A Method of Receiving Telegraph Signals as Displayed or Photo- graphed by Magnetically Deflected Cathode Rays.
Year: 1899

page_text: Date of Application, 12th Aug., 1899
Complete Specification Left, 3rd May, 1900- Accepted, 7th July, 1900
Date of Application, 12th Aug., 1899
Complete Specification Left, 3rd May, 1900- Accepted, 7th July, 1900
PROVISIONAL SPECIFICATION.
A Method of Receiving Telegraph Signals as Displayed or Photo-
graphed by Magnetically Deflected Cathode Rays.
We, SIEMENS BROS. & Co., LIMITED, of 12, Queen Anne's Gate, Westminster,
in the County of London, Electrical Engineers, do hereby declare the nature
of this invention (as communicated to us from abroad by Siemens & Halske
Aktien Gesellschaft, of Markgrafen Strasse 94, Berlin, S.W., Electrical
Engineers,) to be as follows:-
:-
In contrast to the up to now usually employed method of transmitting tele-
graphic signals, a considerable increase in speed may be obtained when in the
receiving apparatus all mechanical parts, which have to be moved by the signal-
ling current, are avoided. The present invention attains this in the following
way:―
A strip of sensitized paper which is intended to receive the transmitted signals
is moved by a motor, clockwork or similar appliance at a suitable speed. It
The
is placed with the other necessary parts of the receiver in a dark room.
strip of paper is exposed to cathode rays, which are deflected from their normal
position in a manner corresponding to the signals to be given by the received
current flowing through a coil of wire (which may contain iron.) These deflec-
tions can be used in different ways for producing telegraphic signals on the
paper strip. When shorter and longer signals are required, for instance dots
and dashes corresponding to the Morse code, current impulses of shorter and
longer periods are sent through the deflecting coil, causing the cathode rays
to remain deflected for a shorter or longer time. These positions of the cathode
rays are then fixed on the evenly moved paper strip in the form of dots and
dashes. An arrangement like this is shewn in Fig. 1, but with the modification,
that the cathode rays do not act directly on the sensitised paper but indirectly
through the light which they create on a fluorescent screen.
A
(a) represents a Wheatstone apparatus for automatic quick sending. The
current flowing through this apparatus is sent through the line to the receiver b
where it passes through the electro-magnet M. In front of this electro-magnet
the cathode ray tube e is placed, which is excited in a suitable manner.
bundle of the rays emitted from the cathode K passes through the opening in
the metal disc o and strikes the fluorescent screen f, where it becomes visible
in the form of a spot S. The rays d are deflected to the position $1 or $2 accord-
ing to the direction of the current flowing through the electro-magnet M. In
case the position S¹ corresponds with the telegraphic current, a lens q is so
placed that the light rays, corresponding to this position, are projected against
the paper strip p, where, according to their duration, they are fixed as dots
and dashes; the light rays corresponding to the position S & S² are screened off
and are therefore not photographed. It is to be understood that signals other
than the Morse signals can be received in this way.
According to a modified method of using the deflected cathode rays, the deflec-

page_text: tion according to its magnitude is applied to indicate certain letters or other
signs. The current impulses sent into the line by the transmitter have in this
case generally the same duration. The different current intensities which are
to correspond to the different signals, are either produced by the insertion of
resistances into a circuit of a constant potential or by connecting the line during
the sending of the current in such a manner, that it is acted on by different
electromotive forces. These may be obtained by connecting the telegraph lines
according to the different signals, with different contacts of a row of contact
blocks between which there are contacts for different electromotive forces.
In the first instance the transmitter is of the known Wheatstone type for high
speed telegraphy, which works with a perforated strip of paper and in which
each hole in the paper effects the closing of a certain circuit. It is of advantage
to use with this an auxiliary contact which is inserted into the circuit and which
is worked by the transmitter itself in such a manner that the absolute closing
and opening of the circuit is effected by the auxiliary contact after the contact
which corresponds with the hole in the paper has been established, or before
it is interrupted. In this way all the sparking is in the known manner removed
to the auxiliary contact which can easily be exchanged.
a is the
An arrangement of this kind is shewn diagrammatically in Fig. 2.
previously perforated paper-strip of the transmitter, which is moved over the
contact levers b, b, b. Whenever a hole in the paper strip a appears over one
of the pins & the pin is lifted up by the spring e and at c a contact is made.
All the points c are connected with the pole of the battery f. Between the con-
tact levers b, b, b, the adjusted resistances W are connected. The last of these
resistances is connected to earth. Whenever one of these levers makes a con-
tact, the circuit is closed through a definite fraction of the resistance and a
current of a definite strength is produced, which causes a definite deflection of
the cathode rays. The receiving apparatus shewn in Fig. 2 differs from that
shewn in Fig. 1 by the following arrangement. The zero position of the cathode
rays is, through the influence of the adjusting magnet m, situated on the lower
part of the fluorescent screen on the place marked S.o, and is deflected by the
electro-magnet M in steps to S1, S2, S3. Each of these deflections represents a
different letter. The illuminated spots $ are projected by a lens 7 and the
mirrors 1, 2, 3, to a hole in the diaphragm t behind which the sensitised paper
strip p is moved. On the face of the mirrors letters of opaque material are fixed,
the images of which are then photographically fixed on the paper strip as in-
stantaneous photographs, the time of each current impulse being very short.
For projecting the different illuminated spots S1, S2, S3, on to the one place
where the letters etc. are to be photographed, other known means, for instance,
prisms or a separate lens for each point may be used. Fluorescent letters may
be fixed to the spots which would light up through the influence of the cathode
rays and would be projected on the sensitised paper.
A third method for using the deflection of cathode rays for telegraphic pur-
poses is as follows.
If the cathode rays, instead of being acted on by a single electro-magnet M,
are acted on by two or more, which are fixed at an angle relatively to each other
and which are influenced by different telegraphic currents, each of which at the
transmitting station can be varied as regards strength and direction, combined
magnetic fields are created, which produce deflections of the cathode rays in
various directions. In this way it is possible to obtain a deflection of the cathode
rays all round the zero position and with each of these deflections (as described
above) it is possible to project a certain letter on to the place where the moving
sensitised paper strip is exposed.
1 1

page_text: A Method of Receiving Telegraph Signals as Displayed or Photo-
graphed by Magnetically Deflected Cathode Rays.
We, SIEMENS BROS. & Co., LIMITED, of 12, Queen Anne's Gate, Westminster,
in the County of London, Electrical Engineers, do hereby declare the nature
of this invention (as communicated to us from abroad by Siemens & Halske
Aktien Gesellschaft, of Markgrafen Strasse 94, Berlin, S.W., Electrical
Engineers), and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
In contrast to the method of transmitting telegraphic signals hitherto usually
employed, a considerable increase in speed may be obtained when in the
receiving apparatus all mechanical parts, which have to be moved by the signal-
ling current, are avoided. The present invention attains this in the following
way:
A strip of sensitised paper which is intended to receive the transmitted signals
is moved by a motor, clockwork or similar appliance at a suitable speed. It
is placed with the other necessary parts of the receiver in a dark room. The
strip of paper is exposed to cathode rays, which are deflected from their normal
position in a manner corresponding to the signals to be given by the received
current flowing through a coil of wire (which may contain iron.) These deflec-
tions can be used in different ways for producing telegraphic signals on the
paper strip. When shorter and longer signals are required, for instance dots
and dashes as for the Morse code, current impulses of shorter and longer
periods are sent through the deflecting coil, causing the cathode rays to
remain deflected for shorter or longer times. These positions of the cathode
rays are then fixed on the paper strip in the form of dots and dashes.
arrangement like this is shown in Fig. 1 of the drawings accompanying our
Provisional Specification but with the modification, that the cathode rays do
not act directly on the sensitised paper but indirectly through the light which
they create on a fluorescent screen.
An
A
a represents a Wheatstone apparatus for automatic quick sending. The
current Howing through this apparatus is sent through the line to the receiver b
where it passes through an electromagnet coil M. In front of this electromagnet
the cathode ray tube c is placed, which is excited in a suitable manner.
bundle of the rays emitted from the cathode K passes through the opening in
the metal disc o and strikes the fluorescent screen f, where it becomes visible
in the form of a spot S. The rays are deflected to the position S¹ or S accord-
ing to the direction of the current flowing through the electromagnet M. In
case the position S¹ corresponds with the telegraphic current, a lens q is so
placed that the light rays, corresponding to this position, are projected against
the paper strip p, where, according to their duration, they are fixed as dots
and dashes; the light rays corresponding to the position S and S are screened off
and are therefore not photographed. It is to be understood that signals other
than the Morse signals can be received in this way.
According to a modified method of using the deflected cathode rays, the deflec-
tion according to its magnitude is applied to indicate certain letters or other
signs. The current impulses sent into the line by the transmitter have in this
case generally the same duration. The different current intensities which are
to correspond to the different signals, are either produced by the insertion of
resistances into a circuit of a constant potential or by connecting the line during
the sending of the current in such a manner, that it is acted on by different

page_text: electromotive forces.
These may be obtained by connecting the telegraph lines
according to the different signals, with different contacts of a row of contact
blocks between which there are contacts for different electromotive forces.
In the first instance the transmitter is of the known Wheatstone type for high
speed telegraphy, which works with a perforated strip of paper and in which
each hole in the paper effects the closing of a certain circuit. It is of advantage
to use with this an auxiliary contact which is inserted into the circuit and which
is worked by the transmitter itself in such a manner that the absolute closing
and opening of the circuit is effected by the auxiliary contact after the contact
which corresponds with the hole in the paper has been established, or before
it is interrupted. In this way all the sparking is in the known manner removed
to the auxiliary contact which can easily be exchanged.
a
The last of these
An arrangement of this kind is shewn diagrammatically in Fig. 2
of the drawings accompanying our Provisional Specification. is the
previously perforated paper-strip of the transmitter, which is moved over the
contact levers b, b, b. Whenever a hole in the paper strip a appears over one
of the pins & the pin is raised by the spring e and at e a contact is made.
All the points c are connected with the pole of the battery f. Between the con-
tact levers b, b, b, the adjusted resistances W are connected.
resistances is connected to earth. Whenever one of these levers makes a con-
tact, the circuit is closed through a definite fraction of the resistance and a
current of a definite strength is produced, which causes a definite deflection of
the cathode rays.
The receiving apparatus shewn in Fig. 2 differs from that
shewn in Fig. 1 by the following arrangement. The zero position of the cathode
rays is, through the influence of the adjusting magnet m, situated on the lower
part of the fluorescent screen on the place marked S.o, and is deflected by the
electromagnet M in steps to S¹, S2, S3. Each of these deflections represents a
different letter. The illuminated spots S are projected by a lens and the
mirrors 1, 3, to a hole in the diaphragm t behind which the sensitised paper
strip is moved. On the face of the mirrors letters of opaque material are fixed,
the images of which are then photographically fixed on the paper strip as in-
stantaneous photographs, the time of each current impulse being very short.
For projecting the different illuminated spots S1, S2, S3, on to the one place
where the letters etc. are to be photographed, other known means, for instance,
prisms of a separate lens for each point may be used. Fluorescent letters may
be fixed to the spots S¹ which would light up through the influence of the cathode
rays and would be projected on the sensitised paper.
P
A third method for using the deflection of cathode rays for telegraphic pur-
poses is as follows.
.
If the cathode rays, instead of being acted on by a single electromagnet M,
are acted on by two or more, which are fixed at an angle relatively to each other
and which are influenced by different telegraphic currents, each of which at the
transmitting station can be varied as regards strength and direction, combined
magnetic fields are created, which produce deflections of the cathode rays in
various directions. In this way it is possible to obtain a deflection of the cathode
rays all round the zero position and with each of these deflections (as described
above) it is possible to project a certain letter on to the place where the moving
sensitised paper strip is exposed.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is :-
1. Rapidly acting telegraphic receiving apparatus wherein cathode rays,
deflected by one or more magnets or the like, produce on a fluorescent screen
visible signals different according as the duration, direction or extent of the
deflections differs.
2. For applying apparatus such as is above referred to for signalling according

page_text: to the Morse or like code, the use of a travelling strip of sensitised paper or the
like on which dots and dashes are photographed according as the deflection of the
cathode ray is maintained by the transmitter for a shorter or longer period.
3. The modified arrangement according to which signals are photographed
on the travelling strip, distinguished by their different distances from a zero
line, resulting from different extents of deflection of the cathode ray caused by
transmitted currents of different strengths.
Dated this 2 day of Vox 1000
ABEL & IMRAY,
Agents for the Applicants.