close

Вход

Забыли?

вход по аккаунту

?

Патент USA US2408193

код для вставки
Sept. 24,1946. - " .
-
'
D. A. BELL _E‘l_'AL>
ELECTRICAL
APPARATUS
Filed Aug. 11,’ 1942
2,403,192
"
’
2_ Sheets-Sheet l
,éo
W
m
_
if“
v.
Sept. 24, 1946.
D. A. BELL ETAL '
2,408,192
ELECTRICAL APPARATUS
Filed Aug. 11, 1942
2' Sheets-Sheet 2
07
0,6
Patented Sept. 24, 1946 v -
2,408,192
‘UNITED STATES PATENT OFFICE ‘
David Arthur‘Bell and Arthur Henry 'Ashford- '
Wynn, London,. England, assignors'to A. -C.
' Cossor Limited, ‘London , England, a. company
of Great Britain
Application August ll, 1942,'Serial No."454,391v
In Great Britain August 16, 1941
‘
1
.
7 Claims.
' "
(Cl. 250—36)
,
This-invention relates to the thermionic valve
feedback oscillator of the‘ kind in which the ‘fre
quency' is controlled by a reactance valve. A
reactance valve isga thermionic valve, having a
theinvention is carried into effect in amanner
which is preferable for some purposes, the react
ance across which the control grid voltage for
the reactance valve is developed is arranged to
control grid excited substantially in phase quad
rature with the generated oscillatory voltage, and
carry, not only the oscillation frequency. output
current of ‘the oscillator valve, but also the oscil
so connected that its output current ofoscillation
lation frequency output current of. the reactance
frequency flows through at least part of the tuned
valve. This'arra'ngement will somewhat disturb
circuit which substantially determines'the fre
the phase relationships, and will lessen the degree
quency of the oscillator. In this manner there 10 of frequency control obtainable for a given change
is introduced into the tuned circuit :an effective
in mutual conductance of the reactance valve;
reactance, the magnitude of which is vdependent
but these disadvantages may sometimes be un
important, especially if onlyqa small degree of
upon the mutual conductance of the‘reactance
valve. The phase quadrature voltage for the con
frequency control is required.
» .
~
‘
trol grid is usually obtained from the generated 15 Intheaccompanying drawings each of the ?g
oscillatory voltage by meansw'of a phase-shifting
network-comprising a resistance in series with a
reactance,
‘
‘
r
I.
7
7'
~
ures shows the circuit diagram of an oscillator ’
' embodying‘ the invention.
1 Figure l, shows‘an oscillator ge erallyv similar
~
One‘of the difficulties in' arranging a circuit of
this kind'for operation at'very high'frequencies
to the vHartley oscillator. _
20
'
,
‘
»
-'
'
Figure 2 shows an ‘oscillator generally similar
is the amount of power dissipated in the resist“
to the Colpitts- oscillator.
ance of the phase-shifting network‘ At such
frequencies the reactance is very low, even if it
Figures 3 and 5 show oscillators eachgenerally
similar to the ordinary tuned-anode oscillator.‘
consists simply of inter-elec'trodeand' stray ca
'pacities; andithe resistance-must therefore also
be low in order that sufficient voltage may be
developed across the reactance. 'An object-of the
present invention is to overcome this dif?culty.
,
,
‘
I
.
Figure .4 shows‘ an oscillator generally similar
25 to' the ordinary cathode-coupled oscillator.
In Figure 1, for the oscillator valve V1, a pen
tode is selectedyto provide the necessary high
impedance. Its suppressor grid is directly con
' The invention is applied to oscillators wherein
nected to cathode, while, its screen grid‘ is main
the tuned circuit which substantially determines 30 tained. at constant positive potential relative to
the frequency of the oscillator ‘is of they parallel
cathode by ‘condenser ‘C15 and resistance R13, the
resonant type, andr-wherein'the output'current
latter connected to the positive high tension line.
of oscillation frequency of the ‘oscillator valve
The direct current supply from the high tension
line to the anode is provided through resist
flows through at least part of said tuned'circuit.
. In an oscillator in which theiinvention' islcar
ance R11.
ried into effect the substantially phase'quadra
ture voltage for the reactance valve control "grid
.
g
The“ oscillation frequency output current of
valve V1 passes from its anode through blocking '
condenser C1z- to the tuned circuit L101, which
substantially determines the oscillation fre
is developed across a reactance which is effec
tively connected in series betweenlthe tuned cir-'
cuit and the oscillator valveso that it carries the 40 quency; and thence from the tapping on induct
ance L1 (which'tapping in the Hartley oscillator
oscillation frequency output current'of the oscil
is normally connected directly to cathode) .to
cathode'through- the capacitances‘ci andwCs, ef
It is desirable that the oscillator valve should
fectively in parallel with each other, through con
have high impedance, so that the" inclusion .of
the reactance in series shall not seriously disturb .45 denser C5 designedtooffer negligible reactance
'at the oscillating frequency. In parallel with
the phase relationship of the anode current and
capacitance‘ C4, choke Ch isv provided to carry
the direct component of ‘ the anode'current of
_ In, a preferred arrangement, the‘ reactance
reactancevalve V2. ~-_-Capacitance C4 may consist
across which the control grid voltag?for the
reactancelv'alve is developed is e?ectively vcon 50 solely of the stray capacity across choke Ch and
lator
the
valve.
'
anode'voltage.v
‘
,
'
’
.
.
'-
,
_
.
.,
>
._
1
_
nected between the tuned circuit and the cathode
of the'os'cillator valve, and either one end jor the
other of this reactance is maintained at earth or
capacitance C9 may consist solely of the inter
‘elect-rode andstray capacities between control
other zero oscillation potential.
' .Thevcontrol grid of valve ,V1'is coupled to the
‘
-
'
gridandcathode of valve V2“
\
' '
>~
'
In an oscillator‘ in which a: modi?edv formiof 55 lower end of tunedcircuit L101 by condenser C3,
2,408,192
.3
>
4
also maintains the mean potential of the con
and is connected to cathode through grid leak
resistance R2.
Reactance valve V2 may be a pentode similar
to that employed for V1 Its suppressor grid is
directly connected to cathode, while its screen‘
trol grid of valve V2.
'
The control grid voltage for valve V1 is pro
vided by coil L2 coupled with inductance L1 of
the tuned circuit L1C1.
The oscillation frequencyv control) grid voltage
for~~valve1V1i-is developed ‘across capacitances C4
grid is maintained at constant positive potential
relative to cathode by condenser Cs and'resist
and C9 in parallel with each other. The oscilla
tion frequency output current of valve V2 passes
1. throughblocking condenser C1 to the tuned cir~
ance R3, the latter connected to the positive high
tension line. The direct current supply from the;
high tension line to the anode of valve-V2 ,i-sprm V
vided through resistance R1.
The control grid of valve Vzis‘coupleda-to earth
cuit' L‘1C’1'“ to earth, and thence through oscil
lation-vlfrequencycoupling condenser C5 to the
cathodeiofzvalveVz‘.
for oscillation frequencies by condenserCs'}. and,v
FigureAishowsrthe circuit diagram of an os
cillator'embodying the invention but generally
C9, in parallel with each other, is applied between
similar. to theiordinary cathode-coupled oscil
control grid and cathode of“ valve V2: This volt~
lator;v The oscillation frequency output current
age will be in quadrature with the oscillation-free
of valve V1 ?ows from anode through the high
quency output current of oscillator valve V1, which
tensionv source (which may be provided with a
?ows through these capacitances. Theoscilla
tion frequency output current of reactance valve 20 by-pass condenser not shown) to earth and
thencetothe tuned .icircuit. L101. From .the- tap
V2‘ will; therefore; be ‘in quadrature with that: of
pingr on; inductance: L1 it: passes-.1 to. cathode
oscillatorr-valve‘Vn Its path ‘is’ from the anode
through-capacitances 1C4 and Cain parallel" with
of 'valve' V2, through blocking ‘condenser C7,. to
each; other (condenser; C5 offering ~ negligible 1 re
the'sa-me endof tuned oircuitlirCi that‘isi'coupled
through condenser‘ C12'to theranodeof ‘valve V1. 25 actance‘ at : oscillation ~: frequencies) .- The direct
component-.o?theaanode current of valve V1‘ is
From the tapping on inductance L1it‘is returned
passed‘: from cathode to ‘earth throughj choke Ch
directly to' cathode of valve-V2. Itiwill,.there
andrthelower part of inductance L1.
fore; introduce into the-tunediicircuit L101 an'ef
The oscillation frequencwoutputi current. oi
fective reactance,- the magnitudegof which is de
the voltage developed acrossvcapacitancesrClf-iand
pendent up on the mutualiconductance' offreact
30 valve V2 ipassesthrough blocking ‘ condensenCr ‘to
ance valve V2;
The mutual conductance of "valve-2V2 iscon~
trolled by direct current source »B'.in seriesi'zwith
modulating source -E.' The oscillation frequency
coupling condenser-C5 should-‘offer high reactance
at modulation frequencies.
Figure 2 shows a circuit=diagram of ‘an oscil
lator embodying the invention, but 1 generally
similar to the Colpitts oscillator;v Theaoscillation
frequency output current‘ of "valve Viipassesrfrom i
it's anode through blockingicondenser'?iz tothe
ther:tuned ‘circuit L101‘. From‘ thertapping on in
ductance‘ L1 it is returned; directly to the f cath
ode of: valve V2. - Thepmutual‘ conductance: of‘ re
actance" valve= V2 is rcontrolled‘ by“ direct. current
source B inaseries with modulation source, E,
connectedcbetweenearth and control grid; Choke
cm; which offers, low‘- reactance, at modulation
frequencies but high reactance at oscillation fre
quencies;v is inserted; to : prevent; shortt-circuiting
of; the; control ‘ grid :of '1valver:V2~ to earth,~ for: os
cillationfrequency:v Condenser C5 cifersrhighre
actance, and-choke Chi low reactance; .atmodu
tuned circuit L1C1’C21 From‘ the tapping-oncom
denser' chain ‘C1'C2 (which tapping in the Colpitts
oscillatoris normally connectedi'dire'ctly to cath
lationfrequenciea so the cathodes of both valves
ode), it passesthrough‘capacitance CQ'andfosciL
oscillatorzembodying the invention but-generally
lation frequency coupling condenser‘ C's-‘to: the
earthed cathode vof ‘valve‘Vi'; The capacitance C9
may consist solely- of“ interrelectroderand stra;7
capacities between control grid'and‘ cathode- of
valve V2. Condenser C5, as inFi'gure 1, offers 50
negligible reactance-at oscillation frequencies but
high reactance at modulationifrequencies; ,
are atszero; potential forqmod-ulation' frequencies.
Figure :5 shows the ‘circuit. diagram' of :another
similar toitheaordinary- tuned anode. oscillator.
Unlike. that - shown-in, Figure 3, this circuit is- ar
rangedso-that'the cathodes of the. two valves are
directly" connected"' together; Capacitances C4
and; C1 are- again effectively Y connected‘ in- par
allel: with .- each other "for: oscillation frequencies,
al'idxin: series betweenthe cathode ofvalve V1 and.
The oscillation frequency output‘ current of
the-earthed : end of" tuned- circuit; L1C1; condenser
reactance valve V2‘ passes from its anode through
blocking condenser C7 to the tuned circmtL1C1C2. 55 G5~ offering negligible reactance at'. oscillation
frequency.‘
From the- tapping on condenser chain C102 it
The’ oscillation frequency‘ output current of
passes/through capacitance C5 to the'cathodeof
valve V2 passes through'blockingwcondenserrCw to
valve‘ V2} The'capacitance» Ct, across which :the
the tuned circuit: L'1C‘1 and thence through ca
control grid; voltage for valveVz is developed,
therefore carries the oscillation frequency output 60 pacitances Grand C9. in-parallelfwith each other
t'O’ithe' cathode-oft valve V2. As in Figure 2,
currents of both of-valves V1‘ and‘Vz. The'qua‘d
therefore, the capacitances C4 and C13,‘ in par
rature relationship between‘ the oscillation fre
quency output‘ currents of vthe two‘valvesv will
allel-“witheach other, carry the oscillation fre
quency output currents of both of'valves- V1 and
therefore be somewhat disturbedL
Figure 3' shows the circuit diagram‘of an 0s’
cillator embodying the invention but generally
similar to the ordinary tuned-anode'oscillator.
Capacitances Cl and C9 are effectively connected
iii-I parallel with each other forioscillation fre
V2.
’
To‘v obtain a high degree of frequency control
for a given modulating voltage, "it is desirable to
apply, the‘ modulating voltage to the control grid
oil the, reactance : valve.
This‘ arrangement - has
quencies, and in series between theearthed- end 70 been. indicated, ineeach. of the. circuit diagrams
of tuned'cifcuit‘L'rCi and‘the cathode of “valve
V1; the oscillation frequency-output" current of
valve V1 therefore-?ows through'these capaci
tances. Choke Ch carries theD. Ci'component
shown inthedrawings-t Themutualconductance
of valve V2 :ma-y,» however, alternatively I be. . conf
trolled by modulating;v the. potential ‘of the» screen
grid, or of‘ the suppressor. grid; Qfjthereactance
75
of the anode current of ‘oscillator valve V1 and
2,408,192 '
6
respondingly vary the effective resonant frequency
of said oscillation circuit and to thereby control
the frequency of the oscillations produced.
valve, while maintaining these grids always at
cathode potential for oscillation frequencies.
The invention may be applied for the purpose
of obtaining a frequency modulated signal, and
4. In a system for generating oscillations of
controllable frequency, an electron discharge tube
themodulating source may then be for example
a source of speech currents or of television sig
having oscillation generating electrodes and a ‘
parallel-tuned oscillation circuit operatively cou
nals. The invention may alternatively be applied
for the purpose of automatic frequency control
pled to said electrodes to produce sustained elec
trical oscillations of a frequency determined by
the resonant frequency of said circuit, inductive
and the modulating source will then be a fre
quency error detector.
We claim:
,
reactance means exterior of and connected in
series between an electrode of said tube and said
circuit so as to be traversed by substantially the
total oscillation current to said circuit and to de
>
1. In a system for generating oscillations of
controllable frequency, an electron discharge tube
having oscillation generating electrodes and a
parallel-tuned oscillation circuit operatively cou
pled to said electrodes to produce sustained elec
trical oscillations of a frequency-determined by
velop an oscillation potential relatively phase
shifted with respect to the generated oscillation
potential, a reactance control electron tube hav
ing input and output circuits coupled to said re
the resonant frequency of said circuit, reactive
actance means and said oscillation circuit, re
spectively, and means for varying the output
oscillation current of said reactance tube to cor
respondingly vary the effective resonant frequency
of said oscillation circuit and to thereby control
the frequency of the oscillations produced.
5. In a system for generating oscillations of
controllable frequency, an oscillator comprising an
electron discharge tube having oscillation gener
impedance means exterior of and connected in
series between an electrode of said tube and said
circuit so as to be traversed by substantially the
total oscillation current to said circuit and to
develop an oscillation potential relatively phase
shifted with respect to the generated oscillation
potential, a reactance control electron tube hav
ing input and output circuits coupled to said re
active impedance means and said oscillation cir
cuit, respectively, and means for varying the out-'
put oscillation current of said reactance tube to
correspondingly vary the effective resonant fre
quency of said oscillation circuit and to thereby
control the frequency of the oscillations pro
duced.
2. In a system for generating oscillations of
controllable frequency, an electron discharge tube
having oscillation generating electrodes and a
parallel-tuned oscillation circuit operatively cou
pled to said electrodes to produce sustained elec
trical oscillations of a frequency determined by
the resonant frequency of said circuit, reactive
impedance meansv exterior of and connected in
series between an electrode of said tube and said
circuit so as to be traversed by substantially the
total oscillation current to said circuit and to
develop an oscillation potential relatively phase
shifted with respect to the generated oscillation
potential, a reactance control electron tube hav
ing at least a cathode, a grid and an anode,
means for coupling the grid-cathode path‘ of said
reactance tube to said reactive impedance means
and for coupling the anode-cathode path of said
reactance tube to said oscillation circuit, and fur
ther means for varying the output oscillation cur
rent of said reactance tube to correspondingly
vary the effective resonant frequency of said oscil
lation circuit and to thereby control the fre
quency of the oscillations produced.
3. In a system for generating oscillations of
controllable frequency, an electron discharge tube
having oscillation generating electrodes and Ya
parallel-tuned oscillation circuit operatively cou
pled to said electrodes to produce sustained elec
trical oscillations of a frequency determined by
the resonant frequency of said circuit, capacita
tive reactance means exterior of and connected
in series between an electrode of said tube and
said circuit so as to be traversed by substan
tially the total oscillation current to said circuit
and to develop an oscillation potentialrelatively
phase shifted with respect to the generated oscil
lation potential, a reactance control electron tube
having input and output circuits coupled to said
reactance means and said oscillation circuit, re
' spectively, and means for varying the output os
cillation current of said reactance tube to cor
ating electrodes and a resonant oscillation gen
erating circuit determinative of the generated
30 frequency and operatively connected to said elec
trodes to maintain sustained electrical oscillations,
I said circuit being traversed by the oscillation out
put current of said tube, reactance means con
nected in series between an electrode of said tube
and said oscillation circuit, a reactance control
electron tube having input and output circuits
coupled to said reactance means and to said os
cillation circuit, respectively. and means for vary
ing the output oscillation current of said reactance
40
tube to correspondingly vary the effective resonant
frequency of said oscillation circuit and to there
by control the frequencyzof the oscillations pro
duced.
,6. In a system for generating oscillations of
controllable frequency, an oscillator comprising
an electron discharge tube having a cathode and
an anode, a resonant oscillation generating circuit
determinative of the generated frequency and
connected to said anode and cathode, and means
to maintain sustained oscillation in said circuit,
reactive impedance means connected in series be
tween said oscillation circuit and said cathode, a
reactance control electron tube having input and
output circuits coupled with said impedance
means and said oscillation circuit, respectively,
and means for varying the oscillation output cur
rent of said reactance tube to correspondingly
V . vary the effective resonant frequency of said
' oscillation circuit and to thereby control the fre- . .
quency of the oscillations produced.
'7. In a‘system for generating oscillations of
controllable frequency, an electron discharge
tube having oscillation generating electrodes and
an oscillation circuit operatively coupled to said
“ electrodes to produce sustained electrical oscilla
tions of a frequency determined by the resonant
frequency of said circuit, reactive impedance
means exterior of and connected in series between
an electrode of said tube and said circuit so as
to be traversed by substantially the total oscil
lation current to said circuit and to develop an
oscillation potential relatively phase shifted with
respect to the generated oscillation potential, a
reactance control electron tube having an input
75 circuit coupled with said reactive‘ impedance
2,408,192
7
means and having an output circuit connected to
both said oscillation circuit and said reactance
means to cause said reactance means to be tra
versed by'the oscillation frequency output cur
rent of both said oscillator tube and said re
actance tube, and means for varying the output
oscillation current of said reactance tube to cor
'8
respondingly vary the effective resonant fre
quency of said oscillation circuitv and to thereby
control the frequency of the oscillations pro
duced.
>
DAVID ARTHUR BELL.
ARTHUR HENRY ASHFORD WYNN.
Документ
Категория
Без категории
Просмотров
0
Размер файла
610 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа