Document 436332

Sept. v17, 1929.
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1,728,816’ .
W.'C. WHITE
SIGNALING SYSTEM
Fil'ed Jan ._ 19. 1924
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Patented Sept. 17, 1929
UNITED STATES PATENT OFFICE
WILLIAM C. WHITE, 0F SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC
COMPANY, A CORPORATION OF NEW YORK
‘SIGNALING SYSTEM
Application ?led January 19, 1824. Serial 1T0. 887,861.
My present invent-ion relates to signaling vice 1. Oscillations produced in this oscil
systems, and more particularly 1.012121151111171 latin circuit are supplied by means of a’
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ting apparatus for high frequency signallng. coup ing coil 16 to the‘ grid circuit of device
The~object of my invention is to provide 2, this grid circuit including a grid con
=5 improvements in apparatus for producing denser 1 , a by-pass condenser 18, and a se
and amplifying high frequency currents and ries resistance 19. The high frequency os
utilizing- such currents for signalmg‘pur cillations thus supplied to the grid circuit
poses, such for example as radio telegraphy.
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of device 2 are amp l?ed and supplied through
The novel features which I believe to be a blocking condenser 20 to a storage circuit
I. characteristic of my invention are set forth made up of the variable inductance 21 and
with particularity in the appended clainis; condenser 22. This storage circuit is cou
my invention itself, however, both as to its pled in the manner indicated to loading coil
organization and‘ method of operation will 23 on the antenna 3. This antenna may be
best be understood by reference to the fol of the multiple tuned type havin as many
ll lowing description taken in connection with separate loa ing coils as desire . In the
the accompanying drawing in which I have present case only two, 23 and 24 are shown.
shown dia ammatically a cii‘cuitorganrza
The current for heating cathodes 4 of the
tion where y my invention may be carried two devices is furnished through transform
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into e?ect.
_
ers 26, 27 from an alternating current source
I have indicated in.the drawin ,a radio connected to supply mains 25. The grid con 70
transmitting system comprising a t rec-elec denser 13 in the rid circuit of device 1 is
trode electron discharge device 1 of the shunted by a cholgring inductance 28 and a
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30
thermionic type, which is .employed for the
urpose of producing high frequency OSCll
lhtions, and a second device 2 of the same
type which is employed for amplifying the
oscillations roduced by the ?rst device, and
means of a key 32 conn'wted in a circuit with
grid 6. Current for the operation of the
comparatively small the system thus far de- ‘
resistance 29, which are connected in se
ries with a relay device 30, this relay device
being connected in shunt to the keymg con 75
denser 31. The relay 30 may be actuated by
then supplying the ampli?ed oscillations to any suitable source of power supplied by the
transmitting antenna 3.. Devices 1 and 2 mains 33 for operating the relay 30.
each comprise the usualcathode 4, anode 5 and
When the power output.of an oscillator is
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anode or plate circuits of the two devlces is scribed is quite satisfactory. When the re
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40
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furnished by a ‘source of high potential di
rect current connected to the supply conduc
tors 7 and 8. The positive terminal of the
direct current supply source is connected to
lay 30 is closed oscillations will be produced
and as soon as the relay is opened a negative
charge of su?icient value to interrupt the pro
duction of oscillations will be built up on the
the anodes 5 through choking inductances grid by reason of the presence of condensers
9 and 10, which revent the high frequency 13 and 31. As soon as oscillations are
currents produced, in the system from ?owing stopped the negative charge on the id tends
through the source of supply. The anode 5 to leak off and there is a tendency or the de
of device 1 is connected through a blocking
condenser 11 and a portion of the inductance
12 to the cathode 4. The grid 6 of device
1 is connected through a grid condenser 13
and a portion 14 of the inductance 12, to the
cathode 4. A ortion of the inductance 12
vice to start oscillating again. As soon as
oscillations start again, the negative charge
on the grid again will be built up and the pro
duction of oscillations will be interrupted.
The length of time between these intermit
tent oscillations depends on the leakage of the _
is also shunted by a condenser 15. This con grid charge which in turn depends upon the
denser in connection with the coil 12 forms insulation of the grid circuit and of the tube.
an oscillating circuit which determines the With low power devices these intermittent
frequency of the oscillations produced by de oscillations are not of su?icient intensity to 100
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be objectionable. but when considerable power a negative biasing voltage is obtained which
used this effect is objectionable because it is twice that of the alternating current volt
causes interference. The magnitude of these age of the secondary 42 and this total voltage
oscillations is a function of the tube efficiency, is divided between the two recti?ers 43 and 44,
the higher the ciiiciency the greater the mag which are connected in series. The use of the
nitude because of the\fact that a higher ini
tial voltage is required to start oscillations.
recti?ers for furnishing the biasing voltage '
for the grid also has a particular advantage
To 0\ crcomc this disadvantage I have pro— in the case of the power ampli?er tube.
vidwl a rut-ans for furnishing a negative bias When the key 32 is opened and the production
upon the grid 6 of oscillator 1, which is ef
fective, as soon as relay 3O is'opencd.
negative bias is provided by means of an al
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in a positive direction and this impulse may
ternating current which is impressed upon be sufficient to reverse the potential of the
the grid circuit by means of a transformer 34. grid and produce dynatron action. The rec
The portion 35 of the secondary turns of ti?ers 43 and 44 however, minimize the ampli 80
transformer 34 is connected in series with the tude of the positive grid potential and there
thermionic recti?er 36, the anode 37 of which fore tend to prevent the occurrence of dyna
is connected through a high resistance 38 to tron action.
While I have shown and described only one
one side of the keying condenser 31. The
smoothing condenser 39 is provided for embodiment of my invention, it will be‘ ap-'
smoothing out the variations in the alternat parent that many modi?cations in the circuit
ing potential thus applied to the grid, and in arrangements employed may be made with
suring the proper operation \of the rectifier. out departing from the scope of my invention
The cathode 40 of the recti?er 36 may be as set forth in the appended claims.
heated by means of alternating current sup
What I claim as new and desire to secure 90
plied by the turns 41 of the secondary of by Letters Patent of the United States, is:
transformer‘ 34. It will be observed that
when the relay 30 is closed this source of bias
ing potential is short circuited. The high re
sistance 38 is provided to prevent the ?ow of
excessive current through the recti?er 36 dur
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of oscillations by oscillator 1 is interrupted
This the grid 6 of ampli?er 2 is given an impulse
ing periods when the key 32 is closed. This
method of keying is also preferable to those
in which oscillatlons are interrupted by the
building up of a negative charge on the grid
1. The combination with an electron dis
charge‘ device having a cathode, an anode,
and a grid, of means for impressing a nega
tive potential upon the grid of said device
comprising a source of alternating current
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and a rectifying device having asymmetric
conductivity serially connected in a circuit
between said cathode and said grid, the grid
of said electron discharge device being sub
through a grid condenser as both the starting stantially insulated from the cathode with
and the stopping of oscillations are more respect to direct current except through said
abrupt. This gives a cleaner signal and also rectifying device and the space within said
discharge device whereby said rectifying de
permits of higher speed signaling,
When the ke 32 is closed the potential of vice is e?’ective to prevent a reversal in di
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rection- of the current ?ow in the grid circuit. 2. The combination with an electron dis
The resulting rush
the ‘grid of oscillator 1 is suddenly raised from
a negative value to zero.
of current due to this change has a tendency
to make the grid positive and cause a sudden
rush of plate current. This has a tendency
to make the grid still more positive by rea
son of dynatron action, and as a result the
tube 1 may draw so much current that it will
be destroyed. The use of the series resistance
charge device having a cathode, an anode
and a grid and having grid and anode cir
cuits, of means for supplying signal repre
senting high frequency oscillations from the
anode circuit to a transmission circuit, and
means for impressing a negative potential
upon the grid comprising a low frequency
29 eliminates this difficulty by limiting the source of alternating current, and a rectify
ing device having asymmetric conductivity
?rst rush of grid current.
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A biasing potential for the grid of ampli serially connected in the grid circuit, the grid
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?er 2 is also provided from the alternating of said electron discharge device being sub’
current source. Transformer 41, the pri stantially insulated from the cathode with
inary of which is connected to the alternating respect to direct current exceptv through said
current source has its secondary 42 connected rectifying device and the space within said
to thermionic recti?ers 43 and ‘44. One end discharge device whereby said rectifying de
of the secondary 42 is connected to the anode vice is effective to prevent a reversal in direc
of recti?er 44 and to the cathode of recti?er. tion of the current flow in the grid circuit.
3. The combination with an electrondis
43 while the other end of the secondary 42 is
connected through condensers 45 to the‘ charge device having a cathode, an anode and
cathode of recti?er 44 and to the anode of a grid, of a circuit between cathode and grid
recti?er 43.
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The anode of recti?er 43 is con
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which includes a series condenser, a circuit
nected to the grid 6 of ampli?er 2 through a in shunt tosaid condenser which includes a
choking inductance 46. By this arrangement resistance and a. second condenser, and a
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source of alternating current and a recti?er
connected in shunt to said second condenser.
4. The combination with an electron dis
charge device having a cathode, an anode and
a grid, of a circuit between cathode and grid
which includes a series condenser, a circuit
in shunt to said condenser which includes a
resistance and a second condenser, and a
source of alternating current, a high resist
75 ance, and a recti?er connected in shunt to
said second condenser.
5. The combination with an electron dis
charge device having a cathode, an anode and
a id, of a circuit between cathode and grid
80 w 'ch includes a series condenser, a circuit in
shunt to said condenser which includes‘ a re
sistance and a second condenser, a source of
alternating current and a recti?er connected
in shunt to said condenser, and a signaling
85 device connected in shunt to said second con
denser.
In witness whereof, I have hereunto set my
hand this 18th da of January, 1924.
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ILLIAM C. WHITE.
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