Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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This invention pertains to a video image control system for causing
a video image to be displayed on a video display tube and to travel selective-
ly in a plurality of directions on the face of the tube. This invention is
particularly useful in conjunction with entertainment devices of ~he kind
wherein images are displayed on vidèo tubes and controlled by an opera~or.
Heretofore, various types of schemes have b0en arranged for controlling
~he posi~ion of images displayed on picture tubes for purposes of entertain-
ment but many of these systems are typifie~ by relatively expensive components
and circuitry rendering the entire apparatus somewhat expensive and dificult
to service as well as inflexible in adapting to different programs and displays.Accordingly, there is a substantial need for a relatively simplified
video image control system with a high degree of flexibility and such is pro-
vided in accordance with the present invention herein.
In general, there is provided a video image control system for causing
a video image to be displayed on a video display tube and for causing the image `
to travel selectively in a plurality of directions on the display tube. The
system includes a pulse generating clock means for generating a continuous
stream of signals at a predetermined frequency. A first counting means com-
prising,in general, a pair of predetermined counters i9 coupled to count the
signals from the clock means and to provide a first output signal upon attain-
ment of a predetermined count and also a second output signal upon attainment
of a multiple of the first named predetermined count. A video adder is employ-
ed of a type for receiving and com~ining horizontal sync pulses, vertical sync
pulses, and information signals so as to provide a composite video signal of
a type to be ooupled to the video display tube. Means supplying the first and
second output signals to the adder permit the first and second output signals
to function as horizontal and vertical sync pulses respectively. A second
counting means ~preferably coupled to count the clock signals from the same
clo~k source as above) provides a third output pulse therefrom upon attain~ent
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o~ a predetermined count and a four~h output pulse upon attainment of a multi-
ple of one of the predetermined counts. Means for generating an information
signal in response to the conjoint occurrence of both the third and fourth
output pulses and for supplying the information signal to the video adder servesto provide the composite video signal thereof with its information portion to
be displayed. Finally, means for selectively varying the count of the second
counting means serves to relatively displace the information signal in time so
as to move the image along at least one coordinate axis on the video display
tube.
lQ The single figure of the drawing discloses a video image control sys-
tem according to the invention.
A video image control system 10 for causing a video image to be dis-
played on a video display tube ll ( such as a T.V. picture tube) and caused to
travel thereon selectively in a plurality of directions includes a pulse-
generating clock means 12 such as a 6MHz clock of conventional construction.
Accordingly, signals are generated along line 12 at a 6MHz frequency to be
counted by the predetermined counter 14 which functions to generate an output
pulse in response to every 255 counts received at the input side.
Counter 14 is of a conventional binary ~ype which is preset by one
count in order to establish an output signal therefrom after counting 255 addi-
tional counts for purposes as will be explained further below. Thus, a first
output signal 16 ~unctions as a horizontal sync pulse to be supplied to the t
video adder 17 also of conventional con~truction via line 15. Adder 17 is of a
general type known to the art wherein horizontal sync pulses, vertical sync
pulses, and in~ormation signals can all be combined to generate a composite
video signal on its output side as representedcby line 18.
The horizontal sync pulses 16 are counted by a second predetermined
counter 19 whereby, upon arriving at a suitable multiple thereof, such as 255
~again preset by one), an output signal 21 will serve to function as a vertical
sync pulse f~d via line 20 to video adder 17 for purposes noted above.
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Accordingly, at this point, video display tube 11 is in a position to
receive information signals superimposed upon the raster generated by the hori-
zontal and vertical sync pulses 16, 21 respectively.
These inform~tion signals are fed to adder 17 along an input repre- -
sented by lead 22 in a manner where~y the video image being displayed on tube 11can be advanced or retarded along each of a pair of substantially mutually
perpendicular axes or coordinates by means as now to be described.
Accordingly, the position of the image on tube 11 can readily be con-
trolled by a second set of counters 23, 24 each of which constitutes a conven-
tional binary counter having ~eight) outputs generating a count representing a
total of 256. Counter 23 is designated as a horizontal image locating counter
and is preferably fed directly from clock means 12 via an input represented by
lead 26 whereby, upon attainment of a predetermined count of 256, for example,
counter 23 serves to provide a third output pulse 27 on the output line 28 via
mode control swit~h 25 so as to provide ~in one mode of operation) an input to
the vertical image locating counter 24. Counter 2~ is also a aonventional
binary predetermined counter capable of attaining a count up to and including :~
256.
Each of counters 23 and 24 is arranged to provide a single output on
lead 29, 31 respectively from AN~ gates 32, 33. Thus, third output pulse 27 alsoappears via lead 29 as an input to AND gate 37.
Accordingly, only when there is a common state on each of the eight
terminals 34 into AND gate 32 will there be an output signal 27 appearing on
line 29 and similarly only when there is a common state on each of the inputs
36 will there be an output signal 30 on line 31. However, upon the conjoint
occurrence of signals on both lines 29, 31 an AND gate 37 of conventional con-
struction serves to provide an information signal on line 22 for adder 17 to
utilize in providing the composite video output on line 18~
.. Having in mind only ~he foregoing explanation, it is readily evident
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that the image generated on tube 11 will remain stationary at only a given
location in view o the fact that the first coun~ing means including counters
14 and 19 produces pulses 16 and 21 at the same rate as the second counting
means including counters 23 and 24.
However, in order to induce a relative change in position of the im-
age across the face of tube 11 along one or more coordinate axes, the count
from the horizontal and/or vertical image locating counters 23, 24 is varied by
applying a preset selectoT input as now to be descxibed.
Counter 23 is coupled directly to a preset selector 38 of known type
wherein a preset count of 0, 1 or 2 is respectively applied via the leads 399
41~42 and, thus, counter 23 can start its count one count behind counter 14
~remembering that counter 14 is preset to a count of 1), even with counter 149
or one count ahead of counter 14 depending upon whether the preset selector has
been operated to select input 39, 41 or 42 respectively. A similar preset
selector 43 serves to control counter 24 so that it, too, can operate one count
behind, or one count ahead, or even with the count generated from ~he verti¢al
sync generator counter 19.
As shown in the drawing, preset selectors 38 and 43 are respectively
shown controlled by manually operated handles 44, 46 wherely a player can,
through manual manipulation of the handles 44, 46, control the positioning of
an image on tube 11 merely by varying the state of one or both selectors 38, 43.
From the foregoing, it will be readily apparent that there has been
provided a simplified readily servicible image control system suitable and
adapted for use as an entertainment device or other manually controlled means
whereby differences in the counts generated between horizontal and vertical
sync pulses on the one hand and the horizontal and vertical image locating
counters on the other hand serves to provide selected relative positioning of
the images on the screen.
The mode contxol switch 25 may be shifted so that armature 25a opens
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the circuit to lead 28 while coupling lead 15 to lead 28 for supplying hori-
zontal sync pulses 16 to counter 2~ without any relative displacement between
their respective counts. However, the output from the vertical image locating
counter 24 is still free to introduce a relative displacement of the image
under control of manual preset selector 43.
The attainment of a full count (of 256) by counter 23 serves to gate
out the vertical image locating coun~er 24 via AND gate 37 to adder 17 when
counter 24 has attained its full count.
The switch 25 merely determines the input to the counter 24 --- as
either the horizontal sync pulses 16 themselves through the line 15, or alter-
natively the output of the horizontal image locating counter 23. ~he outpu~ 27
of the counter 23 will be close in time to the horizontal sync pulse 16 but
not exactly so unless the selector 38 is preset to "one" in which event both
counters 14 and 23 produce outputs after ~wo hundred fifty-five ~255) clock
pulses. If, however, preset selector 38 is set at "zero" or "two"; the hori-
zontal image locating counter 23 will produce an output after 256 or 254 clock
pulses respectively. If the switch 25 is set at the position shown in the
drawing, these pulses at incrementally longer or shorter periods will, of
course, be applied as the input to the vertical image locating counter 24 and
the output of that counter will then, of necessity, be at a time different
from the output of the vertical sync generator ~counter) 19. Vertical move-
ment of the image will thus occur.
The use of the switch 25, then, merely determines whether the exact
horizontal sync count is employed as an input to the vertical image counter 24,
or the ouiput of the horizontal image locating counter would be used for that
purpose. In either case the output of both counters 23 and 24 are applied to
their respective gates 32 and 33 to the gate 37 and then to the video adder 17.
With the switch in the position as shown in the drawing, adjustment o~ the pre-
set selector 38 by itself will cause both vertical and horizontal movement.
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Selector 43 will, of course, cause further vertical movement.
With the switch 25 in its alternative position, the preselectors 38
will cause adjustment of the counter 23 alone, and the preselector 43 will
cause adjustment of the counter 24 alone. In this mode vertical and horizontal
adjustment are totally independent of each other.
