US3786482A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for generating and displaying characters by tracing continuous strokes
Assignee: Raytheon Co
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Filing: 1972-03-13
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Granted: 1974-01-15
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Expires: 1992-03-13
Abstract
Abstract A character display system for tracing a succession of strokes on a display tube to thereby generate the character. The digital information necessary to generate the proper number of strokes in the correct sequence is stored in a character read-only memory, each location of which provides memory words of 16 bits, one or more portions of each memory word being latched into one or more data registers at predetermined time intervals after the memory word is available. A multiplexer is provided to route the correct bit from the memory or the one or more registers to each of the six multiplexer outputs to create control words of six bits. Control logic is provided to respond to the control words to generate digital signals for selectively incrementally charging two capacitors to control the vertical and horizontal deflection fields respectively of the display tube. The charging of each capacitor is accomplished by combinations of whole and fractional units of positive charging current above a predetermined negative level to provide the appropriate analog signals for the deflection circuitry. The control word also controls the unblanking amplifier of the cathode ray tube circuitry. A control read-only memory is provided to accept information indicative of the character and provide outputs indicative of the number of strokes required for that particular character and memory address information for the character read-only memory.
Inventors
- 👤 J Puckett
- 👤 S Kurtin
- 👤 A Goldman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 17:28
CPC Classifications
G; G09; G09G; G09G1/00; G09G1/06; G09G1/08; G09G1/10
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
260 words
In a display system for forming a character on a display screen by sequentially generating a plurality of strokes, each of the strokes having a length and direction determined by a control word, with different characters having differing numbers of control words utilized for the formation of the character, the combination comprising: input means for receiving an input signal indicative of the character to be formed; a character memory comprising a plurality of memory word storage locations for storing memory words of a predetermined bit length, said predetermined bit length being less than the total bit length of the control words utilized for the formation of at least a portion of the characters which can be displayed by said display system; a control memory responsive to said input signal for deriving a first group of data indicative of the number of control words used to form the selected character and a second group of data indicative of the beginning address in said character memory of memory words indicative of the control words which define the character to be formed; means responsive to said second group of data for sequentially addressing locations in said character memory to successively provide output memory words from said character memory; means accepting said memory words and deriving control words therefrom; means responsive to said control words for sequentially generating strokes on the display screen to form the character; and means responsive to said first group of data for indicating the occurrance of the number of control words needed to define the character to be formed.
Claim 2
Dependent Claim
260 words
In a display system for forming a character on a display screen by sequentially generating a plurality of strokes, each of the strokes having a length and direction determined by a control word, with different characters having differing numbers of control words utilized for the formation of the character, the combination comprising: input means for receiving an input signal indicative of the character to be formed; a character memory comprising a plurality of memory word storage locations for storing memory words of a predetermined bit length, said predetermined bit length being less than the total bit length of the control words utilized for the formation of at least a portion of the characters which can be displayed by said display system; a control memory responsive to said input signal for deriving a first group of data indicative of the number of control words used to form the selected character and a second group of data indicative of the beginning address in said character memory of memory words indicative of the control words which define the character to be formed; means responsive to said second group of data for sequentially addressing locations in said character memory to successively provide output memory words from said character memory; means accepting said memory words and deriving control words therefrom; means responsive to said control words for sequentially generating strokes on the display screen to form the character; and means responsive to said first group of data for indicating the occurrance of the number of control words needed to define the character to be formed.
Claim 3
Dependent Claim
50 words
The combination according to claim 1 wherein said means accepting said memory words includes at least one data register and a multiplexer, said data register accepting a portion of each memory word, the multiplexer selectively transferring data from said character memory and said data register to create the control words.
Claim 4
Dependent Claim
32 words
The combination according to claim 2 wherein said means for sequentially generating strokes includes control logic responsive to said control words for generating deflection signals and signals for unblankiNg the display screen.
Claim 5
Dependent Claim
46 words
The combination according to claim 1 wherein said means responsive to said second group of data includes an address counter which provides a starting memory address to the character memory and said character memory then sequentially provides the memory words for the character to be formed.
Claim 6
Dependent Claim
73 words
The combination according to claim 3 wherein the display screen has an electron beam and said control logic includes a decoder for decoding the control words to provide a first set of digital information for controlling the X-axis deflection of the electron beam, a second set of digital information for controlling the Y-axis deflection of the electron beam and a single bit of information for controlling the ON-OFF state of the electron beam.
Claim 7
Dependent Claim
47 words
The combination according to claim 5 wherein said means for sequentially generating strokes further includes a first and second capacitors, each of which produces a voltage ramp of unique slope in response to said first and second sets of digital information, respectively, to deflect the electron beam.
Claim 8
Dependent Claim
70 words
The combination according to claim 6 wherein each of said first and second sets of digital information provides a charging current to each of said first and second capacitors, respectively, the magnitude of the charging current being determined by the information present in each set and the cumulative charge on the capacitor being determined by the net charging current previously applied to the capacitor by preceding sets of digital information.
Claim 9
Dependent Claim
55 words
The combination according to claim 5 wherein said means for sequentially generating strokes further includes a first and second capacitors, and a first and second sets of current sources to provide a first and second charging current to said first and second capacitors, respectively, in response to said first and second sets of digital information.
Claim 10
Dependent Claim
56 words
The combination according to claim 8 wherein each of said sets of current sources includes one continually conductive current source, the other current sources each having an input for receiving one bit of the digital information of the respective set of digital information and each being rendered conductive in response to one state of said input.
Claim 11
Dependent Claim
44 words
The combination according to claim 9 wherein said one continually conductive current source provides a negative net charging current to said capacitor and the other current sources provide positive charging current to said capacitor whereby the cumulative charging current is the algebraic sum thereof.
Claim 12
Dependent Claim
22 words
The combination according to claim 7 wherein each of said first and second capacitors is provided with a selectively actuable discharge path.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-01-14 | 1977-07-16 | 1978-01-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-14 | 1981-07-16 | 1982-01-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-14 | 1985-07-16 | 1986-01-15 | $7700.00 | Window Closed / Lapsed |