June 7, 1960
2,940,005
P. M. G. TOULON
VARIABLE DISCONTINUOUS INTERLACED SCANNING SYSTEM
Original Filed July 18, 1951
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Pierre M. 61 Toulon
FIG. IO.
BY
ATTORNEYS
June 7, 1960
2,940,005
P. M. G. TOULON
VARIABLE DISCONTINUOUS INTERLACED SCANNING SYSTEM
Original Filed July 18, 1951
6 Sheets-Sheet 3
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INVENTOR
Pierre M.G. TouIOn
BY
ATTORNEYS
June 7, 1960
P. M. ca. TOULON
2,940,005
VARIABLE DISCONTINUOUS INTERLACED SCANNING SYSTEM
Original Filed July 18, 1951
6 Sheets-Sheet 4
1071;;
1NVENTOR
Pierre M. G Tou Ion
ATTORNEYS
June 7, 1960
2,940,005
P. M. e. TOULON
VARIABLE DISCONTINUOUS INTERLACED SCANNING SYSTEM
Original Filed July 18, 1951
6 Sheets-Sheet 5
FIG. I6.
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23
INVENTOR
\
BY
Pierre
M.G.Toulon
j/Zw
ATTORNEYS
June 7, 1960
P. M. G. TOULON
2,940,005
VARIABLE DISCONTINUOUS INTERLACED SCANNING SYSTEM
Original Filed July 18, 1951
6 Sheets-Sheetv 6
Line 1
N=4 (04)
Line 2
Line 3
Line 4
Line 5
First Field-Odd Lines - Uses ()1 And 04 0f Fig-5
Second Field- Even Lines- Uses 08 And 05 Of Fig 5
FIG. I9.
Le end
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m —' Green
- Yellow
INVENTOR
Pierre M. G. Toulon
BY
ATTORNEYS
2,040,005
Patented June 7, ‘1960
rents corresponding to the illumination o'fall’ thel‘p‘o‘ints
of a line, generallyall the points of "a ‘horizontalfli'rie.
Then one explores‘separatelythedifferentsuccessive‘l es
VARIABLE 'DISCONTINUOUS ' INTERLACED
"SCANNING SYSTEM
Pierre Marie'Gabl-iel iToul‘on,-=Pittsburgh, Pa., assignor,
or ' better (interlaced ' transmission) ,"one" transmits’?rs'tfof
all the odd lines corresponding to ‘a'?r'st scanning'of the
picture, then ‘the eeve'n‘l-in‘es ‘corresponding to ”a__se’coitd
scanning of the same picture, then again the‘otldline'siof
by‘mesne-assignmentsfto Moore-ianileHall, Washington,
D-.C., a partnership
I
the image following, and‘ soon alternatively. A
Continuation of “application iSpar. iNo. v237,372, July 18,
Discontinuous interlaced fscannin'g‘em'ploy the-it'rlfa?s
11951. This application-301163,1957, Ser. N0. 663,055
‘mission of vsuccessive "electrical 'currents’wlii'ch respective
ly correspond to 'd‘o'ts separate‘d’from one ‘another. These
Claims priority, application France July 19, 1950
i112 ‘Claims. ‘(CL 1315421)
signals ‘correspond respectivelytoithe luminositybt p‘or
‘
‘The ‘present invention is concerned ‘with 1a new process 15
of television 'which'permits ‘the lreduction ofthe band
Width to be used for-transmission while maintaining the
tions of picture lines ‘which'are'scanned‘successivély"by
interlaced scanning in "which the television v*b‘e’a‘m sweeps
the‘ even lines ‘and then “the o’dd;linesiof‘thepicture. This
is explained 'fully in column ‘three “df‘r'riy basic patent
noted above.
same high quality of picture, ion-again, the improvement
of the quality of picture withoutlincreasing the band
7
'
According to the ‘present ' invention ~it ' is "proposed 'to
increase the previous interval ‘of every‘otherlin‘e used in
width necessary for transmission. The invention is appli 20 normal interlace scanning toifour ormorev'line's. ‘Lines
cable particularly ‘to the transmissionof pictures in color,
located in between the lines scanned during the‘?rst frame
especially ‘for the “three-color-process.
are successively's'canned in the "course of‘m'ultiple'succ‘es
The present invention concerns-discontinuous interlaced
sive scanning of ‘succeeding'frames. "To achieve the desired
scanning systems and is an improvement on my basic
result the electron beam ‘is ‘interrupted‘periodically so "that
invention set .forth in United States Patent No. 2,479,880 25 it is lighted for only very short‘t-im'e ‘intervals correspond
granted to me August 23,, '1949'and is a continuation-in
ing to dots which appear on the‘ screenquite‘independent
part of my copending “Key Select,” ‘US. application
'ly of'one another.
_
I
Serial No. 149,062, l?le'd March 11, 1950, now aban
T
he
above
result
is
‘achieved’by
‘varying
'the'fspeedziof
doned, to which reference is imade~foria=detailed discussion
the spot cause'd‘by the’ele'ctr'on'beam' ‘on the’ screen‘fof ‘the
of certain ‘parts of theapparatus disclosed'herein, and a 30 cathode ray tube used. That ‘istheibe'arn'is held ‘sub
continuation of Serial No. 237,372, ?led July 18, 1951,
stanti'ally ‘motionless during “the lighting‘ of afdo't‘an'd‘th'en
now abandoned.
is moved very rapidly to form another “dot‘fe‘moved‘an
Although the ‘present invention is of general ‘applica
appropriate distancewfromv the preceding'dot infaccordance
tion wherever -it is desired to ‘reduce the bandwidth re
with the particular dot interlace system employed. ‘As
quired for -a given --accuracy of transmitted picture or, 35 the speed of the ‘dot ‘when vmoving fromfon‘e ‘spot 3to
conversely, to "increase ‘the accuracy of the transmitted
another is-qu-ite high and the time interval’short
picture for a given width of frequency band, it is‘par
‘compared with vthe time "allotted for 'li‘ghtin'gfa v's‘pio‘t’the
ticularly useful'for the transmission of color pictures by
trace formed is relatively ‘faint and "an ‘accepta’blelpict'ure
the trichrome process.
It isv an object-of-the inventionto reduce the‘frequency
bandwidth required for the transmission of signal data
40
interrupted during theinlter'val of ‘shift ‘or travel'fi’om one
dot to ‘another.
yielding a pictureof ‘given accuracy or, conversely, to in
*
I
"
I F
The electron 'beamco'ntrol electrodes‘are supplied with
crease :the e?ective data which can be transmitted‘ over a
-frequency band of given width 1with a ‘resultant increase
in the accuracy ‘of detailiin the'picture transmitted.
is produced. However, "the‘felectron beam'is preferably
a horizontal saw to‘oth displacement?volt’a'ge"yielding high
45
speed and'a‘vcrti'cal ‘saw ‘tooth displacement voltage’yie'ld
ing low speed. ‘In addition the ‘beam is'gi've'n’a'n initial
In the employment-of-present day techniques for ‘color,
shi?t at the ‘beginning of each line whichiisfmaintained '
one is obliged in'elfe'ctgin order to obtain the-same de?
during the scan of that line. '
'
’ "
=
> '
nition of image, tofitrainsmit in general three times as
‘For
the
purpose
of
understanding
'the‘lnent'io‘n
"the
many signals per second than is necessary in black and
picture or the screen of the cathode "ray tube'being used
white television. As a result, the transmission channels,
may be thought of as being divided‘up‘intdsr'ri'all squares
50
particularly the subterranean coaxial cables, areno longer
representing dots or elemental picture elements which
usable, or one must‘expect a large reduction in de?nition
combine to form a checkerboard. The picture or ‘screen
of the image, i.e. reduction in the number of lines and
is made up of‘a number of vsuch ch'eckerboards, depending
an increase in the ‘size of points.
upon the number of squares or dots in each‘ checkerboard.
The present invention permits, on the contrary, the
For example, such a checkerboard may'be‘c'omposed ‘of
55
transmission of pictures in'color with the presently ‘exist
four dots on a side, making sixteen dots in each checker
ing channelswhile‘maintaining the same quality of image.
board.
7
p
‘
v
_
The invention permits, moreover, the assurance of se
In my basic Patent No. ‘2,479,880 the samenchfe'chken
crecy of transmissionasclaimed in my copending “Key
board was always used 'for successive group's of“sixteen
Select” case, supra. By the word'“sec'recy” it is to be
dots making up the complet'e'picture.‘ ‘As a'result'alvvays
understood that the transmission is made in‘such a way 60 the same sequences were repeated. That‘isfthe’?i'Stdbt
that with a standard receiver not equipped with the ar
scanned of each checkerboard mig'h't'have checkerboard
rangement forming the object of the present invention,
coordinates l, 1 and the next dot scanned "migh't‘ha've
one receives only a scrambled image, whereas only the
apparatus in conformity with the invention in the hands
coordinates 3, 2 of the same checkerboardand'so‘on until
all sixteen dots of each checkerboard comprising 'thepic
of operators knowing the key of the transmission, is able 65 ture were scanned in sequence and the cycle "repeated.
to reproduce the image entirely faithfully.
The point is the second cycle and ‘each succeeding were
The invention is based on the principle of the trans
more repetitions of the ?rst cycle. Sixteen ?elds were
mission of successive eletric currents corresponding to the
required to complete a frame vof the picture and each
points of image which are separated one from the other.
cycle of sixteen ?elds and the ‘frame 'resulting‘w'er'ethe
One knows that ‘in the present systems of television 70 same.
one transmits, one right after the other, the electric cur
It is an object of ‘the present ‘invention ~t'o "provide a
2,940,005
4
3
scanning system which employs a plurality of different
permits the selection'of the exploration of the point in
checkerboards. These different checkerboards may be
used in succession to form successive cycles of diifering
nings. This process consists of the application, electro¢
each square in the course of each of the successive scan
numbers of frames or‘they can be interlocked to form
statically or electromagnetically, of an added deviation
overlapping'cycles. The order of succession of checker
boards used may be-modi?ed to yield a great number of
possible combinations. The order or particular sequence.
of checkerboards selected may be utilized as the key for
secret transmission vas discussed at length in my copending
force at the ‘beginning of ‘each scanning of the picture. In
the example of a checkerboard offour-by-four squares,
application.
‘
'
' and in the absence of all added deviation force, it is ar
ranged so that the result is the normal saw tooth scanning
corresponding to the exploration of_on'e line in four, and
10 it is also arranged that the duration of illumination of
~
the screen corresponds only or solely to one point in
rChcckerboards of four, nine, six, twelve, sixteen, '
twenty, twenty-?ve or more-dots can be used.
four; Under .these'conditions, one only ofthe squares.
(in. the four-byr-four, that is sixteen areas of checkerboard)
In the caseof the sixteen dot checkerboard discussed
in' my basic patent the saw tooth de?ection voltages are
' thatrwhich is located on the upper left_and is designated '
number 1, is alone explored in the course of the ?rst
so selected that only every fourth horizontal line is
scanning.’ In conformity with the invention, the elec
scanned and the beam is turned on only for every fourth
trostatic or electromagnetic force applied additively dur
dot. That is. for the ?rst ?eld only the upper left band >
dot in each checkerboard is scanned, the checkerboards
ing each of the sixteen explorations therefore permits the
This concept may be utilized with repetition cycles using
and image frequency‘obtained in the standard manner,
change of position vof the point explored and the applica
having four dots on a side. With the present invention,
for each dot lighted and additional electrostatic or elec '20 tion of a predetermined order of exploration.
When one employs electrostatic deviation, one applies
trode magnetic voltage isimpressed upon the de?ection
. preferably to the ?rst‘ofthe'deviation plates (vertical and
‘ plates providing a selected variation in the choice of dot
horizontal), the‘voltages of the saw tooth line frequency
to be scanned and in the sequence of dots to be scanned.
the same checkerboard as in my copending application 25 and one applies to the second de?ection electrodes of
each group of de?ectors, which are normally maintained
or it may be combined with a selected sequence of differ
at a ?xed voltage, combinations of signals having the
ent checkerboards as in the present invention.
appropriate values of voltageswhich correspond to the
In the process according to the invention, instead of
selected squareof the checkerboard. If one makes use
exploring alternatively the even lines and odd lines, one
preferably increases the interval between explored lines, 30 of magnetic deviation, one adds by preference, to the de
viation windings fed in the standard manner, the other
that is to say, that one explores for example one line out
windings exercising the desired added force or again one
of three or one line out of four, and one continues after
adds to the current supplied by the generator of the saw
, ward to explore the other lines in the course of succes
tooth voltage to that which is‘supplied ‘by the auxiliary
, sive scannings of the picture. Moreover, one interrupts
' the electronic beam periodically in such a manner that 35 deviation generator;
According to‘ one preferred arrangement, the succes
the scanned line only is lighted during very short in
stants, which thus provide separated points. Accord
ing to a ?rst variation of the invention, the scanning is
to be made at a constant speed. According to a perfected
variation, it is- accomplished at a variable speed so that 40
the spot remains practically stationary during the illumi- .
sive values of voltage necessary to assure the added dis
placemengare obtained by' a static process, and by the
aid of electrical circuits comprising electronic tubes or
recti?ers-
,
‘
'
’
‘
-
According to the invention, one connects to each of
nation of each point, then it moves afterward very rapidly
to a following point, during the same time that the beam
is interrupted. In the arrangement according to the in
the conductors supplying the second plate of the two de~
vention, the electronic beam undergoes, as is usual, ‘a
periods synchronized'with the scanningf
45 at_ Indetermined
the squares of a checkerboard of'four-by-four, that
horizontal vdisplacement in a sawtooth manner, at a high
speed and a vertical displacement likewise saw tooth, at a
low speed, butit undergoes besides, at the beginning of,
each scanning, an additional initial displacement which
is maintained during the scanning.
vlation systems,'-the pulses of rectangular form ‘in the
course of time having a given'amplitude and vproduced
is sixteen vpoints, the amplitudes 'of' these signals have
those. values which correspond, to' the whole numbers
.of successive multiples of a certain 'voltage taken as a
As a consequence 50 unity. They correspond, therefore, to zero, 1V,‘ 2V,
' of the interruption, the beam is rendered visible only for
very ‘limited positions of the screen for each scanning.
The initial displacement at the beginning of each scan
ning has a result that the position of the illuminated
points in the course of successive scannings is ,diiferent.
According to the invention, the image is divided, as
mentioned above, into a certain number of checker
' boards, each comprising a certain number of squares or
areas. For example, each checkerboard comprises four
squares in the horizontal direction and four squares in
the vertical direction, that is, sixteen squares. According
. 3V.
The value four volts would be elfec'tive to give
a deviation equal to that which is normally produced
at the endof each line of scanning by saw tooth, that
is to say, to the interval between two successive lines
of the image; »If one assumes that the checkerboards
and the points are substantially square, that distance is
equal to that ‘which separates two consecutive points ex
plored on each line.
, ~
'
-
-
> One selects, in conformity with the invention," at the
beginning of each scanning of image, the point of the
checkerboard which will be employed in applying to
the vertical and horizontal de?ection plates, the one of
to the new technique, one scans the image as many times
the speci?c values above, that is, zero, 1V, 2V, 3V, in
as there are squares in the checkerboard; for example,
the horizontal direction vand that is zero, 1V, 2V, 3V
sixteen times, and employs each time a different square
of the checkerboard.‘ The order of exploration of the 05 in the vertical direction. One maintains that added volt
age during the entire scanning of an image and one
different areas of the square can be selected at will so
changes the value of it before the beginning of the fol
that there exists a very large number of possible combina
tions in the order of scanning.
Instead of the four-by-four, that is sixteen squares,‘
lowing scanning, which'thus for the‘ remainder] utilizes
one other area in each checkerboard.
'
According to "a preferred arrangement, one employs
one is able, of course, to have all other combinations’, for 70
. a current generator'supplying 16 pulse values of volt
example, two by two squares, that is four squares; three
age shifted in relation to one another. This generator is
by three, that is nine squares; ?ve by ?ve, that is twenty
vsynchronized on the end of image signal and the dura
?ve squares; three by four, that is twelve squares; ?ve
tion of each pulse value corresponds to the duration of
by four and two by three squares, that is six squares, etc.
The invention is characterized by the’ new process which
.a scanning or image, Que limits successively the ampli
2,940,005.:
tude; of each of these. voltage; pulses by means.» of: a;
recti?er of which one regulates. thermarityms a; func
tionof; the scanning chosen; one-thus obtainsneiicdical
1y.w 16_ successive-signals having a duration andydeter
mined, amplitude on each of: the two independent con
ductors. One adds the effect of the corresponding sig
nals to each of the pulse values sov as to act on eachof
signal of 4V with. aisixteen dot checkerboard. The
repetition period or cadence‘ of, those auxiliary signals
maycorrespond to a fraction of a line, a group of lines,
a ?eld, a group of ?elds or a frame, but the law or
sequence of scanning must be the same vat both‘ the
sending and receiving stations and the stations must be
synchronized.
'
i
'
the, secondary ' deviation plates.
It is to be- understood that the invention is notlimited
In the systemwhich has justbeen described‘ a‘ com
to the process in which the electron beam is totally'in
pletescanning of image is eifectuated employing always 10 terrupted, but is also applicable to the case where the
thev same combination of checkerboards. According to
beam is modulated close to cut off or su?‘icientlyv to
an employed variation of. the invention the combination
reduce the spot ‘brilliance a desiredv amountduring beam
varies in the course of scanning. That modi?cation-can
shift of my improved discontinuous interlace scanning.
be realized for consecutive- checkerboards of a same
For someapplications themodulation of the beam as
horizontal line or else modi?ed only at the end, of each 15 just- discussed may be accomplished at the transmitter
linev of = the checkerboard.
and the sending of a carrier wave which has been periodi
In order to. put this preferred arrangement, to WQlik';
cally interrupted or reduced in amplitude can eliminate
one makes; use of. several signal devicegenerators, One
the need of doing so_at the receiver. This can be of
superimposes their elfects uponthe auxiliary de?ection
value where a plurality of receiving sets can be reduced
electrodes. These signals.correspondto'the duration. of 20 to a cathode ray tube‘ supplied from a central. receiver
exploration of one portion ofthe image or to the dura
tion of exploration of one‘ line, or’ else, to the duration
of the exploration of one checkerboard.
-
as in-hotels or the like.
.
The. invention is not limited to the systems in which
one interrupts the beam locally at the receiving set.
The invention also covers those arrangements comprising
With the. present invention the order of- the successive
combinations to be used in the course of scanning is 26 a more or less complete modulation of the intensity of
changed at the beginning of each ?eld, the beginning of
the cathode/beam which appears and disappears periodi
each group of lines scanned, or both, or at the beginning
cally according to a selected sequence on the scanned
of each selected. group. of ?elds, after“ being maintained
line. In view of certain applications one purpose of the
for. the selected period. The successive sequences of
invention is- not to exercise local control at the recep
voltage values to be added can be obtained mechanical 30 tion, but reach the. same resultby exercising at the trans
ly by using means such as a rotating commutator.
mitter on the transmitted signals of image a modulated
However, itis preferred to employ an impulse generator
action so that during certain intervals of time, no effective
in which the pulses are phase shifted to correspond to
signal will appear on the receiving screen. In this case
the number of dots in the particular checkerboard or
the cutoff produced during the ‘displacement of the cath
boards concerned. This impulse ‘generator. is synchro
ode beam is added to the received signal and it has be
nizedon the end of ?eld. A periodic phase shifter may
come unnecessary‘ to provide modulation at the receiv
be used if desired. The complex signal produced by the
ing-set.
_
generator corresponds in lengthto the length of, a ?eld
One
will
understand better the. characteristics, the
scanning or a group of ?elds as the case may be. The
term length as here used is really a graphicrepresenta 40 manner of functioning and the advantages of the inven
tion by a reference to the description and the following
tion of time. The amplitude of successive signals. is
?gures
which ‘are offered, by Way of illustration and
limited’ by the use of a biased recti?er, the amplitude of
not
by
way of limitation: in accordance with different
the biasbeing ?xed in turn in accordance with the order
forms of the invention intended to serve by_ way of, ex
of checkerboard scanning selected. One can obtain
ample and to suggest variations.
periodically sixteen successive signals having a duration
The Figures 1, 2‘, 3, and ,4 explain the order of explora
45
and. amplitude which, can be exactly determined and
tion’ of" pointswhich one is able to select in the course
applied to the de?ection system of. a cathode ray. tube.
of:successive-scannings. The Figure 1 refers to a checker
Periodic phase shift. corresponding to a change of the
board of? 6, points, the-Figure 2 to a checkerboard of 9
combination need be used only if desired. When multi
points, the-Figure 3 to a checkerboard of 12 and theFig
ple, signals are used the effects are. added and act through
50 ure 4 to a checkerboard of 16 points.
the second set of plates ofthe tube de?ecting system.
Figure 5‘ indicates the different combinations from
The same checkerboard'scanning order. may of course
(El-C24 and‘ exploration of which one is able to obtain
be used for scanning an entire frame, but‘ this tends, to
by- means of a?gure of only 4 points.
produce a “moving grid” effect which is a local'?icker
Figure 6 represents the simplest-manner of explora
that. can be eliminated by changing the combination
used in each successive checkerboard or by having dif 55 tion which one is able to obtain by always employing
the same checkerboard combination.
ferent checkerboards. follow each other. The simplest
solution is obtained by altering the dot scanning se
Figure 7‘ is an improved variation in which one em
quence and continuing‘ with the same checkerboard,‘ but
ploys two- combinations C1 and ‘C2; the ?rst’ line em~
it‘is possiblerto have different checker-boards follow each
ploys the points of‘ the combination C1, the second line
other even though the dot scanning sequence for similar 60 the points of‘ the combination ‘C2 and following alter
checkerboards in the sequencevis changed also.
natively.
Excellent results are obtained‘ by the use of two or
Figure 8 is another improved variation in which one
more independent local de?ecting signals the effects of
employs alternatively the combination of C1 and C2__ along
which, are superimposed to produce the‘ auxiliary local
horizontalline and one shifts these combinations on
de?ecting system. One sequence of signals’ may pro 65 the
theend of . line.
vide de?ections for a six dot checkboard, one sequence
Figure 9.is an application of-the principle of the. inven
for another gorup. The combination of the two may
tion to television in color by the three-color process.
in some, case produce a checkboard of a third grouping of
EigurelOdescribes-as a function of time the voltages
dots. Other local signals will produce the discontinuous
scanning within a given checkerboard and so on.‘ The 70 which his desirable to apply successively to the-vertical
and horizontal de?ection electrodes to obtain the; scanning
‘principal thing to guard against is to check the resultant
of 16;.points iii-accordance with the Figure 4.
of all the local signals combined and determine that
Figure 1'1ris:a circuit diagram for obtainingdotinter
they do not interfere with each other’s effects and that
the, resultant does not produce effects suchas described
lacescanning according to the invention as part of a sys
above in connection with the use of» a local de?ection
tern =providing=secrecy of image.
‘
7
FigurelZLis another form of'circuit' diagram compris-v
ing a variation of Figure 11.
>
<
~-
-
8
the digit 1 which corresponds to a new ‘image'
- ~
,
~
9 points,“ and‘ the numbersv inscribed ‘in thepsquares in
numbers,~ 0+.1+2, above and to the left of the cross
Figure 14 is a working diagram showing how the unit
lines, they indicate theauxi-liary de?ection voltages to
be employed according to' the technique already de
scribed in ,connection'with the Figure l.
which in Figurerl3 are taken ‘as part of the generator
'
'
"
5
10
?
Figure, 15 explains how one is able to obtain statically
and at'thebeginning of each exploration the desired dis
placement of the cathode beam.
.
'
Figure 17 shows how one is able to limit the amplitude
of these points so as to obtain a substantially rectangular
signal.
,
.
r
.
,
'
Figure 18 explains as a function, of time how from 20
,
_
'
_
g
,
i
.
,
,
.
0+1+2+3jare necessary for the horizontal de?ection.
Figure 5 represents all the different combinations of
order. of exploration which can be obtained ,with a
checkerboard of onlyl4 points: they are at number fac
torial 4, that is to say 4X3 ><2><1,,th-at is 24. They are
thesepoints one obtains statically the necessary signals
for the exploration of a checkerboard of 16 squares.
Figure 19 is‘ a graphic statement of the invention as
a scanning system.
vertical.
" For covering the 16 elements of the checkerboard of
Figure 4, the 4 values of voltage 0+1+2+3 are neces
sary for the vertical de?ection and 4 values of voltage
tion of time the voltage pulses in point form shifted from
v
v
" m the checkerboard of 12 elements of Figure 3, one
is able to achieve exploration with 4 values of de?ec
tion voltages following the horizontal and 3 following
the
Figure 16 recalls how one is able to obtain as a func¢
one another.
Y 3
UP dicate thelorder of; scanning. As for the inscribed
' ‘
circuit diagram of Figure 13 is, employed by multiples
inparallel'and with certain elements indicated for clarity
symboL.
_
The Figure 2 relates to .the case of ‘a checkerboard of
Figure 13 is ‘an elementary unitcircuit diagram show?
ing how‘ dot interlace scanning’ can be achieved and
used to provide secrecy of image.
.
plored; the cycle is repeatedv'with ‘a 'newrexplorationiof
referred to by C1,.C, . . . C24.
.
_
Figure 6 shows how in a ?rst variation one explores
the whole surface 4 times consecutively, employing the
order of exploration given in the combination of C, only.
,
As represented in Figure 1, the image, which com
prises for example 450 lines of 500 points, is divided
One couldvmake the same exclusive use of any other of
the combinations of 4 elements of Figure 5; if instead of
into a certain number of checkerboards, comprising two
a. checkerboard of 4 points, a checkerboard of 16 points
should be used (Figure 4), one would have 16 factorial
vertical sense. One has therefore'450 divided by 3, that
is 150'checkerboards in the vertical sense. The number 30 combinations, a number which is extremely high. Con-..
fsidering that it is necessary to know the. combination
of points of each line being 500, one will have
to bejemployed. in the exploration to obtain an image
points in the ‘horizontal sense, and three points in the
‘500
2
at the, receiving station with clarity, this method permits
the complete assurance ina very excellent manner of
35 secrecy in the transmission of images.
Figure 7 is an improved variation. ‘One makes use
of a ‘line'of a checkerboard in which the combination C1
appears exclusively (odd' line).. One then employs a
line of a checkerboard in which the combination C,‘
that is 250 checkerboards in the horizontal sense. Ac
cording to the invention one interrupts the cathode beam
periodically in order to cause only one point out of two
to appear.
‘One connects to the de?ection electrodes of the tube 40
a saw tooth scanning voltage'in the manner in which it
appears-exclusively (even line).
‘
I
.
The following line of a checkerboard employs anew
the combination C1 (odd line) and one continues the
exploration of the whole image employing alternatively the checkerboards C1 and C2- for the even and odd lines.
in the vertical sense; but one arranges for the electronic
beam to be displaced in height corresponding to 3 points 45 Figure 8 is another improved variation in which one
'makes alternately on each line of the checkerboard the
in ‘the vertical sense during the scanning of each hori
combinations C1 and C2, being careful to shift the point
zontal line. Under these conditions the point indicated
of starting of the second line in relation to the ?rst. For
by ‘the digit 1 in each of the 15.0 by 200 checkerboards
the third line one returns to the order of succession of
?nds itself explored successively in the course of the
50 the elements C1 and Capt the ?rst line of the checker
?rst scanning. I
board and thus successively for the even and odd lines
When the ?rst scanning of the 150 x 250 ?rst points
of the checkerboard.
.
'
has 1been completed, one begins again, but making sure,
Instead of the two combinations C1 and C2 alterna
according to the invention, to apply permanently the
tively ‘one is able, according to the invention, to employ
proper deviation for the exploration of the digit 2 of the
55 any number. In- employing the checkerboards of Figure
checkerboard.
4 as well in the vertical sense or in the horizontal sense’,
On the Figure 1, one has identi?ed by 0 and +1 the
.and one is ablerto modify at will the amplitude of shift
two , vertical columns of the checkerboard and by
between the adjacent elements of the vertical lines.
0+l+2+3 the horizontal rows of the checkerboard.
Instead of a checkerboard of only four elements, one
The second scanning corresponds to the digit ,2. That
digit is located in the second vertical column (+1) and 60 is able, according to the invention, to utilize any type
of checkerboard, for example, those described in the
in the third horizontal row (+2).
Figures '1 m4; that is: 2 by 3 or 3 by 5, 4 by 4 or 5
One-operates in the same manner a third scanning, cor
by 5, etc. and between these elements the invention per
responding to digit3 with an added voltage of 0 in the
is used in standard receivers: voltage with line cadence
in the horizontal sense and voltage with image cadence
‘the digitr4 with an added voltage of 1 in the horizontal
mits the explorationrwith all possible arrangements.
The Figure 9 represents‘ six groups of vcheckerboards
of 16 points each usable for threeacolor images. One
shall notice that the number of points I (color yellow) is
sense and 0 in the vertical sense.
equal to the sum of the numberof point R ,(red) and B
horizontal sense and +1 in the vertical sense and one
explores thus anew 150 x 250 points of image.
One begins again a fourthscanning corresponding to
Then a ?fth scanning corresponding to the digit 5 with
85
(blue). One obtainsv automatically a phase shift of the
an added voltage of 0 in the horizontal sense and 2 in the 70 points of the different horizontal lines of a‘ pitch of four
vertical sense.
v
7
lines, particularly applicable to three~co1or television
After which, the six scannings having been completed,
with point interlace scanning, by the use of three com
plementary colors, R red, I yellow and B blue.
In the Figure 9, the, lines are horizontal andv ‘follow
that is to say, all the points of image having been ex
.75 one another-in theorder indicated by the numbers 1, ,2,
Finally a sixth scanning, with an added voltage of 1
in the horizontal sense and of 1 in the vertical sense.
59
'3, 14,3, 6, ‘7.8, 9 written to .the right :of theehecker
:board. The sequences are indicated on the right of
ithese numbers. The exploration is made ‘following
the Ehorizontal garrows :L which appear above the
checkerboard. ‘The varrow I refers to theodd images,
{theiarrow f-Pto‘ the even images.
To :facilitate the identi?cation of the elements corre
sponding to the ;colors B,'R:and3‘I (that is to say-:tolblue,
to :red and to yellow) .oneiplaces the letters 1B, lR'and ‘I
.10
'exploratiominithexcase~of"Figure ‘4. ‘.Duringithe half or
the -three~quarters Irema'ining 40f the period, :the "grid 1 is
‘brought to afhigh-lnegative:voltage which practically in
terrupts .-the.=electronic beam and suppresses the effect of
rthe - modulationtbeam.
As :is customary, during :the moment when the grid
.is notlpolarized, tit- controls :the *videopsignal ‘and assures
the Ifaithful lreproduction .of the darkness of the ‘point
undereon‘sideration. ‘When .the electronic beam is in
on some of . the. ones .of the squares :of 1 the checkerboard. 10 :terruptedthe screen is not ‘lighted, IsoLthat the explored
In referring .to vthe numerical indications of the se
points successively appear separate ::one from the other.
quences carried on .the Lrightof the grillof 1Figure:9,»one
For :the purpose of obtaining‘thediiferent scannings
sees that all the points of image .are explored by two
‘with thezselecte'di position in the checkerboard, tone: em
successive scannings corresponding to a ‘group of odd
vploys 1a group of revolving .commutators which apply
lines and a group ‘of even lines. ‘The scanning can'begin 15 continuously ‘on ithe 1 two ‘ de?ection plates 53B ‘and "53D
.on 2a .point 1R, after which come the points JBJ .of the
the voltage valready determined above.
.cycle,‘:RIRlRJB IR] BJR JBR . . . it is of importance
On the ?gure rcan 'be seen the ?rst arm ‘(59, :turninglto
.in:.order tohave .the best results to avoid vertical :lines
contact :the sixteen segments 1- 57, connected :to . the: second
‘of color.
vertical tplate 53D1and=a second term ‘#60, sweeping .also
‘When'the .explorationof the?rst'?eld ‘has begun with 20 .on st-hesixteen segments .58,‘ connected'to the second hori
1R, it is advisable to begin the third line on the .point
zontal de?ection plate 53B. Thesetwoarms :59‘ and‘60
JJ, tthepoint .Ribeing shifted one row vto the right in re
lation to .the ?rst line. The line 5 ‘begins anewon the
.point'R. ‘The line 7 isagain shifted .onerowto theright
and thus in turn to the end of the explorationiof ‘the ?rst
?eld 10f odd lines.
‘During the exploration of the second ‘?eld of even
‘.lines and as indicated by the number to be seen on the
are driven "together by ,a small synchronous motor 61
synchronized on the end of image . pulses ‘I. The number
:of polesin this motor is “a function .oft-he'number images
:to be explored ‘(the number of squares of .the checker
board). :In :the ‘case of :thenc'heckerboardao'f Figure 4,
the motor has'two times sixteen-poles as one must make
asixteen ‘successive explorations ‘of image.
:rightofthe Figure 9, the line ‘2 is explored ‘but .all of the
‘In Figure 151 the‘ different sectors 57 are supplied by
points are shifted two rows to the right with reference 30 (the connections from a source .163 ‘having .a grounded
to theline 1 of the first ?eld. With the exploration of
terminal and comprising .lfour .plugs :supplying {the 'volt
the line 4.occurs.another shift of one row withireference
.to line 2, theme the scanning of the line 16 in the same
manner as :that of v:line 2 and so on .to the ‘end .of the
secondz?eld comprising the even‘lines.
On .the Figure 1.0.one has represented on the ?rstlline
N the order of sixteen successive .scannings of .image.
ages zero,'+1~V, +2V, +3V. Thesegments :58 are also
supplied with di?erent voltages, +1V, .+|_2-V, .etc. ‘from
a source 64 having a grounded terminal. "Thezsuccessive
sectors are'connected :to {terminals having :the indicated
value on the Figure 10. The?rst :line N indicates ‘the
‘voltages vapplied to the successivetsegments :57. The/sec
0n ‘the second iline V one has indicatedthe value of'the
:9nd: line H indicates the :voltages ‘.appliedtothe successive
voltages which are to be applied in v:the vertical senseiand
segments 58. One is able to>represent~in=the ‘following
on the third line H one has :tindicated the values of the 40 31113111161‘ qtheperformance'of thesystem. The position of
voltages which are to be applied in the horizontal/sense
to obtain the selected order of exploration ‘as described
the arms '59 and .60 @issuchthat at the beginning-of the
scanning of reach image,eacl1 armis found at thei'begin
in Figure 4. The choice of these valuesis .easily :under
hing ~ of a ‘segment. During the entire duration of‘the
stood according to the explanation zwhichihas :been given
scanning 'Qf-that segment-the voltages on the ‘plates 53B
.above in connection with Figure 1. The voltages :to be 45 ‘and 5.3.13: ‘are ‘maintained vconstant :soqthat all the-points
:applied in the vertical sense V are successively: 0; '2; 3;
of image corresponding ,to ca 1 determined number = of the
1; 2; 0; =3; 1;‘0; 2; 1; 3;.2; 0; 1; 3;'0; andinthe horizontal
checkerboard are explored. During the ‘rapid return of
sense H,-0; 1; 3; 2; 0; 3; 1;‘(); 2; 3;.1; .0;-2; 1; 3;.2; .0.
the cathode'beam-of the end of image, the scanning arms
The Figure 11 is a construction which permits obtaining
:59 and ‘60 pass from :onersegment to the‘next. New
the different voltagm described onthe Figure 10 and 150 values a are thus 1 applied “to ‘the second electrodes, vertical
enables also exploration of the checkerboards of the Fig
and horizontal, 53B ‘and 5313; the general direction of
ure 4. The output of the receiver of radio 50 is con
nected to a single separator 51 supplying three distinct
rthekcathode beam is modi?ed and ‘the point of image
synchronize the sawtooth voltage generator 54 supply
ing the horizontal de?ection plate 53A of this tube 53.
Horizontal
The pulses of the end of line I also supply, as is well
known to the art, a sawtooth voltage relaxation oscillator
'Vertical deviation voltage: ,_-.. 0; .1; 1; 2; O; 0; 1; 2; 2
:corresponding to a second square of the checkerboard
channels which correspond: the ?rst V to the video sig
‘is likewise explored and so 1.on.
nals; the second I to the end of image synchronization 55 Jlfone had employed ‘a checkerboardaof ‘nine elements
signals; and ‘the third L to the end of line synchroniza
of the Figure -2, the-scanningewillihave‘been realized fol
tion signals. The video signals are applied through a
lowing that given in'tthe table below:
secondary transformer 52 to the modulating grid of a
Order ofexploration: _______ 1;.2; 3; 4; 5; 6; 7; 8; 9
cathode ray tube 53. The signals of the end of line
56 supplying the vertical de?ection plate 530. The
pulses produced by the generator 54 in the sawtooth 65
serve to synchronize a frequency multiplier. Its relation
deviation
volt~
age: ._________ __ ____ _-__ 0; 1; 2;'0; 2; 1; 0; 2; 1
.1111 this case the turning commutators would-have nine
segments instead-of sixteen.
'
I'In the case of the checkerboard with sixteen ‘elements
represented in ‘Figure 4, if the image comprises for ex
ship of multiplication corresponds to the number of
ample
400'lines of 500=points eachyone is able to- divide
checkerboards existing in each horizontal line ofthe tele
thesurface to be scanned in 125 ‘groups in width and
vised image (for example 250 in the case of Figure 1 re
ferred to above). The voltage of the output of multi 70 100 in height. One isiable to-assumeiforthe'purpose of
‘discussion that one ‘has chosen ‘a ‘frequency of image
plier 55 ‘has the effect to bring the grid of the tube 53
equal ‘to 96 per second. The‘necessary time to explore
to a voltage around zero (which allows the modulation
all of the points of image is ‘therefore v96 divided ‘by 16,
coming through channel V), during a fraction only of a
{that is dper second. vUnder thesecondi-tions, the video
period, for example one-half the time for the exploration
in the case of Figure 1 and one-quarter the time for the 175 frequency applied to the control grid of the tube '53‘
‘would be 96 times '100 times 125, ‘that is ‘1,200,000 per‘
2,940,005
point 88 of conductor 85 to the‘de?ection plate 53B of
second and a line frequency of 96,000 per second. The
pulse frequency of the oscillator 55 would be also equal
to 1,200,000pi1l'ses per second. The speed of the syn~
tube 53. Therefore when the arm 75 touches the segment
'76 iti'short'circuits the resistance. 86 and when on the
'chron'ous motor would be 96 divided by 16, that is 6
turns per second. In the system of exploration which
other hand the arm 75 touches the segment 77 this re
has just been described, the complete image is scanned
using always thesame squares of the checkerboard and
the changing of. position of the square used is effected
only at the end of scanning of image. It is desirable
in certain applications to provide two degrees of phase
shift in ~the horizontal direction.
sistance’86, is applied to the terminals of the battery 80
and causes a decrease of voltage having the valueV.
The respective decreases of voltage of 2V through re
sistance 72, and of 1V through the resistance 86 are of
the opposite sense and add their effects on the plate 53B
10 of tube ‘53; In combining thusitheir effects by means
of two commutators one is able to obtain the conditions
.of Figure ,9 in the following manner.
At the beginning of the scanning, the arm 75‘touches
When one uses an exploration of interlaced lines, one
explores onlyoneline of two so that the odd lines of
the ?rst part of segment 76 and the arm 65 touches the
the checkerboard are scanned ?rst, then the even lines.
.?rst part of segment 66. The decrease of voltage is null
Anticipating a horizontal phase shift at the end of each
scanning of image, one is able to change the position
of the square of the checkerboard employed without
on the two resistances 72 and 86. Therefore there is no
de?ection voltage and the explored point is the red point
R of Figure 9.‘ .At the end of scanning of the ?rst line,
making the intervening auxiliary vertical displacement.
the commutator 75 passes from the segment 76 'to the
According to a perfected variation of the invention,
one makes another phase shift at the end of each line.
segment 77, inserting, as has beenseen, the rmistance
86 to the terminals of which appear the voltage of one
According to the invention, the second deviation system
which is added to the ?rst goes into action for each
exploration'of- ?eld corresponding to the even lines. This
combination of de?ectors with a superposed effect on the
volt which applied to the de?ection plate 53B advances
by one row to the right all the points of the line. The
third line of the ?eld is thus scanned with a phase shift
line frequency and the image frequency, enables one to 25
equal to' one unit.
realize by the application in succession of several rotating
After the line 3, the arm of commutator 75 passes
from the segment.77 to the segment 76, placing the re
sistance 86 in short circuit, which supplies no voltage at
commutators such as those in the Figure 12.
Figure 12 is a perfected variation following which one
'
all to the circuit of the de?ection plate. _ Following'the
changes the position of the square explored in each check
erboard, not only at the beginning of each exploration 30 return of the de?ection voltage to zero,'the line 5 under
.
of image, but as well at therbeginning of each line. Fol
lowing‘the invention, one employs in series two con
trolling de'vice's, one synchronized on the end of line
pulses and the other on the end of image pulses. The
simultaneous action of the two commutators permits 35
goes the same scanning as the line 1 has undergone.
After the line 5, the arm 75 returns to the segment 77
and the de?ection voltage of 1V which result assures a
scanning of the line 7 with a phase shift equal to one
obtaining selected types of scaning by interlaced points.
unit. The cycle of operations described repeats itself
until a'complete' exploration of the ?eld of odd lines.
As one is able to see on Figure 12, the high frequency
waves are received at 50. A separator 51 permits the
segmenti66 to the segment 67, and connects the resistance 7
by' separate points. The'single end of image ‘I, synchro
50 264 of the image are'explored in’ the same manner with a
At'that moment the commutator arm 65 passes from
72'to. the terminals of the battery 69. There is thus sup
sending of the 'video signals'in' the ?rst channel V, the
image signals in the channel I and, the end of line signals 40 plie'd’to tliedeilection plate 53B a voltage of ‘2V, which
produces‘ .a' phase shift equal-to two units in the course
in the channel L. A relaxation oscillator 544is syn
of scanning'in the entire ?eld'of even lines." In particular,
chronized with the end of line signals in channel L and
the line _2; whichv is the ?rst line of'the second ?eld, under
supplies the plate 53A of the tube 53. A second ‘relaxa
goes a phase shift equal to two. unitswith' reference to
tion oscillator 56 for scanningis'synchronized with the
frequency of image I and supplies the plate 53C.v The 45 the line,l'. "After the line .2 the arm’ 75 passes to the
s'egmentz77' and causes the application of 3V on the plate
signals of‘the end of line serve "also to synchronize a
53B following the addition of de?ection voltages of'2V
frequency'multiplier 55 which periodically impresses on
already acquiredjand the'decrease of 1V through the re
the grid of the cathodev tube 53A'very high‘frequency.
sis'ta'nce'86f' The ,1ine4 of the second ?eld'and the line
vThe arrangements assure in a general way an exploration
nizes va small synchronous-motor 61 which drives the arm
of commutator 65 at a speed corresponding to half the
frequency of end of image; The arm of commutator 65
is displaced in contact with 'thesegments 66 and 67, the
former connected by’ the conductor 68 Vto‘the ground
terminal of a battery having a value of voltage 2V (the
choice of the value V has been explained on the Figures
l—3)fwhich has its other terminal connected to segment
67 by'the conductor 70. The ‘conductor 71 connects the
arm of the commutator 65 to a terminal of resistor 72
having another. terminal connected 'to they earth pole of
the battery 69 so that at the terminals of this resistance
appears a‘decrease of voltage which represents in some
way the output of that element of the circuit. ,
I
pli'ase'fshift'
with respect toline 1 and so on.
One
succeeds therefore in achievingthe scanning correspond
ing.to the arrangement of exploration chart of Figure 9.
- ‘.The arrangement which has just beendescribed is ap
plied ‘to the case where the deviation action is applied
only on one of the deflection plates (horizontal). It is
evident tha't‘a' similar procedure could also be applied
equally to the secondrvertical de?ection plate.
The new mode ofiexploration which has just been’ de
scribed v?nds an important application in three-color.
The inventioniperniits the suppression of the phenomenon
of'?ic‘keringcolors which generally manifests itself. It
‘may beutilizedequally ‘onpthe receiving screens in which
the’ colors‘. are arranged in the vfor-m of vertical bands.
A second small synchronous motor 73 is synchronized 65 - The'arrangementis notably ‘applicable when the choice
of colors is modi?ed at the end of each scanning of image.
withthe frequency of the end of line by the conductor
The‘ invention permits the utilization of de?ection volt
74 and drives a second arm of commutator 75 at a speed
ages introduced to the circuit of Figures 11 and 12. One
corresponding to half the frequency of the end of line L.
.of itsjvariati'ons is to explore successfully each ?eld in a
The arm 75 turns to contact the segments 76 and 77. The
conductor 78 connects segment 26 to a terminal 79 of 70 single color while being ableto blend the d-i?erent colors
which produces ‘an excellent quality of image. The posi
battery 80 having a value V.‘ This terminal 79 is con
nectedby'the'conductor 83 to the other pole of the
battery 80. The arm of commutator 75 is connected
through resistance 86 to the point 84 of the conductor 82
.by the conductor 85.v The vconductor .87 connects the 75
tion of explored 'points‘follows the principle of explora
tion of the knight’s move or interlaced points, which sup
plies excellent clarity.‘ That’ combination eliminates the
apparent crawling of colors '(stroboscopic effect) in the
13
2.940.006:
event of movement of the eyes as. a result of the per~
sistence of the impression on-the retina. For example,
the connections on the segment (Figure 12) enables one
to achieve the exploration of the type described in-Figures
5 to 9 in such a way that the ?rst. ?eld would be ex
plored by the selection of red elements exclusively on
theodd lines, the second by the exclusive selection of‘
154'
a pulse’ and is; obtained‘ by‘ the; superposition of several
sinusoidal' voltages; of the frequencies n1, nlF, n2F, the
oneebeing. a harmonic of thef'other. The value of the
voltage has a function of time: as represented: at 21 in
the’ Figure;16; Atthe beginning of the signalsof syn
chronization of the. end of image represented at 25 on
that ?gure, one initiates the action of several oscillators.
the yellow elements on the. even lines, the third by the
On- Figure‘ 16, one has represented as a function of
exclusive selection of the blue elements on the odd, lines
time. at Hand 19 the voltages provided by these oscil
and the fourth by the exclusive selection of other yellow 10 lators- at: a frequency of ZF-andv 3F; the curvell results
elements on the even lines. It may happen that certain
from the superposition of the curves l8 and 19. By
points of the surface may never be'scanned. That is
means of a recti?er, properly polarized, one isolates each
notably the case of a square checkerboard of sixteen
ofthe points, which meansto shift the curve'in' the verti
points where the yellow elements are equal to the sum
cal
sense and‘ isolating each of the. points (cross hatched)
of the red and blueelernents together.
15 thus produced. One constructs as many of the curves
That shortcoming can be corrected (a) by employing
as, one desires. having-the; signal of the sameform, and
diiferent widths: of. groups, (b) by. making equal'the area
thesewcu‘rves, areshift'edsthe; one. with respect to the other;
of the red elements, blue and yellow, (0) by lining up
one employs the- technique already- known" and described
in a line the elements. having a certain color.
by the-author. in his. French. patent No. 840,915.
When there are uninterrupted continuous vertical lines 20
Starting; from these two. oscillators n1F and: nlzF, one
of color on the screen, one is able, thanks to the knight’s
creates the; distribution'ofl phase shift currents. From
move scanning, to jump the points and to obtain that the
these- distributions. and by means, of. a coupling of ap
whole scanning of the; ?eld be effected with one color
propriate values,‘v oneis able to create in the independent
alone. As an example of the principle b above, one
circuits the'voltagesin the form of ‘ points, all having the
shall‘ employ it in scanning the ?rst ?eld in such a way
same form and: phase shifted with respect the one to the
to explore the points R onthe odd lines, one will explore
other; The maximaof the curves‘ 21, 22 and 23 in
the second ?eld by selecting the points I on the even
number“ equal to those of‘ the successive signals which
lines, the third in selecting the points B on the odd-lines
one wishes 'to obtain, are regularly distributed in the
‘and the fourth-the points R on the even lines, which will
course» of . time.‘
correspond to a complete image. For the following image, 30
If‘ one. wishes: to obtainan exploration of a checker
one will scan the ?rst ?eld by exploring only the points
board of 16 squares, one is led according to the invention
I on the odd lines and then following each cycle repeats
to utilizingfor example three oscillators having'as a com
itself by moving up one color. The advantages of
mon multiple the frequency of scanning of‘one. entire
knight’s move scanning lie in great part in. the explora
image. One make-suse of 16 points of voltage, regularly
tionof the elements of the same color in each explora
phase shifted the one with respect to the other and; such
tion of image because of the physical separation of the
as represented in the Figure 18.
colors one obtains up to a certain point the knight’s:
move. effect.
Following a perfected variation of the invention, in
stead ‘of using the arrangement of mechanical commu
tators described in the Figures 11 and 12, one is able to
obtain by an entirely static method the auxiliaryv devia
tion, voltages.
The Figure 13 explains how one is able to obtain dur-.~
ingan exactly known time (and corresponding for ex~
‘ample to the duration of a scanning of image) the sig
nals of rectangular form having an exactly determined
The Figure 14 shows; how, by utilizing several times.
the showing of the Figure 13, ‘one is-gable to supply to the
de?ectionplates the severalrequired voltages as desired.’
Thevdifferent points (to they number» 16 for example)
supply. eachtime a group of resistances and recti?ers.
The rectangular voltages which appear‘ successively in
each construction are arranged in parallel through the
decoupling resistances. 12, 12', 12", etc. The terminals of
these resistances, 13, 13', 13", are connected to the
second‘ deflection plate. of the- tube. The etfectsof these
voltagesare'thus. added. To obtain as a function of time
thecross hatch. curve (Figure 18:)v which corresponds to‘
One calls upon an alternating voltage generator G
thev explored picture of- 16 squares just referred to, one
which supplies through a polarized battery, a resistance, 50 should. adjust the ?rst commutator 9 on the segment 0,
11 in which appears a voltage in the form of sawtoothed
the second commutator 9' on the segment 2 and the third
points and a recti?er 7.
on the segment 3v and so on. One obtains thus. the signals
According, to the invention, one is- enabled to limit the
correspondingto the cross hatch curve.
amplitude of this point to an appropriate value by use
It the checkerboard to be explored comprises only four
of a recti?er 8 suitably polarized by a battery 10. For
squares,,it isno longer necessary to call upon a, generator
the exploration of the 4 by 4 squares the voltage of that
G'comprisingw several frequencies, sub-multiples the one
battery can have four dilferent values. On that ?gure
with respect to the. other, ‘but one is able to be satis?ed
one. has represented schematically by the commutator 9
with the employment of' a single sinusoidal voltage,
the means which enable the selection of a desired ampli
thus in this manner the arrangement greatly simpli?es
tude. According to whether the commutator is on the 60 itself.
one or the other of the segments, the pulse is cut to a
Figure 15 describes. a static arrangement giving the
amplitude.
level more or less elevated ‘and one. succeeds therefore in
sameresultasrthe mechanical system described in Figurev
12, that is to say, permitting the change of‘ a phase shift
On Figure 17, one sees to an. enlarged scale, one of
of explored points. not only at the end of- each scanning
the points which has been isolated by means of the recti 65 of image but equally at the‘ end .of each scanning of line.
having a signal having. any desired amplitude.
?er 7. On that curve one has drawn in dots the several
values corresponding to the position of the commutator
One has represented at 90 the receiving set which receives
the radio waves. 107, then ampli?es and separates the
S9. The cross hatched part 24 represents the form of
video signal V, the. end of line signal L and the end of
signal obtained when the commutator 9 is in the second
image signal I.
position. This rectangular shaped signal appears. on the 70
A ?rst oscillator 94" connected on the end of image
terminal 13, which is employed to apply the desired volt
pulses'I; furnishes on the line 97 a voltage of the fre
age to the deviation plate during the remainder of the
quency half of those of the endof image. That line sup
scanning under consideration; a decoupling resistance 12
plies tosecondaries of the transformer: the ?rst 98 is in
is provided on the circuit.
phase, the second 99. in opposition. The voltage supplied
The generator voltage G' is preferably in theform of 75.
by the secondary 98 is recti?ed, by the recti?er 102: so that
2,940,005“.
175
16
a’ pulse of voltage corresponding to a'half alternation’
comprising the picture image. These individual dots
appears in the resistance 108. The recti?er’ 104 and the
resistor 101 contribute to limit the value of that ?rst sig
nal ‘as has just been explained in connection with the
were scanned one afteranother throughout each line in
what was substantially a continuous line prior to appli
Figure 13. In the particular case, one has supposed that
the ?rst signal was 0 so that one has not placed the battery
in series on the recti?er 104.
cant’s patent. The result was often a grayed-out picture
of somewhat drab appearance and uneven in light value.
Applicant’s patent taught discontinuous scanning of
dots in a line- and treated the television screen as divided
into a number of checkerboard patterns, such as shown
The voltage in phase opposition with the proceeding fur
in Figure 4, each containing sixteen dots. The individual _
nished by the secondary 99 permits by means of recti?er
107 obtaining in the resistance 103 a voltage pulse de 10' dots were then scanned in each checkerboard in the se
quence shown by the little numbered squares each of
phased by 180 electrical degrees with respect to that pre
which represents a dot. As a conventional television
ceding. One limits the amplitude of that point and one
tube has ?ve hundred twenty-?ve lines each with four
hundred ?fty dots, the above patent taught the use of
15 a grid comprising about one hundred thirty checker
currents.‘
.
boards high by one hundred twelve wide. Each checker
The effect of the signals obtained at .110 on the re
board isfour dots square, comprising sixteen dots in
sistance 108 and at 120 on the resistance 123 is com
obtains a signal of known value thanks to recti?er 108, to
the battery 119 and the resistance 116 which limits the
bined in 124, by means of the decoupling resistances ‘105'
all. The de?ecting coils of the cathode ray tube are ac
and 125. .By analogous manner one synchronizes ‘on the
cordingly constructed to scan every fourth line, being
half of the end of line frequency another oscillator 93 20 the‘top line of each small checkerboard and every fourth
whichsupplies an alternative distribution line 126. That
dot along the line, being the little squares numbered “1”
in Figure 4. The ?rst ?eld of scanning according to the
above patent is then every fourth dot‘in' every fourth
the voltage of 127 and'by means of recti?er 133 one ob
line, comprising about one hundred twelve dots in each
tains at the resistance 137 a pulse of voltage in phase. 25 of lines 1, 5, 9, l3, 17, 21, etc. The second ?eld com
One limits the amplitude of that pulse by the combined
prises all the dots numbered “2” in each small checker
action of the recti?er 134, by the resistance 132 which
board. vIt will be seen that the displacement between
limits the current and the conductor 135 of vwhich the
dots’ “l” and “2” corresponds to the “knight’s move” in
voltage is conveniently chosen. In the particular case
chess and it is obtained by the superposition of small ,
of the ?gure 'no battery at all 'has been represented so that 30 incremental voltages upon the tube de?ection system.
line supplies a transformer which provides a voltage in
phase 127 and a voltage in opposition 128. One employs
- One employs in the same manner the voltage 128 and
When thesuperposed vincremental voltages are zero the
tube scans tall the “1” dots as described above. When
by means of the rectifier 144 one obtains in the resistance
151 a pulse of voltage in opposite phase. One limits the
the superposed voltages are +2 in the vertical direction
the‘?rst signal is 0.
i
V
and +1 in the horizontal, the tube scans all the “2.”
amplitude of that voltage pulse by means of recti?er 145, 35. dots. It will be seen that the “3” dots are scanned when
of the battery 147V and of the resistance 143 and one thus
thesuperposed voltages vare +3 and +3 as shown in
obtains a signal of rectangular form as explained above
Figure 4.
0
in connection with Figure 13.
,
'
After sixteen ?elds all the squares in every small check-V
erboard were covered and the sequence is repeated be
The signals obtained in 141 at the terminals of the
resistance 137 are utilized through the decoupling re 40 ginning ‘with the seventeenth ?eld, the same small
checkerboards being used throughout. Although the
sistance 139 and those obtained on 148 through the ter-.
above system is a great improvement over the scanning
minals of the resistance 151'are utilized through the de
of alternate complete lines, it has been found particu
coupling resistance 152. The effects are added in 154.
larly in three-color television that the little checkerboards
One combines in 142 the voltages obtained in 125 and
154 and one applies'them to the second de?ection plate 45 tend to stand out from the picture and produce a moving
mosaic or pattern effect. The effect is sometimes seen
53D of the cathode beam tube. The ?rst de?ection plates
in animated billboards where a traveling pattern moves
of that tube receive, as is customary, the sawtooth voltages
across a contrasting background. This action detracts
for scanning; the scanning line 92 synchronized on the
from the television picture and can cause such discom
signal L, the scanning image 143 synchronized on the
pulses of the end of image I. The video current V is 50 fort in viewing that a color television receiver may be
applied to the. control grid of the cathode beam tube
come unbearable.
through a system 91 which periodically interrupts the
The invention as a process or method
beam at the frequency of the pulses. That system is
synchronized on a multiple of the end of line image.
The constructions which have‘ just been described re 55 ' The solution to the above problem, and the instant
invention, lies in charging the small checkerboard so that
late to one form of receiver but it is obvious that equiva
lent arrangements are applicable in the same way to a
a different sequence of dots is used on adjacent checker
boards. In this way the dot arrangement in each little
checkerboard does not impress itself on the observer.
Résumé
60 Each small checkerboard loses its individuality and all
tend to merge together. The observer no longer ?nds
The present application concerns discontinuous inter
himself subconsciously following a small individual square
laced scanning in television systems and is a continua
group of dots moving across the image as if it had in
tion-in-part of copending. application Serial No. 149,062,
dependent existence and a life of its own.
?led May ll, 1950, and van improvement upon applicant’s
In Figure 4 the simplest checkerboard of four dots
U.S. Patent No. 2,479,880.
has been selected and as there shown, twenty-four dif
The invention lies in the particular manner in which
transmitter, iconoscope, image orthocon, etc.
a television screen is scanned so that “color crawl” is
ferent sequences of dot scanning, making twenty~four
diiferent checkerboard patterns which may be scanned.
As a result the group of dots comprising the small
tained. While the invention improves the black and
white image it is especially suited to the-improvement 70 checkerboard never impresses its group individually on
eliminated and a clearer, more brilliant image is ob
of the three color television image.
'
According to. applicant’s .basic patent in the art, see
above, under RCA andmostof the industry is licensed,
a television screen is regarded as divided into several
hundred lines, each line comprising several ‘hundred dots,
the observer and a brilliant even picture free from de
feet is obtained. It will be appreciated that greater
variation is possible where checkerboards having more
than four dots are used.
The four-dot checkerboard is
employed for illustration because of its simplicity.
Of course not 'allthe vtwentyafonr‘variants shown in
'ently believedztotbe the preferredrformsofitheiinventidh,
.Figure 5 need "be ‘used :to {obtain tthe‘tdesired ‘e?ect and
to practice ‘the invention. Figure >16 rshows 1simpli?ed
dispersed or discontinuous {dot iinterlace scanning ac
variations rthereof vwill ‘be 1 dbvious {to those :‘s'kill‘ed i'in ith'e
art "and all such‘changesand (variations‘fwhichffall'iw thin
the spirit of the invention are intended ‘ftobe ‘cover-‘e Yby
the generic 'terms :in the appended claims, ‘which ‘are
cording :to the vsaid patent :where ‘the ‘same checkerboard
is used‘throughout. ';Figures 7 Iandf8 ‘showésimple forms
variably :worded '?to ‘that Tend.
of variable discontinuous I'd'otin'terlace scanning accord
ing to the inventionin ‘whichadjacent checkerboards are
di?erent.
‘
I
Having thus described my invention-l ‘claim:
.1. .In .an ‘electron "beam 'scanning system, ran “explored
A more ‘general statement of ‘the invention in graphic l0
ionn‘is shown fin Figure :19, ‘using C1504; C5 and C8 of
‘Figure :5.
surface de?nedby apluralityl'ofgroups :of elemental are:
areas, each group de?ning substantially ‘a .frectangular
area comprising phosphorsiof-larpluralitylof’colors,inieans
'
forv generating an ‘electron scanning beam, tnieansitfdrfhori
According to the simple iforrn shown in Figure '19,
zontally ‘and vertically ide?ect‘ing-z‘said {beam in ‘synchro
scanning'according to the invention is as follows:
nism with a line andi?eldirequency respectively, ‘periodi
Each :frame comprises siXteeni?elEls-L
15 cal modulation means causing saidébearnltoLapproachmut
at? sufficiently closely to reduce the “effect of "the'beam
Field 1 marked by ‘one "sen dotiin each square
on said explored surfaceIb'elowia‘value’deemed‘to have an
Field 2 marked by one, green .dot'inieach square
undesirable effect on said surface fdu-ri'n’g id‘e‘?e‘ct‘i
of
'Fie'ld‘3 'marked‘by one'blue dotin eachfs'quare
said‘ beam, ‘means for ‘synchronizing said w‘de?ectingtrr'ua'a'ns
‘Field 11 marked ‘by one ‘yellow dot ‘in .each square
20 and said periodical modulation meansis‘o that at de'astZdne
Field 5 marked by two redfdotsIin each square
elemental ‘dot - area in teach 'ofisaid “groups asrseanneniuu'r
Field 6 marked by ‘two green dots in each square
'ing ‘eachi?eld v'andidi?erent elemental dot areas vi'n-‘e'ach
Field 7 marked‘ by -t-wo r'blue dots in "each square
of said groups Kare scanned iuuring-suecessiveone's nrrsaiu
Field 8 marked by .two yellow dots .in each square
:?elds, said de?ecting means having auxiliary de?ecting
The succeeding eight ?elds are, marked by correspond?
means being so constructed thatlitiperiodicaliy‘raltersitlie
'i'n'g'shor‘t colored‘bars. It ‘ivill'be seen that each checker
.bo‘ardl'is surrounded ‘by ‘assure? checkerboard with a dif
scanning sequence ‘of said elementalv dot'fa're'a's within
‘ferent arrangement of Hot vsequence. .A-s a result, ~there
:is .‘no continuity of pattern and therefore no apparent
‘2. The combination s’e?forthiinicil'éiim 11,1131 Which-‘said
modulation ime'ans icau'se's 'ip'e'riodical interruption rot said
.be‘a‘m'in synchronism with sat-.11 de?ection Brneans, teach
Isucc'e'ssivelyscanned individual groups.
Imovementof a‘ checkeiboa'rd across .the picture-image.
The above maybe saints comprise a method of scan
ning which is one form of the invention.
‘
1
-
‘
~
'
said group comprising a-fchecke'r'l-board arrangement 'iha’v
ing at least four elemental dot areas.
3. An electron beam scanning system, comprising an
explored surface de?ned by a plurality of groups of at
As shown in Figures 1 to 5 inclusive, the secondary 35 least four substantially equal elemental dot areas ex
The invention as a device
displacement of a cathode ray beam to a selected dot e.g.
tending substantially equidistantly along two coordinates
and comprising charged particle responsive material for
“3” within a selected checkerboard e.g. C1 is obtained by
superimposing a small voltage upon the main de?ecting
producing a plurality of colors, means for generating an
voltage along each axis. If we can think of the beam as
displaced to a given checkerboard, such as C1, some
where on the picture image, and assume for simplicity
that +1 volt will move the beam one dot corresponding
to the numbered squares making up the checkerboards,
electron scanning beam, means for de?ecting said beam
along said coordinates in synchronism with a line and a
?eld sequence, said beam periodically decreasing the pri
mary electron content of said beam to reduce its light
producing effect on said surface to a nonin-terfering value,
means for so synchronizing said means for de?ecting and
said means for producing periodical decreases in primary
electron content of said beam that a corresponding ele
mental dot area in each of said groups is scanned dur
ing each ?eld and that di?erent elemental dot areas in
then the main de?ecting circuit will direct the beam at “1"
in C1 and to scan dot “3,” selected above, it will be neces—
sary to superimpose one additional volt in the horizontal
direction and one additional volt in the vertical direc
tion. These small superimposed voltage increments are
supplied in a regular patterned sequence by a simple
each group are scanned during successive ones of said
commutating switch device such as shown in Figures 11 '
and 14 which apply small stepped voltages from a bat
tery such as 40 to the de?ection plates 83a-83d of a
cathode ray tube 83 in a preselected sequence to pro
vide a scanning pattern such as that shown graphically
above in which the sequence of dot scanning in adjacent
checkerboards is different, so that continuity of apparent
movement of a dot group is broken. Figure 15 shows a
circuit for obtaining the small incremental voltages in
a desired sequence without a commutator or similar
moving parts which have limitations and disadvantages.
It will be understood that the above discontinuous dot
interlace scanning system is equally applicable to a ?at
screen of the wall type where an electron gun is not em
?elds, said de?ecting means having an auxiliary source
of signals connected thereto being so constructed and‘
arranged that it periodically alters the scanning sequence
of said elemental dot areas within successively scanned
individual groups.
4. An electron beam scanning system, comprising an
explored surface de?ned by a plurality of groups of at
least four substantially equally elemental dot areas ex
tending substantially equidistantly along two coordinates‘
and comprising charged particle responsive material for
60 producing a plurality of colors, means for generating
charged particles, means for applying said charged parti
cles to said surface along said coordinates in synchro
nism with a line and ?eld sequence, that a corresponding
ployed, but a grid having apertures corresponding to ‘ele
elemental dot area in each of said groups is scanned dur
mental picture areas is gated to admit charged particle 65 ing each ?eld and that different elemental dot areas in
?ow in the form of individual “beams” according to a
each group are scanned during successive ?elds, said
desired scanning pattern. Reference is made to my co
means for applying said charged particles comprising
pending applications and U.S. patents among which are
stepped voltage producing means for providing voltages
the following: app, S.N. 321,095 ?led June 12, 1951,
corresponding to the coordinates of the positions of said
now U.S. Patent No. 2,713,517; app. S.N. 508,144 ?led 70 elemental areas on said surface.
May 13, 1955, now abandoned; U.S. Patent No. 2,558,019
5. An electron beam scanning system comprising elec
?led April 2, 1947; U.S. Patent No. 2,595,617 ?led No
tron beam producing means, an explored surface in the
vember 18, 1948; U.S. Patent No. 2,760,119 ?led January
15, 1952.
path of said beam, de?ecting means adjacent said beam
and causing said beam to periodically scan elemental
While there have been described above what are pres 75 dot areas of said surface said de?ecting means compris
2,040,005
‘19
"120
__ing means causing said beam to remain substantially
' 10. A television system comprising. a television re
stationary on each of said elemental dot areas for‘ a pre
ceiver having a picture screen comprising“ a plurality of
;detcrmined time and then causing s‘aid beans to move
-_~rapid1y to the next elemental d'ot are‘aito ‘be. explored,
ibeam modulation means synchronized with said de?ect
ing means and causing the intensity of said‘beam to be
of a plurality of colors, means .to scan‘ said elemental
areas in course of successive ?elds, said means {to‘sc‘an
reduced during said rapid movements, said de?ecting
relative position of'individual elemental ‘areas ‘in suc
cessive groups to be scanned, whereby color crawl is
‘means comprising stepped voltage producing means. hav
ing: opposed ‘recti?er elements for causing said beam
to scan ,di?'erent individual elemental dot areas:of prede 10
groups ‘of elementalrareas, each ' group comprising areas
comprising means "for'eselecting different sequences‘ of
eliminated.
'
9
~
11. The combination set forth in claim 10, said re
termined groups of elemental dot areas in successive ex
ceiver ‘comprising a cathode ray tube having de?ecting
plorations of said surface, said de?ecting means includ
-ing further means periodically'changing the number of
means constructed to cause the beam to move in .a peri
elemental dot areas in each of said groups; " r _'
,
odic sequence of discrete steps.
7
12. The combination set forth in claim 11, means. for
_ 6. ,A television system comprising picture means, said 15 applying discrete electrical values to said de?ecting means
in accordance withv a preselected periodicsequence and
picture means comprising a plurality of groups of ele
means for determining the periodic sequence said groups
mental areas, each .group having areas for producing a
substantially all having the same numberof areas, ‘said
plurality of colors means to scan said elemental areas in
means ,to scan being constructed to provide. a number
course of successive ?elds, said means to scan compris
of ?elds per frame bearing. a whole number relation
ing means vfor selecting different scanning sequences of
.elementalareas in successive groups to be scanned. '
to the number of areas in. each group. 7 .
‘
- 1
7. The combination set forth'in claim ‘6, each ‘group
having ‘the same number of elemental areas.
8,. ,The'combi‘nation' set forth in claim 7, said groups
.'being arranged in horizontal alignment.
,
v ' '9." The combination, set forth in claim 6, each group
References Cited in ‘the ?le of this patent .
UNITED STATES PATENTS
2,093,157
Nakashima .. _____ _,___’_ ‘Sept. ‘14, ‘1937
_ 2,472,774
Mayle' ____ -;_.....>...__-_‘__‘ June 7, 1949
having the same number of elemental areas-said groups
' 2,479,880 ., Toulon _'_,__1_ ________ _'.;_. Aug. .3,‘ 1949
. being arranged in horizontal'and vertical. alignment, ‘said
2,508,267
Kasperowicz ___‘_____ __,,_-May 16, 1950
last means selecting-said ‘elemental areas in a‘predeter
2,586,482
Rose ____ __. _______ __,_'_ ,Feb._ 19,‘ 1952
mined order having-aperiodicity equal to the number of 30
.elemental areas in each group;
' ‘
a
.
2,595,548
-m