CA1195788A - Apparatus for producing a display of data on the screen of a visual display unit - Google Patents
Apparatus for producing a display of data on the screen of a visual display unitInfo
- Publication number
- CA1195788A CA1195788A CA000395759A CA395759A CA1195788A CA 1195788 A CA1195788 A CA 1195788A CA 000395759 A CA000395759 A CA 000395759A CA 395759 A CA395759 A CA 395759A CA 1195788 A CA1195788 A CA 1195788A
- Authority
- CA
- Canada
- Prior art keywords
- display
- screen
- control signal
- signal
- code word
- 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
- 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
-
- G—PHYSICS
- G06—COMPUTING OR CALCULATING; COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F40/00—Handling natural language data
- G06F40/10—Text processing
- G06F40/103—Formatting, i.e. changing of presentation of documents
-
- G—PHYSICS
- G06—COMPUTING OR CALCULATING; COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F40/00—Handling natural language data
- G06F40/10—Text processing
- G06F40/166—Editing, e.g. inserting or deleting
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- Engineering & Computer Science (AREA)
- Theoretical Computer Science (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Computational Linguistics (AREA)
- General Health & Medical Sciences (AREA)
- Health & Medical Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Audiology, Speech & Language Pathology (AREA)
- Artificial Intelligence (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Computer Hardware Design (AREA)
- Controls And Circuits For Display Device (AREA)
- Digital Computer Display Output (AREA)
- Input From Keyboards Or The Like (AREA)
Abstract
ABSTRACT
APPARATUS FOR PRODUCING A DISPLAY OF DATA
ON THE SCREEN OF A VISUAL DISPLAY UNIT
For editing purposes it is desirable to display on the screen (BS) of a visual display unit (AE) control signals which determine the properties of alphanumerical and/or graphic characters. Code words (CW) assigned to the control signals and characters are stored in a page store (SP). A control signal can be displayed on the screen (BS), in response to actuation of a key of a keyboard (TA) assigned to the control signal, by means of a special symbol, for example the write mark. Consecutive positions of this control signal or simultaneously all the positions assigned to this control signal can be displayed on the screen (BS) by means of appropriate key actuation at the keyboard (TA). A switching stage (S) is provided which is supplied by the keyboard with the code word (CWl) assigned to the relevant control signal, compares the code word with the code words stored in the page store (SP), and supplies an image control unit (BST) with signals (S2) for triggering the display of the special signal on the screen (BS) when a comparator (VG) establishes that a code word (CW) read out from the page store (SP) is identical to the code word (CWl) input by means of the keyboard.
APPARATUS FOR PRODUCING A DISPLAY OF DATA
ON THE SCREEN OF A VISUAL DISPLAY UNIT
For editing purposes it is desirable to display on the screen (BS) of a visual display unit (AE) control signals which determine the properties of alphanumerical and/or graphic characters. Code words (CW) assigned to the control signals and characters are stored in a page store (SP). A control signal can be displayed on the screen (BS), in response to actuation of a key of a keyboard (TA) assigned to the control signal, by means of a special symbol, for example the write mark. Consecutive positions of this control signal or simultaneously all the positions assigned to this control signal can be displayed on the screen (BS) by means of appropriate key actuation at the keyboard (TA). A switching stage (S) is provided which is supplied by the keyboard with the code word (CWl) assigned to the relevant control signal, compares the code word with the code words stored in the page store (SP), and supplies an image control unit (BST) with signals (S2) for triggering the display of the special signal on the screen (BS) when a comparator (VG) establishes that a code word (CW) read out from the page store (SP) is identical to the code word (CWl) input by means of the keyboard.
Description
~1~57~
The invention relates to apparatus for producing a display of data on the screen of a visual display unit particularly in a data display terminal of a data transmission system in which a cen~ral unit is connected via a transmission line to the terminal.
In the telecommunications service "screen text"
(video-tex-interactive) it is possible to caU up lnformatlon stored in a central unit via,a telephone line and using a television set as visual display unit. The 10 ' information is displayed on the screen of the television set. Alphanumerical characters and/or patterns composed of graphic characters can be displayed.
Editing devices by means of which inforrnation is prepared in the orm of screen contents are available to those responsible for presenting inforrnation. The screen contents are subsequently transmitted to the central unit whereupon they can be called up by the subscribers.
-- One screen content is referred to as a page~
The page contains for example 960 character arrays which are arranged in 24 rows each containing 40 character arrays.
In the event of the display of alphanumeric characters one character is displayed in each character array. The character array consists for example of 8x10 or 8x12 image points by means of which the individual characters are displayed. The graphic patterns are displayed such that each character array contains one graphic character which is composed of 2x3 graphic elements. The graphic patterns ~' ~1~5~
are constructed from combinations of light and dark graphic elements in various colours although it is not posslble to vary the colour within one character array.
A display terminal for displaying the data has an image control unit which controls the display of the characters on the screen. The image control unit contains a character genërator which stores a predete~ined supply ! ~ of alphanumeric and graphic ~haracters. Using code words which are stored in a page store and whlch represent the addresses in the character generator, data words assigned to the image points of the characters or to the graphic elements are~read out fro~ the character generators and supplled to a visual display unit which contains the screen.
The properties o the displayed characters are determined by control signals which are likewise stored in the page store in the form of code words. The control signals indicate, for example, in which colour the characters are to ~e displayed, whether the characters are to be displayed in flashing form, non-flashing form, of normal height or of double height. When the ~haracters and control signals are coded in serial fashion, each position on the screen assigned a storage zone within the page store is provided with a code word. lf a storage zone stores a code word of a control signalJ generally no character is displayed at the corresponding position on the screen. The assignment of the code words to the ~ ~9571~
characters and to the control stgnals is known, in association with serial coding, for example from the magazine "Funkschau" (1977), Vol. 18, pages 78-82.
In the case of parallel coding the number of S binary characters of the code words asslgned to the display characters increases so that each character can be accompanied by a control signal by way of additional information. In this cas`e the gaps provided for the control signals are dispensed with and characters can be displayed 10 ' at all positions of the screen. It is also possible to combine the parallel coding with the serial coding.
Since the control signals are not displayed and thus in the case of serial coding cannot be distinguished on the screen from tha "interspace" signal, when a screen content (page) is set up or changed it is not possible readily to recognise the pcsitions o control signals which have already been input.
It would be conceivable, following the actuation of an appropriate key on a keyboard provided for the setting up or processing of the screen contents, to display a special symbol, for example the write mark, at all positions at which control signals are stored. However, if a plurality of differen~ control signals are stored consecutively, it would not be possible to recognise the position of a specific control signal in order r for example, to change only this signal.
It is already known to dlsplay a text character-~ _ ~57~
ising a control signal in an additional display row at the lower edge of the screen whenever the write mark ls positioned on the screen in a position which is assigned a control signal. In this way it is possible to recognise the posltion of a control signal which is to be changed.
If, however, the control signal is actuated at another pos * lon, th$s contxol signal must firstly bè found by ~ means of the write mark. In addition a relati~ely large - outlay is required since the additional display r~w must be represented on the screen.
It is an aim of the invention to provide apparatus by means of `which, in a simple f ashion and at a high speed, it ls possible to determine the position assigned to a specific control signal on the screen of a lS visual display unit.
According to this invention there is provldPd -) apparatus for producing a dlsplay of data on the screen of a visual display unit, said apparatus comprising a page store for storing cod~ words representing alphanumeric and/or graphic characters for display, and control signals for determining the properties of the character display, a keyboard by means of which the appropriate code words and control signals assigned to the characters and their display can be input into the page store, an image control unit having a character generator and arranged for controll-ing character display, the keyboard haviny a key assigned to a predetermined control signal and arranged, when ~L~9S78l~
actuated, to cause a display signal for supply to the screen to include a portion representing a symbol corre-sponding to said predetermined control signal such that said symbol will appear at a position on the screen corresponding to the position of the predetermined control signal in the data signal stored in the page store.
, Preferably following a further ac~ùation of the ,; key, said display signal is arranged so as to display the symhol in the next following position on the screen assigned to the predetermined control slgnal.It can even be arranged that following the actuation of a key of the keyboard the display signal is arranged so as to display the symbol at all the positions on the screen assigned to the predetermined control signal.
Convenlently it may be arranged that the write mark is provided as the special symbol and.possibly that -) the display signal is arranged so that slmultaneously to the display of the symbol on the screen, a text character-ising the control signal is shown in an additional display row.
Advantageously it may be that the display signal is arranged so that during the display of the symbol display of the alphanumeric and/or graphic characters is blocked.
In one particular embodiment a switching stage is provided which is arranged to be supplied by the keyboard with the code word assigned to the relevant control signal, whlch is arranged to compare the code word with code words stored in the page store and to supply the image control unit with signals for triggering the display of the symbol on the screen when the comparison establishes the identity of the code word read out from the page store with the code ~ word assigned to the predetermined control signal and :`¦ inp~t by means of the keyboard. ~he swi~ching stage includes a clock pulse generator which is arranged to generate clock pulses wlth which the display of the symbol can be advanced across the screen, and which can be blocked by a signal produced when the comparison indicates that the code word read out from the pagè store is identical to the keyboard-input code word. A further character generator is arranged to store data words w'nich are assigned to sy~bols repre-lS senting the control signals, and which are arranged to be read out when a code word read out from-the page store is ~~ identical to ~he keyboard-input code word.
Embodiments of this invention will now be described, by way of example, with reference to the accompanying drawings in which:-Fig. 1 is a schematic illustration of a first example of an extract from a display row on a screen of a visual display unit and possible correspondlng storage zones in a page store of apparatus ~or producing a data display and embodying this invention;
Fig. 2 is a schematic illustration of a second - exaMple of an extract from a display row on a visual display ~s~
unit screen and possible corresponding storage zones in the page store;
Fig. 3 ls a schematic illustration of extracts from possible forms of display row on the screen;
Fig. 4 is a block clrcuit diagram of a data ~ display termlnal incorporating data display apparatus ¦ embadying th~s ~nvention; ~nd Fig- S is a block circuit diagram of a switching stage of the display terminal shown in Fig. 4.
Referring to Fig. 1, in a display row repre~ented at a it has been assumed that alphanumerical characters ~ABC" are represented in red and flashing form, whereas a graphic character G is represented ln green and flashing form. The correspondlng coaP words for the alphanumerical' characters "ABC" and the graphic character G and associated control signals'are xepresented at b as being a portion from a storage ~one. The ccde words are stored in binary coded fashion, but for reasons of clarity they are represen-ted by mnemo-technical abbreviations or by graphic representations. Following a code word for the "interspace"
signal, one code word for the control signal "~ red"
talphanumerical character red) and one fo'r "Bl on"
(flashing) are stored in the page store. Following two further code words for the "interspace" signal, follow the code words for the alphanumerical characters "ABC". There then follow the code words for the "interspace" signal, . --t~
the control signals "Gr gn" (graphlc character green) and "sep Gr" tpunctiform graphic character, separated graphics) and ~r the graphic character G. The control signals "a red" and "Bl on" prod-~ce flashing representation of the alphanumerical characters "ABC" in red. Similarly the control signals "Gr gn" and "sep Gr" produce the j representation of the graphic character G in"green and (~ with punctiform elem~ts.
' The same reprasentation on the screen is also 10 achieved if, as shown at c in Fig. 1, the control signal n sep Gr" is arranged preceding the alphanumerical characters "ABCn. In either case it is put into effect at the position at which the graphic character G is represented. In the eveAt of representation on the screen in accordance with 15 the display xow a, it is not possible to recognise where and in which sequence the individual control signals are arranged so that correction or updating o~ the display row ~.
is not readily possible.
Referring to Fig. 2, it has been assumed that 20 the alphanumerical characters "ABC" are not to be repre sented in flashing form, and that, as illustrated at a, the graphic character G is to be represented ln block elements and no longer in punctiform elements. The change can be effected in that, as illustrated at b, preceding 25 the alphanumerical characters "ABC" the control signal r'Bl off" (non flashing) is inserted and prec~ding the graphic character G the control signals "con Gr" (block ~1~57'~8 graphic character, contiguous graphics) and "Bl on"
are inserted. Howe~er if the positions of the individual control signals are known, it is possible to achieve the same result by erasing the control signals "Bl on" and "sep Gr" and inserting the control slgnal "Bl on" prior to the graphic character G.
In order to be able to amend the s~tore contents represented in Fig. 1 under c lnto the store contants represented in Fig. 2 under c it is necessaxy to determine the position of the control signal UBl on". On the keyboard a key is actuated which is assigned to this contxol signal.
When the store is read out for display on the screen, it is checked whèther the appropriate code word is contained in the page store. If ~his is so, a special symbol, for example the write mar~, ls represented at the appropriate position, as illustrated in Fig. 3 at a. As several such - control signals exist, it is now possible, following a fuxther actuation of the same key, to display the following identical control signal while the display of the previously displayed control signal can be maintained. It is also possible to provide, following actuation of an appropriate key, simultaneous display of all those positions on the screen which are assigned to this specific control signal.
In the first case where the special symbol marking a position of the control signal represents the write mark, the "interspace" key can be actuated 80 that ~9S~
the control signal "Bl on" is erased. In the other cases the write mark for the erasure must be brought to the appropriate posltion.
It ls also possible to dlsplay one or n!ore than one alphanumerical character as the special symbol. For example, as illustrated at b in Fig. 3, the control signal i "Bl on" can be repxesented by the alphanumer~-cal character i (~, "H" in a simple fashion since the last six binary characters agree in both code words. In order to be able to distinguish ' this alphanumerical character used as a special symbol from the conventional alphanumerlcal characters, it is possible to represent it in inverse form, i.e. by exchanging back-ground and foreground colours, or in underlined form.
It is further possible, as illustrated at c in Fig. 3, to use a symbol which represents a mnemo technical abbreviation o~ the function of the control signal as the special symbol. However for this purpose it is ~ necessary to provide a further character generator which contains data words assigned to the forms oi these symbols.
This character generator can nat~rally form part o~ the character generator contained in the display device. In addition ik is possible to represent the special symbol in accordance with its function. For example the control signal "Bl on" can be used in flashing form as the special symbol.
During the representation of the special symbols, as illustrated at c in Fig. 3, display of the characters ~9~
can be blocked or else, as illustrated at a and b in Fig.
3, the special symhols can be shown in addition to the characters.
The display terminal which is illustrated in Fig. 4 and which is provided for the telecommunications service "screen text" is connected via a modem M to a telephone line: F. The modem M is connected i~known manner to a telephone FA. With the aid of the display terminal on the one hand it is possible to call up information from ' a central unit via the line F, and to represent this information on a screen BS forming part of a display unit ~E. On the other hand it is also possible to construct o~r correct screen contents by means of a keyboard TA and to transmit these screen contents to the central unit via the tr~nk line F. Fuxther screen contents can be intermed-iately stored in a peripheral s~ore PS.
The display terr.~inal contains a control unit ST
~ which controls the time flcw and normally contains a microprocessor. The keyboard TA is connected to the control unit ST. In addition the display terminal contains a page store SP which stores the code words CW of at least one screen content - i.e. one page. The page store SP is followed by an image control unit BST which, in dependence upon the content of the page store, emits video signals to a d$splay unit AE provided with the screen BS. The image control unit BST contains a character generator Z
which is addressed by the code words CW and which contains 7~
data words assigned to the forms of the alphanumerical or graphic characters which are to be repxesented. The display termlnal further contains a switching stage S by means ~f which it is possible to display specific control signals on the screen sS. Further details of the display terminal shown in Fig. 4 will be described below in conjunction with the block circuit diagram of~the switching (~ stage S as provide~ by Fig. 5.
In the operation of the sw~tching stage illustrated in Fig. 5 it has been assumed that the write mark is provided as the special s~mbol. Switch SW1 normally occupies the solid-line position, and by the use of signals Sl which are switched through to the control unit ST as signals S2 the write mark is normally moved via the keyboard~
In the case of display of the control signals the switch SWl occupies the broken-line position. Following the actuation of the key assigned to a specific controi signal on the keyboard TA, the latter on the one hand emits the code word CWl which represents the control signal to a code word store CS and on the other hand emits a start signal S3 to a clock pulse generator TG. The clock pulse generator TG noT~ emits signals S4 by which the movement of the wrlte mark is controlled.
In the case of the display of the control signals, the switch SW2 is closed and the page store SP is read out in synchronism with the movement of the write mark. The code words CW are supplied to a comparator VG. When a code ~ ~357~
word C~ is identical to a stored code word CWl, the comparator VG emits a signal S5 which ~locks the clock pulse generator TG and consequently hold~ the write mark at the correspondlng positlon. The position which is assigned to the control signal is marked in this way~ .
Following the reactuatlon of the key, with the aid of the slgnal S3 the clock pulse generator TG is ag~ain started 1 ( ~ and the write mark is moved over the screen BS until the ! comparator VG again emits a signal S5 and again blocks ~ the clock pulse generator TG. In this way it is possible to search the entire page store SP for a specific control signal by mu~tiple actuation of the key.
If, as the special symbol, characters represent-ing a mnemo-technical abbreviation of the control signal are to be represented at the appropriate positions on the screen BS, or if a text characterising the control slgnal is to be represented in an additional display row on the ~--' screen BS, a further character generator Zl can be provided which stores the appropriat~ data words. The signal S5 and the code word CWl are then conducted to this character generator Zl and the latter emits the appropriate data words by way of signals S6 to the image control unit BST.
If all the positions on tha screen BS which are assigned to a specific control signal are to be displayed, the data words of the special symbol are s~ored under that address within the character generator Z that corresponds to the particular code word CWl.
When the comparator VG establishes the identity of the input code word CWl with the read out code word CW, the appropriate special symbol is displayed on the screen BS. In this case the clock pulse generator TG is 5 not needed and ~he signal S5 can be directly conducted to the image control unit BST.
l - By means of the emboaiments descr~bed above it i o is also possible to characterise not only the control signals but also those positions on the screen BS at which 10 ~ graphic patterns are represented in punctlform fashion in the same arrangement as the alphanumerical characters. These graphic patterns are normally stored in a write/read store from where they are c~lled up under predetermined addresses (DRCS, dynamically rede~inable character set). The addresses of these pattexns are then stored at the corresponding positions in the page store. If these addresses are called up by the keyboard those positions are shown on the screen ~--J BS at which the corresponding graphic patterns are to be displayed.
The appara~us described ~bove has the advantage that the setting up, the correction and the updating of a screen content can be carried out in a simple fashion and at a very high speed since the position on the screen assigned to a specific control signal is directly displayed.
The invention relates to apparatus for producing a display of data on the screen of a visual display unit particularly in a data display terminal of a data transmission system in which a cen~ral unit is connected via a transmission line to the terminal.
In the telecommunications service "screen text"
(video-tex-interactive) it is possible to caU up lnformatlon stored in a central unit via,a telephone line and using a television set as visual display unit. The 10 ' information is displayed on the screen of the television set. Alphanumerical characters and/or patterns composed of graphic characters can be displayed.
Editing devices by means of which inforrnation is prepared in the orm of screen contents are available to those responsible for presenting inforrnation. The screen contents are subsequently transmitted to the central unit whereupon they can be called up by the subscribers.
-- One screen content is referred to as a page~
The page contains for example 960 character arrays which are arranged in 24 rows each containing 40 character arrays.
In the event of the display of alphanumeric characters one character is displayed in each character array. The character array consists for example of 8x10 or 8x12 image points by means of which the individual characters are displayed. The graphic patterns are displayed such that each character array contains one graphic character which is composed of 2x3 graphic elements. The graphic patterns ~' ~1~5~
are constructed from combinations of light and dark graphic elements in various colours although it is not posslble to vary the colour within one character array.
A display terminal for displaying the data has an image control unit which controls the display of the characters on the screen. The image control unit contains a character genërator which stores a predete~ined supply ! ~ of alphanumeric and graphic ~haracters. Using code words which are stored in a page store and whlch represent the addresses in the character generator, data words assigned to the image points of the characters or to the graphic elements are~read out fro~ the character generators and supplled to a visual display unit which contains the screen.
The properties o the displayed characters are determined by control signals which are likewise stored in the page store in the form of code words. The control signals indicate, for example, in which colour the characters are to ~e displayed, whether the characters are to be displayed in flashing form, non-flashing form, of normal height or of double height. When the ~haracters and control signals are coded in serial fashion, each position on the screen assigned a storage zone within the page store is provided with a code word. lf a storage zone stores a code word of a control signalJ generally no character is displayed at the corresponding position on the screen. The assignment of the code words to the ~ ~9571~
characters and to the control stgnals is known, in association with serial coding, for example from the magazine "Funkschau" (1977), Vol. 18, pages 78-82.
In the case of parallel coding the number of S binary characters of the code words asslgned to the display characters increases so that each character can be accompanied by a control signal by way of additional information. In this cas`e the gaps provided for the control signals are dispensed with and characters can be displayed 10 ' at all positions of the screen. It is also possible to combine the parallel coding with the serial coding.
Since the control signals are not displayed and thus in the case of serial coding cannot be distinguished on the screen from tha "interspace" signal, when a screen content (page) is set up or changed it is not possible readily to recognise the pcsitions o control signals which have already been input.
It would be conceivable, following the actuation of an appropriate key on a keyboard provided for the setting up or processing of the screen contents, to display a special symbol, for example the write mark, at all positions at which control signals are stored. However, if a plurality of differen~ control signals are stored consecutively, it would not be possible to recognise the position of a specific control signal in order r for example, to change only this signal.
It is already known to dlsplay a text character-~ _ ~57~
ising a control signal in an additional display row at the lower edge of the screen whenever the write mark ls positioned on the screen in a position which is assigned a control signal. In this way it is possible to recognise the posltion of a control signal which is to be changed.
If, however, the control signal is actuated at another pos * lon, th$s contxol signal must firstly bè found by ~ means of the write mark. In addition a relati~ely large - outlay is required since the additional display r~w must be represented on the screen.
It is an aim of the invention to provide apparatus by means of `which, in a simple f ashion and at a high speed, it ls possible to determine the position assigned to a specific control signal on the screen of a lS visual display unit.
According to this invention there is provldPd -) apparatus for producing a dlsplay of data on the screen of a visual display unit, said apparatus comprising a page store for storing cod~ words representing alphanumeric and/or graphic characters for display, and control signals for determining the properties of the character display, a keyboard by means of which the appropriate code words and control signals assigned to the characters and their display can be input into the page store, an image control unit having a character generator and arranged for controll-ing character display, the keyboard haviny a key assigned to a predetermined control signal and arranged, when ~L~9S78l~
actuated, to cause a display signal for supply to the screen to include a portion representing a symbol corre-sponding to said predetermined control signal such that said symbol will appear at a position on the screen corresponding to the position of the predetermined control signal in the data signal stored in the page store.
, Preferably following a further ac~ùation of the ,; key, said display signal is arranged so as to display the symhol in the next following position on the screen assigned to the predetermined control slgnal.It can even be arranged that following the actuation of a key of the keyboard the display signal is arranged so as to display the symbol at all the positions on the screen assigned to the predetermined control signal.
Convenlently it may be arranged that the write mark is provided as the special symbol and.possibly that -) the display signal is arranged so that slmultaneously to the display of the symbol on the screen, a text character-ising the control signal is shown in an additional display row.
Advantageously it may be that the display signal is arranged so that during the display of the symbol display of the alphanumeric and/or graphic characters is blocked.
In one particular embodiment a switching stage is provided which is arranged to be supplied by the keyboard with the code word assigned to the relevant control signal, whlch is arranged to compare the code word with code words stored in the page store and to supply the image control unit with signals for triggering the display of the symbol on the screen when the comparison establishes the identity of the code word read out from the page store with the code ~ word assigned to the predetermined control signal and :`¦ inp~t by means of the keyboard. ~he swi~ching stage includes a clock pulse generator which is arranged to generate clock pulses wlth which the display of the symbol can be advanced across the screen, and which can be blocked by a signal produced when the comparison indicates that the code word read out from the pagè store is identical to the keyboard-input code word. A further character generator is arranged to store data words w'nich are assigned to sy~bols repre-lS senting the control signals, and which are arranged to be read out when a code word read out from-the page store is ~~ identical to ~he keyboard-input code word.
Embodiments of this invention will now be described, by way of example, with reference to the accompanying drawings in which:-Fig. 1 is a schematic illustration of a first example of an extract from a display row on a screen of a visual display unit and possible correspondlng storage zones in a page store of apparatus ~or producing a data display and embodying this invention;
Fig. 2 is a schematic illustration of a second - exaMple of an extract from a display row on a visual display ~s~
unit screen and possible corresponding storage zones in the page store;
Fig. 3 ls a schematic illustration of extracts from possible forms of display row on the screen;
Fig. 4 is a block clrcuit diagram of a data ~ display termlnal incorporating data display apparatus ¦ embadying th~s ~nvention; ~nd Fig- S is a block circuit diagram of a switching stage of the display terminal shown in Fig. 4.
Referring to Fig. 1, in a display row repre~ented at a it has been assumed that alphanumerical characters ~ABC" are represented in red and flashing form, whereas a graphic character G is represented ln green and flashing form. The correspondlng coaP words for the alphanumerical' characters "ABC" and the graphic character G and associated control signals'are xepresented at b as being a portion from a storage ~one. The ccde words are stored in binary coded fashion, but for reasons of clarity they are represen-ted by mnemo-technical abbreviations or by graphic representations. Following a code word for the "interspace"
signal, one code word for the control signal "~ red"
talphanumerical character red) and one fo'r "Bl on"
(flashing) are stored in the page store. Following two further code words for the "interspace" signal, follow the code words for the alphanumerical characters "ABC". There then follow the code words for the "interspace" signal, . --t~
the control signals "Gr gn" (graphlc character green) and "sep Gr" tpunctiform graphic character, separated graphics) and ~r the graphic character G. The control signals "a red" and "Bl on" prod-~ce flashing representation of the alphanumerical characters "ABC" in red. Similarly the control signals "Gr gn" and "sep Gr" produce the j representation of the graphic character G in"green and (~ with punctiform elem~ts.
' The same reprasentation on the screen is also 10 achieved if, as shown at c in Fig. 1, the control signal n sep Gr" is arranged preceding the alphanumerical characters "ABCn. In either case it is put into effect at the position at which the graphic character G is represented. In the eveAt of representation on the screen in accordance with 15 the display xow a, it is not possible to recognise where and in which sequence the individual control signals are arranged so that correction or updating o~ the display row ~.
is not readily possible.
Referring to Fig. 2, it has been assumed that 20 the alphanumerical characters "ABC" are not to be repre sented in flashing form, and that, as illustrated at a, the graphic character G is to be represented ln block elements and no longer in punctiform elements. The change can be effected in that, as illustrated at b, preceding 25 the alphanumerical characters "ABC" the control signal r'Bl off" (non flashing) is inserted and prec~ding the graphic character G the control signals "con Gr" (block ~1~57'~8 graphic character, contiguous graphics) and "Bl on"
are inserted. Howe~er if the positions of the individual control signals are known, it is possible to achieve the same result by erasing the control signals "Bl on" and "sep Gr" and inserting the control slgnal "Bl on" prior to the graphic character G.
In order to be able to amend the s~tore contents represented in Fig. 1 under c lnto the store contants represented in Fig. 2 under c it is necessaxy to determine the position of the control signal UBl on". On the keyboard a key is actuated which is assigned to this contxol signal.
When the store is read out for display on the screen, it is checked whèther the appropriate code word is contained in the page store. If ~his is so, a special symbol, for example the write mar~, ls represented at the appropriate position, as illustrated in Fig. 3 at a. As several such - control signals exist, it is now possible, following a fuxther actuation of the same key, to display the following identical control signal while the display of the previously displayed control signal can be maintained. It is also possible to provide, following actuation of an appropriate key, simultaneous display of all those positions on the screen which are assigned to this specific control signal.
In the first case where the special symbol marking a position of the control signal represents the write mark, the "interspace" key can be actuated 80 that ~9S~
the control signal "Bl on" is erased. In the other cases the write mark for the erasure must be brought to the appropriate posltion.
It ls also possible to dlsplay one or n!ore than one alphanumerical character as the special symbol. For example, as illustrated at b in Fig. 3, the control signal i "Bl on" can be repxesented by the alphanumer~-cal character i (~, "H" in a simple fashion since the last six binary characters agree in both code words. In order to be able to distinguish ' this alphanumerical character used as a special symbol from the conventional alphanumerlcal characters, it is possible to represent it in inverse form, i.e. by exchanging back-ground and foreground colours, or in underlined form.
It is further possible, as illustrated at c in Fig. 3, to use a symbol which represents a mnemo technical abbreviation o~ the function of the control signal as the special symbol. However for this purpose it is ~ necessary to provide a further character generator which contains data words assigned to the forms oi these symbols.
This character generator can nat~rally form part o~ the character generator contained in the display device. In addition ik is possible to represent the special symbol in accordance with its function. For example the control signal "Bl on" can be used in flashing form as the special symbol.
During the representation of the special symbols, as illustrated at c in Fig. 3, display of the characters ~9~
can be blocked or else, as illustrated at a and b in Fig.
3, the special symhols can be shown in addition to the characters.
The display terminal which is illustrated in Fig. 4 and which is provided for the telecommunications service "screen text" is connected via a modem M to a telephone line: F. The modem M is connected i~known manner to a telephone FA. With the aid of the display terminal on the one hand it is possible to call up information from ' a central unit via the line F, and to represent this information on a screen BS forming part of a display unit ~E. On the other hand it is also possible to construct o~r correct screen contents by means of a keyboard TA and to transmit these screen contents to the central unit via the tr~nk line F. Fuxther screen contents can be intermed-iately stored in a peripheral s~ore PS.
The display terr.~inal contains a control unit ST
~ which controls the time flcw and normally contains a microprocessor. The keyboard TA is connected to the control unit ST. In addition the display terminal contains a page store SP which stores the code words CW of at least one screen content - i.e. one page. The page store SP is followed by an image control unit BST which, in dependence upon the content of the page store, emits video signals to a d$splay unit AE provided with the screen BS. The image control unit BST contains a character generator Z
which is addressed by the code words CW and which contains 7~
data words assigned to the forms of the alphanumerical or graphic characters which are to be repxesented. The display termlnal further contains a switching stage S by means ~f which it is possible to display specific control signals on the screen sS. Further details of the display terminal shown in Fig. 4 will be described below in conjunction with the block circuit diagram of~the switching (~ stage S as provide~ by Fig. 5.
In the operation of the sw~tching stage illustrated in Fig. 5 it has been assumed that the write mark is provided as the special s~mbol. Switch SW1 normally occupies the solid-line position, and by the use of signals Sl which are switched through to the control unit ST as signals S2 the write mark is normally moved via the keyboard~
In the case of display of the control signals the switch SWl occupies the broken-line position. Following the actuation of the key assigned to a specific controi signal on the keyboard TA, the latter on the one hand emits the code word CWl which represents the control signal to a code word store CS and on the other hand emits a start signal S3 to a clock pulse generator TG. The clock pulse generator TG noT~ emits signals S4 by which the movement of the wrlte mark is controlled.
In the case of the display of the control signals, the switch SW2 is closed and the page store SP is read out in synchronism with the movement of the write mark. The code words CW are supplied to a comparator VG. When a code ~ ~357~
word C~ is identical to a stored code word CWl, the comparator VG emits a signal S5 which ~locks the clock pulse generator TG and consequently hold~ the write mark at the correspondlng positlon. The position which is assigned to the control signal is marked in this way~ .
Following the reactuatlon of the key, with the aid of the slgnal S3 the clock pulse generator TG is ag~ain started 1 ( ~ and the write mark is moved over the screen BS until the ! comparator VG again emits a signal S5 and again blocks ~ the clock pulse generator TG. In this way it is possible to search the entire page store SP for a specific control signal by mu~tiple actuation of the key.
If, as the special symbol, characters represent-ing a mnemo-technical abbreviation of the control signal are to be represented at the appropriate positions on the screen BS, or if a text characterising the control slgnal is to be represented in an additional display row on the ~--' screen BS, a further character generator Zl can be provided which stores the appropriat~ data words. The signal S5 and the code word CWl are then conducted to this character generator Zl and the latter emits the appropriate data words by way of signals S6 to the image control unit BST.
If all the positions on tha screen BS which are assigned to a specific control signal are to be displayed, the data words of the special symbol are s~ored under that address within the character generator Z that corresponds to the particular code word CWl.
When the comparator VG establishes the identity of the input code word CWl with the read out code word CW, the appropriate special symbol is displayed on the screen BS. In this case the clock pulse generator TG is 5 not needed and ~he signal S5 can be directly conducted to the image control unit BST.
l - By means of the emboaiments descr~bed above it i o is also possible to characterise not only the control signals but also those positions on the screen BS at which 10 ~ graphic patterns are represented in punctlform fashion in the same arrangement as the alphanumerical characters. These graphic patterns are normally stored in a write/read store from where they are c~lled up under predetermined addresses (DRCS, dynamically rede~inable character set). The addresses of these pattexns are then stored at the corresponding positions in the page store. If these addresses are called up by the keyboard those positions are shown on the screen ~--J BS at which the corresponding graphic patterns are to be displayed.
The appara~us described ~bove has the advantage that the setting up, the correction and the updating of a screen content can be carried out in a simple fashion and at a very high speed since the position on the screen assigned to a specific control signal is directly displayed.
Claims (12)
1. Apparatus for producing a display of data on the screen of a visual display unit, said apparatus comprising a page store for storing code words representing alpha-numeric and/or graphic characters for display and control signals for determining the properties of the character display, a keyboard by means of which the appropriate code words and control signals assigned to the characters and their display can be input into the page store, an image control unit having a character generator and arranged for controlling character display, the keyboard having a key assigned to a predetermined control signal and arranged, when actuated, to cause a display signal for supply to the screen to include a portion representing a symbol corre-sponding to said predetermined control signal such that said symbol will appear at a position on the screen corre-sponding to the position of the predetermined control signal in the data signal stored in the page store.
2. Apparatus as claimed in claim 1, wherein following a further actuation of the key, said display signal is arranged so as to display the symbol in the next following position on the screen assigned to the predetermined control signal.
3. Apparatus as claimed in claim 1 or claim 2, wherein following the actuation of a key of the keyboard the display signal is arranged so as to display the symbol at all the positions on the screen assigned to the predetermined control signal.
4. Apparatus as claimed in claim 1 wherein the write mark is provided as the special symbol.
5. Apparatus as claimed in claim 1 wherein the display signal is arranged so that simultaneously to the display of the symbol on the screen, a text characterising the control signal is shown in an additional display row.
6. Apparatus as claimed in claim 1 wherein the display signal is arranged so that during the display of the symbol display the alphanumerical and/or graphic characters is blocked.
7. Apparatus as claimed in claim 1 wherein a switching stage is provided, which switching stage is arranged to be supplied by the keyboard with the code word assigned to the relevant control signal, to compare the code word with code words stored in the page store, and to supply the image control unit with signals for triggering the display of the symbol on the screen when the comparison establishes the identity of the code word read out from the page store with the code word assigned to the predetermined control signal and input by means of the keyboard.
8. Apparatus as claimed in claim 7 wherein the switching stage includes a clock pulse generator arranged to generate clock pulses with which the display of the symbol can be ad-vanced across the screen, and which clock pulses can be blocked by a signal produced when the comparison indicates that the code word read out from the page store is identical to the keyboard-input code word.
9. Apparatus as claimed in claim 7 or claim 8, wherein a further character generator is arranged to store data words assigned to symbols representing the control signals, and which data words are arranged to be read out when a code word read out from the page store is identical to the keyboard-input code word.
10. Apparatus as claimed in claim 1 wherein a visual display unit is arranged to receive the display signal.
11. A data display terminal including apparatus according to claim 1 and a modem for connection to a data transmission line.
12. A data transmission system comprising a central unit connected via a transmission line to a data display terminal according to claim 1.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE3104639A DE3104639C2 (en) | 1981-02-10 | 1981-02-10 | Circuit arrangement for displaying control characters on a screen of a display device |
| DEP3104639.8 | 1981-02-10 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1195788A true CA1195788A (en) | 1985-10-22 |
Family
ID=6124464
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000395759A Expired CA1195788A (en) | 1981-02-10 | 1982-02-08 | Apparatus for producing a display of data on the screen of a visual display unit |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0057750B1 (en) |
| AT (1) | ATE18820T1 (en) |
| CA (1) | CA1195788A (en) |
| DE (1) | DE3104639C2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3244115C2 (en) * | 1982-11-29 | 1987-01-22 | Siemens AG, 1000 Berlin und 8000 München | Method for displaying control characters on a display unit of a text station |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5027332B1 (en) * | 1969-10-08 | 1975-09-06 | ||
| DE2114665B2 (en) * | 1971-03-26 | 1973-03-15 | Licentia Patent Verwaltungs GmbH, 6000 Frankfurt | CIRCUIT ARRANGEMENT FOR A DISPLAY DEVICE WORKING IN VIDEO LINE MODE, CONTROLLED BY DIGITAL CODES |
| DE2636788C3 (en) * | 1976-08-16 | 1980-01-31 | Siemens Ag, 1000 Berlin Und 8000 Muenchen | Data storage for data display devices |
-
1981
- 1981-02-10 DE DE3104639A patent/DE3104639C2/en not_active Expired
- 1981-10-13 AT AT81108293T patent/ATE18820T1/en not_active IP Right Cessation
- 1981-10-13 EP EP81108293A patent/EP0057750B1/en not_active Expired
-
1982
- 1982-02-08 CA CA000395759A patent/CA1195788A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| EP0057750B1 (en) | 1986-03-26 |
| EP0057750A3 (en) | 1982-09-08 |
| ATE18820T1 (en) | 1986-04-15 |
| EP0057750A2 (en) | 1982-08-18 |
| DE3104639C2 (en) | 1986-05-28 |
| DE3104639A1 (en) | 1982-09-09 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |