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Патент USA US2406812

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Sept. 3, ‘1946.
E. M. DELORAINIE
AL _
2,406,812
FACSIMILE SYSTEM AND METHOD
Filed Jan. 30, 1945
4 Sheets—$heet l
TRIM/5M1 TTEE
INVENTORS
EDMOND M. DELOR?/NE
HENRI a. BUSIGNIES
BY
LOU/S n. m-Rasn
I
ATTQEE'VEY
a
Sept.v3, 1946.
'
'
i E. M. DELORAINE ET AL
2,406,812.
FACSIMILE SYSTEM AND METHOD
Filved Jan. so,‘ ‘1945
4 Sheets-Sheet 2
INVENTORS
EDMOND M. 0540mm:
HENRI a. BUSIGN/Es
LOUIS ?- “ROS/9
u
'
TORNEY
Sep‘t. 3,1946.
'
E. M. DELQRAINE ETAL
2,406,812
‘
FACSIM'ILE SYSTEM AND METHOD
Filed Jan. 50, 1945'
4 Sheets-Sheet 3
20
(351
TRANSMITTING DRUM
0
' um=
v ARENBLY
- 75 HORIZONTRL
DEFLECTOR
“CILLRTOR
INVENTORS
EDMOND M. DELOR?/Né'
HENRI G. SUSIE/WES
“W
.ATTOIMZEY
Sept. 3, 1946.
E. M. DELORAINE ET AL _
. 2,406,812
FACSIMILE SYSTEM AND METHOD
Filed Jan. so, 1943 >
4 Sheé’cs-Sheet 4
INVENTORS
EDMOND M. BELOW/NE
HENRI 6. BUSIGN/ES
BY
tall/5 H. BIRD-SH
2,406,812
Patented Sept. 3, 1946
UNITED STATES PATENT OFFICE
2,406,812
FACSIMILE SYSTEM AND METHOD
Edmond M. Deloraine, New York, Henri G.
Busignies, Forest Hills, and Louis A. de Rosa,
Staten Island, N. Y., assignors to Federal Tele
phone and Radio Corporation, Newark, N. J., a
corporation of Delaware
Application January 30, 1943, Serial No. 474,144
11 Claims. (Cl. 178—5)
2
1
from the particular description of a few embodi
ments thereof made with reference to the ac
This invention relates to communication sys
tems and more particularly to radio communica
tion systems of the built-up character or simu
lated facsimile type.
companying drawings, in which:
Fig. 1 is a diagrammatic View illustrating a
'
possible form of transmitter-receiver equipment;
It is often necessary to provide a system ‘in
which communication can be maintained despite
relatively‘ high level interference.
Fig. 2 is a schematic showing of the trans
mitting apparatus of Fig. 1 with the cover partly
In the time
broken away;
Fig. 2A is a detail of the light shutter of the
‘of war, high level interference may be in the
form of intentional jamming by enemy stations.
At the same time it is quite necessary to main
10
tain communication despite these attempts of
the enemy to disrupt the same. As a general
rule telegraphic code communications are easier
to read through interference than the voice sig
transmitter;
Fig. 3 is a schematic diagram of the transmit
ter-receiver
apparatus
explaining ‘operation
thereof;
.
Fig. 4 is a diagram of an embodiment of the
nals. Telegraphic code signals, however, may be 15
receiver scanning circuit;
jammed by transmitter stations sending out im
pulses having substantially a telegraphic code
tion of the circuit of Fig. 4; and
'
Fig. 5 is a. set of curves explaining the opera
Fig. 6 is a diagram of the oscillograph screen
explaining the reproduction of a character.
It is a principal object of our invention to
Turning ?rst to Figs. 1 and 2', I0 represents a
provide a communication system which will be
casing covering a form of transmitter-receiver
effective even in the presence of high level in
apparatus which may be used in accordance with
terference.
our invention. This housing 10 includes a trans
It is a further'object of our invention to pro
mitter portion comprising keyboard ll, knob [2,
vide built-up character systems in which the re
ceived signals are rendered effective by visual 25 the purpose of which will be stated later, and a
knurled knob 14 which may be used for starting
indicating or recording means.
the drive motor for the transmitter equipment
It is a still further object of our invention to
when a synchronous motor is used. The trans
provide a system wherein the signals are trans
mitter preferably is in the form generally similar
mitted during an interval which is short relative
to the spacing therebetween, and are character 30 to that disclosed in our copending application,
character.
7
ized by a steep wavefront and a relatively high
peak to average power.
It is a still further object of our invention to
provide at the receiver means for eliminating
relatively low level interference signals before
reproducing the received signals.
In accordance with our invention, we provide
a transmitter for transmitting a high level signal
composed of a relatively short train of impulses,
Serial No. 469,056, ?led December 15, 1942. This
arrangement comprises a drum 20, Fig. 2, ro
tated by some means not shown. On drum 20
are arranged perforations 2| which each repre
sent a series of signal elements forming a par
ticular character to be transmitted. Within
drum 20 is provided a photo cell 22 and exter
nally of the drum is provided a light source 23
and re?ecting mirror 24 serving to direct the
the impulses each representing a portion of a 40 light from 23 generally toward photo cell device
22. The light, however, is prevented from im
desired character. At the receiver these signals
pinging on cell 22 by reason of shutters 25 con
are translated .and visually reproduced on an
trolled by selectively operated keys 26. Prefer
oscillograph screen 01' some well known type of
ably, drum 20 is maintained continuously in rota
recording medium. Preferably, a limiter is pro
tion at a speed several times higher than the
vided at the receiver to pass only those portions
normal operating cadence of the keys 26. Thus,
of the received signal above a predetermined
upon depression of any selected key 26 the drum
energy level. Since the interference signals are
will rotate a plurality of times. The shutter ar
generally lower in amplitude, for the same power
expended, the interference is quite largely elimi
nated by the limiting action at 'the receiver.
When a limiter is not provided the interference
will generally form only a background for the
rangement is designed to permit transmission of
only one character even though the drum is
brought into transmitting position a plurality of
times for each key depressed. This single trans
mission is timed to start at the beginning of the
stronger wanted signals.
selected character.
A‘better understanding of our invention and
The shutter operation may be better under
the objects and features thereof may be had 55
3
2,406,812
stood by reference to Fig. 2A. Support plate
20A is provided with a light passing opening 2 !A.
A cam with a raised portion 22A is arranged for
rotation with the drum 28. The movable shutter
plate 23A is provided with a light passing open
ing 24A and a lug portion 25A, and is held in
4
arrangement 33 is operated in timed relation with
the transmitting drum 20. This scanning control
mechanism may be of a type to be later explained.
The output from scanning control 33 operates
the horizontal or line and the vertical or frame
scanning source 34 from which the scanning
waves are applied to cathode ray tube 35 coupled
depression of a key, pull bar 26A pulls shutter
to the output of receiver 35. The output of re
plate 23A to the right tensioning spring 28A
ceiver 36 is preferably limited to remove the lower
until pull bar cam 21A is positioned above the 10 level interference in clipper 38 and the clipped
place normally by untensioned spring 28A. Upon
releasing cam.
Rotation of the cam causes pro
jection 22A to raise pull bar 26A releasing shutter
plate 23A when the proper drum position is
reached. Spring 25A upon release pulls plate
23A to the left and the momentum of the shutter
23A is sufficient to cause opening 24A to register
with 2|A permitting passage of light and at the
same time momentarily slightly compressing
spring 28A, which upon its return will again put
the openings out of alignment. The characteris
tics of the spring 28A and the weight and friction
of shutter plate 23A are proportioned to provide
only one opening of the shutter for a single key
operation. Upon release of the key, draw bar
26A returns to engagement with lug 25A on
shutter plate 23A under control of a key return
means, not shown.
In order that only one key may be depressed
energy applied to a control grid 3'! to control the
intensity of the cathode ray beam in accordance
with the input signals.
Thus, if signals are being received at 36 from
- some distant station, motor 39 is operated to
drive scanning control 33 at substantially the
same speed as the transmitter drum, it being un
derstood that all communicating equipments will
have transmitter drums operating at substan
tially the same speed. By use of knownv forms
of speed control operated by knob I2 the motor
at the receiving station may be adjusted to a de
sired speed. However, in an embodiment of our
invention, to be described more fully later, the
maintenance of synchronism of the receiver and
transmitter is not essential. Line and frame
scanning waves are generated at 34 and applied
to the de?ector plates of 35. As the scanning
at one time, we provide any known form of block
takes place, the cathode ray beam is altered in
ing mechanism which may prevent depression of 30 intensity by signals impressed on grid 37. The
any otherkey while one is in the depressed posi
gear assembly 3| may be ordinary reduction gear
tion. This mechanism may, as is well known in
ing for driving the transmitter drum at a lower
the art, comprise a row of balls of such dimension
speed than motor 30.
that depression of one key pushes the balls to
Transmitter drum 2!! is preferably made of very
gether so that no other key can be depressed until
light material and may constitute merely an
the ?rst depressed key has been released and re
opaque ?lm with the signal elements photograph
turned to its normal position. Alternatively,
ically reproduced thereon as transparent rec
notched bars 21 as shown may be provided as a
tangles. Since the transmitter drum is very light
keyboard blocking mechanism.
in Weight a relatively small motor is required to
The photo cell 22 may be connected to a radio 40 drive it at the desired high speeds. By using
transmitter i5, Fig. 1, from which the impulse
transparent ?lm, different sets of character ele
trains de?ning the characters are transmitted
ments may be readily substituted having differ
for radiation. The transmitter is operated for
ently shaped characters so that should the enemy
only a short interval relative to the character
capture one of the transmitter equipments and
spacing and so may have a very high signal level
begin sending signals to confuse the messages, it
with respect to the average power consumed.
is merely necessary to change to a drum having
Likewise, the pulses preferably have a very steep
differently shaped characters in order that the
wavefront. The equipment may also be provided
true message can be distinguished from the false
with a radio receiver [5 coupled to receiver equip
message from the enemy station.
ment in casing 59. A visual reproducing arrange 50
It is clear that the scanning control mechanism
ment such as a cathode ray screen I6, Fig. 1, may
of mechanism 33 may be of any desired type pro
be provided for reproducing the received pulses
ducing impulses for determining the frame and
from a distant station.
scanning frequencies for the received signal. For
The keys are preferably operated in non-pe- ,
example, mechanism 33 might constitute any im~
riodic fashion by the operator thus producing a
pulse contacts, one for each revolution of the
random distribution of the transmitted char—
drum, to provide for the frame synchronizing con
acters.. The enemy cannot then jam the trans
tact wave and the other having as many contacts
mission by sending pulses of similar character to
as there are lines in the juncture of this in
the character grouping since he cannot know the
stance '1.
timing of the operators signals, as there is no
If the character is to be reproduced only once,
?xed timing. As a consequence, the jamming 60 it is necessary that the drive motor be synchro
pulses generally will fall between the character
nized with the transmitter so that the character
signals and will appear on different parts of the
screen.
To jam the signals by transmitting energy to
cover effectively the whole receiver screen would
require a jamming transmission of at least several
times the peak signal power. Such a transmitter
is so large as to be considered impractical.
will appear properly on the cathode ray screen.
In accordance with our invention, however, means
65 may be provided rendering such synchronous re
lationship unnecessary. An arrangement of this
modi?cation of our invention may be better un
derstood by the description made with reference
to Figs. 4, 5 and 6.
Turning to Fig. 3, a better understanding of
Turning ?rst to Fig. 4, there are provided two
the transmitter and receiver equipment may be 70 drums ill) and 4| mounted on the same shaft as
had. In this ?gure is shown a motor 30, which
drum 32 of Fig. 3 and rotated therewith. Drum
may be a variable speed motor or any other suit
‘40 is provided with a single contact element 42
able type, coupled through a gearing mechanism
connected through shaft 43 with a source 44.
3| to transmitting drum 20. A scanning control
Cooperating with disc 40 is a brush 45 coupled
2,406,812»
5
6
through a condenser 46 to the grid of a gas dis
charge tube 41. Tube 41 is connected over rel
atively high resistor 48 to a source of positive
voltage supply and a condenser 49 is connected
cathode ray beam is alternately positioned at Al,
A2, A3, A4 to make the four dotted representa
between resistance 433 and‘the plate of tube 41.
Because of the large resistance and the positive
voltage the voltage of the condenser is built up
tions of the ?rst line of scanning. Each line of
scanning will be broken by the serrated waves
so that only one-fourth of the normal line will
be present in each character.
This will cause a
dotted representation of the received character.
in accordance with the curve A of Fig. 5. How
In order to accomplish switching of the beam
during each line of scanning at a sufficiently high
ever, upon rotation of disc It to such a posi
tion that the conductive segment 42 is in con— 10 rate to provide division of the shortest line im
tact with brush 125 and animpulse is impressed
pulse, the square waves associated with each of
upon the grid of tube El. causing the tube to
the saw-tooth waves should be at least ten times
break down and discharge condenser 49. When
the frequency of the saw-tooth. For the second
contact {i2 passes brush t5, the charging cycle
line the beam is again switched alternately to
of the condenser is repeated. Thus, a saw-tooth
voltage of curve A, Fig. 5, is produced. This
may serve as the normal framing control for
the four positions Al, A2, A3, A4 corresponding
to the second line of the scanning and so on until
the entire character has been reproduced four
times on the screen. Should the receiver be out
of synchronism with the transmitter then the
the oscillograph. However, in order to reproduce
the signal by framing impulses on the upper and
lower halves of the screening for the circuit, ar 20 entire pattern may be shifted on the screen to
the positions shown at the right of Fig. 6. In
rangement is provided. An oscillator 50 pro
this arrangement Al has become split into four
ducing square waves of the type shown in curve
B of Fig. 5 is coupled over condenser 5! to one
portions, A2 and A4 into two portions each but
of the grids of mixing tube 52. Similarly, the
A3 is produced in its entirety on the screen of
saw-tooth output from condenser-resistance cir 25 the oscillograph. It is thus seen that by break
ing the signal up into four parts on the repro
cuit 48—li9 is applied over coupling condenser
duction there will always be at least one of the
53 to another grid of tube 52. The tube is pref
characters reproduced completely.
erably relatively high biased by means of the
It is clear that instead of making four images
condenser-resistance biasing network 54. Tube
52 becomes conductive in di?erent amounts by 30 some other number might be chosen with a cor
responding controlof the scanning mechanism
the application of the square wave B and the
to produce the desired number of frames.
saw-tooth wave of curve A to produce a result
It should be clearly understood that many
ant output curve such as shown at C of Fig.
modifications may be made in the system of our
5. It will thus be seen that the cathode ray
spot as controlled by the vertical de?ecting 35 invention as disclosed in these particular ex
amples. Instead of a cathode ray cscillograph
plates traces a broken line formed by the upper
other known forms of oscillographs may be sub
portions U of wave C and a second scanning
line represented by the lower portions L of wave
stituted, if desired. Likewise, the details of the
C. This will thus produce separate framing im
transmitter construction and receiver construc
pulses for the upper and lower halves of the 40 tion may be varied at will without departing from
cathode ray screen.
The cathode ray beam is
the scope of our invention.
While we have described above the principles
meanwhile controlled in brilliance by the signals
of our invention in connection with speci?c ap
applied to the grid 31, Fig. 1, reproducing the
paratus, and particular modi?cations thereof, it
character in two positions as shown by Al and
A3, Fig. 5. Preferably, the grid is biased so 45 is to be clearly understood that this description
is made only by way of example and not as a
that the beam is completely out off in the ab
sence of received energy.
The second disc 4| is provided with '7 con
limitation on the scope of my invention as set
ductive segments 6| to 6'3, inclusive, which are
brought successively into contact with brush 55
similarly to the operation of segment ‘42 with
accompanying claims.
brush 45. Thus, seven separate impulses are im
pressed on the grid of tube 56 for each rotation.
mitter means for transmitting a series of im
forth in the objects of our invention and the
'What is claimed is:
1. A communication system comprising trans
pulses de?ning a character during a period of
time which is short relative to the time between
source of high potential and serves to charge a 55 characters, a series of signal elements related to
a selected signal character to be transmitted, said
condenser 58. The time constant of circuit
pulses having a sharp wave front and a high ratio
51-58 is made such as to produce the desired
of peak to average power, receiving means for re
saw-tooth voltage effect for the line scanning.
ceiving said series of pulses, interference mini
It should be clear that if a different number of
lines is desired, a corresponding number of seg 60 mizing means at said receiver for eliminating all
energy below a predetermined level substantially
ments should be provided on disc 4|. The saw
lower than the peak energy level of said signal
tooth wave generated in circuit 5‘i—58 is applied
elements, and reproducing means for reproducing
to a mixing tube 10 similar to tube 52 and a
the character represented by said signal elements.
square wave is also supplied to the mixing tube
2. A communication system according to claim
rroma separate oscillator ‘I l. The resultant out
put wave is in the form of a serrated saw-tooth
1 wherein said transmitter means comprises char
shown in curve D of Fig. 5. This resultant wave
acter designating means provided with different
is applied to the horizontal or line de?ecting
character designations, means for selecting a de
electrodes of the oscillograph. This serrated
sired one of said character designations, means
wave will thus produce alternate line scanning
to position said character designating
70 operating
positions at Al, A2, respectively, Fig. 6.
means into character transmitting position in the
In operation of the circuit the received im
order of twenty times in a predetermined cycle,
pulses are applied to the control grid of the
and means operating to transmit said selected
Tube 56 is connected over a resistance 51 to a
cathode ray oscillograph. During the time while
the ?rst line impulses are applied to the grid the
character once only during said predetermined
cycle.
2,406,812
7
3. A communication system according to claim
1 wherein said transmitter comprises a rotary
drum, said drum being provided with sets of
perforations representing said series of signal
elementslfor each character to be transmitted,
photo-electric means and a cooperating light
source cooperating with one another through said
perforations, shutter means normally covering
said perforations, key means for selectively oper
8
means responsive to operation of a selected key
of said keyboard mechanism for transmitting the
series impulses representing said selected char
acter for a predetermined relatively small frac
tion of said predetermined cycle at an energy
level high with respect to the average transmit
ted power, whereby said selected characters are
transmitted at a high energy level and at random
intervals dependent upon the operation of said
ating said shutter means to uncover selected ones 10 keys, receiver means for receiving said transmit
ted series of pulses, visual indicating means for
of said sets of perforations to permit cooperation
reproducing said character from said received
of said light source and said photo-electric means,
drive means to rotate said drum at a predeter
series of pulses, and manual adjustable means for
mined speed relatively high with respect to the
adjusting the operation of said indicating means
operation time of said keys whereby said charac
to synchronize it with the transmitted pulses.
ter designations are positioned in transmitting
position a plurality of times during said cycle,
and means to close said shutter means after pas
sage of a relatively small fraction of the time of
7 . A communication system according to claim
6 further comprising means for eliminating re
ceived energy below a predetermined level sub
stantially lower than said transmitting energy
said cycle.
‘20. level to minimize interference effects.
8. A communication system according to claim
4. A communication system according to claim
6 wherein said relatively small fraction of said
1 wherein said transmitter means comprises char
cycle includes a period su?icient to transmit said
acter designating means provided with different
character designations, means for selecting a de
character once only, said receiver and visual indi
sired one of said character designations, means
operating to position said character designating
cating means further comprising means for re
producing said character a plurality of times at
different positions, whereby at least one of said
means into character transmitting position in the
reproductions will be complete.
order of twenty times in a predetermined cycle,
9. The method of communication comprising
and means operating to transmit said selected
character once only during said predetermined 30 transmitting a series of impulses related to a
selected character during a period of time which
cycle, and said reproducing means comprises
visual indicating means for reproducing the se
is short relative to the time between characters,
shaping said impulses to provide a sharp wave
lected transmitted character in four separate
front and a high ratio of peak to average power,
scanning positions, whereby at least one of said
reproduced characters will be complete on said 35 receiving said transmitted pulse series, and vis
ually reproducing said selected character from
indicator.
said received pulse series, whereby said repro
5. A communication system of the type using
duced characters will have a greater visual bril
a keyboard mechanism operating in a predeter
mined time cycle for selecting a particular char
liance than interference energy because of said
high energy level.
acter represented by a series of signal elements
10. The method of communication comprising
for transmission and a receiver with character
transmitting a series of impulses related to a se
indicating and reproducing means, comprising
lected character during a period of time which is
character designating means provided with dif
ferent character designations, means for posi
short relative to the time between characters,
shaping said impulses to provide a sharp wave
tioning said character designating means into
character transmitting positions a relatively great
front and a high ratio of peak to average power,
number of times during the selecting time cycle,
receiving said transmitted pulse series, clipping
and means responsive to operation of a key of
said received pulse series'to eliminate all energy
below a predetermined level substantially lower
said keyboard mechanism selected at random for
transmitting the series impulses representing said
than said peak energy level to reduce interference,
and reproducing said received clipped pulse series.
selected character for a predetermined relatively
small fraction of said predetermined cycle at an
11. The method of communication comprising
transmitting several series of impulses related to
energy level high with respect to the average
a selected character during a period of time which
transmitted power, whereby said selected char
acters are transmitted at a high energy level and
is short relative to the time between characters,
shaping said impulses to provide a sharp wave
at random intervals dependent upon the opera
tion of said keys.
front and a high ratio of peak to average power,
6. A communication system of the type using
receiving said transmitted pulse series, and vis
a keyboard mechanism operating in a predeter
ually reproducing said selected character from
mined time cycle for selecting a particular char 60 said received pulse series in several positions,
acter represented by a series of signal elements
whereby said reproduced characters will have a
fOr transmission and a receiver with character
greater visual brilliance than interference energy
indicating and reproducing means, comprising a
because of said high energy level and at least
one unitary reproduction despite lack of syn
character designating means provided with dif
ferent character designations, means for posi 65 chronism in transmission and reception.
tioning said character designating means into
EDMOND M. DELORAINE.
character transmitting positions a relatively great
HENRI G. BUSIGNIES.
number of times during the selecting time cycle,
LOUIS A. DE ROSA.
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