Improvements in Submarine Cable Telegraphs.
Year: 1898

page_text: Date of Application, 8th Nov., 1898
Complete Specification Left, 8th Aug., 1899-Accepted, 8th Feb., 1900
Improvements in Submarine Cable Telegraphs.
A communication from ALBERT C. CREHORE, of Hanover, Grafton County, State
of New Hampshire, U.S.A., Professor of Physics, and GEORGE O. SQUIER,
Lieutenant Colonel in the United States Army.
I, WILLIAM LLOYD WISE, of 46, Lincoln's Inn Fields, in the County of London,
Consulting Engineer and Chartered Patent Agent, do hereby declare the nature
of this invention to be as follows:-
This invention or discovery relates to the transmission of intelligence over sub-
marine cables in which as is well known the speed of transmission is very slow
as compared with the speed on land lines, due to the comparatively large distri-
buted electrical capacity of a submarine cable, despite the continued search for
appliances designed to increase the speed and the legibility of the received signals.
Heretofore in this branch of telegraphy, the signals have been transmitted by
applying to the cable an electromotive force which is at its maximum at the
beginning of a pulse, and the waves of electro-motive force impressed upon the
circuit, graphically represented, appear as in the broken line Fig. 1, the character-
istic feature of the waves being that they are square-topped."
"6
It has been discovered by my correspondents that the speed of transmission is
increased over that which it has heretofore been possible to attain, by simply
abandoning the use of the square-top wave of impressed electro-motive force, and
substituting therefor an electro-motive force which does not rise suddenly and fall
off abruptly, but, on the contrary varies gradually and continuously from zero
through a maximum and back to zero gradually and continuously.
Graphically the waves of impressed electro-motive force employed according to
the improved system are represented approximately as in Fig. 2. of the accom-
panying drawings wherein is represented two semi-waves of opposite sign respec-
tively. The same form of electro-motive force when varied as to the succession of
the individual waves or pulses for the purpose of transmitting the letters A and B
of the International code is represented in Fig. 3.
In carrying out this invention the electro-motive force may be generated in any
desired way, but it is preferably generated by a dynamo or magneto-electric
machine. Preferably the said machine is constructed to generate a varying
electro-motive force of sine wave form.
When the electro-motive force is generated by a machine as in the case of an
alternating electro-motive force, the control thereof, so that the sinuses may be
impressed on the circuit at the desired times and intervals, may be effected in any
desired manner, manually or automatically, but by preference they are impressed
automatically by means of a perforated tape.
In the accompanying drawings:-Fig. is a graphic delineation of the form of
varying electromotive force heretofore employed in transmitting the letters A, B.
and C, over a cable using the present International code. Fig. 2, shows a complete
alternating electro-motive force wave. Fig. 3, represents the impressed electro,

page_text: motive force waves used according to this invention to transmit the letters A
and B, using the present International code. Fig. 4 is a general diagram of one
form of apparatus which may be used in telegraphing over submarine cables
according to the improved method.
Referring to Fig. 4, A is the transmitting end of a submarine cable upon
which the pulses are to be impressed in accordance with a code, and E2, is the
earth connection. B, typifies a generator of alternating electro-motive force of
sine wave form, being for that purpose provided with a suitable coil or coils rotated
by any suitable power in a magnetic field. As shown a shuttle armature is
provided and is wound with two coils b, b, having a common connection to line
through a ring H, revolving with the armature and provided with a collector
brush bearing on the said ring. The other termini of the coils b, b are connected
through the sides e, c respectively, of a pole changer C, on the armature shaft,
with the brushes or terminals D, D), of the transmitting device, thereby delivering
at each brush or terminal a sine wave electro-motive force of one sign for one
brush and of the opposite sign for the other brush, so that there is continuously
present at the said transmitting part an electro-motive force of either sign ready
to be impressed upon the circuit." A shuttle form of armature is shown, but it is
preferable to use a form which more readily gives an electro-motive force closely
following the sine wave form. The field in which the coils are rotated may be
maintained in any desired way, as by a local generator M supplying a field coil
of the machine. The circuit of the machine is completed to earth through perfora-
tions in a transmitting tape E, upon which the brushes D) bear after the usual
manner, the perforations being of such size that the current flowing shall in each
case begin and terminate at zero or approximately zero, and the tape being fed
beneath the brushes at a speed synchronous with the production of the alternating
electro-motive force. For this purpose the tape is provided with a central row of
feeding perforations, as well understood in the art, to be engaged by a toothed
wheel F, which runs in synchronism with the generator B. The perforations of
the tape when properly arranged will cause electromotive forces of sine wave form
to be applied to the cable in the manner graphically represented in Fig. 3.
In practice it is found that by the substitution of this form of electro-motive
force for the present square-topped form without alteration of any of the other
elements of the present system, the speed of working over a given cable is
materially increased.
While it is preferable to use a varying electro-motive force of the sine form, it
is not to be understood that the invention is limited thereto, but includes any
form whose characteristic difference from the square topped electro-motive force
wave heretofore used is that the electro-motive force shall change gradually and
continuously from zero through a maximum to zero.
Dated this 8th day of November 1898
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C.,
Chartered Patent Agent.
A communication from ALBERT C. CREHORE, of Hanover, Grafton County, State
of New Hampshire, U.S.A., Professor of Physics, and GEORGE O. SQUIER,
Captain in the United States Army.

page_text: Consulting Engineer and Chartered Patent Agent, do hereby declare the nature
of this invention and in what manner the same is to be performed to be particu-
larly described and ascertained in and by the following statement;
This invention relates to the transmission of intelligence over submarine
cables, in which, as is well known, the speed of transmission has hitherto usually
been very slow as compared with the speed on land lines, on account of the com-
paratively large and distributed electrical capacity of submarine cables, notwith-
standing the continued search for appliances designed to increase the speed
and the legibility of the received signals.
Heretofore in this branch of telegraphy, the signals have been transmitted by
applying to the cable an electro-motive force which is at its maximum at or
near the beginning of a pulse, and the waves of electro-motive force that have
been impressed upon the circuit may be graphically represented by the broken
line in Fig. 1 of the drawings filed with my Provisional Specification, the
characteristic feature of the waves being that they are "square-topped."
'
Now, it has been discovered by my correspondents and stated by me in the
Specification of Letters Patent previously granted to me and numbered 6787 of
1897 that the speed of transmission can be increased over that which has usually
hitherto been attained, by simply abandoning the use of an impressed electro-
motive force, having square-topped waves and substituting therefor an electro-
motive force which does not rise suddenly and fall off abruptly, but; on the
contrary, varies gradually and continuously from zero through a maximum and
back to zero gradually and continuously.
Fig. 2 is an approximate graphic representation of two consecutive semi-waves
of opposite signs of the impressed electro-motive force employed according to the
improved system. Fig. 3 represents a series of semi-waves and interruptions of
this electro-motive force used for the purpose of transmitting the letters A, B
and C of the International code.
In utilizing this discovery the electro-motive force may be generated in any
desired way, but it is preferably generated by a dynamo or magneto-electric
machine. Preferably the said machine is constructed to generate a varying
electro-motive force having waves as nearly sinusoidal as practicable.
When the electro-motive force is generated by a machine, as in the case of an
alternating electro-motive force, the control thereof, so that the sinuses may be
impressed on the circuit at the desired times and intervals, may be effected in any
desired manner, manually or automatically, but by preference they are impressed
automatically by means of a perforated tape.
Fig. 4 of the drawings filed with my Provisional Specification is a general
diagram of an example of apparatus according to this invention for telegraphing
over submarine cables with approximately sinusoidal waves.
A is the transmitting
end of a submarine cable upon which the pulses are to be impressed in accordance
with a code, and E2 is the earth connexion. B is a generator of alternating and
as nearly as may be sinusoidal electro-motive force; "such a generator should for
this purpose be provided with a suitable coil or coils rotated by any suitable
power in a magnetic field. In the example, a shuttle armature is provided and
is wound with two coils b, b having a common connexion to line through a ring H
(which revolves with the armature) and a collecting brush bearing on the said ring.
The other ends of the coils b, b are connected through the sides c, c, respectively, of
a pole changer C on the armature shaft, with the brushes or terminals D, D) of
the transmitting device, so as to deliver at each brush or terminal an approxi-
mately sinusoidal electro-motive force of one sign for one brush and of the
opposite sign for the other brush, so that there is always present in the said
transmitting device an electro-motive force of each sign ready to be impressed
upon the circuit. An armature of shuttle form is shown in the drawings but it is
preferable to use one of a form which more readily gives an electro-motive force
closely following the sinusoidal form-for example, a drum wound armature with

page_text: a two segment commutator and a single collector ring connected to the centre
of the winding. The field in which the coils are rotated may be maintained in
any desired way, as by a local generator M2 supplying a field coil of the machine.
The circuit of the machine is completed to earth through perforations in a trans-
mitting tape E, upon which the brushes D bear after the usual manner, the
perforations being of such size that the current flowing will in each case begin and
terminate at zero or approximately zero, and the tape being fed beneath the
brushes at a speed synchronous with the production of the alternating electro-
motive force. For this purpose the tape is provided with a central row of feeding
perforations, as well understood in the art, to be engaged by a toothed wheel F
which runs in synchronism with the generator B. The perforations of the tape
when properly arranged will cause approximately sinusoidal electro-motive forces
to be applied to the cable in the manner graphically represented in Fig. 3.
In practice it is found that by the substitution of electro-motive force of the
form stated for electro-motive force of square-topped form without alteration of
any of the other elements of the present system, the speed of working over a
given cable is materially increased and that a great improvement in speed is
produced by using a tape with two rows of perforations for transmitting as
described pulses in opposite directions therethrough in accordance with the code
employed. It will be obvious that it is not absolutely necessary to employ an
alternating-current generator when using a doubly perforated tape and terminals
or brushes as described, it being sufficient if the two terminals or brushes be
supplied with uni-directional pulsating currents of opposite signs.
While it is preferable to use a varying electro-motive force of sinusoidal form,
it will be understood any other form of wave may be used whose characteristic
difference from the square topped electro-motive force wave heretofore used is
that the electro-motive force will change gradually and continuously from zero
through a maximum to zero.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, I declare that what
I claim is
1. In a submarine cable telegraph apparatus comprising a transmitting tape
having two rows of perforations, means for supplying unidirectional pulsating
currents (preferably sinusoidal in form), and means for moving the tape past two
terminals or brushes located on one side of the tape and adapted to make connexion
through the perforations of the rows respectively with a contact device on the
other side of the tape, in which the movement of the said tape is such that the
periods of connexion between the brushes or terminals and the said contact device
coincide with pulsations of current and the contact of the respective brushes or
terminals causes pulses of current to pass through the cable in opposite directions
substantially as described.
2. In a submarine cable telegraph the combination of a transmitting tape having
two rows of perforations, two terminals or brushes on one side of the tape and
adapted to make connexion through the perforations of the rows respectively
with a contact device on the other side of the tape, means for keeping the said
terminals or brushes supplied with unidirectional pulsating currents (preferably
sinusoidal in form) of opposite signs, and means for moving the tape past the
said terminals or brushes so that the periods of connexion between the brushes
or terminals with the contact device will coincide with current pulsations sub-
stantially as described.
3. Submarine cable telegraphic apparatus constructed, arranged, and operating
as hereinbefore described with reference to and shown in the drawings filed with
my Provisional Specification.
4. The hereinbefore described improvement in submarine telegraphy which
consists in transmitting the signalling waves or pulses by impressing upon the

page_text: cable electromotive forces which change gradually and continuously from zero
through a maximum to zero in the manner set forth.
Dated this 8th day of August 1899.
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C.,
Chartered Patent Agent.