US 3772677 A
Recordation of letters and/or picture signs with the help of an electron beam on a picture screen of an electron-beam tube, whereby the sign configurations are recorded with any selected tilt and/or offset depending on command data, by a recordation deflection which is controlled by previously established recordation data of the signs and which proceeds from a basic deflection.
Claims available in
Description (OCR text may contain errors)
United States Patent 1191 Soinmer [451 Nov. 13, 1973  METHOD AND ARRANGEMENT FOR THE 3,320,595 /1967 Yanishevsky 340/324 A X MODIFIED RECORDATION 0 SIGN lgdllcglfee ettaLl a ewse a CONFIGURATIONS 3,423,626 1/1969 Bouchard et a]. 340/324 A X  Inventor: Reudiger Summer, Raisdorf, 3,537,096 /1970 Hatfield 340/324 A Germany  Assignee: Dr.-Ing. RudolfHell Primary f qfil Trafton An t t 22 Filed: July 28, 1971 may at on l g a  Appl. No.: 166,800  ABSTRACT Recordation of letters and/or picture signs with the  Foreign Apphcauon Pnonty Data help of an electron beam on a picture screen of an July 1, Germany P electron beam tube whereby the Sign configurations are recorded with any selected tilt and/or offset de- U-S- Cl- A, pending on command data a recordation deflec-  Int. Cl. G08b 5/36 tion which is controlled by previously established  Field of Search 340/324 A cordatioh data f the signs and which proceeds f a basic deflection.  References Cited UNITED STATES PATENTS 9 Claims, 9 Drawing Figures 3,329,948 7/1967 Halsted 340/324 A s am CONFIGURATION GENERATOR 22 27 41 74 23 25 I N'E" 27 itllfifs ill? y DEVIC DEVICE DEVICE 1 FORM DEFLN ADDER TWIST- GEN. ms
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' Ru'diger Sommer I A;0RNEYS METHOD AND ARRANGEMENT FOR THE MODIFIED RECORDATION OF SIGN CONFIGURATIONS BACKGROUND OF THE INVENTION radio link and to record the data again at the receiving place. Hereby, the entire information, which is obtained when scanning, is transformed, and a large bandwidth is required, on the one hand, and on the other hand, only a relatively slow transmission is possible.
For this reason, simplifications have already been made for the transmission of graphic symbols such as letters or of curves: not the exact sign is transmitted but, according to the so-called incremental method, lines of the characters and curves are approximated by small, fixed, given deflection steps, so-called incremental steps. Usually, eight deflection steps are applied, namely in the direction of the axes and angle bisectors of cartesian coordinates, whereby the deflection values have an equal length for X and Y directions. If furthermore deflection steps of half length are allowed, 24 deflection steps are obtained. Thus a better approximation of the signs-tobe-transmitted can be obtained, but, for instance for a curve of equal length, more information must be transmitted.
Another possibility of approximating the signs-to-betransmitted is to approximate curvatures by means of polygon paths and to respectively transmit the coordinates of the individual bending points of the approximated curve, whereby, on the recording side, the electron beam connects these points again to become a closed curvature.
These methods, however, have the disadvantage that complicated characters or curvatures can only be approximated very badly and that very much information must be transmitted in the case of very sharp curvatures.
Furthermore, only line drawings consisting of line paths which continue one after another can be transmitted and recorded. The recordation of area] signs is possible by means of cross hatching, but then again very much information must be transmitted.
Furthermore it is already prior art with electronic composing devices to file graphic symbols, which are to be recorded, in a memory at the recording place in the form of recordation data. During the recordation, i.e. composing, this recordation data is called out by means of command data, i.e., setting instructions from the memory, and controls the recordation on the picture screen of an electron-beam tube from a position which is also given by command data, the so-called basic deflection. This recordation is effected since the electron beam experiences a so-called recordation deflection which is controlled by the recordation data. Thereby, the electron beam is deflected on the picture screen in the X and Y directions and controlled in intensity to trace light and dark elements of the desired pattern.
Such an arrangement, however, would not be sufficient yet for instance for the transmission of weather maps since in such a case, a very large number of different signs is required, and these signs would furthermore have to be stored several times since they are required in shifted or twisted positions namely in each respective modified form.
If all of these sign configurations were to be stored at the recordation place, a very large memory would be required which would render the device expensive and not profitable. Furthermore the application of the device would be limited since the signs can only be recorded in the form in which the recorded data is stored.
SUMMARY OF THE INVENTION This invention thus has the task to provide a method for the modified recordation-of letters and/or picture signs with the help of an electron beam on a picture screen of an electron-beam tube, whereby, in particular, the wish exists to record a large amount of information with the help of very few signs stored on the receiving side and with a low amount of transmitted information.
This invention obtains this by shifting the signs once or several times, during the recordation, depending on command data and/or twisting them once or several times. Thus it becomes possible to utilize in multiple ways a stored sign, i.e. to illustrate it in many shifted or twisted positions.
Furthermore there arises the possibility to provide new sign configurations with the help of the command data from the stored signs, consisting of compositions, preferably by means of shifting and/or twisting in a suitable manner. These new sign configurations may be further modified by further shiftings or twistings. Thus enormous savings of storage space are obtained, and a faster transmission of the information and a faster recordation of the signs is guaranteed since no picture information but only command data is transmitted.
According to this invention, this single or multiple shifting and/or single and/or multiple twisting is effected by one or several coordinate transformations of the recording deflection. The coordinate transformation or coordinate transformations are efiected in an advantageous manner by means of analog influencing of the X and Y components of the recording deflection, namely according to the functions:
X=X,,+(X+a) cos (Y'+b) sin+A Y=Y,,+(X'+a) sin -(Y'+b) cos+B, whereby X, and Y are the coordinates of a reference point for the basic deflection, a, b, the values of the shifting in X and Y direction, (1) the twisting angle, X, Y the instantaneous values of the deflection of the not shifted and twisted sign, A, B a further shifting.
If only one twisting or only one shifting is supposed to be effected, the inapplicable constants a, b, A, B or dz become zero. In order to twist the signs, preferably analog function generators are applied which change the X and Y components of the recordation deflection, depending on command data.
In an advantageous manner, the X and Y components of the recordation deflection are loaded with constant voltages in order to shift the sign configurations, and the magnitude of these voltages is given by the command data.
The particularly advantageous further development of the invention consists in giving the command data into an address register of a memory which can be programmed, as primary addresses, that a storage word is respectively among the primary addresses containing an order for recordation of a secondary address under which the recordation data are filed in the memory and called out for recording. With successive recordation data of one sign configuration, the recordation data are preferably called for recordation by successively incrementing an address counter.
During the recordation, the electron beam is deflected according to a raster during its recordation deflection, corresponding to the raster according to which the sign has been originally scanned. The lightdark scanning of the electron beam during the recordation deflection is effected according to the light and dark values of the recordation data which is obtained during the original scanning of the sign configuration and stored.
Advantageous possibilities for obtaining the recordation data are to scan a sign pattern electro-optically or to screen the sign pattern onto a so-called storage tube and then to scan the same electrically.
In order to execute the method of the above invention, a circuit arrangement is proposed with a memory for the recordation data, an electron-beam tube with horizontal and vertical deflection coils, horizontal and vertical deflection generators for the production of the X and Y components of the recordation deflection, depending on the recordation data which is read out in response to the command data, and function generators which are connected between the deflection coils and the deflection generators and which can be adjusted by the command data.
These function generators are, in an advantageous manner, oppositely coupled operational amplifiers which are designed as adders for the shifting of the sign configurations and sine and cosine generators for the twisting of the sign configurations.
The final sine and/or cosine generators or control members can be adjusted continuously according to one embodiment of the invention, with the help of the command data, but they can also be designed as voltage dividers which allow adjustment in discrete steps.
According to an advantageous further development of the invention, the final sine and/or cosine control members consist of voltage dividers which reconstruct the values for a given quadrant, and from which the values for remaining quadrants of the sine and/or cosine function are obtained by means of quadrant selection switches.
Other objects, features and advantages of the invention will be readily apparent from the following description of a preferred embodiment thereof, taken in conjunction with the accompanying drawings, although variations and modifications may be effected without departing from the spirit and scope of the novel concepts of the disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a principal circuit diagram of a weather-map transmission device;
FIG. 2 shows a schematic illustration of the circuit of a recordation device;
FIG. 3 shows a circuit example for the memory system of the central control device of FIG. 1;
FIG. 4 shows the memory system of FIG. 3 for the case where a twisting code is transmitted to a twisting code register;
FIG. 5 shows a principal circuit for the execution of the analog twisting of the X and Y deflection of the electron beam;
FIG. 6 shows a circuit arrangement of an analog twisting device with fixed angle values;
FIG. 7 shows a function generator for the cosine values of the twisting angles according to FIG. 6;
FIG. 8 shows a function generator for the sine values of the twisting angles according to FIG. 6; and
FIG. 9 shows a sign configuration which is composed of several individual signs.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In the drawings the same reference characters have been applied to corresponding parts in several views,
With a weather-map transmission device according to FIG. 1, the weather data which are obtained by the specially-distributed weather stations 1, 2, 3 and 4 are transmitted to a central station 5 in which a calculator 6 evaluates and codes the data. From the central station 5, the weather data is transmitted to a receiving station 9 via a data-transmission control 7, and a transmission line or radio link as indicated at 8.
A monitor-recordation device 10 which corresponds to the recordation device of a receiving station in its construction is in the central station. The receiving station 9 has a data-transmission control 11 from which the recording device 12 itself is controlled.
In FIG. 2, the principal construction of the recordation device has been illustrated. The command data, which corresponds to the weather data-tobe-furtherprocessed, reaches a central control device 14 via an input line 13, and this central control device 14 contains a digital calculator, a memory and a control unit for the recordation. From the command data which arrive from the central station, the basic coordinates of a reference point (e.g., X Y FIG. 9) of the sign-tobe-recorded are obtained and guided to an adder 21 via lines 15 and 16, digital-analog converters l7 and 18, and lines 19 and 20. Furthermore the recordation data of the sign configuration is supplied to the sign configuration generator 24 via lines 22 and 23 in response to command data which identifies the kind of configuration to be generated. The basic configuration is generated by X and Y deflection generators 25 and 26 which are connected to a shifting device 27 in order to enable the sign configuration to be shifted. With the help of the shifting device 27, an italic recordation of the signs can also be obtained by means of coupling between the X and Y deflection; this is particularly advantageous for the recordation of letters or similar characters. The resultant X and Y deflection signals reach an analog twisting device 28 from the shifting device 27, and in this twisting device 28, the twisting of the sign configurations according to an analog function is effected. Then another shifting of the individual sign configurations can be effected with the help of a further shifting device 29 which is of particular importance when signs are composed, as will be explained later with reference to an example of mounting a wind arrow relative to a weather-station circle. The twisted and/or shifted signs now reach the adder 21 to which the basic coordinates of the sign configurations are supplied via the lines 19 and 20. Furthermore, a vector generator 30 is connected to the adder 21 via lines 31 and 32 and produces the deflection voltages which are required for the recordation in the case that curves are to be recorded and the coordinates of individual points are given by the central station which are to be connected with each other at the recording side as polygon paths. The vector generator 30 is connected to the control device 14 via lines 33 and 34. Furthermore the vector generator 30 supplies signals to a brightness control 37 via lines 35 and 36. Signals reach a dot-size control 39 from the control device 14 via line 38, the control 39 having its output connected to a focusing coil 40. The adder 21,
where the individual voltages are composed to become the entire deflection voltage, further transfers the deflection voltages via a format-twisting device 41, a picture-tube correction unit 42 and amplifiers 43 and 44 to X and Y deflection coils 45 and 46 of a picture tube 47. If a not-squared picture window is applied during the recordation, a better utilization of the surface of the recordation carrier (such as film material) can be obtained with the help of the format twisting device by adapting the picture format to the recordation format by fixed angular twistings (rotations) such as around 90.
In the picture-tube correction unit 42, correction are effected which are to even out non-linearities of the picture tube.
In FIG. 3, the address coding within the central control device 14 is given with the help of a memory system which can be programmed. The selection of the signs is effected from the central station via command data such as a seven-bit signal supplied at input 470 leading to an input register 48. By means of adding five fixed bits from input 49, the number of the bits is increased to 12 and is fed via address counter 50 into an address register 51 of a memory 52 which can be programmed. Now a stored word is found in the memory 52 under a so-called primary address which, among other things, contains an order key which is recognized in the order-decoding device 53, and the order key informs whether the symbol is a normal one or a further order such as a twisting order, an advance order or a similar thing. If one is concerned with normal signs the remaining bits will be the secondary address which is guided to the counter 50 via a line 54. The recordation data of the signs-to-be-recorded are at this secondary address. The further recordation data which belong to the sign configuration are found in the directly adjacent (directly following) storagelocations of the memory 52 by means of a further counting (incrementing) of the address counter 50. This information, i.e., the recordation data, are given out via a line 56.
In FIG. 4, acircuit example has been given for the twisting-order coding with the help of the memory 52. Command data 47 containing a twisting order reaches the address register 51 of the memory 52 via the input register 48. The twisting code is found directly at the primary address and it is taken over into a twistingcode register 57 from which the control of an analog twisting device is effected.
FIG. shows the circuit of an analog twisting device for the X and Y deflection of the electron beam. Final cosine and sine control members (cos and sin adjusting members) 59 through'62 are controlled from the register 57, and they are connected to the outlets of two operational amplifiers 63 and 64 which are operated as adders and cause shiftings according to the supplied values a and b in the X deflection 65 and in the Y' deflection 66.
These shifted deflection signals first pass through the final sine and cosine control members 59 through 62 and then the quadrant selection switches 67 through 70 belonging to them. After this sign-twisting device has been passed, the X and Y deflection signals reach the adders 71 and 72 in which, on one hand, the basic deflection signals X,,, Y, are suppled via the digital to analog (D-A) converters l7 and 18 and, on the other hand,
a further shifting is effected for instance a reverse shifting A, B. From the adders 71 and 72, the deflection coils 45 and 46 are controlled by the line amplifiers 73 and 74 which may include relevant parts of circuits such as those indicated at 41-44 in FIG. 2. The network which is shown in FIG. 5 reconstructs the equation of the coordinate transformation with the help of which the shifting and twisting are effected.
FIG. 6 shows a particular embodiment of an analog twisting device with which the values of the angle twistings are given as fixed function values. As in FIG. 5, the X and Y deflection signals reach final sine and cosine control members 59. through 62 from the deflectionsignal generators 65 and 66 via the adders 63 and 64, and the final control members 59 through 62 are connected with the twisting-code register 57 via continuous control lines 75 through 82. The desired twisting angles are adjusted in the final sine and cosine control members 59-62 by the twisting-code register 57 via lines 75 through 82.
In order to have a better overall view, the final sine and cosine control members have been illustrated separately in FIGS. 7 and 8. FIG. 7 shows a final cosine control member corresponding to the final control members 59 and 62. A sine control member is shown in FIG. 8 corresponding to the final control members 60 and 61 of FIG. 6. These final sine and cosine control members consist of an initial resistor 83 forming voltage dividers with the resistors 84 through 91, which can be connected to ground potential via switches 92 through 99. The voltage dividers represent analog values of angle functions for given angles which are adjusted via lines 75 through 82 of the twisting-code register 57. Since sin a cos (90 -01), the sine is obtained from the cosine by effecting the control of the voltage dividers of the final sine control member according to FIG. 8: the angle sine 10 is illustrated by connecting switch 99 with the control line 65 for the cos of The other angles are obtained correspondingly.
Since these final sine and cosine adjusting members 59 through 62 are only embodied for angles from 0 through but twisting angles larger than 90 are also desired, quadrant switches 100 through 103 FIG. 6, are connected in circuit after the final sine and cosine control members 59 through 62 and are also connected to the twisting-code register 57 via control lines 124 through 127. Thus the angular functions of twisting angles between 90 and 360 can be obtained by giving the outputs of components 59-62 the corresponding polarities.
The quadrant switches 100 through 103 each consists of an operational amplifier 105 which has a feedback coupling via a resistor 104 with a plus input 106 and a minus input 107. The minus input 107 adjoining the output of a final sine or cosine control member via resistors 108 and 109, respectively and the plus input 106 being connected with the resistors 110 and 111. Switches 112 and 113 are positioned between the resistors 108 and 109, and 110 and 111, and these switches are actuated via the control lines 124 through 127. When the switch 112 is closed, the negative input 107 is closed for a short time, i.e., the positive input 106 is effective; when the switch 113 is closed, the negative input 107 is effective. The connection of the switches 112 and 113 of the quadrant polarity generators 100 through 103 via the lines 124 through 127 is selected in such a way that the polarities of the sine and cosine functions result which correspond to the transformation equations. Furthermore, the values of Sina and/or cosa or i: 1 can easily be obtained when both switches 112 and 113 are closed or one is open.
The outputs of the quardrant polarity generators are connected in such a way that the Y deflection appears at the outputs of the polarity generators 100 and 102 and the X deflection at the outputs of the polarity generators 101 and 103. As in FIG. 5, adders 71 and 72 are provided with the help of which an additional shifting or reverse shifting of the signs can be effected over the values A and B. The deflection voltages reach the deflection coils 45 and 46 of the recordation tube via the line amplifiers 73 and 74, from the adders 71 and 72.
In FIG. 9, an example for the composition of a sign configuration from several individual signs has been shown. A case is shown which occurs often when weather maps are recorded, namely the recordation of a weather station which is composed of a station circle 114 with cloud covering indicated at 1 15, a wind arrow 116 composed of several partial symbols 117, 118, 119 and 120, and which has an angle of inclination y indicating the wind direction.
The speed of the wind is given by the partial symbols 117 through 120, whereby 117 is assigned to represent the value 50 knots, 1 18 to represent the value knots, 119 to represent the value 5 knots and 120 to represent the value zero knots. Since usually the speed of the winddoes not need to be stated more exactly than within 5 knots, the desired wind direction and speed can be illustrated by combining four or more partial symbols. This combination is effected by a succession of the corresponding partial symbols to result in the desired new wind-arrow symbol which then is shifted a certain amount and, then, depending on the wind direction 'y, recorded while twisted around the center of the station circle 114. First of all, the station circle 114 is recorded in a positioning raster 121 as a normal sign without twisting, with the basic coordinates X Y, being measured from a cross point such as 122 where X 0, Y 0. Then the center of the station circle is selected as a basic reference point with coordinate X =X 1 and Y=Y l for the wind arrow 116 which is still to be recorded. Depending on the diameter of the station circle, the center of the station circle can be positioned on a cross point such as X= X,,2, Y=Y,,2 of the positioning raster 121 or be between the cross points. If the center is not positioned on a cross point. an adjacent cross point (e.g. X =X 2, Y =Y 2) will be selected as the basic reference point for the wind arrow. The deviation of this point from the center of the station circle is to be designated as AX A. AY B.
Before the deflection signals of the wind arrow now' reach the twisting device 28, FIG. 2, a coordinate transformation is effected at displacements of X a, Y b, from the basic reference point (X 2, Y,,2), whereby a and b determine the position of the untwisted wind arrow (indicated in dash outline at 1160) relative to the center of the station circle. Then, a twisting is effected around the selected basic reference point (having coordinates X X02, Y Y.,2) at an angle amount y corresponding to the wind direction which is supposed to be illustrated by the wind arrow. The rotated wind arrow is indicated in dot dash outline at 116b. After the rotation, a reverse shifting of the wind arrow is effected at values AX A and AY B, so that the wind arrow again is tangent to and is positioned symmetric to the station circle 114, with respect to its longitudinal extension.
This reverse shifting drops out (A 0, B 0) when the station center is on one of the cross points of the positioning raster 121.
After all parameters for twisting and shifting are taken into account, the deflection of the electron beam itself can be effected according to a filter raster 123 corresponding to the raster according to which the patterns of the signs and/or partial symbols have been scanned when the recordation data was originally generated.
In the course of the recordation deflection, the electron beam is also controlled to produce light and dark segments corresponding to the bright-dark values of the recordation data.
The term recordation is used herein to refer to the display and/or recording of data, and is not intended to require the making of a permanent record, nor to require the making of a visible record since the image on the picture screen of the electron beam tube may be used to expose photographic film which requires subsequent development to render it visible.
The term sign configuration is intended to cover graphic symbols such as weather symbols as well as characters and the like, both in a normal disposition and in transposed or composite arrangements as taught by the present invention.
The term transform is used herein to refer to translation and/or rotation (twisting) of sign configurations as contemplated by the present invention.
1 claim as my invention:
1. The method of recordation of sign configurations on a picture screen of an electron beam tube with the use of an electron beam, wherein the significant points defining the shapes of a series of basic signs are represented by stored digital recordation, X and Y deflection data and wherein the stored digital recordation deflection data for the respective basic signs is available from storage in response to respective recordation data signals, for generating corresponding basic recordation deflection signals, said method comprising responding to digital recordation data signals with respect to selected sign configurations including certain modified sign configurations to be generated by means of the electron beam tube to generate successively the corresponding basic recordation X and Y deflection signals of the significant points of such signs, and
transforming certain of the basic recordation deflection signals relative to others in response to input command data so as to transpose certain of the basic signs relative to others on said picture screen, thereby to produce modified sign configurations without the need for storage of specific recordation deflection data therefor,
the transformation of the basic signs being effected by at least one coordinate transformation of the recordation deflection signals,
the coordinate transformation or the coordinate transformations being effected by an analog influencing of the X and Y components of the recordation deflection signals.
2. A method according to claim 1, characterized in that the X and Y components of the recordation deflection signals are transformed according to the functions:
Y=Y +(X+a) sin+(Y+b) cos+B, wherein: X, and Y are the coordinates of the basic deflection, X, Y the instantaneous values of the deflection signals for the basic signs which are not shifted and twisted, a, b, the values for effecting a first shifting in the X and Y directions, (1 the angle of twisting, and A, B the values for effecting a further shifting in the X and Y directions.
3. A method according to claim 1, characterized in that the X and Y components of the recordation deflection signals are supplied to analog function generators in order to twist the basic signs, the parameters of the analog function generators being adjusted in accordance with the input command data.
4. A method according to claim 1, characterized in that constant voltage values are added to the X and Y components of the recordation deflection signals in order to shift the basic signs, the magnitudes of said voltage values being given by the input command data.
5. The method of recordation of sign configurations on a picture screen of an electron beam tube with the use of an electron beam, wherein the significant points defining the shapes of a series of basic signs are represented by stored digital recordation, X and Y deflection data and wherein the stored digital recordation deflection data for the respective basic signs is available from storage in response to respective recordation data signals, for generating corresponding basic recordation deflection signals, said method comprising:
responding to digital recordation data signals with respect to selected sign configurations including certain modified sign configurations to be generated by means of the electron beam tube to generate successively the corresponding basic recordation X and Y deflection signals of the significant points of such signs, and
transforming certain of the basic recordation deflection signals relative to others in response to input command data so as to transpose certain of the basic signs relative to others on said picture screen, thereby to produce modified sign configurations without the need for storage of specific recordation deflection data therefor,
the input data being supplied to an address register of a memory which can be programmed, certain storage words at the primary addresses containing recordation deflection data and certain storage words containing secondary addresses where recordation data are filed.
6. A method according to claim 5, characterized in that, with successive recordation data of one sign configuration or with successive sign configurations, the recordation deflection data are called from a secondary address in response to further counting of an address counter.
7. An apparatus for the recordation of sign configurations including an electron beam tube with an electron beam for the recordation of signs on the picture screen of the tube, and a memory system for storing recordation X and Y deflection data representing the significant points defining the shapes of a series of basic signs for readout as corresponding basic recordation X and Y deflection signals, said apparatus comprising:
function generators for differentially acting on said basic recordation deflection signals and responsive to input command data to transform selectively certain of said basic recordation deflection signals relative to others in accordance with respective different transformation parameters contained in said command data, thereby to produce modified sign configurations on said picture screen without the need for storage of specific recordation deflection data therefor, and means connected to said function generators and responsive thereto for controlling the scanning of said tube in accordance with said X and Y deflec- I tion signals, for successive scanning of said significant points,
the function generators comprising oppositely coupled operational amplifiers.
8. An apparatus for the recordation of sign configurations including an electron beam tube with an electron beam for the recordation of signs on the picture screen of the tube, and a memory system for storing recordation X and Y deflection data representing the significant points defining the shapes of a series of basic signs for readout as corresponding basic recordation X and Y deflection signals, said apparatus comprising:
function generators for differentially acting on said basic recordation deflection signals and responsive to input command data to transform selectively certain of said basic recordation deflection signals relative to others in accordance with respective different transformation parameters contained in said command data, thereby to produce modified sign configurations on said picture screen without the need for storage of specific recordation deflection data therefor,
and means connected to said function generators and responsive thereto for controlling the scanning of said tube in accordance with said X and Y deflection signals, for successive scanning of said significant points,
the function generators for shifting signs comprising adders for receiving translational parameters from the input command data and those for twisting the signs comprise angular control members for receiving angle infonnation from said input command data,
the angular function control members consisting of voltage dividers which are provided with electronic switches which allow thereconstruction of the values or sine and/or cosine functions.
9. An apparatus according to claim 8, characterized in that the voltage dividers are provided for the function values of one quadrant, and that the function values of the remaining quadrants are reconstructed by means of polarity switching.