflection system the beam always has a certain Will have lag compared to the applied deflection voltage. This is in the fourth vertical column clearly visible in the table; in particular that the lag is initially variable as a function of time and then approximates the constant value 1. Finally at the next step after the eleventh vertical step Braking step, after-run 0 is reached.

The in F i g. 1 is shown in the embodiment example a read-only memory consisting of capacitors and diodes in which the information is saved over the individual steps of each character. In an optical display device for direct Consideration is addressed to each individual character position, since each character is continuously regenerated must to get the picture. In the case of conventional storage methods, the addressing time forms the character position a substantial part of the total cycle time, the remaining part of the actual character writing time not applicable. The pond writing time is only part of the total cycle time in which the addressing takes place and must share the actual writing. In the exemplary embodiment under consideration, however, the procedure is as follows: that the extended code (video information) to a

as address and then the memory for the will be addressed again in the next cycle. In the read-only memory 25 used in the exemplary embodiment a block of words (a sub-matrix) is addressed for the next character during the time, in which the beam is readjusted to the basic position of the next character by the coarse deflection will. Each addressed word block (sub-matrix) contains the data for all of the characters belonging to the relevant character Steps.

As already stated, a considerable number of steps are required for each character, for which the control signals are generated at intervals of 125 nanoseconds. The time constant of the fine deflection system is 175 nanoseconds. Therefore, the deflection system cannot reach a steady state between the control signals for the individual steps. As a result, the beam moves continuously after the initiation of a character write cycle, and this mode of operation takes advantage of the uniform intensity of a device operating at constant beam speed, combined with the digital accuracy of a read-only memory, while also eliminating drift errors.
As described in more detail below, the only memory used in the exemplary embodiment consists of a capacitor-diode circuit (FIG. 2). The capacitors form a capacitor matrix that is created by etching a base plate made of polyester that is coated with copper on both sides. A group of lines, the so-called time signal lines, run on one side of the plate and a second group of lines, the so-called interrogation lines, run at right angles thereto on the opposite side of the plate. At every cut

point of a time signal line with an interrogation line is due to the presence or absence of capacitor plates Bit information ("0" or "1") is available on both sides of the disk. The ones with capacitor pads The intersection points provided are arbitrarily defined as binary ones, and the intersection points without Capacitor deposits as binary zero.

When generating the character must be determined at each grid point, whether the electron beam after

7 8

is to be deflected up, down, left or right and whether the control signal for negative vertical deflection is

the beam must be scanned light or dark. is placed in order to avoid the otherwise intended end

Thus, for each of the 40 possible steps of a point, opposing beam movement must be

Character 5 information bits required. These have an effect. For both coordinate directions the

detii read-only memory 25 on lines 81 to 85 using the same technique. While the

The horizontal condition remains the same as the information bits corresponding to the deflecting long vertical line

directions + A ", —X, + Y, - / as well as the intensity (Z)! the same, so that none of the

The mode of operation of the time pulse lines interrogated by capacitors in the exemplary embodiment is connected to the horizontal control signal lines F i g. 2 briefly described. F i g. 2 shows the partial arrangement. Output signals on lines 81 to 85 evaluation for a specific character with the five digits to one as block 87 in FIG. 1 shown interrogation input lines hX, -X, f K, -K and Z. As long as amplifier and control circuit is given. If the character is not selected, a positive query amplifier and control circuit comprises query reference signal to the input terminal 41 and thus to amplifier and control circuits for the A 'counter 91 and the resistors 43 to 47, which the five outputs 15 the / -Counter 93 as well as for the light-dark control went \ -X, -X, -t Y, Y and Z are assigned. 95. Each control signal is presented as a parallel 5-bit word

The discharged in Normalbetricb the character-selection, wherein 2 bits for the X and Y counters 91 terminal 41 set potential is about f3 volts. and 93 and an intensity control bit for the healing at approximately the same height, the potential of the dark control 95 is determined. A signal - \ - X TP1 to TP 40 designated time pulse inputs 20 on the line 97 switches the A 'counter 91 further by 1, so that in the idle state the voltage above the signal --X on the line 99 switches the A'-counter capacitors is normally 0. If through the 91 back one unit. Similarly, the character selection decoder 21 switches the relevant character a signal - \ Y on the line 101 the y-counter is selected by 1, the next at the character selection and a signal - Y on the line 103 switches terminal 41 resulting Potential about 0 volts. 45 move him back one unit. The X and / Counters 91

A diode 51 is connected to each of the 5 output lines and there are no binary counters 93 , since the operation of 52, 53, 54, 55 is connected and a reference potential of binary counters with 8 megahertz is not suitable for this application via the 7.5 kOhm resistor 49 for biasing is. In the present exemplary embodiment applied to these diodes. When a character is selected, as is known, the characters are in a box of, the character selection terminal 41 is generated. Accordingly, the low potential before the generation of the character for the A 'counter has a capacity of 8 units and the approximately 2 microseconds to about OVoIt, and / -counter has a capacity of 12 units. There are all capacitors of the associated mark, various options for technical exterior - charged accordingly. Because a time pulse of about lead this counter. The output signals of these - 3 volts and 70 to 100 nanoseconds duration of the 35 counters are converted to analog signals corresponding to the count value with resistors 107, 109 , 111 and 115 in succession to each of the time pulse connections TP1. is placed, a control signal arises wherever there is a capacitor and is present at the emitters of the driver circuits 117, which is fed via the 119, 121 and 123 for the deflection system. Thus closed output diodes 51 to 55 to the zuehöti- the driver current is conducted with a frequency of 8 Megagen interrogator (not shown). 40 hertz switched up or down in steps and as each of the five interrogation amplifiers is connected to the deflection system 125 lines of the permanent memory with 64 output staircase-shaped signals, each of which gives. As shown in the drawing, the drive corresponds to one of the 64 characters. On the intensity yoke driver 117 and 119 the A 'windings 127 and 129 control line 67 signals are generated in the manner of the deflection system 125 in push-pull mode, while the beam is only generated during the character generation 45 / current driver 121 and 123 the windings 131 or follow is keyed lightly. 133 drift. The X and / windings are through

The deflection device described works in the connected resistors 137, 139 and 141, respectively

Push-pull that for the horizontal and the vertical and 143 so attenuated that the magnetic field is

Deflecting a positive signal in each of the two with an even speed due to the reason

possible directions is given. 50 of the pulses applied at 8 megahertz changes so that

A character of uniform intensity given to the connection TP1 (see FIG. 2) is produced. in the

Pulse leads to the delivery of a ^ output signal of the embodiment is a deflection system with a

while the capacitors 69, 71 and 73 are used on the lines inductance of 100 microhenry

+ A \ + /, or Z. In a similar way, each of the connected damping resistors generates 2 kOhm

subsequent time pulse will be an output signal on the 55. The same technique can be used with electrostatic

associated output lines 56 to 59 and 67, the deflection by using the time constant RC

in turn via the connected diodes 51 instead of the electromagnetic execution

to 55 a corresponding signal is applied to the lines 81 for example time constants LjR used

to 85, which in turn are indicated by the. In one embodiment, the

closed interrogation amplifier is sensed. 60 individual lines 0.4 mm long, i.e. i.e., they put approximately

The in Fig. The pattern shown in Fig. 2 is an arbitrary point; the device ran synchronously, d. h., for chooses and does not apply to any particular character, each character was assigned 40 time impulses. With special ones is only used for illustration purposes, but the device can also work asynchronously Basics. (variable number of time pulses or steps per

From Fig. 3 a it can be seen that when generating the 65 character), and in the simplest version character B requires a sequence of 11 deflection control signals, this only requires one additional sensing line to each time a control signal applied to generate the long vertical bar indicating the end of the character after which in the upper part, as already said, a hold.

In the device described above, the character selection signal for the character selection decoder 21 taken from a circular memory, in which only coded 6-bit signals the stored characters represented. In such an operation, the requirements on the buffer memory are very low, since the Video signals are available from permanent storage and are not stored in circular storage have to. The device described combines the

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Advantages of the scanning method with those of the vector method. It can be characters of uniform Brightness can be generated with a fine line width. In addition, there is the digital accuracy of the permanent memory and avoidance of adjustment and drift errors. There is also no need for monoscope devices resulting loss of reliability and the loss of reliability due to the equalization of two independent analog ones Subsystems required additional maintenance.

1 sheet of drawings

Claims (4)

the required beam claims for the character in question: movements individually one after the other according to the respective character to be generated for execution 1. Arrangement for generating characters generated by elementary steps. on the screen of a cathode ray tube with 5 A number of different methods of a magnetic deflection system and a decoupling and devices are already known with which letter steering control by moving the electron beam, digits and other characters on the screen beam along a corresponding to the characters. can image from cathode ray tubes,
corresponding path and corresponding light-dark In a first known method is the Keying a time pulse distributor and an io entire screen through the beam in horizontal Includes step generator, which scanned evenly on the basis of one of it or vertical lines, and the supplied signal the characters to be generated in each case are created by selective light and Characters are identified and blanked either as point buttons or as ais applied time signals of the time pulse distributor pattern of horizontal or vertical lines. Of the Step control signals the advantage for the character in question 15 is that the beam always covers the screen required beam movements individually after sweeping over at a constant speed, so that on the other hand according to '' 'output of the respective to be generated with a constant signal value for the luminance characters to carry out elementary control a uniform brightness of the point or steps generated, thereby marked line pattern results. The disadvantage with this procedure net that the deflection coils are directly connected to step 20 but that the video format for all respective equal control signals applied, whereby the characters to be mapped must be saved, all step control signals would be smaller than that, which would result in a considerable effort for the storage time constant of the deflection system, so that the assurance results when a good character quality er deflection control a new step is already desired in each case. Control signal is received when the electron beam is 35. Another method is an image scanned by the previous control signal of the character to be displayed and the win-step end point has not yet reached. One of the signals to control the beam in a second 2. Arrangement according to claim 1, thereby used tube. On the screen a so-called indicates that the ir'axima ¹ '; temporal distance monoscope tube are images of the required between the delivery of the ^c control signal for a 30 th character, which are scanned with the electron beam elementary step to the Abienksi ^ uerung and the, whereby a secondary electron start of the actual execution of this electrical current is created, which for Brightness control of the synchronization step by means of the electron beam equal to chronically deflected beam in the actual images time interval between two successive tubes is used. is the step control signals. 35 "Here too there is the advantage? ' the uniform 3. Arrangement according to one of claims 1 to 2, jet speed, and characters can be used as a result marked that for the points where the lovable curve shapes are made. It results Electron beam has a right or acute angle, however, the disadvantage of a larger line width, should go through, first a superfluous step - one to compensate for screen errors in the Control signal can be generated that must accept the beam over the 40 monoscope tube. aside from that point in question, and that arises because of the presence of two electrodes If a step control electron beam tube system reaches this point, it causes a loss of reliability signal can be generated, which at least the over and the need for the exact comparison of both countless step control signal counteracts so that systems. the electron beam, although the point concerned 45. In a third process, the characters Reached at average speed, composed of vectors, that is, straight lines but does not go beyond that. strung together lines of different lengths 4. Arrangement according to one of claims 1 to 3, and direction. Each line piece is through two ends through it characterized in that the timing pulse defines points, and the electron beam is each divider (27) the time signals to the step generator (25) 50 along this line directly from one point to the next Gives time intervals that are most equal to one another. One advantage is that with this method and are smaller than the time constant of the deflection - very fine lines can be generated. Also not applicable systems of the cathode ray tube. the scanning of the entire area that the character covered; the beam only needs the required 55 loan lines to traverse, saving time will. However, there is the disadvantage that the speed The invention relates to an arrangement for generating speed with which the electron beam moves from point to point of characters on the screen of an electrical point, is not constant. When reaching a beam tube with a magnetic deflection system 60 point, the beam stands still, while its and a deflection control by moving the EIek speed somewhere on the line reaches a maximum beam along one of the characters. This results in an uneven promising path and a corresponding light-dark division of the holy wedge in the characters, which only comprises keying, a time pulse distributor and a step through complex circuits for brightness control, which can be compensated on the basis of an input to it. Also, a stylization of the signal to be generated in each case of the characters must be accepted,
identified and on the basis of the time assigned to it. According to the German Auslegeschrift 1 265 463 is a signals of the time pulse distributor Step control signals Method for displaying characters on the