U.S. patent number 3,750,135 [Application Number 05/189,496] was granted by the patent office on 1973-07-31 for low resolution graphics for crt displays.
This patent grant is currently assigned to Lektromedia Ltd.. Invention is credited to Peter M. Carey, Owen L. Holmwood.
United States Patent |
3,750,135 |
Carey , et al. |
July 31, 1973 |
LOW RESOLUTION GRAPHICS FOR CRT DISPLAYS
Abstract
A system for generating and displaying graphical information for
interactive computer display terminals using graphic display
mediums employing a raster pattern, such as a cathode ray tube. The
system uses programmable character elements for constructing
graphic characters in such manner that they are highly adaptable
for display by conventional television monitors. Each graphic
character is constructed by the character elements in an individual
cell pattern and a plurality of these adjacently located cell
patterns render a continuous graphic diagram. All of the cells
which make up the graphic diagram are of the same size and
typically eight dots by twelve dots and a plurality of graphic
element or font types may be used in these cells to generate the
various graphic characters. One form of traphic element cell
pattern generates the graphic characters in individual cells by
means of a plural-point pattern and preferably a six-point pattern
and in another form the graphic elements generates the graphic
character by means of a plural-bar pattern and preferably a
four-bar pattern. The system includes a mimic style keyboard along
with cursor controls which are used to create the continuous
graphic diagram. An eight bit word representing each character is
loaded into a buffer or scanned storage and after a complete
diagram has been composed a page representing this diagram may then
be loaded into a permanent storage. The system is operable in an
origination mode, a storage mode, a presentation mode and a
modification mode. A unique programmable read-only memory and
associated logic including a unique gating structure permits the
display of alpha-numeric data generated at an alpha-numeric
keyboard, along with the display of the above mentioned graphic
character patterns.
Inventors: |
Carey; Peter M. (Beaconsfield,
Quebec, CA), Holmwood; Owen L. (Montreal, Quebec,
CA) |
Assignee: |
Lektromedia Ltd. (Montreal,
Quebec, CA)
|
Family
ID: |
22697579 |
Appl.
No.: |
05/189,496 |
Filed: |
October 15, 1971 |
Current U.S.
Class: |
345/471; 345/68;
348/552; 345/472 |
Current CPC
Class: |
G09G
5/222 (20130101) |
Current International
Class: |
G09G
5/22 (20060101); G06f 003/14 () |
Field of
Search: |
;340/324AD,154 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Trafton; David L.
Claims
We claim:
1. A system for generating graphic displays on the screen of a
monitor having a plurality of raster locations thereon and being
operable with a raster, said system comprising memory means,
control means operatively connected to said memory means for
controlling same, first pattern forming means including selected
locations in said memory means and operating in conjunction with
said control means for generating a first type of graphic character
elements combinable in a single raster location toform a graphic
character, first switch means operatively associated with said
first pattern forming means to select certain of the first type of
character elements in a desired arrangement and combined to form a
first graphic character in a raster location, second pattern
forming means including other selected locations in said memory
means and operating in comprising memory means, control means with
said control means for generating a second type of character
elements combinable in a single raster location to form a graphic
character, said second type of graphic character elements differing
in appearance with respect to said first type of graphic character
elements, second switch means operatively associated with said
second pattern forming means to select certain of the second type
of character elements in a desired arrangement and combined to form
a second graphic character in another raster location, means
operatively associated with said first switch means and second
switch means and said first and second pattern forming means for
generating a signal permitting selective generation of either said
first type of graphic character elements or second type of graphic
character elements, and cursor means to position the various
graphic characters formed from said types of character elements in
a desired arrangement to form a graphic display.
2. The system for generating graphic displays of claim 1 further
characterized in that the first pattern forming means generates
bar-type character elements, and that said second pattern forming
means generates point-type character elements.
3. The system for generating graphic displays of claim 1 further
characterized in that the first pattern forming means generates
bar-type character elements and that a maximum of four of such
bar-type elements constitutes the graphic character in any one
raster location, and said second pattern forming means generates
point-type character elements and that a maximum of six of such
point-type elements constitutes the graphic character in any one
raster location.
4. The system for generating graphic displays of claim 1 further
characterized in that means is provided for adding alpha-numeric
characters to the graphic displays in order to generate a composite
informational display of graphic characters and alpha-numeric
characters.
5. A method for generating graphic-type displays on the screen of a
monitor operable with a raster, said method comprising establishing
a plurality of raster locations of predetermined font size on the
screen associated with the monitor, generating and introducing
first input signals to a memory, generating a first type of
character elements from said first input signals and which are
combinable to form graphic characters of said predetermined font
size in certain of said raster locations, generating and
introducing second input signals to said memory, generating a
second type of graphic character elements from said second input
signals which are distinct from said first type of character
elements and combinable to form graphic characters of said
predetermined font size in certain other of said raster locations,
generating a characterization signal which characterizes either the
first type of graphic character elements or the second type of
graphic character elements for each particular raster location,
transmitting the characterization signal to said memory and
selecting the proper types of character elements for each raster
location therefrom, and positioning the graphic characters formed
in said raster locations in a desired arrangement to form a graphic
display.
6. The method of claim 5 futher characterized in that the first
type of character elements are bar-type character elements and that
the second type of character elements are point-type character
elements.
7. The method of claim 5 further characterized in that the first
type of character elements are bar character elements and that a
maximum of four bars can exist in any one raster location, and that
said second type of character elements are points and that a
maximum of six points can exist in any one raster location.
8. The method of claim 5 further characterized in that each graphic
character is stored, processed and transmitted as an eight-bit data
word.
9. The method of claim 5 further characterized in that
alpha-numeric characters are generated and displayed along with the
graphic characters.
10. A display system for interactive computer display terminals,
said system comprising a first input means capable of generating a
multi-bit binary graphic word, said first input means comprising
first selection means enabling generation of a first type of
graphic character elements and second selection means enabling
generation of a second type of graphic character elements,
characterization means also operatively associated with said first
input means to generate a first characterization element comprised
of at least one bit to distinguish between said first and second
types of graphic character elements, each of said first type and
each of said second type of graphic character elements defined by
one binary word being combinable in a single raster location to
form a graphic character therein, second input means capable of
generating a multi-bit binary alpha-numeric data word, first
storage means operatively associated with said first input means to
receive certain bits of said multi-bit graphic word and said first
characterization element, second storage means operatively
associated with said second input means to receive certain bits of
said multi-bit alpha-numeric data word, means operatively
associated with said first and second input means to generate a
second characterization element to distinguish between said graphic
words and alpha-numeric data words, selector means operatively
connected to said first and second storage means to receive said
graphic words and alpha-numeric data words and said second
characterization element and select between alpha-numeric data
words and graphic words, and clocking means for clocking either
said graphic words or alpha-numeric data words to said monitor to
display characters defined by said words.
11. The system of claim 10 further characterized in that a main
register is operatively connected to said selector means to receive
either the graphic work or alpha-numeric data word selected by said
selector means, and said clocking clocking means is operable with
said main register to generate a video-signal from the word
received by said main register.
12. The system of claim 11 further characterized in that a mixer is
provided for receiving the video-signal and a television type input
signal and forming a signal complex therefrom for display through
said interactive computer display terminals.
13. The system of claim 10 further characterized in that the
display system for the interactive computer display terminals is a
monitor having a screen operable by a raster pattern.
14. The system of claim 10 further characterized in that the
display system for the interactive computer display terminals is a
television monitor.
15. The system of claim 11 further characterized in that said
clocking means is a column counter for determining a particular
column in a raster location, and that row counter means is
operatively associated with said first and second storage means for
determining the row location in any of the columns in said raster
location.
16. The system of claim 10 further characterized in that said first
storage means comprises a first memory and a first gating circuit
which are operatively connected to said selector means and said
second storage means comprises a second memory and a second gating
circuit which are operatively connected to said selector means.
17. The system of claim 16 further characterized in that said first
memory and said second memory are read-only memories.
18. The system of claim 10 further characterized in that said first
selection means comprises first switch-type means for generating
plural-bar character elements and said second selection means
comprises second switch-type means for generating plural-point
character elements.
19. Circuit active means for determining the coordinate positions
of two types of distinct character elements in a raster location on
a display screen and where said character elements are combinable
in a desired arrangement to form characters, said circuit active
means comprisng a receiving memory device for receiving a multi-bit
word defining the character elements and representing a character
comprised of said character elements, a gating matrix for receiving
certain of the bits of said multi-bit work defining the character
elements, a character generating memory device receiving another
bit from said multi-bit word characterizing the type of character
elements, first location counter means operatively connected to
said character generating memeory device and generating signals
representing a first coordinate axis location for said elements,
said last named signals being introducable into said gating matrix
for gating certain of the bits representing certain of the
character elements from said gating matrix, register means
operatively connected to said gating matrix on receiving the gated
bits, and second location counter means operatively connected to
said register means and being operable with the certain gated bits
to determine a second coordinate axis location which is relatively
perpendicular to said first axis location to thereby define the
coordinate positions of the character elements in said raster
location.
20. The circuit active means of claim 19 further characterized in
that said receiving memory device is a buffer memory and said
character generating memory device is a read-only memory unit.
21. The circuit active means of claim 19 further characterized in
that said receiving memory device is a buffer memory and said
character generating memory device is a programmable read-only
memory.
22. The circuit active means of claim 19 further characterized in
that a plurality of different types of character elements can be
used to generate the graphic characters and that the bit introduced
into said receiving memory device represents the type of character
elements introduced into said gating matrix.
23. The circuit active means of claim 19 further characterized in
that said characters are graphic characters and that a plurality of
different types of character elements can be used to generate
different graphic characters, one of said character element types
comprising a series of bar-lik elements and the other said
character element types comprising a series of point-like elements,
the bit of said multi-bit word introduced into said receiving
memory device characterizing between the point-like elements and
the bar-like elements.
24. A data output circuit for gating certain bits of multi-bit
words in response to a plurality of input signals and where certain
of the bits in certain of said multi-bit words represent
information bearing graphical elements and certain of the bits in
other of said multi-bit words represent an information bearing
alpha numeric element and a characterization bit in said multi-bit
words distinguishes between said two types of elements; said data
output circuit comprising a plurality of first gating members
receiving certain of the bits of multi-bit word, memory type signal
generating means receiving the characterization bit, a plurality of
second gating members also receiving certain of the bits of another
multi-bit word, second memory type signal generating means also
receiving said characterization bit, first clocking means for
generating first clock signals and introducing said first clock
signals into each said signal generating means, each said signal
generating means generating a plurality of input signals in
response to said clock signals upon receipt of a selected
characterization bit and introducing said input signals to said
gating members thereby gating certain of said bits from the gating
members which have received such bits in response to certain of the
input signals, register means for receiving said gated bits, and
second clocking means for introducing clocking signals into said
register means for transmitting said gated bits on a serial
basis.
25. The data output circuit of claim 24 further characterized in
that each said signal generating means is a read-only memory unit
and which memory unit comprises a decoding matrix and a word select
matrix.
26. The data output circuit of claim 24 further characterized in
that said gating members are NAND gates and includes a number of
NAND gates at least equivalent to the number of bits in said
multi-bit word representing the first type of elements.
27. The data output circuit of claim 24 further characterized in
that the input signals to said gating members are signals
designating a first coordinate location position and the clocking
signals generated by said second clocking means are signals
designating another coordinate location position.
28. The method of displaying graphical information along with
alpha-numeric information through computer interactive display
terminals and where the graphic information comprises at least two
types of character elements combinable to form at least two
different types of graphical characters, said method comprising
generating a multi-bit word representing each alpha-numeric
character, generating a multi-bit binary word of the same binary
length as the first named binary word and representing one of said
two types of graphical characters, generating a multi-bit binary
word of the same binary length as the first named binary word and
representing the other of said two types of graphical characters,
processing all of said multi-bit binary words in substantially the
same manner, and displaying the multi-bit words as graphical and
alpha-numeric characters on the display screen of a monitor.
29. The method of claim 28 further characterized in that each of
said multi-bit words comprise eight binary bits.
Description
BACKGROUND OF THE INVENTION
This invention relates in general to certain new and useful
improvements in the generation and display of information for
interactive computer display terminals, and more particularly, to
the generation and display of such information on graphic display
mediums which employ a raster pattern.
In recent years various systems relating to the generation and
displaying of graphical information for interactive computer
display terminals has been receiving increased prominence. There
have been a number of techniques developed for the display of
information stored in computer memory and information which is
introduced externally through an operator, such as by means of a
keyboard entry device. This data which may include alpha-numeric
information and/or other graphical information is then generated
and depicted on a display screen through an electron beam under
computer control.
Increased prominence in the use of computer interactive terminal
displays has resulted in large part from the high degree of
effectiveness achieved by pictorially displaying objects,
oftentimes along with alpha-numeric data, for a wide variety of
purposes. In many cases, pictorial displays are used for the
shaping or designing of computer control machine parts, the
production of intricate high resolution photographic masks or the
like. Computer interactive terminal displays are also used in the
solving of pictorial problems such as highway planning,
topographical mapping and other problems which are readily solved
through visual examination of a physical phenomena.
Computer interactive terminal displays are also used in gaining
insight into complex natural or mathematical phenomena through a
simulation of various types of physical situations in a computer
with attendant display devices to present the results of the
simulation. For example, an organic chemist desiring to synthesize
a particular molecule creates a picture of the molecule on the
display screen and then initiates a program by which the computer
presents a selection of simpler molecules from which the desired
substance can be synthesized. In like manner, these graphic
displays are also used in the study of blood flow, the study of
elementary particle interaction in electric fields and
determination of polls and zeros on a complex plane, etc.
In more recent times, computer displays employing cathode ray tube
display mechanisms have been used for educational purposes such as
in the training of pilots through simulating pilot practice
take-offs and landings and in other operations where an individual
may learn to control a manually operable mechanism through
simulation training. Widespread use has also been made of
closed-circuit television systems for the displaying of lectures,
along with pictorial illustrations of information written on
blackboards and the like.
Two broad classes of computer display systems are now in common
use, namely the calligraphic display and the raster pattern
displays. These systems are designed to reproduce and display
graphical symbology and pictures or parts thereof along with
alpha-numeric data through computer interactive display terminals
in any sequence transmitted by a computer. In the calligraphic
display an electron beam moves from place to place in a pattern
that traces out the individual lines and characters which make up
the picture. The calligraphic display system is advantageous in
that the information to be displayed can be stored in the computer
memory in essentially any order. The raster pattern display
generates a pictorial image in essentially the same manner as the
conventional television monitor, but the information for raster
display must be sorted from top to bottom and left to right so that
it can be placed on the screen in correct sequence.
Notwithstanding, the electronic sophistication of the calligraphic
display requires rather complex deflection amplifiers, deflection
yokes and other complex related components which render the system
materially more complex and accordingly this type of system carries
a considerably higher purchase or lease cost.
One of the common graphic display systems which uses a calligraphic
pattern involves the presentation of a diagram or character by
means of a series of interconnecting lines, or strokes with
coordinate positions supplied by stored information in the
computer. The computer memory associated with the presentation of
displays of this type only stores the coordinates of each end of
the line in order to describe the full length of the line. Such a
display system, however, requires a cathode ray tube unit that can
be randomly scanned and hence this type of display is not
compatible with standard television signals.
One of the primary methods employed for displaying graphic diagrams
or characters when using conventional television monitors involves
the construction of a diagram on a point-by-point basis using a
matrix of dot elements which may be individually controlled. In
this method, a sequential scanning action compatible with standard
television techniques is employed thereby permitting the use of
standard television monitors. However, in order to describe a
character such as a line with this technique, it is necessary to
store every individual point along the line in order to reconstruct
the line on the screen. Therefore, this system requires an
extremely large memory unit.
There have been several attempts to obviate the problem of
displaying both alpha-numeric characters and graphic characters on
a cathode ray tube screen with a raster pattern, but these attempts
have not been particularly effective when a standard television
monitor was employed. Usually that equipment which is commercially
available involves a substantial purchase or lease cost and
generally requires skilled operators. In addition, many of these
systems do not have write capabilities which materially limits the
effectiveness of the display system.
GENERAL DESCRIPTION
The present invention, therefore, provides a system which is
capable of originating, storing, presenting and modifying graphical
information and presenting this graphical information in
combination with alpha-numeric information for interactive computer
display terminals. This system is uniquely designed so that the
same transmission and processing equipment used for simple
alpha-numeric information displays can be utilized. Furthermore,
the system of the present invention is highly effective in that it
can be used for the display of this alpha-numeric and graphical
information on a conventional television monitor raster screen,
without the necessity of expensive and highly complicated attendant
or auxiliary equipment in order to accomplish this purpose. The
system of the present invention is also highly effective in that it
can be operated by relatively unskilled personnel requiring only a
minimum degree of training and further, the original purchase or
lease cost, operating cost and maintenance cost of this subject
system is considerably lower when compared to other commercially
available systems.
The present invention includes both a system and a method for
generating graphic displays; and more particularly, the invention
is described as a system and a method for generating graphic
displays on the screen of a monitor operable with a raster pattern.
In general terms, the system comprises first pattern forming means
for generating a first type of character elements combinable to
form a graphic character, first switch means operatively associated
with the first pattern forming means to select certain of the first
type of character elements in a desired arrangement and combined to
form a first graphic character in a raster location. The system
also comprises second pattern forming means for generating a second
type of character elements combinable to form a graphic character,
second switch means operatively associated with the second pattern
forming means to select certain of the second type of character
elements in a desired arrangement and combined to form a second
graphic character in another raster location. Finally, the system
comprises cursor means to position the various graphic characters
formed from said types of character elements in a desired
arrangement to form a graphic display.
The method of the present invention could be described in general
terms as a method for generating graphic-type displays on the
screen of a monitor operable with a raster as aforesaid, and where
the method comprises establishing a plurality of raster locations
of predetermined font size on a screen associated with the monitor,
generating a first type of character elements combinable to form
graphic characters of predetermined font size in certain of said
raster locations, generating a second type of graphic character
elements which are distinct from said first type of character
elements and combinable to form graphic characters of said
predetermined font size in certain other of said raster locations.
Finally, the method includes positioning the graphic characters
formed in said raster locations in a desired arrangement to form a
graphic display.
The system for generating the graphic displays more specifically
can be characterized in that the first pattern forming means
generates bar-type character elements and preferably, four-bar
character elements, and further, that the second pattern forming
means generates point-like character elements and preferably
six-point character elements. In this manner, a maximum of four of
such bar-type elements constitutes a graphic character in any one
raster location and that a maximum of six of the point-type
elements constitutes a graphic character in any other raster
location. In a preferred embodiment, the system of the present
invention includes means for adding alpha-numeric characters to the
graphic displays in order to generate a composite informational
display of graphic characters and alpha-numeric characters.
The present invention can also be described in general terms as a
display system for interactive computer display terminals and where
the system comprises a first input means capable of generating a
multi-bit binary graphic word, and second input means capable of
generating a multi-bit binary alpha-numeric data word. The system
also further comprises first storage means operatively associated
with the first input means to receive certain bits of the multi-bit
graphic word, and second storage means operatively associated with
the second input means to receive certain bits of said multi-bit
alpha-numeric word. The display system also comprises selector
means operatively connected to said first and second storage means
to select between alpha-numeric data words and graphic words.
Finally, the system includes clocking means for clocking either the
graphic word or the alpha-numeric data word to the monitor to
display the characters defined by the words.
The display system for the interactive computer display terminals
of the type mentioned above, can be further characterized in that a
main register is connected to the selector means to receive either
the graphic or the alpha-numeric data word which is selected by the
selector means. In addition, the system includes a clocking means
which is operable with the main register to generate a video-signal
from the word received in the main register. Further, a mixer may
be provided for receiving the video-signal and a television type
input signal to form a signal complex therefrom for display through
the interactive computer display terminals. The display system for
these interactive computer display terminals is a monitor having a
screen operable by a raster pattern and more specifically a
television monitor.
In a preferred embodiment, the clocking means is a column counter
for determining a particular column in any raster location and that
row counter means is provided and operatively associated with the
first and second storage means for determining the row location in
any of the columns in this raster location. The first storage means
and the second storage means are read-only memories and preferably,
programmable read-only memories. In addition, a first gating
circuit may be interposed between the first and second storage
means and the selector means and a second gating circuit may be
interposed between the second storage means and the selector means.
The first input means is a graphic-type keyboard comprising first
switch-type means for generating plural-bar character elements and
second switch-type means for generating plural-point character
elements. The second input means is an alpha-numeric-type keyboard
capable of generating both arabic and numeric and other forms of
characters.
The present invention can also be described in general terms as a
circuit active means for determining coordinate positions of
character elements in a raster location on a display screen and
where the character elements are combinable in a desired
arrangement to form the desired characters. This circuit active
means comprises a first storage member receiving a multi-bit word
defining the character elements and representing a character
comprised of these character elements, a gating matrix for
receiving certain of the bits of said multi-bit word defining the
character elements, a second storage member receiving another bit
from the multi-bit word characterizing the type of character
elements. The circuit active means further comprises first location
counter means operatively connected to the second storage member
and generating signals representing a first coordinate axis
location for these elements. These signals are introducable into
the gating matrix for gating certain of the bits representing
certain of the character elements from the gating matrix. Finally,
the circuit active means includes second location counter means
operable with the certain gated bits to determine a second
coordinate axis location, to thereby define the coordinate
positions of the character elements in the raster location.
In more specific terms, the circuit active means can be
characterized in that the first storage member is a buffer memory,
the second storage member is a gating matrix and the third storage
member is a read-only memory unit, and preferably a programmable
read-only memory. In addition, the circuit active means can be
further characterized in that a plurality of different types of
character elements can be used to generate the graphic characters
and that the bit introduced into the second storage member
represents the type of character elements introduced into the
gating matrix. The different types of character elements which are
used to generate the different characters include in one form a
series of bar-like elements and in another form, a series of
point-like elements, and that the bit of a multi-bit word which is
introduced into the second storage member characterizes between the
point-like elements and the bar-like elements.
In other general terms, the present invention can also be described
as a data output circuit for gating certain bits of a multi-bit
word in response to a plurality of input signals and where certain
of the bits in the multi-bit word represent a first type of
elements and certain of the bits in the multi-bit word represent a
second type of elements. Further, the multi-bit word includes a
characterization bit which distinguishes between the said two types
of elements. The data output circuit comprises a plurality of
gating members for receiving certain of the bits of the multi-bit
word, signal generating means receiving the characterization bit
and first clocking means for generating first clocking signals and
introducing these clock signals into the signal generating means.
The data output circuit further includes the fact that signal
generating means generates a plurality of input signals in response
to these clock signals and introduces the input signals into the
gating members to thereby gate certain of the bits in response to
certain of the input signals. The circuit further includes register
means for receiving the gated bits and clocking means for
introducing clocking signals into the register means to thereby
transmit these gated bits on a serial basis.
In more detail, the signal generating means of the data output
circuit described above is a read-only memory unit and this
read-only memory unit comprises a decoding matrix and a word select
matrix. The gating members are preferably a series of NAND gates
present in a number at least equivalent to the number of bits in
the multi-bit word representing the second type of elements. The
input signals to the gating members are signals which designate a
first coordinate location position and the clocking signals which
are generated by the second clocking means are signals which
designate another coordinate location position.
In a preferred embodiment, the present invention provides a unique
means of generating a plurality of font patterns on the screen of a
monitor to produce graphic characters and these graphic characters
are formed from different types of character forming elements. The
monitor is preferably of the type which uses an electron beam
raster to control a series of dots on the screen surface, such as a
television display screen. The screen is made up of a plurality of
columns and rows or lines which form a plurality of raster
locations and each raster location is formed of a plurality of the
dots and preferably with an aspect ratio of 3:2. Typically, each
raster location will contain an eight by twelve dot structure.
The first of these font patterns is made up of plural-bar character
elements and preferably a four-bar font pattern where a maximum of
four bars can exist in a desired orientation in any font or raster
location. The second of these font patterns is made up of
plural-point character elements and preferably a six-point font
pattern where a maximum of six points can exist in a desired
orientation in a font or raster location. The graphic characters
are made up of these graphic elements, and a group of raster
locations in combination, each having a graphic character displayed
therein form a graphic display.
The graphic characters are generated by means of a first input
means in the form of a graphic keyboard which contains a first set
of keys capable of generating the plural-bar pattern and a second
set of keys generating the plural-point pattern. Other forms of
input means which employ different types of input switches or the
like could be used as well. Furthermore, it is also possible to use
signal inputs in place of manually actuated inputs such as keys or
switches in order to generate the desired graphic characters.
In order to provide a total informational display, alpha-numeric or
other forms of characters can be visually depicted on the screen of
the monitor along with the graphic characters. For this purpose an
alpha-numeric keyboard or other input mechanism is employed. The
alpha-numeric keyboard preferably contains a first set of input
switches such as numeric keys and a second set of input switches
such as arabic keys and possibly other non-descript input switches
or keys. Again, it is possible to use other input forms which are
not manually operable as described in connection with the graphic
keyboard mentioned above. One entire graphic display constitutes
one page which can be permanently stored in a computer memory or
the like. In the display of any page, the characters which are
introduced from the input means and the data words in the computer
memory are introduced into a scanning memory. Thereafter, these
data words and the other character information introduced into the
scanning memory are processed for visual display on the screen of
the monitor.
A system is provided for generating the graphic and alpha-numeric
display from the information introduced into the scanned storage.
These characters are introduced into a first memory or buffer
memory in the form of a plural bit word and preferably an eight bit
word. The graphic characters are preferably formed from eight bit
digital codes and the alpha-numeric characters may also be formed
of this eight bit digital code, or other codes as desired.
The first four least significant bits in this eight bit data word
are used to represent the plural-bar characters and these first
four least significant bits plus the next two least significant
additional bits of this eight bit data word are used to represent
the six-point characters. The seventh bit distinguishes between the
plural-point character elements and the plural-bar character
elements and the eighth bit distinguishes between the graphic
characters and the alpha-numeric characters.
A second storage member such as a read-only memory and preferably a
programmable read-only memory receives the seventh bit from the
buffer memory. In addition, the read-only memory receives multiple
row count inputs and preferably four row count inputs from a row
counter and is capable of generating output location coordinate
signals. The read-only memory is desirably formed of a decoding
matrix and a word select matrix, the latter of which receives the
row count signals from the row counter. The output of the decoding
matrix is passed through a series of buffers to generate the output
signals which are introduced into a gating circuit. The combination
of the gating circuit and read-only memory form a graphic character
generator. This gating circuit receives the first six bits of any
word introduced into the buffer memory and also receives the
location signals from the read-only memory as aforesaid. The gating
circuit is preferably formed of a series of NAND gates which are
operable by the six bits and the location coordinate signals from
the read-only memory. The alpha-numeric character generator is also
comprised of a read-only memory and a gating matrix and operates in
a similar manner.
The eight bits of the multi-bit word contained in the buffer memory
is introduced into a selector mechanism and this selector mechanism
receives the output of the gating circuit, as well as the
alpha-numeric input. When the eight bit is true, the word which is
gated from the gating circuit represents a graphic character and
when the eighth bit is not true, the word which is introduced into
the selector is an alpha-numeric data word. The output of the
selector which contains eight bits is introduced in parallel
arrangement into a main register which also receives eight clock
signals from a column counter and these eight clock signals
essentially represent a second set of location coordinates for each
of the bits in the eight bit word introduced into the main
register. The output of the main register is introduced into a
mixer and combined with a television input to provide a
video-television signal complex. This signal complex is then
introduced into the monitor for display.
Having thus generally described the invention, reference will now
be made to the accompanying drawings which illustrate a preferred
embodiment of the present invention and in which:
FIG. 1 is a schematic view showing the geometric construction of
both graphical characters and alpha-numeric characters on a display
screen;
FIG. 2a is a diagramatic view showing the dot structure in one
raster location on a screen and the generation of a graphical
character using a six-point pattern;
FIG. 2b is a schematic view showing the data bit positions for each
point in the raster location in order to achieve the graphic
character pattern illustrated in FIG. 2a;
FIG. 3a is a diagramatic view showing the dot structure in one
raster location on a screen and the generation of a graphical
character using a four-line pattern;
FIG. 3b is a schematic view showing the data bit positions for each
line in the raster location in order to achieve the graphic
character pattern illustrated in FIG. 3a;
FIG. 4 is a schematic view of a system for displaying and storing
graphical characters along with alpha-numeric characters on a
television raster monitor (appearing on sheet 2);
FIG. 5 is a schematic view of the circuitry of a programmable read
only memory included in the system illustrated in FIG. 4 (appearing
on sheet 1);
FIG. 6 is a gating structure used in the generation of a plural-bar
pattern and forming part of a gating circuit included in the system
of FIG. 4;
FIG. 7 is a schematic view of a gating structure used in the
generation of a plural-point pattern and forming part of the gating
circuit included in the system of FIG. 4; and
FIG. 8 is a schematic view of a combination of the gating
structures of FIGS. 6 and 7 to form the gating circuit.
DETAILED DESCRIPTION
Referring now in more detail and by reference characters to the
drawings which illustrate a preferred embodiment of the present
invention, FIG. 1 illustrates a display screen operable with a
raster pattern, such as a standard television display screen. The
screen used for the purpose of describing the present invention
will contain 32 vertically extending columns which represents a
total of 32 raster locations or cells per line and 16 horizontally
extending rows which represents a total of 16 lines. Accordingly, a
screen of this size would contain 512 raster locations or cells and
hence could display a maximum of 512 graphic characters and/or
alpha-numeric characters at any point in time. One complete graphic
display may or may not use all of the possible 512 raster or
character locations or cells and the complete graphic display at
any point in time is referred to in the art as one "page."
Accordingly, a screen of the size mentioned above having five
hundred twelve raster locations would permit generation of a page
with a maximum number of 512 character locations. It should be
recognized that the screen and, therefore, the page could be
composed of any desired number of characters by altering the number
of character columns and character rows or lines. Each raster
location on the screen which defines one character location has
been assigned a size of twelve horizontal dot rows by eight
vertical dot columns or a total raster location size of 96 dots
with an aspect ratio of 3:2, inasmuch as many graphic display
systems using interactive computer display terminals employ this
raster location size. Nevertheless, it should be understood that
essentially any size raster location could be employed for the
purposes of the present invention. One such raster location has
been illustrated in FIG. 1 and designated with reference numeral 2.
This raster location or cell 2 is materially enlarged with respect
to the remainder of the figure for purposes of clarity.
While the cell size in many of the prior art graphic display
systems were also assigned an eight dot by 12 dot pattern only
approximately five dots by seven dots were used in the entire cell
for the display of any character. Generally, the character was
graphically displayed in the upper left-hand corner of the cell so
that three dot columns and five dot rows were not used in these
prior art cell patterns. In this manner, various alpha-numeric
characters were displayed with spaces automatically existing
between the lines of characters.
Referring again to FIG. 1, it can be observed that a graphic
diagram may be composed of all graphic characters or alpha-numeric
characters including both arabic and numeric characters. As used
herein, the term "graphic character" represents a character other
than an alpha-numeric character, and particularly a character which
alone or in combination with other characters presents an
illustration for visual review, rather than for reading as in the
case of alpha-numeric text. Accordingly, the term "graphic" or
"graphical" could represent any type of geometric construction such
as a line, whether it be curved, curvilinear or straight, lines
segments, points, or the like. Generally, a graphic character would
represent only a segment of a final display so that if a circle
were to be portrayed, a group of graphic characters, each
representing an arc, would be combined in such manner to form the
circle. The term "graphic display" represents the presentation of
graphical characters combined to form a geometric or like pattern
as opposed to alpha-numeric text. The term "informational display"
as used herein represents the presentation of either graphical
characters and/or alpha-numeric characters alone, or in combination
with other forms of information.
With further reference to FIG. 1, it can be observed that graphical
diagrams are composed by constructing a series of adjoining
graphical characters and these graphic characters are each formed
by various character elements in each of the raster locations. By
illuminating various of the character elements in each raster
location a portion of a graphic character and hence a font pattern
is generated. In a preferred embodiment of the present invention
one form of font pattern is generated by a plural-point pattern and
preferably a six-point pattern and, another form of font pattern is
generated by a plural-bar pattern and preferably a four-bar
pattern, and any of the eight dot by twelve dot raster locations
may be used for the displaying of the six-point or the four-bar
graphic characters. Furthermore, any of these raster locations may
also be used to display the conventional numeric characters or
arabic characters also in a manner to be hereinafter described.
Each graphic character is stored, processed and transmitted as an
eight-bit data word and may be displayed in any of a number of
discreet character or raster locations on the screen arranged in
the character rows and character columns as aforesaid. The
positioning of such characters, the number of characters per line
and the number of character lines present is determined by the
graphical display to be presented. Furthermore alpha-numeric
characters may be displayed along with the graphic characters as
indicated above, and the coordinates of these characters would be
determined by coordinate information in the computer storage.
An eight-bit data word is used to represent the numeric characters
and the arabic characters included in the alpha-numeric code, as
well as the graphical characters as aforesaid. In both the
graphical and the alpha-numeric characters only seven of the bits
of each eight-bit word are used to describe the character, thereby
providing 128 possible combinations. The eighth and most
significant bit in each character word is a characterization bit
for determining whether the accompanying seven bits represent an
alpha-numeric character or a graphical character. Each eight bits
which represent one word and hence one character, constitute one
byte in the digital code system employed herein. However, it should
be understood that other digital codes could be employed such as a
four bit BCD code to represent numeric characters, a five bit code
to represent any arabic or numeric character, and that the present
invention is not limited to the eight bit code employed herein.
Further, a byte could contain less than eight bits and a character
word could be comprised of a plurality of bytes so that if a four
bit code were employed, one character word could be represented by
two bytes of bit information.
The font patterns or "font" for the graphic characters in each
raster location are more fully illustrated in FIGS. 2a and 3a; FIG.
2a showing a raster location with the plural-point pattern such as
the six-point pattern and FIG. 3a showing a raster location with
the plural-bar pattern such as the four-bar pattern. Each point in
the six-point pattern may be controlled independently and each
point comprises four dots in the raster location so that all six
points in the font are represented by a total of 24 dots in the
raster location. The term "dot" is used in its conventional sense
in that each dot represents an area of the size which is electron
beam scanned at any point in time and is generally individually
controllable with respect to all dots in the screen structure. The
points in the plural-point pattern are substantially larger than
the dots in the dot structure of the raster location so that one
point essentially covers four dots in the dot structure and
furthermore the points are somewhat rectangular in shape.
Furthermore, each of the six points are separated by two dot spaces
and are located in rectangular arrangement in the manner as
illustrated in FIG. 2a. The status of each point is defined by the
six least significant bits in the eight bit data word, namely bits
B-1 through B-6 and the seventh bit B-7 is provided to distinguish
between a six-point character and a four-bar character. Finally,
the eighth bit B-8 in the character word is used to identify the
graphic character word as aforesaid, the eighth bit being a logical
"zero" for alpha-numeric characters and a logical "one" for graphic
characters.
The four-bar pattern is more fully illustrated in FIG. 3a; each of
the bars in the four-bar pattern being represented by one binary
bit in the seven-bit word and each of the four bars may be
controlled independently. Each bar in the four-bar pattern is
approximately two dots wide and are located in the raster location
so that they assume the appearance of a cross when all bars are
illuminated in the manner as illustrated in FIG. 3a. Thus, if any
one of the four bars in the four-bar font pattern is illuminated,
the central position of the font will be illuminated. The status of
each of the bars in the four-bar pattern is defined by the four
least significant bits in the eight-bit word. Again, bits B-7 and
B-8 are used in the same manner as in the case of the six-point
pattern, except that bits B-5 and B-6 are not used in the four-bar
pattern.
The graphic patterns are produced by actuation of the keys on a
keyboard (to be hereinafter described) in any desired pattern in
order to achieve a desired graphic display. For example, the
operator of the system could generate a linear graph having an
abscissa axis designated as "X-AXIS" and an ordinate axis,
designated as "Y-AXIS" through generation of successive straight
lines by using the four-bar character fonts. In like manner, by
actuating proper keys on the keyboard, the operator can generate a
series of points which form a cruve 3 coordinated by the ordinate
and abscissa axises mentioned above. The term X-AXIS and the term
Y-AXIS could be conveniently generated through actuation of the
keys on an alpha-numeric keyboard (to be hereinafter described) and
suitably placed on the screen with respect to the display of the
linear graph. Each font raster location is used to generate a
plurality of points which only form a portion of the curve 3, and
therefore it can be observed that a plurality of adjacent and
continuous raster locations together will generate the entire curve
3 in the form of a low resolution dot structure. In this manner,
the illustrations of the various preselected plural-points in each
of the adjacent continuous raster locations will appear as one
complete continuous curve due to the low resolution of the display
achieved by this system.
A system S for generating the informational displays which includes
the display of the graphic characters and the alpha-numeric
characters, as aforesaid, is more fully illustrated in FIG. 4. As
indicated above, this system is operable with almost any type of
computer interactive terminal display monitor employing a raster
pattern; but is particularly designed for use with cathode ray tube
systems, such as a conventional television monitor. One of the most
preferred forms of cathode ray tube systems employs a screen with a
phosphorus coating which is scanned by an electron beam. Generally
a cathode in the tube will emit an electron stream through a grid
and this electron stream will be focused on an accelerating anode.
A pair of oppositely disposed deflection plates will enable the
electron beam to in effect scan or sweep the screen.
The screen which essentially constitutes one frame is typically
scanned in about one-thirtieth of a second, and preferably contains
a pair of interlaced fields which form the frame and where each
field is scanned in about one-sixtieth of a second. The beams in
the two fields will generally scan from left to right, probably
with overscanning, and will retrace in a substantially shorter
period of time than the scan or sweep period. The beam will be
modulated by the grid and the intensity of the light will be a
function of the voltage applied to the grid. Furthermore, the beam
will be deflected either electromagnetically or electrostatically,
though electrostatic deflection is the preferred form.
This system S is capable of being used in essentially four basic
modes of operation, namely origination, storage, presentation and
modification. The origination mode is used to generate new
informational displays which include graphic characters and/or
alpha-numeric characters, and is generally achieved by actuation of
the keyboards to be hereinafter described. After an informational
display has been created on the screen of a monitor (and which
display constitutes one page) this informational display or page
can then be stored in a computer memory by operation of the system
in the storage mode. In the presentation mode of operation, the
information in the storage, such as this above mentioned page, for
example, could be presented on the screen of the monitor in the
manner as it was originally stored. In the modification mode of
operation, the stored page would also be presented for display on
the screen of the monitor, but certain modifications to the page
would be performed. These modifications can be achieved by adding
information to the page on display, such as alpha-numeric
characters or graphic characters, or by altering or deleting some
of the characters included in the page on display.
The system S for generating the informational display generally
comprises a graphic keyboard 10 and an alpha-numeric keyboard 11 in
the manner as illustrated in FIG. 4, and which keyboards would
normally be mounted in a suitable operators console (not shown).
The alpha-numeric keyboard 11 generally includes a keyboard block
12 containing numerically labeled keys for introducing numeric
characters. The keyboard 12 would normally include nine keys
labeled with successive digits "1" through "9" and a tenth key
labeled "0." The keyboard 11 would also contain a keyboard block 13
with 26 keys having the letters of the alphabet imprinted on the
surface of these keys. As indicated above, the keyboard would
contain 26 keys for the generation of arabic characters, though it
should be understood that the exact number of keys would be
dependent upon the particular type of alpha-numeric characters to
be generated. For example, characters can conveniently be generated
in the Russian Language which requires an additional number of keys
and the keyboard block 13 would thus be provided with the proper
number of keys. The keyboard 11 is also provided with a space bar
14 for the generation of spaces between any of the alpha-numeric
characters. It should also be recognized that this keyboard 11
could be provided with additional keys having punctuation marks,
such as periods, commas, asterisks, or the like, as desired.
The alpha-numeric keyboard 11 is further provided with a clear
switch 15 and a load switch 16 for purposes which will be more
fully defined hereinafter. All of the aforesaid switches on the
keyboard 11 are preferably push button type switches which enable
an energized state upon actuation and are biased to return to the
deactivated position. Furthermore, these switches may all be
provided with internally located lights, such as small conventional
neon tubes (not shown) so that the face of the switch will be
illuminated upon actuation thereof. The alpha-numeric keyboard
could also be provided with display tubes such as multi-segment
cold cathode display tubes (Nixi tubes) which wuld be energized
upon actuation of any of the keys on the keyboard 11. Typically, a
thirteen segment cold cathode tube could be energized to indicate
the actuation of any particular key on the keyboard. In this
manner, the operator could visually inspect the alpha-numeric
information he plans to introduce into the system, prior to the
actual introduction of this information into the system. Suitable
anode and cathode shift registers along with a display shift
register and the attendant circuitry can be provided for this
purpose.
The graphic keyboard 10 is preferably a mimic style keyboard which
is used to compose the graphic diagram and generally includes a
plural-bar keyboard block 17 and a plural-point keyboard block 18.
The plural-bar keyboard block 17 will normally contain a number of
bar-keys which are equivalent to the number of bars present in any
font. Since any font can be generated with any or all of the four
bars in a four-bar pattern, the keyboard block 17 will contain two
horizontally located keys 19 and 20 and two vertically located keys
21 and 22 in the manner as illustrated in FIG. 4. The keys 19
through 22 are all located in positions on the keyboard block 17 so
that they generate a graphic display in any particular raster
location in the same pattern as they appear on the keyboard block
17. Thus, actuation of the keys 19 and 20 will produce a horizontal
line in the raster location. Actuation of the keys 21 and 22 will
produce a vertical line in the raster location, and actuation of
all four keys will produce a cross similar to that appearing on the
keyboard block 17.
The keyboard block 18 is also provided with a number of keys
equivalent to the number of points in any font pattern or appearing
in any raster location. As indicated above, each font pattern will
employ a total of six points and, therefore, the keyboard block 18
is provided with six keys 23 located in the form of a rectangle, in
the manner as illustrated in FIG. 4. Thus, actuation of all of the
keys 23 on the keyboard block 18 will produce a font pattern which
is equivalent to the arrangement of the keys 23 on the keyboard
block 18.
The graphic keyboard 10 is further provided with a load switch 23
and a clear switch 25 as well as cursor controls 26. The cursor
controls 26 are of the type normally associated with cathode ray
tube display systems and permits the operator of the system to
properly position the graphic characters on the display screen of
the monitor. When composing any of the graphic characters, the
operator will normally position the cursor to locate the first
graphic character. The cursor is of the type which can be moved,
up, down, forward and reverse.
The output of the graphic keyboard 10 and the output of the
alpha-numeric keyboard 11 both serve as inputs to a scanned storage
27 which also has output and input lines to a computer storage C
which is described in more detail hereinafter. The scanned storage
27 also provides an output synchronized to column counter 41. The
scanned storage 27 is a storage member of conventional
construction, preferably a recirculating shift register containing
a series of multi-stable elements, though other forms of scanned
storage members can be used in the present invention. The scanned
storage 27 examines the outputs of the keyboards 10 and 11 for
further processing in a manner to be hereinafter described. The
scanned storage 27 also serves as an intermediate buffer for
introducing data words into the computer storage C.
The output from the scanned storage 27 is connected to an eight-bit
data word recirculating buffer memory 30. The recirculating buffer
memory 30 is only schematically illustrated in block diagram form
since memories of this type are commercially available and
generally include a series of bi-stable elements, sufficient in
number to accommodate each bit of a generated byte or word, along
with recirculating controls.
As indicated previously, the first six least significant bits in
the data word represent the form of the graphic character, the
seventh bit determines whether the character is composed of plural
bars or plural points and the eighth bit determines whether the
character is a graphic character or an alpha-numeric character.
Accordingly, the buffer memory 30 is provided with a bit-8 output
line 33 connected to a selector 34 and which output line 33 will be
energized when bit-8 is true. Accordingly, if bit-8 is in fact
true, then the character generated will be a graphic character.
The buffer memory 30 has a bit B-7 output connected to a
programmable read-only memory 35 forming part of a graphic
character generator C.sub.1, and a bit B-7 output connected to a
similar programmable read-only memory 35' forming part of an
alpha-numeric character generator C.sub.2. The graphic character
generator C.sub.1 includes a special gating circuit 36 which
receives six outputs from the read-only memory 35 in a manner to be
hereinafter described in more detail and this gating circuit 36 is
more fully illustrated in FIGS. 6, 7 and 8 of the drawings. The
output of the graphic character generator C.sub.1 is introduced
into the selector 34 by means of a line 37 and the output of the
alpha-numeric character generator C.sub.2 is introduced into the
mixer 34 by means of a line 37' which will be generated only when
bit-8 is not true or "0."
The programmable read-only memory 35 internally includes thirty-two
locations which are addressable by five-bit address words. Four
bits of these address words are derived directly from a row counter
38 which controls the eight by twelve dot raster location and
specifies which of the twelve rows or lines in the raster location
is being scanned at any point in time. The row counter 38 also has
a four bit address word input to the read-only memory 35' and also
specifies the raster location being scanned at any point in time.
The fifth bit in the address word is the seventh bit in the
seven-bit data word defining that a graphic character is contained
in the buffer memory 30. Thus, it can be observed that the buffer
memory 30 is sized to contain one complete character word and in
this connection would probably include eight multi-stable elements,
such as flip-flops and recirculating controls therefor.
The status of bit-7 in the data word contained in the buffer memory
30 essentially defines whether graphic characters are to be formed
from the four-bar pattern or the six-point pattern. The first 16
locations in the read-only memory 35 are programmed to generate the
four-bar pattern and locations 17-31 in the read-only memory 37 are
used to generate the six-point pattern. The output of the read-only
memory 37 which defines the pattern of the graphic character to be
displayed is introduced into the special gating circuit 36.
The gating circuits 36 and 36' also receive the first six least
significant bits of the data word in the buffer memory 30 and
permits the gating of outputs to the selector 34 through the lines
37 and 37', respectively, in the manner as illustrated in FIG. 4.
The selector 34 is provided with eight outputs connected to a main
data shift register 40 also receiving eight inputs from a column
counter 41. The main data register 40 is essentially an eight
location parallel input-serial output shift register. This column
counter 41 specifies which of the eight columns in the font is
being scanned at any point in time and operates in conjunction with
the row counter 38 to determine the coordinate position of any dot
in the font. The output of the main register 40 may be mixed with a
television input signal in a mixer 42 and then displayed on the
screen of a raster pattern monitor 43, such as a conventional
television screen.
The scanned storage 27 has an output to and receives an input from
the computer storage or so-called "permanent storage" or "computer
memory", as aforesaid, through a suitable control circuit 32. The
computer storage and the means for accessing the storage are well
known in the art and are therfore neither illustrated nor described
in any substantial detail herein. The computer storage C will
normally assume the form of a magnetic drum or disc of the type
capable of having digital data recorded thereon. The control
circuit 32 which permits accessing of the computer storage C is
normally provided with a control panel and may be included with the
computer; it being understood that the system S of the present
invention is essentially auxiliary or peripheral to the
computer.
A number of commercially available read-only memories can be used
in the system of the present invention. As indicated above,
however, one of the read-only memories 35 will be described in
detail and one of the preferred forms of programmable read-only
memories is more fully illustrated in FIG. 5 of the drawings. This
programmable read-only memory 35 includes a word select matrix 44
receiving the fout bit inputs from the row counter 33 and which are
designated as R.sub.0, R.sub.1, R.sub.2 and R.sub.3. The bit-7
input designated as "B-7" is introduced into an enable gate 45 and
the four outputs of the word select matrix 44 are anded with an
enable output from the gate 45 in a series of four AND gates 46.
The outputs of each of the AND gates 46 are introduced into a
decoding matrix 47 which contains a series of memory elements, such
as flip-flops (not shown). The decoding matrix 47 permits the
generation of six outputs, each passing through output buffers 48
which thereby produce the six line count outputs D.sub.0 and
D.sub.1 through D.sub.5, and these six line count outputs are
introduced into the gating circuit 39.
This type of programmable read-only memory can be programmed
electronically after manufacturing, or during manufacturing by
designing the final metalization to correspond to the desired
memory configuration. Furthermore, the programmable read-only
memory 35 described above can be programmed by alteration of the
specific memory elements included in the decoding matrix 47 to
create logical "ones" and locigal "zeros" in selected bit
positions.
The operator of the system of the present invention can compose
essentially any graphic character using either the plural-point
pattern or the plural-bar pattern and in order to generate the
characters which form the graphic diagram the operator will actuate
the various push-button switches on the graphic keyboard 10. As the
switches are actuated, the internal lights in these switches will
illuminate. When the operator is satisfied that the character has
been composed correctly, the load switch 24 will be actuated so
that the eight-bit word representing the entered character may be
transferred to the scanned memory 27 which essentially serves as a
temporary storage. The push-button switches on the graphic keyboard
10 which have been actuated will still remain illuminated so that
the operator may then position the cursor to the next location and
enter the same graphic character again by actuating the load switch
24. In like manner, the operator may reset the switches by
actuating the clear switch 25 which extinguishes all of the
keyboard lights after the memory 27 has been cleared. The operator
may thereafter compose a new graphic character by actuating any of
the push-button switches 19-23. Thus, in order to draw a continuous
straight line, it is only necessary to set up the first character,
such as through actuation of the switches 19 and 20 or 21 and 22,
repeatedly step the cursor 26, and actuate the load switch 24.
Alpha-numeric characters may be introduced along with the graphic
characters in the graphic display in order to provide a total
informational display and these alpha-numeric characters may be
injected substantially anywhere on the screen with respect to the
graphic characters. As indicated above, the one limitation
regarding the generation of the alpha-numeric characters and the
graphic characters is that only one character can be stored in any
one raster location, whether a graphic character or an
alpha-numeric character. Once the complete diagram has been
composed, the page representing that diagram is located in the
scanned store 27 and this page may then be introduced into the
permanent storage 32 under computer control. A standard eight-bit
data communication code, such as the ASCII code, may be used to
transmit all of the graphic and/or the alpha-numeric data.
An informational diagram entered into a computer storage by the
above means may be recalled under computer control at any time and
upon recall this diagram, in the form of a page, will be
transferred from the permanent storage 32 to the scanned store 27
where the page will again be displayed through the screen of the
monitor 43. Recall in this form may occur in either the
modification or presentation modes of operation. In the
presentation mode of operation the informational display will be
reproduced in its original form upon demand and in the modification
mode, the origninal display will be altered as described above.
A six-bit address word which provides line count information to the
gating circuit 36 and to the gating circuit 36' is provided in each
of the thirty-two locations in each of the read-only memories 35
and 35'. As the address of the read-only memory 35 is scanned by
the advancing row counter 38, the six-bit address word read out of
the read-only memory 35 is mixed in the gating circuit 36 with the
six remaining bits of the data word in the buffer memory 30 to
generate each graphic character. The alpha-numeric character is
generated in substantially the same manner using the six bits of
the data word in the buffer memory 30 when these six bits are
detected to represent an alpha-numeric character. The structure of
this gating circuit 36 (to be hereinafter described) and the gating
circuit 36', as well as the format of the pattern program in the
read-only memories 35 and 35' are such that upon mixing, an output
is generated and this output will create a video-signal when
applied to the eight parallel inputs of the main data register 40.
Furthermore, the video-signal will be cleared as the main register
40 is clocked by the column counter 41.
For purposes of clarity, the portion of the gating circuit 36 used
in the generation of the plural-bar graphic output is illustrated
in FIG. 6 and the portion of the gating circuit 36 which is used in
the generation of the plural-point graphic output is illustrated in
FIG. 7, the combination of these two gating structures forming the
gating circuit 36 and being schematically illustrated in FIG.
8.
Gating circuit 36' of the type used in the generation of
alpha-numeric characters are known in the art and therefore the
gating circuit 36' is neither illustrated nor described in any
further detail herein.
As indicated previously, only four bits in the eight-bit word are
used to generate any of the bars in the plural-bar font pattern and
the four bits which describe the bars in any such font are the four
least significant bits, B-1 through B-4, of this eight-bit word.
Therefore, in the generation of a plural-bar font pattern, the bits
will assume the following conditions:
B-8 = 1 Distinguishes between graphic and alphanumeric characters.
B-7 = 0 Distinguishes between the four-bar and six-point pattern.
B-6 = M M is either a "0" or "1" state. B-5 = M B-4 = N B-3 = N N
is assigned a "" or "0" state according to the combination of bars
in the four-bar pattern to be displayed. B-2 = N B-1 = N
the gating circuit 36 comprises a plural-bar gating structure 49
which generally includes six input NAND gates G1 through G6. It can
be observed that the NAND gates G1 through G4 receive the first
four least significant bits in a data word generated by actuation
of any of the keys on the plural-bar keyboard block 17. The gates
G5 and G6 also receive bits B-2 and B-4, respectively. In like
manner, the input NAND gates, G1 through G6 receive the respective
address line counts D.sub.1 through D.sub.6 generated in the
read-only memory 37. The outputs of the NAND gates G1, G3, G5 and
G6 are combined in a NAND gate G7 which produces column 0.sub.4 and
0.sub.5 outputs. The output of the input gate G2 is introduced into
another NAND gate G8 which provides column outputs 0.sub. 6,
0.sub.7 and 0.sub.8. Finally, the output of the input NAND gate G4
is introduced into a NAND gate G9 which provides column outputs
0.sub.1, 0.sub.2 and 0.sub.3. It can be observed by reference to
FIG. 6 that these outputs 0.sub.1 through O.sub.8 are introduced
into the main shift register 40 for ultimate mixing with a
television input signal.
Actuation of all of the keys 19 through 22 on the keyboard block 17
will generate a bar pattern equilvalent to that illustrated in FIG.
3a and thus, it can be seen that all twelve locations in rows 0 and
1 through 11 will be illuminated at output columns 0.sub.4 and
0.sub.5. In like manner, rows 5 and 6 in the font will be
illuminated at all columns 0.sub.1 through 0.sub.8. In this case,
bits B-1 through B-4 will each assume a "one" state upon actuation
of all such keys 19 through 22. Further, it can be observed that
bit B-1 will cause the illumination of output columns 0.sub.4 and
0.sub.5 in rows 0 through 4; bit B-2 will cause illumination of
rows 5 and 6 in output columns 0.sub.6, 0.sub.7 and 0.sub.8 ; bit
B-3 will cause illumination of columns 0.sub.4 and 0.sub.5 in rows
7 through 11; and bit B-4 will cause illumination of rows 5 and 6
in columns 0.sub.1 through 0.sub.3. Generation of any bars in a
font by means of any one or more of bits B-1 through B-4 will cause
illumination of the center section of the font (shaded area in FIG.
3a), namely rows 5 and 6 in columns 0.sub.4 and 0.sub.5.
Actuation of the keys on the keyboard block 17 to produce the
four-bar font pattern just described will render a logic output
from the read-only memory 35 in accordance with the chart
illustrated in FIG. 3b. It can be seen that the address line count
D.sub.1 will achieve a logical "one" state in rows 0 through 6,
address line count D.sub.3 will achieve a "one" state in rows 5
through 11 and further, rows 5 and 6 will achieve a "one" state in
each of address line count outputs D.sub.1 and D.sub.6.
In row 0, only the bit B-1 is relevant and if the bit B-1 is "one"
then positions 4 and 5 in this row 0 will be illuminated. The row
count lines from the counter 38 are used to address the read-only
memory 35 in the manner as previously described and on line 0, the
output word form the memory 35 is 1000000. When this output is
applied to the gating structure illustrated in FIG. 6, along with
bits B-1 through B-4 applied to gates G1 through G4, respectively,
it can be seen that gate G1 will produce a "zero" output, while
each of gates G2 through G6 will each produce a "one" output. Gate
G7 will produce a "one" output since not all of the inputs to the
gating structure 49 is a "one" input. Thus, outputs 0.sub.4 and
0.sub.5 will be generated and therefore a logical "one" is loaded
into positions 4 and 5 of the main register 40. Further, if the
data for row 0 is clocked out of the main register 40, the two
central positions in the line, namely positions 0.sub.4 and 0.sub.5
are illuminated.
The same procedure is followed in determining the status of any
other dot in the four-bar pattern illustrated in FIG. 3a for
purposes of illumination. Thus, for rows 0 through 4, the same
procedure will follow if B-1 is a logical "one" for these rows. In
rows 5 and 6 several possibilities exist so that if bit B-4 is a
logical "one" then positions 0.sub.1 through 0.sub.5 will be
illuminated and if bit B-2 is a logical "one," then positions
0.sub.4 through 0.sub.8 of these rows 5 and 6 will be illuminated.
Furthermore, if bits B-2 and B-4 are both logical "ones," then the
word which emerges from the read-only memory 35 on rows 5 and 6 is
111111. Thus, it can be seen for example, that a vertical bar
through the entire twelve dot by eight dot raster location would be
described by the character 10XX0101.
As indicated previously, if any one of bits B-1 through B-4 achieve
a logical "one" state then the center shaded area in FIG. 3a,
namely positions 0.sub.4 and 0.sub.5 in rows 5 and 6 will be
illuminated. The outputs for the logical states of bits B-1 through
B-4 in a data word are as follows:
a. If bit B-1 is a logical "one," the output of gate G1 is "zero"
and outputs 0.sub.4 and 0.sub.5 are true;
b. If bit B-2 is a logical "two" the output of gates G2 and G5 are
"zero" and outputs 0.sub.6, 0.sub.7, 0.sub.8, 0.sub.4 and 0.sub.5
are true;
c. If bit B-3 is a logical "one," the output of gate G3 is "zero"
and outputs 0.sub.4 and 0.sub.5 are true; and
d. If bit B-4 is a logical "one" the output of gates G4 and G6 are
"zero" and outputs 0.sub.1, 0.sub.2, 0.sub.3, 0.sub.4 and 0.sub.5
are true.
Illumination of rows 7 through 11 in the raster location are
generated in substantially the same way as rows 0 through 4 and
thus, it can be observed that the pattern generated through the
programmable read-only memory 35 interacts with bits B-1 through
B-4 to produce the four-bar pattern. It should be observed, that
other plural-bar patterns, such as a five-bar and six-bar pattern
could also be generated. In this case, a larger data word would
probably be employed so that if a six-bar pattern is used, a
ten-bit data word would be generated. In addition, the read-only
memory 35 would be expanded as well as the gating structure 49 in
order to accommodate the additional outputs which are
generated.
As mentioned above, six bits in the eight-bit word are used to
generate any of the points in the plural-point font pattern and the
six bits which describe the points in the font appearing in any
such raster location are the six least significant bits B-1 through
B-4 of this eight-bit word. Therefore, in the generation of a
plural-point font pattern, the bits will assume the following
logical conditions:
B-8 = 1 Distinguishes between graphic and alphanumeric characters.
B-7 = 0 Distinguishes between the four-bar and six-point pattern.
B-6 = N B-5 = N B-4 = N B-3 = N N is assigned a "one" or "zero"
state according to the combination of points to be displayed in the
six-point pattern. B-2 = N B-1 = N
the gating circuit 36 also comprises a plural-point gating
strucutre 50 which generally includes six input NAND gates G11
through G16. It can be observed that the NAND gates G11 through G16
receive the first six least significant bits in a data word
generated by actuation of any of the keys 23 on the keyboard block
18. In like manner, the input NAND gates G11 through G16 receive
the respective address line counts D.sub.1 through D.sub.6
generated in the read-only memory 35. The outputs of the NAND gates
G11, G13 and G15 are combined in a NAND gate G17 which produces a
column 0.sub.2 and a column 0.sub.3 output. The outputs of the NAND
gates G12, G14 and G16 are combined in a NAND gate G18 which
renders a column output 0.sub.6 and a column output 0.sub.7 . It
can be observed by further reference to FIG. 7 that the outputs
0.sub.6, 0.sub.7, 0.sub.2 and 0.sub.3 from the respective gates G17
and G18 are introduced into the main register 40 for ultimate
mixing with a television input signal.
It can be observed that actuation of all of the keys 23 on the
keyboard block 18 will generate a point-pattern equivalent to that
illustrated in FIG. 2a. Thus, it can be seen that row locations 1,
2, 5, 6, 9 and 10 will be illuminated at output columns 0.sub.2,
0.sub.3, 0.sub.6 and 0.sub.7 in the manner as illustrated in FIG.
2a. In this case, bits B-1 through B-6 will assume a "one" state
upon actuation of all of the keys 23 on the keyboard block 18.
Further, it can be observed that bit B-1 will cause illumination of
output columns 0.sub.4 and 0.sub.5 in rows 1 and 2; bit B-2 will
cause illumination of output column locations 0.sub.6 and 0.sub.7
in rows 1 and 2; bit B-3 will cause illumination of output column
locations 0.sub.2 and 0.sub.3 in rows 5 and 6; bit B-4 will cause
illumination of output columns 0.sub.6 and 0.sub.7 in rows 5 and 6;
bit B-5 will cause illumination of output column locations 0.sub.2
and 0.sub.3 in rows 9 and 10; and bit B-6 will cause illumination
of output column locations 0.sub.6 and 0.sub.7 in rows 9 and
10.
Actuation of all of the keys 23 on the keyboard block 18 to produce
the six-point font pattern illumination just described will render
an output from the read-only memory 35 in the manner as illustrated
in FIG. 2b. It can be seen that the address line count D.sub.1 and
the address line count D.sub.2 will achieve a logical "one" state
in rows 1 and 2, address line counts D.sub.3 and D.sub.4 will
achieve a logical "one" state in rows 5 and 6, and further, address
line counts D.sub.5 and D.sub.6 will achieve a logical "one" state
in each of rows 9 and 10.
It can be observed that none of the bits B-1 through B-6 are
relevant with regard to rows 0, 3, 4, 7, 8 and 11 and no
illumination will occur in any of these rows in any raster
location. Considering row 1, it can be observed that the only bits
which are relevant are bits B-1 and B-2. The row count lines from
the row counter 38 are used to address the read-only memory 35 in
the manner as previously described and in the case where bits B-1
and B-2 are relevant in rows 1 and 2, the output word from the
memory 35 is 110000. When this output from the memory 35 is applied
to the gating structure 50 illustrated in FIG. 7, and where either
bits B-1 and B-2 are applied to gates G11 and G12, it can be seen
that gates G11 and G12 will produce a logical "one" output while
each of gates G13 through G16 will produce a logical "zero" output.
Hence, the outputs at gates G17 and G18 will be logical "ones" to
thereby render outputs 0.sub.2, 0.sub.3, 0.sub.6 and 0.sub.7
true.
The four possible combinations of bits B-1 and B-2 are set forth in
the following table:
Gate Outputs Outputs B-2 B-1 G11 G12 G17 G18 0.sub.2,0.sub.3 0.sub
.6,0.sub. 7 0 1 1 0 0 0 0 1 0 1 1 0 1 0 1 0 1 0 0 1 0 1 1 1 0 0 1 1
1 1
thus, by an examination of the above, table, it can be observed
that if only bit B-1 is relevant, gate G11 will produce a logical
"zero" output and gate G12 will produce a logical "one" output
thereby rendering outputs 0.sub.2 and 0.sub.3 true and gate G18
will produce a logical "zero" output thereby rendering outputs
0.sub.6 and 0.sub.7 not true. Further, if bit B-2 is the only
relevant bit in rows 1 and 2, it can be observed that gate G11 will
have a logical "one" output and gate G12 will have a logical "zero"
output. Moreover, gate G27 will have a logical "one" output,
thereby rendering outputs 0.sub.6 and 0.sub.7 true.
A similar logical process occurs with regard to rows 5 and 6 where
bits B-3 and B-4 are the relevant bits. In this case, it can be
observed that if the switches 23 on the keyboard block 18 are
actuated in proper manner, bit B-3 and bit B-4 will be relevant
thereby producing a logical "zero" output at gates G13 and G14 and
also at G17 and G18. Therefore, all of the outputs 0.sub.2,
0.sub.3, 0.sub.6 and 0.sub.7 will be rendered true. Hence, it can
be observed that the pattern stored in the programmable read-only
memory 35 interacts with bits B-1 through B-6 of a character word
to produce the six-point pattern.
The outputs for the logical states of bits B-1 through B-6 in a
data word are as follows:
a. If bit B-1 is a logical "one," the output of gate G11 is "zero"
and outputs 0.sub.2 and 0.sub.3 are true;
b. If bit B-2 is a logical "one," the output of gate G12 is "zero"
and outputs 0.sub.6 and 0.sub.7 are true;
c. If bit B-3 is a logical "one," the output of gate G13 is "zero"
and outputs G2 and G3 are true;
d. If bit B-4 is a logical "one," the output of gate G14 is "zero"
and outputs 0.sub.6 and 0.sub.7 are true;
e. If bit B-5 is a logical "one," the output of gate G15 is "zero"
and outputs 0.sub.2 and 0.sub.3 are true; and
f. If bit B-6 is a logical "one", the output of gate G16 is "zero"
and outputs 0.sub.6 and 0.sub.7 are true.
In accordance with the above, any combination of the foregoing will
produce a font pattern of any selected points when the bits
controlling these points are logical "ones."
It should be observed that other plural-point patterns such as a
ten-point or twelve-point pattern could also be generated. In this
case, a larger data word would also be employed so that if a
ten-point pattern is used a ten-bit data word would be generated.
In addition, the read-only memory would be expanded as well as the
gating structure 50 in order to accommodate the additional outputs
which are generated.
FIG. 8 is a schematic view of a combination of the gating
structures 49 and 50 to produce the gating circuit 36. It can be
observed that the NAND gates G11 through G16 as well as G5 and G6
in the gating structure 49 serve as the combination input gates.
Gates G7, G17 and G18 are also employed in the manner as
illustrated in FIG. 8. By examining the logic of the gating
structures 49 and 50, it can be observed that the output of the
gate G12 which is essentially a combination of gates G12 and G2
renders outputs of 0, when combined with bits B-7 and B-8 in a NAND
gate G19. The output of gate G7 is combined with a bit B-8 input
and a not bit B-7 input in a NAND gate G20 and generates outputs
0.sub.4 and 0.sub.5. The output of gate G18 is combined with the
bit B-8 input in a NAND gate G21 and generates outputs 0.sub.6 and
0.sub.7. The output of gate G17 is combined with the bit B-8 input
in a NAND gate G22 and, therefore, renders an output of 0.sub.2 and
0.sub.3. Finally, the output of gate G14 is combined with the bit
B-7 and bit B-8 inputs in a NAND gate G23 to render an output
G.sub.1. It can be observed that the bit B-5 and bit B-6 inputs are
anded with the bit B-7 inputs in NAD gates G24 and G25
respectively, before being introduced into the respective NAND
gates G15 and G16. All of these aforesaid outputs are introduced
through a gating matrix 51 consisting of eight NAND gates which
are, in turn, connected to the main data shift register 40 in the
manner as illustrated in FIG. 8. For the purpose of describing the
gating circuits of FIGS. 6 - 8, the bits which have been designated
as B-(x) such as B-5 have been illustrated as B.sub.(x) such as
B.sub.5 in the drawings.
It can be seen that the display system of the present invention is
highly effective with standard display monitors using a raster
pattern, and particularly with television monitors for displaying
both alpha-numeric and graphical characters in order to generate a
complete informational display. The system of the present invention
is highly effective in that it is capable of accepting ASCII coded
alpha-numeric data for display on one or more television monitors
and in addition, the composite of the television input with the
video-signal produced by the system of the present invention is
compatible with substantially any commercially available television
monitor. Furthermore, it is possible to write in the main register
40 through actuation of the keyboards 10 and 11 and to record this
information into the computer storage C through the control circuit
32. The generated graphical characters are formed by plural-point
or plural-bar font patterns and the nature of these displays lends
to easy viewability. Moreover, the system of the present invention
is very conventient to author and present conceptual information
for construction purposes.
The components in the system of the present invention have been
uniquely selected so that the graphic characters generated by the
system S would be displayed along with the standard alpha-numeric
data and further, the graphical information uses a data format
which is completely compatible with the data format of
alpha-numeric information. In addition, the same storage medium
which is used for the retention of alpha-numeric data is also used
for the retention of the data representing graphic characters.
Thus, the data for the graphical characters could be randomly
stored in a computer memory along with the alpha-numeric data or
separated therefrom. The exact addressing scheme used in the
computer is not part of the present invention since the system S of
the present invention is peripheral thereto, as stated above.
However, one effective form of recording a page containing
alpha-numeric characters and graphical characters employs a
modified form of associative addressing where the data representing
the graphical characters can be stored in positions related to the
storage positions of the alpha-numeric data.
There are many auxiliary components which can be used with the
system S of the present invention and many substitutes of
components which can be made. For example, a vido-signal generator
could be used in place of the mixer 42 for converting the generated
characters and the television input into a composite video-signal
and for also providing timing and synchronizing pulses.
Furthermore, either fast or slow memory organizations may be
employed depending on the requirements of the user of this
system.
The system of the present invention may also be provided on, an
optional protection control for displaying fields of fixed data and
fields of variable data. In this control system memory locations
allocated to fixed data are placed in a "protect" condition to
prevent the fixed data from being erased or read out and to enable
the operator to erase only the variable data. A protection control
is provided for permitting the operator to hold the data constant
in the protection fields while varying the data in the
non-protected fields. When the protection control is off, all
character locations will be unprotected and the data may be entered
or altered in any location. When the protection control is switched
on, the data in the assigned locations will thereafter become
protected. The fields assigned to the protected and variable data
may be of any length. Furthermore, this protection control system
could be constructed in such manner that the protected characters
written into the computer memory C will be displayed at half of
normal intensity.
It should be understood that the display system of the present
invention is not limited to the exact configuration illustrated in
the drawings and that many changes, modifications, variations and
other uses and applications of the subject system will, however,
become apparent to those skilled in the art after considering this
specification and the accompanying drawings. All such changes,
modifications, variations and other uses and applications which do
not depart from the spirit and scope of the invention are deemed to
be covered by the invention which is limited only by the claims
which follow.
* * * * *