US3786478A

US3786478A - Cathode ray tube presentation of characters in matrix form from stored data augmented by interpolation

Info

Publication number: US3786478A
Application number: US00281596A
Authority: US
Inventors: P King
Original assignee: Massachusetts Institute of Technology
Current assignee: Massachusetts Institute of Technology
Priority date: 1972-08-17
Filing date: 1972-08-17
Publication date: 1974-01-15
Anticipated expiration: 1991-01-15

Abstract

Apparatus is disclosed for displaying a selected character on the face of a cathode ray tube at a particular location from information previously stored in a memory. The cathode ray tube is swept in a raster scan with a superimposed sinusoidal deflection in the y-axis direction. The intensity modulation which produces a dot-like representation of a character occurs at a particular time during the scan depending upon the desired location of the character. The intensity modulation as a function of time is unique for each character and occurs along the sinusoidal deflection. The required storage capacity of the memory storing the character information is reduced by an interpolation technique.

Description

United States Patent 1191 King, Jr.

[ CATIIODE RAY TUBE PRESENTATION OF CHARACTERS IN MATRIX FORM FROM STORED DATA AUGMENTED BY INTERPOLATION [75] Inventor: Paul Allen King, Jr., Cambridge,

Mass.

[73] Assignee: Massach usettes Institute of Technology, Cambridge, Mass.

221 Filed: Aug. 17, 1972 211 App]. N0.: 281,596

Related US. Application Data [63] Continuation of Ser. No. 50,641, June 29, 1970.

[52] US. Cl 340/324 AD, l78/D1G. 3 [51] Int. Cl. G06f 3/14 [58] Field of Search 340/324 AD;

[56] References Cited UNITED STATES PATENTS 3,396,377 8/1968 Strout 340/324 AD 3,422,737 1/1969 Bailey, Jr. .l 340/324 AD 1 Jan. 15, 1974 3,573,789 4/1971 Sharp et al l78/DIG. 3

Primary ExaminerThomas B. Habecker Assistant ExaminerMarshall M. Curtis Attorney-Thomas Cooch et al. and Arthur A. Smith, Jr.

[57] ABSTRACT Apparatus is disclosed for displaying a selected character on the face of a cathode ray tube at a particular location from information previously stored in a memory. The cathode ray tube is swept in a raster scan with a superimposed sinusoidal deflection in the y-axis direction. The intensity modulation which produces a dot-like representation of a character occurs at a particular time during the scan depending upon the desired location of the character. The intensity modulation as a function of time is unique for each character and occurs along the sinusoidal deflection. The required storage capacity of the memory storing the character information is reduced by an interpolation technique.

7 Claims, 34 Drawing Figures l sz PATENTEU 3,786,478

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Contents Contents Window Output Output Rule of SR1 of SR2 matrix time value used ABCDE FGHIJ E load word 01110 1 .0 0 1. 5 0 00111 0 E] 2 0 1 #1 2 5 1 011 105219595 3 0 1 #1 3 5 l 01 110 [g] u. 0 1 #1 load new word 7-5 0 095100 10011 [10 i 8. o 0 8. 5 0 05259510 01001 E! 9. 0 0

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sum

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W2 /3 u 12 m OW?! 0W 0 ow 0w SECONDARY SCAN PRIMARY SCAN F|G.|6(A) F|G.I6(B) INVENTOR5 PAUL ALLEN KING, JR.

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sum

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I (First) Column M (B 's) Column i (SR2) FIG. 14

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BY r ATTORNEY PATENIEUJAH 15 mm SHEET 1 405 2 INVENTOR:

PAUL ALLEN KING, JR

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INVENTOR PAUL ALLEN KING, JR.

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Claims

1. A character generator for providing selected characters at desired locations on the face of a cathode ray tube comprising: means for providing a digital code representation of a selected character, means for storing said character digital representation at a display address in a first memory in response to said character selection means, a cathode ray tube having a scanning beam, means for providing a raster scan having a sinusoidal vertical deflection to said tube, means for obtaining a stored character code from said first memory when its display address corresponds with the position of the raster beam, a second means for storing in binary form a different matrix representation of each character corresponding to each character code, means for selectively reading out the character matrix representations as serial binary signals from said character matrix storage means in response to said character codes from said first memory, means for intensity modulating said sinusoidal deflection in its linear region in synchronism with said serial binary signal to provide a dot matrix representation of the selected character in response to the character matrix representation signal.

2. The apparatus of claim 1 comprising in addition: means for providing synchronizing pulses in response to said sinusoidal deflection, said means for obtaining said character matrix being connected to said synchronizing pulse means to provide the character matrix at a predetermined position of said raster scan and said sinusoidal deflection in response to said synchronizing pulses, said means for intensity modulating said sinusoidal deflection being connected to said synchronizing pulse means to provide a series of intensifying pulses corresponding in number of the number of rows in a column of the matrix, said initial intensifying pulse of the series being responsive to said synchronizing pulses to occur near the zero-crossing region of the sinusoidal deflection.

3. A character generator for providing selected characters at desired locations on the face of a cathode ray tube comprising: means for time sequentially recovering character codes from storage, each code representative of the characters to be generated on the cathode ray tube, means for applying a raster scan to said tube in response to and synchronized to pulses generated by the time sequence of character codes, the time of occurrence of each character code corresponding to its desired location on the raster, means for applying a large sinusoidal vertical deflection to the raster scan, said sinusoidal scan being responsive to said synchronizing pulses, means for storing a matrix for each character in a time-sequential binary form, means for providing each recovered character to said matrix storage to cause said matrix storage to provide a dot matrix for the character code in the form of a time-sequential binary pulse stream beginning at a time corresponding to the desired location of the character on the raster scan, means for providing said matrix as intensification pulses to said cathode ray tube in the linear region of the sinusoidal scan in response to said synchronizing pulses, whereby said character is represented in its dot matrix form at the desired location on the cathode ray tube.

4. A character generator for providing selected characters at desired locations on the face of a cathode-ray tube comprising, a first memory for storing a plurality of character codes of a characTer set in serial form in the time sequence that each character is to be represented on the face of the tube, a second memory having a unique character dot matrix stored in binary form for each character of the character set in the first memory, means for providing a vertical scan frequency corresponding to a multiple of the average frequency of occurrence of character codes, means for providing a raster scan to said tube, means for providing said vertical scan frequency as a vertical deflection to said raster scan, means for sensing said vertical deflection to provide timing pulses, means for synchronizing said raster scan to said timing pulses, means for sequentially providing each stored character code from said first memory to said second memory, the second memory providing a serial binary signal in response to each character code, means for providing intensifying pulses to the cathode-ray tube of a frequency higher than that of the vertical scan frequency and synchronized with said timing pulses in response to said serial binary signal to form the dot matrix of each stored character code, said character matrix being responsive to said intensifying pulses to provide said character dot matrix to said cathode ray tube, said synchronization of the raster scan, vertical scan deflection and intensifying pulses producing a character representation for each stored character which is invariant and at the same position on the face of the tube from scan to scan.

5. A character generator for providing selected characters at desired locations on the face of a cathode-ray tube comprising: means for selecting one of said characters, means responsive to said selecting means for providing a different digital code representation for each of a plurality of characters to be generated, means for designating the position on the face of the cathode-ray tube where said character is to be presented, a rotating magnetic drum containing address positions along its periphery corresponding with fixed positions on the face of the cathode-ray tube, means for storing in the drum address corresponding to a position on the face of the tube the digital code corresponding to the character to be presented at that position, means for reading out the stored digital code of each character on each revolution of the drum, a cathode ray tube having a scanning beam, means for providing a raster scan having a sinusoidal vertical deflection to said tube a second means for storing binary signals, each corresponding to a different character code, means for providing such second storage means the serial binary signal of a character in response to the digital code representation of that character produced by said rotating drum, means for synchronizing the raster scan and sinusoidal deflection with the serial binary signal so that each bit of the serialbinary signal derived from each stored character code on the drum corresponds to a fixed position on the face of the tube, means for intensity modulating the beam of said cathode ray tube with said serial binary signal to cause said intensity modulated beam to provide a dot matrix representation of the character stored at the corresponding drum address.

6. The apparatus of claim 5 comprising in addition: means for comparing adjacent bits in the serial binary signal occurring during the upward sweep of the sinusoidal scan to provide an additional intensifying bit intermediate two intensifying bits of said serial binary signal.

7. The apparatus of claim 6 comprising in addition: means for storing two such successive serial binary signals, means for comparing bits of these signals which occur in a row of the matrix representation of the character to provide an additional intensifying bit when intensifying bits occur in the serial binary signals corresponding to the row, means for providing these additional intensifying bits as a serial binary signal During the downward sweep of the sinusoidal scan.