US3587083A - Character generation and display system - Google Patents

Character generation and display system Download PDF

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US3587083A
US3587083A US671317A US3587083DA US3587083A US 3587083 A US3587083 A US 3587083A US 671317 A US671317 A US 671317A US 3587083D A US3587083D A US 3587083DA US 3587083 A US3587083 A US 3587083A
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pulse
generating
input
output
character
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US671317A
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Matthew P Tubinis
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Xerox Corp
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Xerox Corp
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    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G1/00—Control arrangements or circuits, of interest only in connection with cathode-ray tube indicators; General aspects or details, e.g. selection emphasis on particular characters, dashed line or dotted line generation; Preprocessing of data
    • G09G1/06—Control arrangements or circuits, of interest only in connection with cathode-ray tube indicators; General aspects or details, e.g. selection emphasis on particular characters, dashed line or dotted line generation; Preprocessing of data using single beam tubes, e.g. three-dimensional or perspective representation, rotation or translation of display pattern, hidden lines, shadows
    • G09G1/08—Control arrangements or circuits, of interest only in connection with cathode-ray tube indicators; General aspects or details, e.g. selection emphasis on particular characters, dashed line or dotted line generation; Preprocessing of data using single beam tubes, e.g. three-dimensional or perspective representation, rotation or translation of display pattern, hidden lines, shadows the beam directly tracing characters, the information to be displayed controlling the deflection and the intensity as a function of time in two spatial co-ordinates, e.g. according to a cartesian co-ordinate system
    • G09G1/10—Control arrangements or circuits, of interest only in connection with cathode-ray tube indicators; General aspects or details, e.g. selection emphasis on particular characters, dashed line or dotted line generation; Preprocessing of data using single beam tubes, e.g. three-dimensional or perspective representation, rotation or translation of display pattern, hidden lines, shadows the beam directly tracing characters, the information to be displayed controlling the deflection and the intensity as a function of time in two spatial co-ordinates, e.g. according to a cartesian co-ordinate system the deflection signals being produced by essentially digital means, e.g. incrementally

Definitions

  • ABSTRACT A character generation and display system for characters comprised of a series of connecting line segments of various slopes which are formed by deflection waveforms resulting from integrating over a uniform period of time pulse trains having different frequencies.
  • FIG. 20 9 FIG. 20 6.
  • FIG. 25
  • FIG. 26 I 5 1 FIG 2H FIG 21 (We A TTORNE Y8 PATENTEDJUHZQIBYI 3,587,083
  • FIG 4 MATTH' W R TUiNm A TTORNEYS PATENTEUJUNZ-ZIQYI $587,083
  • FIG.5F FIG. 56 FIG. 5H FIG.5I FIG. 5/
  • FIG. 6A FIG. 63 FIG. 60
  • This invention relates generally to character generation and, more specifically, to generation of a large number of alphanumeric symbols utilizing a plurality of line segments.
  • Another object of the present invention is to improve the generation of stroke-type characters for display by cathoderay tubes.
  • FIG. 1 is a block diagram of a character generator system in accordance with the principles of the present invention
  • FIG. 2 A through I represent signal waveform diagrams helpful in understanding the manner in which the character of FIG. 2A is generated
  • FIG. 3 illustrates a typical character core matrix which may be used in accordance with the principles of the present invention
  • FIG. 4l schematically illustrates the deflection waveform generator in accordance with the principles of the present invention
  • FIG. 5 A through 1 illustrate the various character segments which are used to generate a complete repetoire of characters using the principles of the pleseht invention
  • FIGS. 6A through C illustrate other characters which may be generated in accordance with the principles of the present invention.
  • FIG. 1 a digital storage register 2 for the storage of character selection signals in accordance with the various conventional codes.
  • the input to this register may be coupled to the output of a computer or other similar data generating or storage device.
  • This storage register 2 has an output coupled to a conventional character decoder 4 which decodes the particular character code supplied by the digital register and selects a character set wire for that particular character which is threaded in the character code matrix 6.
  • a conventional character decoder 4 decodes the particular character code supplied by the digital register and selects a character set wire for that particular character which is threaded in the character code matrix 6.
  • the exact nature of the character code matrix 6 will be described in more detail hereinafter in connection with FIG. 4.
  • FIG. I also shows a clock pulse source 8 which generates a train of pulses at a uniform pulse repetition frequency and supplies this pulse train to a suitable distributor 10 which, for example, may be a conventional ring counter.
  • a suitable distributor 10 which, for example, may be a conventional ring counter.
  • the outputs from the stages of this ring counter or distributor 10 are supplied to the character core matrix 6 as will be described in more detail hereinafter.
  • the output of the character core matrix is provided asja parallel input to the deflection wavefonn generator 12 which utilizes the information supplied thereto from the character core matrix 6 to generate particular deflection waveforms characteristic of the character decoder.
  • the deflection waveforms are supplied to a suitable display device 14 such as via the deflection plates or coils of a conventional cathode-ray tube.
  • FIG. 2 illustrates the actual technique utilized in forming the particular characters desired.
  • FIG. 2A shows an upper case letter "A.”
  • the short intersecting lines associated with this character divide V the character into a number of segments, in this case, nine segments. The segments are drawn so that at the end of one segment the next segment begins and that all the segments appear to be connected to form a set of continuous linear lines having different slopes.
  • FIG. 2B and FIG. 2F show the horizontal waveform l6 and the vertical waveform 18, respectively, formed by the deflection waveform generator 12 previously referred to in connection with FIG. 1 These waveforms, when applied to the deflection system of a cathode-ray tube, will generate the character A as shown in FIG. 2A.
  • FIG. 2B illustrates a first group of pulses 20 at a particular frequency, for example f for a time duration equal to 6:. This period is subdivisible into six equal time increments equal to 1.
  • another group of pulses 22 of a polarity opposite those of pulses 20 are shown occuring during a time period equal to 7t--6t,, these pulses 22 being of a similar frequency as were pulses 20 previously referred to.
  • FIG. 2F shows the vertical waveform 18 which may be generated by integrating a first series of pulses 26 of a frequency f occurring for a duration equal to 3:, a second series of pulses 28 of an identical frequency but of an opposite polarity, and a third set of pulses 27 equal in duration to a period of time t and a frequency of f For the period of time between 7t and 9! no pulses occur since the vertical deflection waveform has a constant amplitude.
  • FIGS. 2C, D, and E show the particular pulses generally designated by reference numerals 21, 23 and 25, respectively, necessary in connection with the operation of the deflection waveform generator to permit the aforementioned pulse series of varying frequency to be integrated thereby forming the particular deflection waveforms described.
  • FIGS. 26, H, and I show the pulses, generally designated ny reference numerals 29, 31 and 33, respectively which permit the generation of the particular pulse trains of varying frequency previously alluded to.
  • the broken vertical lines in some of the pulses of these FIGS. indicate the substantially simultaneous ending and beginning of two adjacent pulses. This has been shown in favor of a complete pulse.
  • the deflection waveform generator 12 includes six pulse sources or generators 30 each having its own unique frequency. As shown in FIG. 4, these frequencies have been designated 1",, f f3, f f and f,,.
  • the output of each pulse source 30 is connected to a pulse shaper and splitter circuit 32 of conventional design to shape the pulses generated by pulse source 30 into rectangular pulses of both polarities. Those pulses having a positive polarity are provided at the output designated by the positive sign while those pulses having a negative polarity are provided at the output designated by the negative sign.
  • Each of the outputs from a pulse shaper and splitter 32 is provided generally to the input of two AND gates 34 and 36.
  • the AND gates 34 have their outputs connected in common to the input to a conventional current integrator 38 which may be a capacitance circuit to produce an output voltage which is the integral of the input current applied thereto.
  • the output of AND gates 36 are connected in common to provide an input to integrator circuit 40 which may be of similar design as integrator 38.
  • the outputs of these integrators are connected through suitable amplifiers 42 and 44, respectively, to, for example, electromagnetic deflection coils 46 and 48 to control the horizontal and vertical displacement of the electron beam in the conventional cathode-ray tube 14.
  • the pair of AND gates 34 whose outputs are connected in common and which are associated with each frequency source 30 influence the deflection of the electron beam either in the positive x direction or negative x direction depending upon its particular input from the pulse shaper and splitter circuit 32. Accordingly, the pair of AND gates 36 whose outputs are connected in common for each frequency source 30 control the deflection of the electron beam in the positive y or negative y direction also depending upon their input from the pulse shaper and splitter circuit 32.
  • each of the AND gates 34 and 36 have three inputs, one of which, as previously described, originates from the frequency pulse source 32. Another input is provided in the case of AND gates 34 from a flip-flop 50. In the case of AND gates 36, this second input is derived from flip-flop 52. The function of these flip-flops will be described in more detail hereinafter.
  • the third input to the AND gates 34 and 36 originates from one of a plurality of pulse generating circuits 54 which have been designated r 2 t,, I, I r I, and 1,
  • These pulse circuits may be of any conventional design such as a monostable multivibrator and function to produce upon a trigger signal at their inputs a pulse having a specified and equal time duration equal to t.
  • the trigger signal which initiates the pulse from these pulse sources 54 is delivered to terminals 55 through 63, respectively, which correspond to identically designated output terminals from the character core matrix 6 shown more fully in FIG. 3.
  • the outputs of these pulse sources 54 are connected to the gates identified by the subscript and the following .r" or y" designation.
  • the output of the pulse source designated I is applied to the input of AND gates 34 associated with the frequency pulse source 30 having a frequency f,.
  • the outputs of the pulse sources 54 having an x" designation are connected as inputs to a NOR gate 64 which provides a reset input to flip-flop 50.
  • the outputs of the three pulse sources 54 having a y" designation are also connected as inputs to a NOR gate 66 which provides a reset input to flip-flop 52.
  • the set input of these flip-flops 50 and 52 are connected, respectively, to input terminals 68 and 70 which also derive signals from the character core matrix 6.
  • the purpose of these flip-flops 50 and 52 is to control the application of the pulses of the proper polarity through AND gates 34 and 36 depending upon the segment of the character to be generated. This will become more evident in connection with the description of the character core matrix of FIG. 3.
  • FIG. 3 shows in detail the character core matrix 6 previously referred to.
  • This matrix comprises 14 columns of magnetic cores arrayed in l3 rows,
  • each column representing a segment in a character which can be generated in accordance with the principles of the present invention.
  • Input signals are received from the character decoder 4 previously alluded to in connection with FIG. 1.
  • the matrix then produces in parallel pulses at its output terminals which ultimately effect the deflection waveform supplied to the cathode-ray tube display device 14.
  • the character core matrix utilizes bistable magnetic cores 72 as the bistable elements, however, other suitable bistable elements may be employed as well.
  • These magnetic cores are made of any suitable magnetic material having two opposed stable states of magnetic remanence which are designated the zero state and the one state in accordance with convention.
  • all of the cores of the matrix are in a zero state which may be altered by the application of a magnetizing field applied to any one of the cores by means of a set wire threaded through the core or combination thereof.
  • this positive magnetizing field is of sufficient intensity
  • the core is switched from the zero state to the one state.
  • Subsequent application of a negative magnetizing field of sufficient intensity by means of a reset wire threaded through the core causes the core to be switched from the remanence condition representing the one state to the remanence condition representing the zero state.
  • an output pulse is generated on an output or read wire also threaded through the core.
  • the set wire 74 for the character A actually consists of two electrically parallel set wires, one designated A and the other designated A These wires are threaded through particular cores in a manner to be explained hereinafter.
  • An output terminal representing each stage of the distributor or ring counter 10 is connected to one of the input terminals 76 which is coupled to the reset wire 78.
  • These reset wires are conventionally threaded through every core in the column.
  • the connection of these reset wires to the ring counter 10 is such so as to permit the sequential energization of the reset wires as the ring counter advances.
  • the wires are energized in a sequence beginning from the left and going to the right of the FIG. is viewed.
  • negative magnetizing pulses are applied sequentially to the column reset wires of the character core matrix. These negative magnetizing pulses cause those cores in the one state in that particular column to return to the zero state.
  • the cores which have not been set to the one state remain in the zero state upon application of the negative reset magnetizing field.
  • a read wire 80 which is connected to an output terminal corresponding in reference numeral to an input terminal of the deflection waveform generator of FIG. 4.
  • the energization of the reset wire for each column of the character core matrix generates the read pulses which will ultimately draw a particular line segment of a character on the screen of the cathoderay tube.
  • FIG. 3 there are 14 columns in the matrix, thereby limiting the number of characters which can be drawn to those which require 14 or less segments. However, any number of characters may be synthesized within the 14 segments. Obviously, if it was desirable to synthesize character of more complexity than those using l4 segments, the number of columns in the core matrix could be increased to accommodate these more complex characters or symbols.
  • FIGS. 2, 3, and 4 a typical operation of the circuit constructed in accordance with the principles of the present invention will be described in generating the character A.” Assuming that the character decoder has identified the coded character stored in the storage register 2 and a particular set wire 74 is energized in the character core matrix. Those cores in the character core matrix which are threaded by this set wire are changed from their zero state to their one state.
  • the ring counter commences its advancement, resetting the coresin the first column. This generates an output pulse at terminals 56 and 63 which initiate a timed pulse of duration r at the output of pulse generators 54 designated t x and t y, respectively.
  • These timed pulses are applied to the input of AND gates 34 and 36, respectively, associated with frequency sources f and f
  • flip-flops 50 and 52 With flip-flops 50 and 52 in their initial reset condition, these AND gates 34 and 36 are enabled to pass a specified number of pulses from their respective pulse shaper and splitter circuits 32 depending upon the frequency of the pulse source associated therewith.
  • These pulses are applied to the current integrating circuits 38 and 40 which integrate the succession of pulses into a substantially linear ramp signal which deflects the electron beam in the display device 14 accordingly.
  • the ring counter then advances one stage to reset the cores associated with the second column thereby generating two or more read or trigger pulses at output terminals 56 and 63 respectively.
  • these pulses initiate, in the example of the character "A,” a similar number of pulses to be integrated by current integrators 38 and 40 to deflect the beam again. This process is repeated until the character A has been completely traced on the screen of the cathode-ray tube.
  • the set wire is threaded through a core associated with read wire 82'and output terminal 84.
  • This core is in the same column as the last core threaded for this particular character.
  • the read pulse generated when this core is reset to its zero condition may be utilized to reset the distributor 10 rather than have it continue through the remaining five columns.
  • additional read wires 86 and 8d are provided to generate a signal at output terminals 68 or 70, respectively, which indicates the times a pulse from one of the pulse generators 54 is to be applied to a gate associated with the negative output of the pulse shaper and splitter circuit 32.
  • This decision is made by flip-flop or 52, depending upon whether it is a negative x or negative y signal. In either case, one of these flip-flops is set to provide a disabling signal to AND gate 34 or 36 and an enabling signal to AND gates 34 or 36 which permit negative pulses to pass to the integrating circuit during the generation of the timed pulse from generator 34. As the trailing edge of this timed pulse occurs, flip-flop 50 or 52 is reset via the connection between the reset input of the flip-flop and NOR gate 64 or 66.
  • an additional row of cores associated with read wire 90 are provided in the character core matrix and are associated with output terminal 92.
  • This output terminal is connected to a suitable circuit 94 such as a monostable multivibrator of similar design as pulse generators 54.
  • This circuit upon the receipt of a read pulse at output terminal 92 generates a pulse of sufficient amplitude and polarity to block the cathode-ray beam from striking the screen of the cathode-ray tube.
  • the duration of this blocking signal is equal to the duration of the pulses generated by any one of the pulse generators 54. In this manner, any character or symbol may be generated and displayed.
  • the interval between advancement in the distributor preferably is equal to the time r so as to permit the completion of each segment of the character before resetting the next column in the character core matrix.
  • FIG. 2 is presented for purposes of illustration only and the waveforms included therein are shown in idealized form. The frequencies and pulse widths are not exact and are provided for their relative value at best.
  • FIG. 5 there is shown in relative perspective actual character components or line segments utilized in accordance with the principles of the present invention to make up a particular font of characters which can be generated and displayed.
  • the particular frequencies are a matter of choice depending upon the font desired and it is not necessary to specify the frequencies involved except to the extent that the subscripts indicate the relative frequencies they designate. For example, frequencyf is greater than the frequency j ⁇ , and less than the frequencyf Obviously, if one of the components or line segments illustrated in FIG. 5 may be in any desired quadrant of the Cartesian coordinates by selecting the proper polarity of the pulses to be integrated.
  • FIG. 6 shows three exemplary characters which may be generated using the line segments of FIG. 5 in the concepts of the present invention.
  • the pulse generated at output terminal 84 of the character core matrix of FIG. 4 previously alluded to for purposes of resetting the distributor or ringcounter 10 may be used to generate proper deflection voltages to cause the beam to be repositioned at a new initial reference position from which the next character may be initiated. This reference position may be the lower left-hand corner of the space allotted for the next successive character.
  • a character signal generating system for generating horizontal and vertical deflection signals which control an electron beam to trace any of a plurality of predetermined characters each of which is composed of segments having various slopes and lengths, said system comprising:
  • each of said pulse generating means including a pulse train splitting circuit means for splitting each of said pulse trains into a pair of split pulse trains of like frequency to each other but of opposite polarity with each other;
  • e. means for generating in response to a code signal representative of one of said predetermined characters any one of a plurality of predetermined sequences of gate pulses to said gating means.
  • c. means coupled to each of said conductors of said first and second pluralities for generating on selected ones of said conductors successive pulse trains during substantially uniform time intervals indicative of segments of a particular character to be displayed, at least one of said successive pulse trains having a pulse repetition frequency different from that of another one of said pulse trains;
  • a character signal generating system for generating horizontal and vertical deflection signals which control an electron beam to trace any of a plurality of predetermined characters each of which is composed of segments having various slopes and lengths, said system comprising:
  • a. horizontal means having an input for generating a horizontal analog signal as a function of the number of pulses received thereby;
  • vertical means having an input for generating a vertical analog signal as a function of the number of pulses received thereby;
  • a first plurality of gates each having two inputs and an output, said output being coupled to said first conductor
  • a plurality of pulse splitting means for generating two substantially identical output pulse trains of opposite polarity on first and second outputs, respectively, in response to an input pulse train at the input thereof, said output pulse trains having a frequency dependent on frequency of said input pulse train;
  • k means for selectively generating and applying any one of a plurality of predetermined sequences of gate pulses to the input of said gates of said first and second pluralities in accordance with one of said predetermined characters.

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  • Engineering & Computer Science (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Details Of Television Scanning (AREA)
  • Video Image Reproduction Devices For Color Tv Systems (AREA)
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US671317A 1967-09-28 1967-09-28 Character generation and display system Expired - Lifetime US3587083A (en)

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US67131767A 1967-09-28 1967-09-28

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DE (1) DE1774884B1 (enrdf_load_stackoverflow)
FR (1) FR1582728A (enrdf_load_stackoverflow)
GB (1) GB1234580A (enrdf_load_stackoverflow)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3689917A (en) * 1970-09-16 1972-09-05 Computer Image Corp Frequency selector and synthesizer
US3691551A (en) * 1969-05-02 1972-09-12 Casio Computer Co Ltd System for generating tracing signals for displaying or recording characters
US3696394A (en) * 1968-12-11 1972-10-03 Casio Computer Co Ltd Method and arrangement for generating tracing signals
US3713134A (en) * 1970-09-16 1973-01-23 Corning Glass Works Digital stroke character generator
US3742484A (en) * 1971-12-28 1973-06-26 Xerox Corp Character generating apparatus employing bit stream length correction
US3775760A (en) * 1972-04-07 1973-11-27 Collins Radio Co Cathode ray tube stroke writing using digital techniques
US3786482A (en) * 1972-03-13 1974-01-15 Lexitron Corp Apparatus for generating and displaying characters by tracing continuous strokes
US3921163A (en) * 1973-02-20 1975-11-18 Thomson Csf Alpha-numerical symbol display system
US3952297A (en) * 1974-08-01 1976-04-20 Raytheon Company Constant writing rate digital stroke character generator having minimal data storage requirements
US4637047A (en) * 1983-11-01 1987-01-13 Pioneer Electronic Corporation Level indication apparatus for digitally encoded audio signal data
US6467605B1 (en) 1971-04-16 2002-10-22 Texas Instruments Incorporated Process of manufacturing

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3946365A (en) * 1973-12-13 1976-03-23 Bantner John A Graphic symbol generator

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3329947A (en) * 1963-03-07 1967-07-04 Burroughs Corp Electronic character generator

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3696394A (en) * 1968-12-11 1972-10-03 Casio Computer Co Ltd Method and arrangement for generating tracing signals
US3691551A (en) * 1969-05-02 1972-09-12 Casio Computer Co Ltd System for generating tracing signals for displaying or recording characters
US3689917A (en) * 1970-09-16 1972-09-05 Computer Image Corp Frequency selector and synthesizer
US3713134A (en) * 1970-09-16 1973-01-23 Corning Glass Works Digital stroke character generator
US6467605B1 (en) 1971-04-16 2002-10-22 Texas Instruments Incorporated Process of manufacturing
US3742484A (en) * 1971-12-28 1973-06-26 Xerox Corp Character generating apparatus employing bit stream length correction
US3786482A (en) * 1972-03-13 1974-01-15 Lexitron Corp Apparatus for generating and displaying characters by tracing continuous strokes
US3775760A (en) * 1972-04-07 1973-11-27 Collins Radio Co Cathode ray tube stroke writing using digital techniques
US3921163A (en) * 1973-02-20 1975-11-18 Thomson Csf Alpha-numerical symbol display system
US3952297A (en) * 1974-08-01 1976-04-20 Raytheon Company Constant writing rate digital stroke character generator having minimal data storage requirements
US4637047A (en) * 1983-11-01 1987-01-13 Pioneer Electronic Corporation Level indication apparatus for digitally encoded audio signal data

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FR1582728A (enrdf_load_stackoverflow) 1969-10-03
DE1774884B1 (de) 1971-07-29
GB1234580A (enrdf_load_stackoverflow) 1971-06-03

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