DE1265463B - Method and device for displaying characters on cathode ray tubes - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. α .:

Number:
File number:
Registration date:
Display day:

G06k

German class: 42 m6- 15/20

R39106IXc / 42m6
October 27, 1964
April 4th 1968

The invention relates to a method for displaying characters, in particular characters, on the Screen of a cathode ray tube in which a multitude of pulse-shaped signals representing the coordinates of preferably equally long sections of a character to be displayed are generated and for deflecting the electron beam, deflection circuits are supplied which are associated with the cathode ray tube are coupled.

In a known method, the corners of the characters to be displayed are generated in that the Electron beam is guided along directly on a path that has the corresponding kinks. The known method therefore requires a very large bandwidth and is only a relatively small one Write speed possible. A wide range also requires a relatively complicated training the equipment required to generate and amplify the Signals as well as for deflecting the electron beam, ao

In a further known method, a basic figure is created on the screen of the cathode ray tube written, which consists of an upright rectangle with a crossbar and a symbolic one Eight is supposed to represent. For this basic character, by blanking character sections, other characters, for example the characters of the Arabic numerals. These characters indicate the normal form of the Numbers only approximate again. Nevertheless, the corners are also in this known method of the characters written immediately, so that the known method except for the disadvantage that it is too much leads to poorly legible characters, also has the disadvantages of the method discussed above.

In contrast, the invention is based on the object to create a method of representing characters that is not just a clear representation of a Allows a multitude of different characters, but also manages with a small bandwidth, so that the display can be done at high speed using simple means.

This object is achieved according to the invention in that the electron beam is directed to all sections of the character containing, no sudden changes in direction exhibiting curve along and undesirable parts of the curve that do not correspond to the sign in per se known Way is darkened.

In the method according to the invention, use is made of the possibility of blanking the write beam in such a way that a curve is deliberately drawn which is dependent on the final form of the method and device for displaying
of signs on cathode ray tubes

Applicant:

Raytheon Company, Lexington, Mass. (V. St. A.)

Representative:

Dipl.-Phys. R. Kohler

and Dipl.-Phys. H. Schwindling, patent attorneys,

7000 Stuttgart, Hohentwielstr. 28

Named as inventor:
Franklin Kruger Stauffer,
Sudbury, Mass. (V. St. A.)

Claimed priority:
V. St.v. America November 19, 1963
(324 707)

of the character to be displayed deviates significantly, so that this curve is steady and without erratic Changes in direction can be designed and when running through this curve for the character parts that are not required are darkened. It is known to use the writing beam of an oscilloscope on the way from the rest point to the starting point of a character and at the transition between To darkly feel free line ends of the character, similar to how it has been customary for decades to rewind of the writing beam of an oscilloscope to be felt darkly. Hiding parts to show discontinuities Avoiding it in a written curve, however, does not take place in this known method either.

Since, in the method according to the invention, the writing of a continuous curve causes sudden changes Changes in the course of the deflection signals over time can be avoided for drawing the characters required signals are transmitted on low bandwidth channels. That leads to a significant Reduction of the technical effort required to display such characters and / or to a faster transfer.

Particularly easy to read characters can be achieved in a further embodiment of the invention in that the pulsed signals are smoothed before being fed to the cathode ray tube.

The invention also relates to a device for carrying out the method according to the invention.

809 537/290

This device is characterized in that it comprises a pulse generator and evaluation networks assigned to the characters to be displayed, to which the pulses are fed one after the other by means of a distributor, as well as a circuit for selecting the output signals of an evaluation network for the x and j> signals, which are then fed to the Deflection circuit for the cathode ray tube are supplied, and that a masking network is provided to which the pulses from the pulse generator are also fed, as well as a circuit for selecting the input signals of a masking network which supplies masking signals assigned to the characters, which are then fed to the masking circuit for the cathode ray tube. Furthermore, the pre-clearing according to the invention can have filter elements for smoothing the pulse-shaped signals, which are preferably formed by delay lines provided with taps.

Other objects and advantages of the invention will appear from the following description in which the invention described and explained in more detail with reference to the exemplary embodiments shown in the drawing will. It shows

F i g. 1 shows an example of a symbol developed according to the invention,

F i g. 2 is a diagram of the j-deflection voltage for drawing the letter "R" in italics according to FIG. I ₃

F i g. 3 is a graph of the x deflection voltage for the letter "R" in italics after F i g. 1,

F i g. 4 the fade-out waveform, which is such that unwanted parts of the letter "R" come after F i g. 1 can be removed.

F i g. 5 shows the block diagram of a generator in italic characters according to the invention and

F i g. 6 shows the block diagram of a further embodiment of a generator of italic characters according to the invention.

F i g. 1 shows a character representing the letter "R", selected for the purpose of explanation, which appears on the face of a cathode ray tube when the j> voltage waveform of FIG. 2 and the x voltage waveform of FIG. 3 is applied to the deflection circles of a cathode ray tube. The appropriate blanking waveform as shown in FIG. 4 is used to mask out the unwanted parts of the letter "R" that are caused by the uninterrupted passage of the electron beam. The beam of a cathode ray tube such as the electrostatic cathode ray tube of FIG. 5, for example, begins its run at the beginning of the first section, which begins at point 0 and extends to point 1 of the letter "R". This movement of the beam is the result of the vectorial addition of the j and x voltages according to Fig. 2 and 3 respectively on the y and x plates of the cathode ray tube. The generation of these waveforms is discussed in conjunction with the circuit diagram of FIG. 5 described. While the spot generated by the write beam from point 0 to point 1 according to FIG. 1, it did not appear on the surface of the cathode ray tube because a suitably timed masking signal 60 was applied to the control grid of the cathode ray tube in order to suppress the electron beam from point 0 to point 1, although corresponding deflection voltages were applied have been. At point 1 the fade-out wave stops and the visible part of the letter "R" appears from point 1 to point 9. At point 9, instead of moving sharply to the right, the ray is allowed to move towards the first horizontal bar of the letter begin, which would require a high bandwidth for the x and y waveforms because of the right-angled corner, to move on in the vertical direction comparatively without interruption, namely to points 10, 11 and 12. While this creates a part that is suitable for the representation is undesirable, it allows the generation of comparatively steady x and y waveforms, as shown in FIGS. 2 and 3 can be seen, in which the corresponding points show the corresponding course of these waves. In order to mask out this undesired part of the letter between points 9 to 12, a corresponding masking wave 61 is provided which suppresses the beam during this part of the x and j deflection voltages. The beam is then released again in order to continue from point 12 to point 26, as can be seen from FIGS. 2 and 3 can be seen. At point 26, the blanking voltage 62 is applied to the control grid of the cathode ray tube and suppresses the write beam as it moves from point 26 to point 35, as shown in FIG. 1 to 3 show. So the unwanted loop as well as between points 9 and 12 is hidden. The smear of the letter "R" is then drawn onto the face of the cathode ray tube by not blocking the beam between points 35 and 39. In this way, a character with comparatively smooth outlines has been recorded on the surface of the cathode ray tube, and another blanking wave 63 is used to suppress the lower portion of the smear.

It will be understood that the same x and j ^ deflection voltages can be used to write the letter "P" in italics, except that the fade voltage wave must travel from point 26 to point 40 in order to make the smear of the Suppress the letter "R". By creating characters in this manner, high speeds can be achieved with a minimum of bandwidth for deflection. Furthermore, the beam that writes the character has a uniform writing intensity since the character is divided into sections of equal length during the time it is not blanked out.

F i g. Figure 5 shows the block diagram of a character generator which generates the x and j deflection waveforms and the blanking waveform which are applied to the x and plates and the control electrode of a cathode ray device 68 with electrostatic deflection. It will be understood, however, that it is not necessary to use this type of tube since a cathode ray tube with magnetic deflection or a tube with combined magnetic deflection for positioning the character and electrostatic deflection for displaying the character can be used. In order to generate a specific character, for example the letter "R", a pulse generator 70 for generating successive square waves on individual output lines is provided in the first place. B. a number of bistable multivibrators through which a

5 6

single pulse passes through it to produce an output signal of approximately 1000 ohms. This way one will generate one from each stage. It goes without saying that a complete set of x and j weighting resistors would also use a delay line or a pulse generator for each letter together with one of the successive pulses on successive diode gates. Every beginning output lines could be used to generate 5 weighting resistors for the x and j> waveforms. In the present exemplary embodiment, 40 output lines 101 to 140 , which are closed, are provided on the suitable x and j amplifiers 94 and 98, respectively. These are preferably the 40 segments of the letter "R" according to FIG. 1 known DC amplifiers corresponding to an output. These 40 lines are generated in parallel to the signal that corresponds to the value of the feedback to an x-weighting network 72 and to a j-Be io resistor 150 or 152 of the amplifier's proportional weighting network 74. The signals are nal and the value of the selected evaluation is also inversely proportional to a suppression or blanking level, such as that supplied in the network 76 which suppresses undesirable parts of the amplifiers known in the art in the case of letters. The shown is from.

It goes without saying that the evaluation of the individual device 72 evaluates, ie that its resistance value is selected in such a way that the write beam is selected so that it, together with the evaluation, has a uniform writing speed resistance i? 101 in the circuit 74 the correct x- is steered. This is accomplished by generating the and y waveform to move the ray from point 0 character in the area in which it is displayed to point 1 of the letter "R" in FIG. 1 lead. 20 is divided into essentially equal sections. In the same way, the line 102 leads to the x resistor. This means that the writing beam in each position R1 and to the j-resistor .R 102, which cause section, travels approximately the same distance and therefore that the beam writes from position 1 to position 2 at a constant speed. This will lead. This process is continued until the arrangement ensures consistent characters have been written and a sity even in parts of the writing track that are not even-line output at resistors R 40 and R 140 , and avoids the need for the grid in place was. The x and j output signals are combined into the cathode ray tube with a complicated intensity in that they are switched in parallel with modulation in addition to the normal fade-out wave and fed on output lines 80 and 82, respectively, which will be described later. The x and y appear. The currents in the individual evaluation resistors 30 are then selected so that resistors are fed to an x-diode switching network, the x- and j-voltage waveforms that are in the 84 and a j-diode switching network 86, FIG. 2 and 3 are shown, which are used by the switch to, for example, a run of the letter "R" to FIG. Select 1 in the x and 7 of the 26 letters of the alphabet. A direction as described above are derived. "R" switching signal 87 of about 4 volts is applied to the diode 35. It goes without saying that a conventional rake 90 can be applied to this diode in the non-conductive amplifier, which can bring a sufficient stand and conduct the Diode 91 has too bandwidth to allow the x and j deflection waves. This form of selection enabling signal to be transmitted. The output of the Verw is also fed to the F-selection circuit 86. All amplifiers 94 are fed to a filter in the manner of a different switching lines are fed through a suitable delay line in order to compensate for the small steps not indicated in the drawing bias voltage, which is kept negative by the generation of the individual. Failure to conduct the diode 90 causes the character-forming sections to be conditional, the diode 91 conducts and the x- waveform for the book The output signals of amplifiers 94 and 98 are rods "R" fed to a DC amplifier 94, each one in the manner of a delay line will arise. The switching signal for the 45-built filter 154 or 156 is supplied in the same way. These filter letters "R" are fed to the diode 95 in order to smooth the waveforms which are produced at the output of each of the "R" diodes96 and which are obtained on one another by the following output signals of the j-weighting network. of the waveforms, because of their subdivision, to be fed to the j-amplifier 98 in a stepped manner to work 74. Eliminate it, eliminate it. These x and j delay lines ensure that the "R" selection signal 87 is uninterrupted throughout the 50 of the usual, tapped type of the entire duration of the letter "R" and consists, for example, of a plurality and of one DC source supplied by series-connected LC delay elements, which can be actuated by a not shown, of which a suitable number of mechanical or electrical switching with taps is misunderstood, to the desired ratio of adjustment. For example, a delay in the rise time can be achieved, for example the output signal of a teletypewriter or computer has a ratio of 10: 1. Furthermore, the total number that is used to set each of the 26 letter delay elements is preferably selected so that the lines are applied. While no total delay time values are substantially equal to the time for the evaluation resistors of networks 72 and 72 specified to record a section on 74, the values generally chosen to be the area required by a cathode ray array are The amplitude of the taps is reversed, minus the delay time between two specific sections to be displayed. For example, an ensemble of are proportional. For example, if the evaluation ten taps are used to give a given resistance i? L a value of say 10,000 steps or a given level to be compensated in ohms, in order to divide an x-voltage for deflection 65 into ten equal sections, each Abvom Point 0 to point 1 according to F i g. To generate 1, the value of a resistor would have to be connected to the output of, for example, every third one, which would deflect the beam of the series-connected £ C-GHeder and to a point 10 in the ^ -direction, a valuation resistor. The single ones

7 8

Evaluation resistors, which are applied to each tap using the same evaluation and masking, are all made essentially the same in terms of their resistance technology, which is a subdivision of the status value to be displayed and all characters follow in essentially the same sections, by means of a common output line with the be generated. It will also be understood that the Im input of their corresponding x or j deflection pulse generator 70 is connected to an amplifier at the beginning of the write sequence. The delay line, which can be character triggered or run continuously through likewise of a commercially available type and that the character selection circuit can be, for example, a nine-tap dialing pulse sequence of 40 pulses is generated, the character selection corresponding to the delay line seen with a delay - and blanking network of about 0.04 microseconds per tap and one io works 83, 84 and 86 is performed. While that pre-total delay time of 0.45 microseconds. The exemplary embodiment lying for the sake of simplicity has a typical ratio of delay to will only describes alphabetical letters, can rise time of more than 10: 1. Even if the delay line in front of each desired character creates a maximum possible evaluation and fade-out technique according to the smoothness of the character outlines, it can be left to subdivide the part of the character to be displayed if a less smooth character is in the essentially the same sections can be produced, tolerated, and lower costs and while still a simple structure is important in the illustrated embodiment. Example Separate Sections of a Character Separate As further shown in FIG. 5, if the filters 154 designed as evaluation resistors for each section are connected to a delay line, it is also possible to connect a total of, for example, the usual ^ deflection amplifier 158 and only six evaluation resistors for each x and y of these to the x Plates 162 of the cathode ray array network instead of the forty shown, line 68. Likewise, the filter 156 is connected to the y- in conjunction with a diode selection matrix for je-deflection amplifier 160 corresponding to the j plate- des characters. The six resistors are connected to a geten 164 leads. The x and ^ deflection amplifiers are connected by 35 common output lines. Anyone of the usual type and capable of the required band resistances will then be transmitted in a binary manner over a range of a few megahertz. evaluates, ie provided with values that approximated a now is the fade-out-port network 76 loading the binary code for the forty possible levels "acting, which is used to match the unwanted parts of the individual segment representing. The letter »R«. For example, the six binary resistors x and j> evaluation resistors can represent a diode matrix with the binary values 1, 2, 4, 8, 16 and 32. To used. For example, a fade-out wave at the point 35 according to FIG. 1, the control electrode 166 of the cathode ray tube can be divided into sixty-four discrete steps with the values of χ or representing resistances, glare circuit 170 generated. The fade-out voltage as shown in FIG. 35 The binary representation of the voltage value of y ~ in FIG. 4 shows, is derived from the fact that diodes at point 35 according to FIG. 2 is connected through the appropriate out * network 76 to the corresponding lines 101 to select the correct combination of the binary weighted 140 so that it generates successive resistances through the diode selection matrix and receives the output pulses of the generator 70 . as it is described in the following, for example with reference to FIG. 6 For example, the diode CR 1 on the line 101 40 is described. For example, if point 35 is connected to the fade-out pulse 60 according to FIG. 4 j value of 33 volts, lines 1 and 6 were generated, which suppresses the write beam between the points of the binary resistors 0 and 1, not shown in detail. In the same way, the network diodes CR9, CR10 and Ci? Ll to the lines 109, 135 are acted upon by the generator 70 via the line, also not shown. The lines 110 and 111 connected to the fade-out corrugation 135 could then be connected to two OR-circuit diodes in the form 61 according to FIG. 4, which are connected to the write, which contain the values 1 and 32 of the beam sections 9 to 12 according to FIGS. Represent 1 to 3 out of six binary resistances. This causes glare. Likewise, the further outputs of the correct value of the .y deflection waveform become the glare waveforms shown in FIG. 4 are generated at this particular point in time. The fade to fade out the remaining, unwanted waveform, however, is generated in the same way that parts of the letter "R" are generated. Each fade-out as it is in connection with the 40 lines according to FIG. 5 diode in the blanking network 76 transmits when conducting has been described, because diodes cannot be evaluated in the same way as resistors in the one blanking pulse by the blanking diode. Switching network 83. This network is similar to FIG. 6 shows a further embodiment for the networks 84 and 86 because a pulse 87 generated for the letter 55 generating x and ^ voltage waveforms to "R" is applied to the diode 174 together with a fade signal in italics to indicate conduction of diode 175 to effect and write characters on the face of a cathode at the correct blanking pulse of the bias and beam tube. In particular, a pulse generator generates fade-out circuit 170 feed. It is shown that 200 a sequence of signals on 16 lines which also correspond to the formation of 16 segments of a character for other letters of the alphabet. Lines blend network 83 pulses are fed and then 201 and 202 show two of these 16 lines as an example, come into effect when the corresponding line leads to the character selection matrix 203 . The character a for selecting the letters for the x and j diode selection matrix contains 16 AND circles for each character, switching networks 84 and 86 are applied. the sixteen lines coming from the pulse generator 200. It will be understood that the present embodiment corresponds to 65 lines. A dial signal, which, for the sake of simplicity, only corresponds to the letter "R" on line 205 , the alphabet is handled. Anything can, however, be fed to AND circuits 207 and 210. If the desired characters or symbols are sent to the AND circles 207 and 210 by the selection signal.

output signals are sequentially developed on lines 208 and 209 of the character selection matrix. The signal on line 205 is also applied to the remainder of the 16 AND circles corresponding to the sixteen lines coming from pulse generator 200. As shown, the signal introduced into AND circuit 210 via line 202 is brought onto line 209. This will appropriately generate encoded signals on lines 215-219 which form a binary encoded signal that constitutes the binary value of each portion of the corresponding x-waveform, for example, to divide the cathode ray tube beam through two segments from point 0 to point 2 of the letter "R" after FIG. 1 lead. Similarly, suitable diodes are connected in a network to produce an encoded binary signal on lines 220-224 representing the binary value of each portion of the j waveform that moves the electron beam from point 0 to point 2 of the letter "R" according to FIG. 1 is moved. Further diodes are provided in the character selection matrix to form the remaining portions of the x and y waveforms and also a suitable masking signal which is applied to the grid of the cathode ray tube of FIG. 1 is to be supplied. The output signal of the x-waveform lines is fed to a DA converter (digital-to-analog converter) 230 of the usual type, which is able to convert the binary signal into an analog output signal. Lines 220-224 with the selected j-waveform are connected to j-waveform DA converter 232, which is also of conventional design and is used to generate an appropriate j-waveform. The outputs of the DA converters 230 and 232 are connected to x and j filters in the form of delay lines before they are coupled to the x and ^ deflection amplifiers, as shown in FIG. 5 is shown. In this embodiment, a character selection matrix for generating an individual letter "R" is shown without it being necessary to provide a special evaluation resistor for each section. Rather, the evaluation is achieved here by applying the correct binary code to a DA converter, which corresponds to the desired signal level for each section of the character. It will be understood that additional lines corresponding to more than 16 sections can be added to this embodiment. Likewise, each section of the character can be blanked out by adding a diode line for the particular time interval corresponding to a particular output signal.

Claims (12)

Patent claims: 1. Method for displaying characters, in particular characters, on the screen a cathode ray tube, in which a plurality of pulse-shaped signals representing the coordinates of preferably equally long sections of a character to be displayed correspond, generated and for deflecting the electron beam deflection circuits are supplied to the cathode ray tube are coupled, characterized in that that the electron beam on one containing all sections of the character, none erratic changes of direction exhibiting curve along and not on the sign corresponding, undesired parts of the curve are darkened in a known manner will. 2. The method according to claim 1, characterized in that that the pulse-shaped signals are smoothed before being supplied to the cathode ray tube. 3. Device for performing the method according to claim 1 or 2, characterized in that that they have a pulse generator (70) and evaluation networks assigned to the characters to be displayed (72 and 74) to which the pulses are fed one after the other by means of a distributor, and a circuit (84, 86) for selecting the output signals of an evaluation network for the x- and j signals then fed to the deflection circuit (158, 160) for the cathode ray tube (68) are, and that a masking network (76) is provided to which the pulses of the pulse generator are also supplied, as well as a circuit (83) for selecting the output signals of a masking network, which supplies the masking signals assigned to the characters, which are then sent to the masking circuit (170) for the cathode ray tube. 4. Apparatus according to claim 3, characterized in that the evaluation networks (72 and 74) have evaluation elements in the form of resistors (Rl to i? 40 and .RlOO to i? 140). 5. Apparatus according to claim 3 or 4, characterized in that each section of the character an evaluation element is assigned. 6. Device according to one of claims 3 to 5, characterized in that the outputs of the evaluation elements (Rl to i? 140) for forming the x or j waveform are each parallel to one another at the input of a feedback direct current amplifier (94 or 98) are connected. 7. Apparatus for performing the method according to claim 1 or 2, characterized in that it comprises a pulse generator (200) and a plurality of circuits (207, 210) which generate a coded output signal corresponding to the coordinates of each section, and one Circuit (230, 232) for combining the coded output signals to form x and j signals and a circuit for generating a masking signal. 8. Apparatus according to claim 7, characterized in that the circuits (207, 210) are AND circuits, that the signals generated by the pulse generator (220) are fed to one input and a selection signal to the other input of the AND circuits that only unidirectional switching elements are connected to the outputs of predetermined circuits to generate encoded x and j signals and digital-to-analog converters (230 and 232) are provided to convert the encoded signals into x and j deflection signals to convert. 9. Device according to one of claims 3 to 8, characterized in that filter elements (154 and 156) are provided for smoothing the x and j signals. 10. The device according to claim 9, characterized in that the filter elements (154 and 156) consist of tapped delay lines. 11. Device according to one of claims 3 to 10, characterized in that circuits 809 537/250 to select different characters are provided. 12. Device according to one of claims 3 to 11, characterized in that circuits are provided to assign the same signals to different characters. Considered publications: German Auslegeschriften Nos. 1 036 718, 1 092 237; French Patent No. 1,222,609; British Patent No. 919,646; U.S. Patent No. 2,766,444. 1 sheet of drawings 809 537/230 3. 68 ® Bundesdruckerei Berlin