GB1401022A - Display apparatus - Google Patents
Display apparatusInfo
- Publication number
- GB1401022A GB1401022A GB1127572A GB1127572A GB1401022A GB 1401022 A GB1401022 A GB 1401022A GB 1127572 A GB1127572 A GB 1127572A GB 1127572 A GB1127572 A GB 1127572A GB 1401022 A GB1401022 A GB 1401022A
- Authority
- GB
- United Kingdom
- Prior art keywords
- line
- xop
- xst
- increment
- lines
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R13/00—Arrangements for displaying electric variables or waveforms
- G01R13/20—Cathode-ray oscilloscopes
- G01R13/22—Circuits therefor
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G5/00—Control arrangements or circuits for visual indicators common to cathode-ray tube indicators and other visual indicators
- G09G5/20—Function-generator circuits, e.g. circle generators line or curve smoothing circuits
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- General Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Theoretical Computer Science (AREA)
- Controls And Circuits For Display Device (AREA)
- Video Image Reproduction Devices For Color Tv Systems (AREA)
Abstract
1401022 Cathode-ray tube displays ELLIOTT BROS (LONDON) Ltd 2 March 1973 [10 March 1972] 11275/72 Heading H4T In a symbol display system in which the symbols comprise one or more lines produced by selective bright-up of selected portions of raster lines traced on a cathode-ray display tube the basic parameters defining each symbol line, such as 1 (Fig. 1), comprising the central co-ordinates (Xc, Yc), the length (L), the width (W) and the angle the line makes with the vertical (#) are utilized by a digital computer 10 (Fig. 2) together with a quantity (h) representative of the spacing between the raster lines to produce outputs representative of Y 1 ; Y 2 ; Xst = (X start) and Xop = (X stop) successive valves of Xst and Xop being incremented by a quantity h tan 6 between Y 1 and Y 2 . The computer output is supplied to an output circuit 11 comprising, as shown in Fig. 3, respective resistors 16, 17 for the Xst and Xop quantities, feeding respective comparators 18, 19 which also receive inputs from a cyclic counter 12 synchronized with the line scan and producing an output at 15 MHz (thus notionally dividing each line scan into 780 sections), the comparators producing, on equality of the two inputs, outputs which are fed via gate 20, which develops a signal during the period when the output from counter 12 is #Xst and #Xop, to the intensity control electrode of the display tube 13 either through a delay circuit 14 and a pulse shaping circuit 15 or through the circuit 15 alone depending on the value of 0. The tube is scanned with a 625 interlaced line raster of which 585 lines are visible so that the Y-resolution is 1 in 585 and with a 4/3 aspect ratio a comparable X-resolution requires each raster line to be divided into 780 sections which therefore determines the frequency of 15 MHz for the cyclic counter 12. Ten bit words define Xst and Xop and ten bit words are also employed to define Y 1 and Y 2 , nine bits being sufficient if the line starts in an even field and finishes in an odd field and the tenth being added to indicate whether or not the first or last (or both) bright-up pulses should be suppressed. Since the increment h varies with the angle # fractional parts must be added for values of 0 between 0 and 45 degrees and this is done by splitting each word into ten bit words specifying respectively, the increment and the increment faction. When # = 45 degrees the X and Y increments are equal and the definition in the X direction is equal to that in the Y direction. However for lines near the vertical (#, small) a large number of Y increments occur for each X increment and for lines near the horizontal (0 large) a large number of X increments occur for each Y increment and in each case, the line has a stepped appearance. To compensate for the former (0 small) the X-definition is increased by a factor of 4 by the use of delay circuitry 14 comprising three 15ns delay circuits and a 4/1 multiplexer (Fig. 4, not shown) and to compensate for the latter (# large) the bright-up pulses are so shaped that each brightened-up portion varies in brightness along its length and blends with the other brightened-up portions to give the illusion of a continuous line (Figs. 5a, 5b and 6, none shown). The delay technique employed to increase the X-definition may be extended such the cyclic counter may operate on a lower frequency, e.g. 7À5 MHz to produce the same definition and when this is done since the width W must remain constant as # varies, the length of the bright-up pulses must vary and to ensure, in this case, that the lengths are correct, the arrangement of Fig. 4 (not shown) is modified by the introduction of a differential delay factor. Since the first part of the initial brightened-up portion and the last part of the final brightenedup portion are produced during a single field only, (Fig. 1) flicker occurs at the beginning and end of a line and to overcome this the length of the line is extended at both ends and the "excess" length blanked so that the flickering regions lie in the blanked off parts.
Priority Applications (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB1127572A GB1401022A (en) | 1972-03-10 | 1972-03-10 | Display apparatus |
IL41679A IL41679A0 (en) | 1972-03-10 | 1973-03-04 | Improvements in or relating to display apparatus |
US338842A US3894292A (en) | 1972-03-10 | 1973-03-07 | Display apparatus |
DE2311826A DE2311826A1 (en) | 1972-03-10 | 1973-03-09 | VISION DEVICE |
IT67662/73A IT980539B (en) | 1972-03-10 | 1973-03-09 | IMMA GINI DISPLAY DEVICE |
FR7308514A FR2175851B1 (en) | 1972-03-10 | 1973-03-09 |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB1127572A GB1401022A (en) | 1972-03-10 | 1972-03-10 | Display apparatus |
Publications (1)
Publication Number | Publication Date |
---|---|
GB1401022A true GB1401022A (en) | 1975-07-16 |
Family
ID=9983223
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB1127572A Expired GB1401022A (en) | 1972-03-10 | 1972-03-10 | Display apparatus |
Country Status (6)
Country | Link |
---|---|
US (1) | US3894292A (en) |
DE (1) | DE2311826A1 (en) |
FR (1) | FR2175851B1 (en) |
GB (1) | GB1401022A (en) |
IL (1) | IL41679A0 (en) |
IT (1) | IT980539B (en) |
Families Citing this family (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4127850A (en) * | 1974-10-03 | 1978-11-28 | Smiths Industries Limited | Scanning display apparatus |
US4145754A (en) * | 1976-06-11 | 1979-03-20 | James Utzerath | Line segment video display apparatus |
DE2655133C2 (en) * | 1976-12-04 | 1983-01-13 | Robert Bosch Gmbh, 7000 Stuttgart | Method for displaying a video signal on the screen of a video display device |
JPS5946397B2 (en) * | 1977-09-09 | 1984-11-12 | 株式会社日立製作所 | Variable precision trend graph display device |
JPS5468119A (en) * | 1977-11-11 | 1979-06-01 | Hitachi Ltd | Trend graph display unit |
JPS54122026A (en) * | 1978-03-15 | 1979-09-21 | Nec Corp | Pattern display system |
US4298867A (en) * | 1979-07-06 | 1981-11-03 | System Concepts, Inc. | Cathode ray tube character smoother |
DE2940088C2 (en) * | 1979-10-03 | 1986-04-10 | Hewlett-Packard Co., Palo Alto, Calif. | Raster display device |
US4454507A (en) * | 1982-01-04 | 1984-06-12 | General Electric Company | Real-time cursor generator |
US4622545A (en) * | 1982-09-30 | 1986-11-11 | Apple Computer, Inc. | Method and apparatus for image compression and manipulation |
US4496976A (en) * | 1982-12-27 | 1985-01-29 | Rockwell International Corporation | Reduced memory graphics-to-raster scan converter |
JPS60191293A (en) * | 1984-03-12 | 1985-09-28 | ダイキン工業株式会社 | Fast linear interpolation circuit for crt display unit |
JPH0732453B2 (en) * | 1985-08-15 | 1995-04-10 | シチズン時計株式会社 | Matrix image forming method |
GB2215570A (en) * | 1988-03-01 | 1989-09-20 | Kontron Instr Limited | Improving the legibility of traces close to the line direction |
US5028914A (en) * | 1988-06-23 | 1991-07-02 | Motorola, Inc. | Method and apparatus for waveform digitization |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3388391A (en) * | 1965-04-07 | 1968-06-11 | Rca Corp | Digital storage and generation of video signals |
US3671957A (en) * | 1969-03-12 | 1972-06-20 | Computer Optics | Character generation display system |
US3668687A (en) * | 1969-11-17 | 1972-06-06 | Sanders Associates Inc | Raster scan symbol generator |
US3686662A (en) * | 1970-11-12 | 1972-08-22 | Int Standard Electric Corp | Circuit arrangement for the presentation of waveforms on viewing screens utilizing raster deflection |
US3792464A (en) * | 1973-01-10 | 1974-02-12 | Hitachi Ltd | Graphic display device |
-
1972
- 1972-03-10 GB GB1127572A patent/GB1401022A/en not_active Expired
-
1973
- 1973-03-04 IL IL41679A patent/IL41679A0/en unknown
- 1973-03-07 US US338842A patent/US3894292A/en not_active Expired - Lifetime
- 1973-03-09 IT IT67662/73A patent/IT980539B/en active
- 1973-03-09 DE DE2311826A patent/DE2311826A1/en not_active Ceased
- 1973-03-09 FR FR7308514A patent/FR2175851B1/fr not_active Expired
Also Published As
Publication number | Publication date |
---|---|
US3894292A (en) | 1975-07-08 |
DE2311826A1 (en) | 1973-09-13 |
IL41679A0 (en) | 1973-07-30 |
FR2175851B1 (en) | 1979-05-11 |
FR2175851A1 (en) | 1973-10-26 |
IT980539B (en) | 1974-10-10 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PS | Patent sealed [section 19, patents act 1949] | ||
PCNP | Patent ceased through non-payment of renewal fee |