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Aug. 23, 1932.
1,872,940
F. G. HALLDEN
RELAY RECEIVING CIRCUIT FOR CARRIER TELEGRAPH SIGNALS
Filed July 1, 1930
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INVENTOR
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ATT'oRNEY
Patented Aug. 23, 1932
‘ UNITED STATES
1,872,940
PATENT, OFFICE.
FREDERICK G. HALLDEN, OF JAMAICA, NEW YORKI ASSIGNOR TO INTERNATIONAL
COMMUNICATIONS LABORATORIES, INC” 0]? NEW YORK, N. Y., A CORPORATION OF
NEW YORK
_
RELAY RECEIVING CIRCUIT FOR CARRIER TELEGRAPH SIGNALS
Application ?led July 1, 1930. Serial No. 465,214.
This invention relates to receiving appara
tus for carrier telegraph signals‘and has par
ticular reference to the ampli?cation of sig
nals after they have been recti?ed. The out
put of the circuit is utilized in the operation
ampli?er tubev 11. The?lament 12 of this
ampli?er tube is energized by a battery 13,
the positive pole of which connects with the
negative pole of the battery 14. The con
necting lead 15 between these two batteries is
of a relay from which any desired type of tapped for a condenser 16 and a high resist
telegraph receiver may be controlled.
ance 17 , these ‘two elements being shunted
One of the principal difficulties experienced across to the grid lead 18 which connects be
in the past in operating a printing telegraph tween the transformer coil 6 and the grid 10.
10 from signals received by radio or over chan
nels upon which carrier Waves have been im
16
The plate 19 of the ampli?er tube is connected
to the winding of a relay 20, and'this plate
circuit has impressed upon it the usual poten~
60
pressed, is that the signal strength as re
ceived varies within quite wide limits, so tial as from a B battery 21.‘ The relay arma
thatvthe stability of the rectifying and am ture 22 is normally held against its front con
plifying circuits is not easily maintained. .tact by a current ?owing from the B battery
The primary object of this invention is to 21 through relay 20 and across from the plate
provide a rectifying and amplifying circuit 19 to the ?lament 12. When this current is
of extreme stability, advantage being taken suppressed by the tube action, the relay. arma—
of a condition in which a normally ?xed plate ture is retracted by the spring 23 so as to com
20 current energizes a relay during the absence plete a circuit to the telegraph receiver as rep
of 'a signal, and when the signal is received, resented by the leads 24.
-
this current is so reduced by a negative bias
‘Referring to Fig. 2, the alternative circuit
on the grid of the ampli?er tube that the re will now be described. The transformer 5 ~
lay will be released.
Since an excessively with its primary winding 4 and secondary
strong signal can do no more than arrest the winding 6 is shown in Fig. 2 the same as in 75
flow of current in the relay-to-plate circuit,‘ Fig. 1. The grid lead 18 is the same. The
the desired stability is obtained. *
condenser'16 is likewise connected across be
In carrying out this invention, an ordinary tween the grid lead 18 and the ?lament con
80
receiving set responsive to radio. frequency
nection 15.
The circuit through rela 20 con- .
oscillations may be used, and the output nects similarly with the plate 19. T e arma
thereof when converted into audio frequency ture 22 in the telegraph receiver circuit 24 is
80
may be ?rst recti?ed and then ampli?ed so as the same.
to operate the controlling relay.
Referring to the drawing:
Figure 1 shows diagrammatically the rec
tifying and amplifying circuits.
Two principal differences are ap
parent: One source of energy, preferably
110 volts direct current, supplies both the ?la
ment potential and the plate potential. This
85
current passes through the . switch 25, the
Fig. 2 shows an alternative arrangement of positive lead connecting with an adjustable
‘ I
l
resistance 26, taps from which connect re
these circuits.
40
45
spectively with the winding of relay 20 and
The radio/receiving set 1 is represented
with its antenna 2 and ground 3. The output
from the radio receiver‘will beunderstood to
be in the form of audio frequency oscillations
which pass through the primary 4 of a trans
resistance reduces the voltage, making it suit
former 5. I The secondary 6 of this trans
former is connected at one terminal with the
nects with the negative side of the energizing
with an additional resistance 27.
This-last
able for the tube ?laments 8 and 12. These
?laments are in series, connected’ by the lead
15.
One terminal of the ?lament 12 con
plate 7 of an ordinary two-element recti?er source. A resistance 28 is connected between
tube 9. This tube includes a ?lament 8 which the ?lament 8 and the conductor 29, the latter
receives its current from the battery 14. The being a connection from the transformer
60
90
other terminal of the transformer coil 6 con winding 6 to the plate 7.
It is obvious that in place of the tubes as
nects with the grid 10 of a three-element
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2
1,372,940
shown, it would be possible to use tubes ducing the current in the plate circuit and
adapted for operation with alternating cur causing the relay 20 to release.
‘
rent applied to the ?laments.
The operation of this invention is as fol
lows:
The half-waves which are recti?ed by the
tube 9 are ?attened out by the action of the
condenser 16 so as to have substantially the 70
When no signal is being received (or, in
other words, during a “spacing” interval),
same effect as a continuous current.
I claim as my invention:
the recti?er tube 9 will be inactive because no
1. Apparatus for rectifying and amplify
current can pass from the plate 7 to the ?la ing telegraph signals comprising a trans
10 ment 8 except that which is generated by the
former, a recti?er connecting therewith, an 75
~ transformer 5.‘ This is evident from the fact ampli?er tube the grid circuit of which is con
that no potential greater than that of the ?la nected to said transformer, a neutral relay
ment is otherwise impressed upon the plate connecting with the plate of said ampli?er
circuit 18. Under these conditions there tube, means normally to maintain a de?nite
15 fore, it is possible to adjust the space current
potential on said grid with respect to its ?la
80
in the tube 11 from the late 19 to the ?la ment and to impress upon said grid in re
ment 12 so as to energize the relay 20 and sponse to a received signal a purely negative
hold its armature 22 in an open circuit po charge from the circuit which includes said
sition with respect to the telegraph receiver
20
25
80
circuit 24. When, however, the signalling
impulse is received and converted by the ra
dio receiver 1 into audio frequency, the im
press of this signal upon the transformer
winding 4 provides an inductivev effect upon
the winding 6, the oscillations from which
are passed to the plate 7 and recti?ed. A
transformer and recti?er tube. _
2. In a telegraph receiving, network, a rec
ti?er. a resistance in the output circuit of said
recti?er, a thermionic ampli?er having a grid
and a plate circuit, a neutral relay included in
said plate circuit and energized by a normal
flow of current therein, means for supplying
90
signal impulses to said recti?er, and means
negative bias is thereby impressed on the grid for applying the variation of the potential
10 of the ampli?er tube and the space current between the terminals of said resistance to
from the plate 19 to the ?lament 12 of this said grid circuit during the continuance of
ampli?er tube 11 ‘is immediately reduced to said signals for the purpose of suppressing
95
the point where relay 20 deenergizes, allowing
the current in said plate circuit and de~ener- ‘
its armature to be retracted by the spring 23 gizing said relay.
so as to close the telegraph receiver circuit 24.
35
3. In a telegraph receiving network, a rec
The “marking’7 signal is thus communicated ti?er having an output circuit, a thermionic
to the telegraph receiver.
ampli?er having an input circuit including a
100
It will be noted that a positive and depend grid and a ?lament, and an output circuit,
able action of the relay 2,0 is obtained in this a resistance in the output circuit of said rec
manner. The reason for this is that a de?nite
40
45
space current is established from the plate 19
to the ?lament 12 according to the character
istics of the tube itself and the plate poten
tial. The operation of the transformer 6 in
association with the recti?er tube 9 can have
only one effect regardless of the strength of
the input signal, that is, to negatively bias the
grid 10 and reduce the space current from the
plate 19. Referring to Fig. 2 the same con
ditions prevail as hereinbefore described with
reference to Fig. 1. The maintenance nor
59
mally of a zero potential on the grid 10 with
respect to the ?lament 12 is effected by the use
of the high resistance 28 in series with the
55
ti?er and the input circuit of said thermionic
ampli?er, said resistance having one terminal
connected to said grid and; another terminal
105
connected to said ?lament, and a neutral re
lay included in said ampli?er output circuit
and energized by a normal flow of current
therein.
,
4. In a telegraph receiving network, the
110
combination of a recti?er having an output
circuit, and a resistance bridged across said
circuit, a relay, an ampli?er having an input
circuit connected to the output circuit of said
recti?er and an output circuit connected to 115
said relay which is energized by the normal
?ow of current'in said circuit.
secondary 6 of the transformer 5. During the
In witness whereof, I hereunto subscribe
spacing interval when no current is generated my name this 30th day of June, 1930.
FREDERICK G. HALLDEN.
by the transformer, the grid 10 of the am
plifying tube 11 is also at zero potential with
respect to its ?lament. Under this condition
a certain current is flowing in the plate circuit
of the amplifying tube 11 through the receiv
ing relay 20. ‘The spring 23 of this relay is
120
adjusted so as to be overpowered by the am
pere turns of its coil and pull the armature
againstthe front contact. The impress of the
a signal biases the grid 10 negatively, thus re~
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y