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Патент USA US2109339

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Feb. 22, 1938.
A‘ MCL. NICOLSON
2,109,339
VARIABLE SPEED TELEVISION
Filed Feb. 8. 1954
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RECEIVER
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AMPLIFIER
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INVENTOR _
Alexander M‘Lean Nuznlsnn
BY M/KQXQW
ATTORN EY
2,109,339
Patented Feb. 22, 1938
UNITED STATES PATENT OFFICE
2, 109,339
VARIABLE SPEED TELEVISION
Alexander McLean Nicolson, New York, N. Y., as
signer to Communication Patents, Inc., New
York, N. Y., a corporation of Delaware
Application February 8, 1934, Serial No. 710,229
'7 Claims. (Cl. 178-63)
This invention relates to the transmission of
intelligence in the form of visible images with
a rapidity su?icient to give the illusion of motion
and particularly to such a system employing an.
5 electrodynamic electrical discharge or arc, which
is propagated along a predetermined path and
modulated in accordance with the light and shade
densities of an object or image being transmitted.
There are several different types of systems for
the transmission of images, which fundamentally
distinguish from one another on the basis of the
method of and apparatus for propagating
light
beam over the object or screen used for observa~~
tion. Such systems are well known. such as the
15 mirror drum, disc, cathode ray. and
electro
dynarnic arc systems, the latter of which are dis
closed in my United States Patents Nos. 1,863,278..
issued June 14, 1932 and 1,839,696, issued January
5, 1932. The present are system differs from
those disclosed in the patents by the process
known as modulation. In the patents the elec
trical discharge or are is varied in intensity, while
in the present invention, modulation occurs by
varying the arc speed. Thus a dark spot is
created by a relatively high speed motion of the
arc, while a bright spot is produced by a rela
tively slow propagation thereof, the intermediate
intensities being produced by intermediate spccds.
An object of the invention is to transmit and
reproduce television images.
Another object of the invention is to scan an
object and reproduce the images thereof with an
eleetrodynamic discharge or are.
A further object of the invention is to repro~
duce television images with a moving electrical
discharge or are whose rate of propagation is
varied in accordance with the light and shade
densities of the object or image being transmitted.
this variation reproducing the image or object.
It is well known that the eye integrates light,
40
within certain limits, similar to that of a photo
graphic ?lm. That is, should light of a definite
iz'atensity be projected on the eye within de?nite
time limits, this light will appear brighter. the
45 longer the projection. We have, therefore, a
method of modulating a constant intensity light
beam to reproduce a television image.
As disclosed in the above-mentioned patents,
the electrical discharge is propagated along elec
trode rails over a definite area. These electrode
rails are provided with a source of voltage to pro
duce the arc. Surrounding the electrode rails is
a magnetic ?eld which provides a force on the
discharge for propagating it along the rails.
If
rs the arc length, the electrode voltage and the ?eld
strength are maintained constant, the arc will
have a constant speed of propagation. Should
the ?eld, however, be varied, the speed will also
vary correspondingly.
The invention will be more fully understood
by reference to the following description read in
conjunction with the accompanying drawing in
which:
Fig. 1 is a diagrammatic representation of
transmitter terminal apparatus, and
10
Fig. 2 is a similar representation of the re
ceiver apparatus involving the invention.
In Fig. 1 an electrodynamic arc screen. similar
to those disclosed in the above—mentioned patents.
comprises electrode rails 5 and i, a ?eld winding
1, which represents a solenoid or other type of
coil of many turns, and a mask 8 with a pinhole
or lens 9 therein. The electrode rails 5 and {l
are energized from a source of direct current
potential l2 under control of a rheostat 13, while
the field winding 1 is supplied from a source of
potential I4 under control 01‘ a rheostat :5. In
this last-mentioned supply circuit is a secondary
of a transformer H, the primary of which is com
nected to an ampli?er Hi. This ampli?er receives
its input from a photosensitive device 19 posi—
tioned in the neighborhood of the screen to re
ccive light variations corresponding to the light
and shade densities of an object, such as ll. which
is explored with the light beam from the arc ,
screen. The ampli?er l8 feeds a transmitter 2!
for transmission from an antenna 2 or over wires
connected at 23.
The above transmitter operates in a simple
manner. An electrical discharge is produced
across the electrodes 5 and 6 from the potential
source I2 and propagated therealong by the ?eld
produced from the source 14. the respective rheo
stats being adjusted to provide the speed oiv prop»
section which is required to produce the images 40
at a suf?cient rate of speed to produce the illu
sion of motion. As the arc travels along its rails.
light therefrom scans the object ll and electrical
currents will be set up in the device H), which
after a predetermined amount of ampli?cation
are impressed upon the transmitter 2|. A por~
tion of the energy from the ampli?er i8, however,
is returned to the ?eld ‘I for the purpose of syn
chronizing the electrical discharge on the rails 5
and 6 at the transmitter. This synchronizing
system is in accordance with the disclosure in co
pending application Serial No. 584,797, ?led Jan~~
uary 5, 1932.
Referring now to the receiver in Fig. 2, the
transmitted impulses are received on an antenna 56
2
2,109,339
39 or over wire lines to terminals 3| and im
pressed upon a receiver 32. The detected cur
rents are then ampli?ed in ampli?er 34 and im
pressed upon an output transformer 35. An are
system similar to the one in Fig. 1 is employed at
the receiver, prime numerals being given to ele
ments corresponding to those in Fig. 1. Now the
incoming impulses impressed on the transformer
35 vary the ?eld excitation in accordance with
10 the light and shade densities of the object 0 and
thus produce a variation in the rate of propa
gation of the are along the electrode rails 5’ and
tem having similar electrode rails and means for
creating a ?eld, and means for varying the en
ergy supplied to both of said ?eld creating means
for varying the speed of said discharges in ac
cordance with the light and shade densities of
nism desired. It is to be understood that the
rheostats l3’ and I5’ must be set to produce sub
stantially the same propagation at the receiver
said object, the intensity of said discharges re
maining constant at all times.
3. In a radio receiving system, a receiving ap
paratus comprising a plurality of electrodes ar
ranged to form a ?eld of view, a constant energy
supply for producing a constant intensity dis
charge at all times between said electrodes and
in a single plane, a ?eld winding producing a
?eld in which said discharge is positioned, an
energy supply for said winding, and means for
varying said last mentioned energy supply in ac
cordance with the light and shade densities of
as at the transmitter.
an image or object, said means including a feed
6’ to produce the image of the object being
scanned.
A similar variation is set up in the
15 transmitter screen, thus producing the synchro
Also that the synchroniz
20 ing variations may have smaller amplitudes than
the modulating variations but the proportionali
ties between them must remain substantially
back circuit connected to said ?eld winding.
4. In a radio receiving system, means for re
ceiving electrical currents corresponding to light
constant. The mask 8’ in Fig. 2 may be a ground
and shade densities of an object, a plurality of
glass through which the image is viewed directly,
electrode rails, a source of energy having a con
25 or it may have a pinhole or lens similar to that
in Fig. 1 and the light projected on a screen for
observation.
The above variable speed television system has
several advantages over similar systems in which
30 the arc current is varied to produce modulation.
The present system requires a minimum of appa
ratus by eliminating certain synchronizing con
trols and permits of a greater variation in the
accuracy of spacing the electrodes to produce
35 television transmission. There are other advan
tages in the use of such a system in view of the
fact that it requires no mechanically moving ele
ments and is especially adapted for variable speed
modulation.
40
What is claimed is:
1. In a television transmission system, the
combination of means for producing a primary
light source having a constant intensity at all
times, said light source comprising an ionized
45 path, means for immersing said light source in a
magnetic ?eld for moving said source, means for
projecting the light from said source to an object
to be scanned, means for translating the light
from said object into electrical currents, means
50 for transmitting said currents to receiving app-a
rat-us, means at said receiving apparatus for im
mersing a second light source similar to said ?rst
light source in a magnetic field, said second light
source having a constant intensity at all times,
55 and means for impressing said received currents
on said immersing means for varying the speed
of said light source in accordance with the light
and shade densities of said object being scanned
by the transmitter.
60
tus comprising a similar electrical discharge sys
stant value producing a constant intensity dis
charge at all times between said rails, and in a
single plane, a ?eld winding for producing a ?eld
in which said electrode rails are positioned, said
:iield being supplied from a constant source of
energy, and means for varying the intensity of
said ?eld in accordance with the light and shade
densities of an image or object to be reproduced.
5. The method of television reception of the
image of a scanned object visible with a constant
r.
nil
intensity moving electrical discharge movable in
a single plane in a magnetic ?eld comprising
varying the speed of said moving discharge by
varying the strength of said magnetic ?eld in
accordance with the light and shade densities
of said scanned object to produce dark elements
by increasing the speed and producing light ele
ments by decreasing the speed of said discharge
in proper proportionalities, the absolute intensity
of said discharge remaining constant at all times.
6. The method of television transmission and
reception of images of a scanned object with
visible moving electrical discharges having con
stant intensities at all times, comprising scanning
said object, obtaining electrical currents char
acterized by the light and shade densities of said
object scanned with one constant intensity elec 50
trical discharge and varying the speed of another
moving electrical discharge having a constant
intensity in accordance with the currents pro
duced with the ?rst discharge while scanning, the
absolute intensity of each of said discharges being
maintained constant.
7. In a television receiving system, means for
producing a primary constant intensity light
2. In a television system, a combination of a
transmitter and a receiver, a plurality of elec
trode rails at said transmitter supplied by a con
source, said light source comprising an ionized
path, means tending to move said light source
stant voltage to produce a constant electrical dis
charge therebetween at all times, means for cre
ating a ?eld in which said discharge is located,
means for scanning an object with the light from
said discharge, means for translating said light
variations into electrical currents, means for
transmitting said currents to receiving appara
single plane, and means for varying the speed of
at a constant speed over a certain area in a
said source per unit area in accordance with the
iight and shade variations of an image to be
reproduced while maintaining said light source
at a constant absolute intensity at all times.
ALEXANDER MCLEAN NICOLSON.
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