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NOV. 5, 1946.
J: A, WORCESTER, JR
2,410,768
SUPER-REGENERATIVE RECEIVER CIRCUIT
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Filed Feb. :5, 1945
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Joseph
Inventor“:
Patented Nov. 5, 1946
PATENT OFFICE ,’
UNITED STATES
2,410,’? 68
SUPERREGENERATIVE RECEIVER CIRCUIT
Joseph A. Vvorcester, J12, Fair?eld, Conn, assign
or to General Electric Company, a corporation
of New York
Application ‘February 3, 1943, Serial No. 474,501
8 Claims.
1
( Cl. 250-20)
2
.
My invention relates to super-regenerative re
ceiver circuits and it has for its object to pro
vide an improved super-regenerative receiver
circuit which is particularly adapted for receiv
ing super-audible frequencies such as pulses and
operation, together with further objects and ad
vantages thereof, may best be understood by
reference to the following description taken in
connection with the accompanying drawing, in
which Fig. 1 represents certain portions of a
television signals.
A super-regenerative receiver of the usual
type is essentially similar to an ordinary regen
erative type of receiver but has additionally a
local source of super-audible oscillations which
are introduced-into the detector circuit of the
receiver in a manner to vary the deteotor’s op
erating point at a uniform rate. This local
oscillation, known as the “quench” or ‘inter~
ruption” oscillation, allows the super—regenera
tive detector to oscillate at the carrier frequency,
in the manner of the ordinary regenerative de
tector circuit, only when the varying operating
point is in a region suitable for the production
of oscillations, The constant interruption of
oscillations in the detector circuit by the quench
oscillations permits ampli?cation of the signal
in the detector to very large proportions. Simi
lar results are obtained in an ordinary regenera
tive circuit when regeneration at the signal fre
quency is carried to the point that the detector
circuit begins to oscillate at a low frequency
receiver circuit embodying my invention; and
Figs. 2 and 3 illustrate certain operating charac
teristics of the circuit of Fig. 1.
Referring to Fig. 1, I have shown an electron
discharge device Ii] having radio frequency in
put circuit H and an oscillatory circuit lZreso
nan-t at the radio frequency. Modulating signals
appearing in the output of the device m are sup
plied to subsequent stages of the receiver over
conductor !3.
The device Ill operates as a self
quenching super-regenerative detector and the
control circuit I4 is provided to increase the in
terruption rate of the super-regenerative circuit.
The electron discharge device It is shown as a
triode having an anode l5, a cathode l6 and a
control electrode H. The cathode i6 is heated
by means of a ?lament [8, power for heating the
?lament l8 being supplied thereto over conduc
tor H! from anyv suitable source through induct
ance 20 acting as a ?lament choke. Inductance
2| serves as a second ?lament choke connected
between the opposite terminal of ?lament l8 and
ground. By-pass capacitors 22 and 23 are con
nected between the respective terminals of the
has the same effect as the quench oscillation pro- 30 ?lament l8 and cathode it. An inductance coil
duced by a separate source of oscillation, and a
26 is connected between cathode is and ground
simultaneously with its oscillation at the signal
frequency. Such a low frequency oscillation
circuit so. operating is'custQmariL referred to as
to serve as an auxiliary feed-back means to in
a self-quenching super-regenerative detec or 01 —
"
cuit.
In such a circuit the repetition rate or
‘with
'nitude of local oscillations.
The oscillatory circuit ‘1 connec e
quench frequency, which iscontrolled by the 35 anode l5
time constant of the grid-cathode circuit of the
detector, determines ‘the maximum modulation
frequency that can be reproduced by the receiver
circuits.
-
_
Accordingly, it is anobject of my invention to
provide a self-quenching super-regenerative cir
cuit in which the signal frequency oscillations of
the receiver circuits are interrupted at a very
rapid rate, thereby permittingv the reproduction
of pulse modulations of very short duration.
Another object of m-yinvention is to provide
an auxiliary discharge path for the grid of a
super-regenerative detector which path is oper
ative only during negative half cycles of quench
oscillations to decrease’ the duration of such negative half cycles.
_
-
The features of my invention which I believe
to be’ novel are' set forth with particularity in
the appended claims. My invention itself, how
ever, both as to its organization and method of ' 61
etween
control electrode l'l comprises a
pair of parallel conductors, or rods, 21 and 28
which function as a transmission line having. a
length approximately equal to a quarter wave
length at the tuned radio frequency and capacitor
29 is‘ provided across the outer extremitiesof
this line to function as means for short-circuit
ing or closing the end of the line at radio fre
quency.
-
g
'
The radio frequency input circuit l i may com
prise the concentric transmission line 24 having
its inner and outer conductors connected at their
upper ends to a suitable antenna (not shown)
and at their lower ends to the coupling loop 25
lying between the parallel rods 2'? and 28. The
outer conductor of line 24 is grounded at its low
ermost point 24'.
Operating potential for the anode it may be
supplied from any suitable source, such as the
battery, 39, through local resistor 35, across
which audio frequency voltages are developed,
2,410,768
3
4
o? designated by line 50, and oscillations must
and ?lter 32, provided to remove radio frequency
and quench frequency voltages from the output
conductor I3.
necessarily cease when electrode I1 is driven to
such a negative value. At the same time capac
Resistors 34 and 35 are connected between the
outer end of conductor 28 and ground to function
as the usual grid leak for the detector Hi. The
point of connection 33 of resistor 34 with con
ductor 28 is shown as coupled to ground through
ually leaks off through resistors 34 and 35 at an
exponential rate, as indicated by the portion of
itance 31 is charged to this high negative voltage.
The high negative charge on capacitance 37 grad
the curve CD, until plate current again begins to
?ow in tube It and the cycle is repeated.
The repetition rate, or frequency, of the quench
oscillations operates to limit the maximum modu
a grid capacitance 31. This grid capacitance
comprises the distributed capacity of the grid rod
28 and its associated wiring to ground.
lation frequency that can be reproduced in the
output circuits of the receiver. This repetition
The action of a radio receiver using super
regeneration is, in general, quite complicated,
especially when receiving super-audible oscilla
rate is controlled primarily by the portion of the
curve CD, that is, the time required for the high
negative charge to be removed from the capac
itance 31. The frequency of the quench oscilla
tions limits the modulation frequency because it
“quench action” which periodically changes the
is necessary to ?lter the quench frequency from
operating point of an electron discharge device
in an oscillatory circuit. Such periodic change 20 the output circuits and such ?ltering can be ac
complished Without adversely affecting desired
may be accomplished by varying either the anode
modulation signals, only by making the repetition
voltage or the grid bias voltage of the device.
rate high compared with the highest modulating
The arrangement of Fig. 1 utilizes the grid bias
frequency to be reproduced.
method of introducing the quench voltage into
The repetition rate of the quench oscillations
the detector circuit and in the operation of the 25
in the portion of the receiver circuits thus far
portions of the receiver circuit thus far described,
described is controlled largely by the capacitance
the electron discharge device in operates in the
31 between grid H and ground. To increase the
usual manner to amplify signals supplied to the
rate to its maximum value, this capacitance is
control electrode i‘! from the radio frequency
input circuit. The oscillatory circuit I2 con 30 reduced to as low a value as possible, the ultimate
in this direction being reached when the value
nected between the anode and control electrode
of capacitance 31 is reduced to the input stray
is adjusted to resonance at the frequency of the
capacity between grid H and rod 28 and ground.
input signals. Since each of the conductors of
The repetition rate may also be increased some
this line has a length equal e?ectively to a quar- ,
ter of a wave length of the received oscillations, 35 what by decreasing the value of grid leak re_
sisters 34 and 35. The value of these resistances
oscillations ‘from the anode l5 are shifted through
must be maintained sufficiently large, however,
180° in traveling between anode l5 and control
that oscillations in the oscillatory circuit 12 are
electrode I‘! in this resonant circuit and, hence,
not clamped to the point that super-regeneration
these signals are supplied to the control elec
trode as an input voltage which is in exactly the 40 is prevented.
In order to permit further increase of the repe
right phase to build uposcillations in the resonant
tition rate of the quench oscillations, in accord
circuit. The amplitude of these oscillations in
ance with my invention; control circuit I4 is pro
creases with each cycle until they reach an inten
vided for the receiver circuits thus far described.
sity su?icient to provide a positivevoltage on
control electrode l ‘I and cause grid current {70:45 ‘This circuit comprises an electron discharge de
vice 40 having its anode 4| connected to the posi_
?ow in the circuit between grid I‘! and cathode
tive terminal of the potential source 38, its con
l6 and comprising resistors 35 and 34 and rod
trol electrode 42 connected to ground and its
28. .Current ?ow through the grid leak resistors
cathode 43 connected to the common point of
34 and 35 provides a negative voltage for control
resistances 34 and 35 by means of conductor 44.
electrode l1, biasing this electrode considerably
tions. The fundamental principle of super-re
generation, however, is based on the impression
of a low frequency variation, usually called
beyond the plate current cutoff point.
The combined stray capacity of conductor 44 to
Hence,
oscillations cease when this actionv occurs, the V
capacitance 3'Lserving to maintain a high nega
_
=n
c electrode H.
The nega
tive charge on capacitance 31 graua *
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ground "an
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the
cathode
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device!!!) are represented by capacitance 45.
In the control circuit l4, since the cathode 43
'
onnected to ground through resistor 35 while
control e . . -.
2 is connected directly to
through resistors 34 and 35 until plate current
ground, the device 40 is nor ‘ . I 2 ~ -conducting
again begins to ?ow in device In and the cycle
and essentially removed from the circuit of
is repeated.
super-regenerative detector In during the time
The operation of this portion of the circuit of
Fig. 1 may be illustrated withgreater clarity by 60 that oscillations are building up in the resonant
circuit l2. Resistor 3'4 is quite small compared
reference to Fig. 2 in which the reference line 53
to resistor 35, the latter preferably being of the
represents, the voltage Eg of‘control electrode H
order of 1 megohm. When the amplitude of the
at which conduction of anode current in device‘ Ill
oscillations in the oscillatory circuit i2 is suffi
is .cut oif and reference line 51 represents zero
potential for control electrode ii, that is, the 65 cient to cause current to ?ow between grid l1 and
cathode is, tending to bias the oscillator tube l3
' potential at which grid current flow in device
beyond cuto? by the potential drop across re
I0 is started.' Curve 52 illustrates the manner
sistor 35, this negative bias is also applied to the
in which oscillations build up in the tuned circuit
cathode of device 40. Since the control elec
l2, starting with zero value at point A and grad
ually increasing in amplitude until, at point B, 70 trode 42 is grounded, the negative bias of cathode
43 causes control electrode 42 to become posi
control electrode l1 reaches a positive potential
tive with respect to the cathode and the positive
and grid current ?ows in device it). When such
voltage applied to anode 4| produces anode cur
grid current flows, the potential of control elec
rent in device 40. This anode current ?ows
trode i1 is rapidly reduced to the value C, which
value is considerably below the plate current cut— 75 through resistor 35 in a direction opposite to that
2,410,768
5
of the grid current in device In. and is effective
charge device non-conductive, and means in
to remove rapidly the negative charge accumu
cluding a unilateral. conducting device connected
lated on the oscillator grid IT.
across at least a portion of said resistor for con
The operation of this portion of the circuit of
trolling the duration of the non-conductive in
Fig. 1 is illustrated in Fig. 3 in which reference 01 tervals.
lines 50 and 5| represent the values of gridvolt
2. In an ultra high frequency super-regenera
age pointed out previously. The curve 52 illus
tive receiver, the combination of an electron dis
trates the manner in which oscillations build up
charge device comprising an anode, a cathode,
in the tuned circuit l2, starting with zero value
and a control electrode, a signal input circuit
at point A’ and gradually increasing in amplitude
connected between said control electrode and
until, at point B’, the amplitude is such ‘that con
cathode, an output circuit connected between
trol electrode ll becomes positive and grid cur
said anode and cathode, a tuned circuit con
rent ?ows inv device It; As stated previously,
nected to couple said input and output circuits
when such grid current flows, the potential of
thereby to produce oscillations in said discharge
control electrode I1 is reduced to the value C’,
device, an impedance connected between said
which value is below the plate current cutoif
control electrode and cathode and including a
point.
.
capacitive element arranged periodically to be
When control electrode I‘! is driven to the po
charged by current ?owing therethrough, said
tential 0' below the plate current cutoff value
of tube Ill, current flows in device 40 and the a capacitive element being disposed when charged
to bias said discharge device to cutoff thereby
negative charge accumulated on capacitances 3'!
periodically to interrupt said oscillations, and
and 45 is rapidly removed by the current flow in
means including a second electron discharge de
tube 4c. The amount of negative bias, that is,
vice responsive to said cutoff bias and connected
the potential C’ to which grid I‘! is driven before
across said impedance for controlling the rate of
conduction in tube 40 is started, may be con
’
.
trolled by adjusting the time constant of re 1 5 interruption of said oscillations.
3. In an ultra high frequency self-quenching
sistor 34 and capacitance 45. The recovery time
super-regenerative receiver, the combination of
of the grid circuit and, hence, the repetition rate
an electron discharge device comprising an an
of the quench oscillations are controlled by the
time constant of resistors 34 and 35 and ca 3 0 ode, a cathode, and a control electrode, a signal
pacitances 31 and 45.
input circuit connected between said control elec
trode and cathode, an output circuit connected
The electron discharge device 40, therefore,
acts as an auxiliary discharge path for the grid
between said anode and cathode, a tuned circuit
connected to couple said output and input cir
I1‘ of the super-regenerative detector. This path
is operative only during negative half cycles of
cuits thereby to build up oscillations in said out
quench oscillations and provides means for de
put circuit, a resistance and a capacitive element
creasing the duration of such negative half
connected in parallel circuit relation between said
cycles. In the usual type of super-rengerative
control electrode and cathode to‘ conduct current
receiver circuit, a quench. frequency of between
upon the attainment of a predetermined in
30 and 80 kilocycles is obtainable. By the addi 40 tensity of said oscillations, said current charging
tion of the control circuit I4 and proper adjust
said capacitive element to bias said discharge de
ment of the values of resistances 34 and 35 and
vice to cutoff and to interrupt said oscillations,
by maintaining capacitances 3'1 and 45 at a mini
and means comprising a second electron dis
mum, repetition rates as high as 1000 kilocycles
charge device having a pair of electrodes con
may be obtained. By using quench oscillations
of such high frequencies, this type of receiver
may be employed in pulse signalling systems and
the quench oscillations may be removed from the
output circuit without disturbing signals of the
pulse frequency.
While I have shown a particular embodiment
of my invention, it is apparent that various modi
?cations may be made. Thus, the quench fre
' nected across at least a portion of said resistance
for controlling the rate of discharge of said ca
pacitive element thereby to control the perio
dicity of said interruptions.
4. An ultra high frequency self-quenching
5m. super-regenerative receiver circuit comprising
a source of signal waves, an electron discharge
quency may be controlled by the application of
suitable bias to grid 42 of electron discharge de- .7
Vice 4!]. It will be understood, therefore, that I
do not wish to be limited to the embodiment
shown since various modi?cations may be made,
and I contemplate by the appended claims to
cover any such modi?cations as fall within the
true spirit and scope of my invention.
,,
and output circuits to build up oscillations in said ~ ~
to output circuit, a resistance and a condenser con
nected in parallel circuit relation between said
What I claim 'asyimnid‘desireetosecur
Letters Patent of the United States is;
device having an anode, a cathode, anda control
electrode, an input circuit for said discharge de
vice connected between said cathode and said
control electrode, an output circuit for said device
connected between said anode and said cathode,‘
a tuned circuit resonant at the frequency of said
signal waves and connected to couple said input‘
0 e co rodeand said cathode, oscillations in
-/said output circuit being periodically interrupted
1. A detector cilgzuit for signal modulated car
krriernwaves comprising an electron discharge de
vice having an anode, a cathode and a control
electrode, an input circuit for said device con
by the flow of grid current through said resist
(3.53 ance and charging of said capacitor when said
oscillations attain a predetermined intensity
thereby to bias said discharge device to cutoif,
nected between said cathode and said control
and means for rapidly removing said biasing po
electrode, an output circuit for said device con
tential including a second electron discharge de
nected between said anode and said cathode, a To vice having a control electrode cathode circuit
tuned circuit resonant at the frequency of said
connected across at least a portion of said re
waves and connected to couple said input and
sistance, said second device being non-conductive
output circuits, means including a resistor con
when said ?rst device is producing oscillations in
nected between said cathode and said control
said resonant line and being rendered conductive
electrode for periodically rendering said dis
by said biasing potential to produce current ?ow
2,410,768
-through said resistance in a direction opposite _
rier waves comprising an electron discharge de
to the flow of said grid current.
5. A self-quenching super-regenerative re
ceiver circuit comprising a source of signal waves,
an electron discharge device having an anode, a
cathode and a control electrode, an input circuit
for said device connected between said cathode
and said control electrode, an output circuit for
said device connected between said anode and
said cathode, a tuned circuit resonant at the fre
quency of said waves and connected to couple
vice having an anode, a cathode and a control
electrode, an input circuit for said device con
said input and said output circuits thereby to
conductive, and means including a source of uni
build up oscillations in said output circuit, means
interposed between said cathode and said con
trol electrode and responsive to the intensity of
directional potential and‘ a second electric dis
charge device connected to control the rate of
discharge of said capacitive means thereby to
control the duration of the non-conductive in—
tervals.
8. A detector circuit for signal modulated car
said oscillations for’ periodically interrupting
said oscillations, and means including a unidirec
nected between said cathode and said control
electrode, an output circuit for said device con
nected between said anode and said cathode, a
tuned circuit resonant at the frequency of said
waves and connected to couple said input‘and
output circuits, capacitive means connected be
tween said cathode and control electrode for
periodically rendering said discharge device non
tional conducting device associated with saidin
rier waves comprising an electron discharge de
terrupting means for controlling the periodicity
of said interruptions.
20 vice having an anode, a cathode and a control
electrode, an input circuit for said device con
nected between said cathode and said control
electrode, an output circuit for said device con
nected between said anode and said cathode, a
nected between said cathode and said control 25 tuned circuit resonant at the frequency of said
waves and connected to couple said input and
electrode, an output circuit for said device con
output circuits thereby to build up oscillations
nected between said anode and said cathode, a
in said discharge device, means for periodically
tuned circuit resonant at the frequency of said
interrupting said oscillations including a capaci
waves and connected to couple said input and
tive element connected between said cathode and
output circuits, means including a capacitive ele
said control electrode and arranged by its charge
ment between said cathode and said control elec
to bias said discharge device to cutoff when said
trode arranged to be charged by current flowing
oscillations attain a predetermined intensity, and
through said device and periodically to render
'means including a unilateral conducting device
said discharge device non-conductive, and means
including a unilateral conducting device con 35 rendered conductive only upon charging of said
capacitive element to increase the rate of dis
nected to control the rate of discharge of said
sipation of said charge.
"
condenser thereby to control the duration of the
6. A detector circuit for signal modulated car
rier waves comprising an electron discharge de
vice having an anode, a cathode and a control
electrode, an input circuit for said device con
non-conductive intervals.
'
'7. A detector circuit for signal modulated car
JOSEPH A. WORCESTER, JR.
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