close

Вход

Забыли?

вход по аккаунту

?

Патент USA US2408897

код для вставки
Get.. 8, 1946.
_
'
I
A. H. TURNER
MICROWAVE
MULTI'BAND
TUNER'
Filed Nov. 29, 1945
l
'Bg
I
v2,408,896 _
v
- 2`Sheets-Sheet 1
,
Cíttomeg
011 3» 1946-
A. H. TURNER
2,408,896
MICROWAVE MULTIBAND TUNER
4
Filed Nov. 29, 1945
2 sheets-sheet 2
3 nDenm
t,
./Zgralfjâf. maar'.
N CM ~
’
Cîtt'orneg
2,408,896
Patented Oct. 8, 1946
UNITED STATES PATENT OFFICE
2,408,896
MICROWAVE MULTIBAND TUNER
Alfred H. Turner, Collingswood, N. J., assigner to
Radio Corporation of America, a corporation
of Delaware
Application November 29, 1943, Serial No. 512,107
6 Claims. (C1. Z50-40)
l
This invention relates generally to ultra-high
frequency apparatus and particularly to an im
proved microwave multiband tuner for covering
a plurality of relatively wide microwave bands.
One of the conventional methods of tuning at
ultra-high frequencies is to employ a resonant
line of suitable design across one end of which
is connected a variable capacitor having a rela
tively high maximum capacity. Such an ar
rangement provides a theoretical limit of 1 to 2v
between minimum and maximum frequency ad
justments. In practice, the theoretical limit is
not attainable because of non-uniform circuit
constants. In addition, the loading effect of the
device to which the tuner is connected reduces
the practicable tuning frequency band.
`
`The instant invention is an improvement upon
applicant’s copending application Serial No.
481,215, filed March 3l, 1.943, entitled “Ultra high
frequency tuner,” which is assigned to the same ‘
assignee as the instant application.
Both inven
tions contemplate the use of a resonant line con
nected at one end to a suitable utilization circuit.
The opposite ends of the line are connected to
gether through one or more variable capacitors
and an inductive element having an inductance
of the order of that of one of the lines. The re
sulting circuit comprises a parallel resonant cir
cuit including the utilization device and the reso
nant lines, having a series-tuned circuit includ
ing the capacitive and the inductive elements
connected across the ends of the lines remote
from the utilization device. Adjustment of the
reactance of the series capacitors effectively pro
vides simultaneous adjustment of both the ca
pacitive and inductive reactances of the circuit.
Such an arrangement provides a theoretical limit
of one to three between the minimum and maxi
mum tuning frequency limits. Of course, the
theoretical limit may not be attainable in actual
2
movable capacitive elements, and may be ar
ranged to rotate with them. The eifective in
ductanceof the inductive element is of the order
of that employed for one of the resonant lines.
It should be understood that two or more tuning
.units of the type described may be connected to
diiferent utilization circuits, such as, for ex
ample, the input and output circuits of the same
ordiiferent’thermionic tubes. It should also be
understood that the rotating capacitive elements
may be suitably ganged by means of any con
venient mechanical arrangement.
The improvements which the instant invention
comprises with respect tovapplicant’s copending
application described heretofore, include means
for tuning over a plurality of relatively wide
ultra-high-frequency
bands,
and
especially
means „ for maintaining substantially constant
the pass band of the tuning apparatus over all
portions of each of the tuning ranges. Further
more, the inductive coupling between the various
tuned circuits is supplemented by capacitive cou
pling in the regions of voltage nodes in the tuned
circuits, for providing additional coupling be
tween said circuits over predetermined portions
of the tuning bands. Simple switching means
is provided for switching between the various
tuning wave bands.
,
It should be understood-that the instant in
vention may employ either open resonant lines or
coaxial resonant lines, as described in applicant’s
copending application identified heretofore, as
portions of the resonant circuits.
Among the objects of the invention are to pro
videan improved method of and means for tun
ing an ultra high frequency circuit. Another
object is to provide an improved method of and
means for varying simultaneously the inductive
and capacitive reactance of an ultra high fre
quency circuit. A further object of the inven
tion is .to provide an improved method of and
means for tuning an ultra high frequency circuit
over a relatively wide band of frequencies. An
other object is to provide an improved method
The tuning means comprises a pair of resonant
lines of the order of one quarter to one half wave 45 of andmeans for varying simultaneously the se
practice, but the practical limits substantially ex
ceed those possible with the conventional tuning
arrangement described heretofore.
length at the operating frequency which ter
minate at one end in the utilization device and
at the other end in iixed capacitor electrodes.
Two movable capacitor electrodes are disposed
invariable capacitive relation to separate ones of.
the ñxed capacitive elements and arranged to
vary simultaneously the capacity between each
fixed and movable-electrode. A lumped induc
tive element, such as, for example, a relatively
small helix, is connected directly between the
ries inductive and capacitive reactance in a plu
rality of ultra high frequency tuned circuits. A
still further object of the invention is to provide
an improved method of and means for tuning
a concentric ultra high frequency kline by ad
justing simultaneously the series inductive and
capacitivereactances connected to said line.
Additional objects of the invention include an
improved method of and means for tuning micro
_wave .apparatus over »a plurality of microwave
2,408,896
3
4
frequency bands. Another object of the inven
cated by the phantom capacitors cl, c2, It Will
tion is to provide an improved microwave multi
band tuner having substantially uniform band
pass characteristics and providing substantially
uniform coupling between coupled tuned circuits
throughout the frequency range of said tuner.
be seen that the distributed capacities cI and c2
will supplement the coupling between the reso
nant lines at the high frequency end of the tun
ing band as illustrated in graph (a) of Figure 2.
'I'he invention Will be described in greater de
tail by reference to the accompanying drawings
of which Figure 1 is a schematic circuit diagram
of a pair of coupled circuits connected according
to the invention; Figure 2 is a family of graphs
A small fixed capacitor I I is connected between
the anode end of the resonant line 4 and the con
trol electrode end of the resonant line 5'. A sim
ilar fixed capacitor I2 is connected between the
control electrode end of the resonant line 4' and
circuits of a multiband microwave receiver in
the anode end of the resonant line 5. These ca
pacitors are connected to the resonant lines at
points which correspond to voltage nodes at the
high frequency end of the tuning band and hence
correspond to regions of voltage maxima at the
low frequency end of the tuning band, thereby
cluding features of the invention, and Figure 4
providing appreciable coupling at the low fre
is a perspective fragmentary view of the struc
tural details of a preferred embodiment o1’ the
invention as shown schematically in Figure 3. -'
Similar reference characters are applied to simi
quency end of the tuning band.
indicating the voltage distribution on a tuned
line comprising one component of the circuit of
Figure l; Figure 3 is a schematic circuit diagram
of the radio frequency, mixer and local oscillator
lar elements throughout the drawing.
When additional inductive elements, not
shown, are connected in series with the tube ends
of the resonant lines at the points marked (x) to
provide tuning throughout an additional rela
Referring to Figure l, a utilization circuit, com
tively lower frequency band, the capacitors II, I2
prising the anode circuits of thermionic tubes 24
and 25, and having an inherent capacitance rep
resented by the interelectrode tube capacities and
effectively are moved nearer the tube ends of the
resonant circuits, thereby improving the mutual
coupling between the lines at the low frequency
the inter tube capacities, is connected to one end
of a first resonant line, represented by an induct
ance 4, and to one end of a second resonant
ond of the lowest frequency tuning band. 'I'he
tuning range of the tuned coupled circuits fur
line, represented by a second inductance 5. The
remaining terminals of the resonant lines 4 and
5 terminate, respectively, in fixed capacitive ele
ments E and l. A first movable capacitive ele
ment 8 is disposed in variable capacitive 'relation
with the first ñxed capacitive element 6. The
juxtaposed capacitive elements 6, 8 form a ca
pacitor, which may be varied. A second movable
capacitive element 9 is disposed in similar vari
able capacitive relation to the second fixed ca
pacitive element l. A third inductive element
l0, which, for example, may be a small substan
tially rigid helix, having an inductance of the
order of the inductance of one of the resonant
lines, is connected between the first and second
movable capacitive elements 8 and 9. The third
inductive element I0 may, if desired, be rotated
simultaneously with the movable capacitive ele
ments 8 and 9, These movable capacitive ele
ments may be individually or interdependently
rotated.
Similarly, the control electrodes, for example,
fixed variable capacitors 53, 54 connected, re
spectively, between the anodes of the tetrode
ther may be adjusted or extended by means of
tubes 24 and 25 of the control electrodes of the
double triode tube 34 to increase the effective
loading capacitances of the utilization devices.
Referring to Figure 3, an ultra-high frequency
multiband receiver circuit comprising an ultra
high frequency amplifier, an ultra high frequency
oscillator and an ultra high frequency mixer or
iirst detector. is shown in combination with tun
ing circuits of the general type illustrated in Fig-,
ure l and described in detail heretofore. A con
centric transmission line 2| connected, for ex
ample, to a suitable receiving antenna, not shown,
is connected to one end of an input coupling
loop 22. The remaining end of the input coupling
loop 22 is connected to ground through a variable
tuning capacitor 23.
~
Y An ultra high frequency balanced amplifier
_such as, for example, a pair of tetrode tubes 24,
25 is self-biased ¿by means of a conventional
common cathode resistor 2B and cathode bypass
of a double triode tube 34 are each connected
capacitor 21 which are connected between the
respectively to one end of third and fourth res
cathodes and ground. The control electrodes of
onant lines, represented by the inductances 4'
each of the tubes are connected to the ends of
and 5', respectively, Likewise, the remaining ~ a center-tapped grid inductor 28 which is induc
ends'of the third and fourth resonant lines, rep
- tively coupled to the input loop 22. The center
resented by the inductances 4', 5', respectively,
terminal of the grid inductor is grounded.
are connected to fixed capacitive elements 6', 1',
The anodes of the first and second triodes 24,
respectively. Similarly, movable capacitive ele
ments 8', 9’ are connected together through a
second small substantially rigid helix I0’ having
an inductanoe of the order of the inductance of
one of the resonant lines.
The resonant lines 4, 4', 5, 5', preferably are
symmetrically arranged and equidistant from
each other to form the diagonally opposite cor
ners of a square or a rectangle whereby the
mutual inductive coupling between the various
resonant lines is maintained at a substantially
constant value.
Y
The mutual inductive coupling between the
several resonant lines is supplemented by the dis
tributed capacities between the tuning capacitors
6', 8' and 1, 9, respectively, and between the tun
ing capacitors 6, 8 and l', 9', respectively, as indi
25 are connected each to one terminal of corre
sponding first and second helical low band in
ductors I5, I6. The remaining terminals of the
low band inductors I5, I6 are serially connected,
respectively, to first and second helical high band
inductors I1, I8. The remaining terminals of
the high band inductors I'I, I8 are connected to
the ends of short resonant lines 4, 5.
The re
maining terminals of the resonant lines 4, 5 are
terminated. respectively, in first and second fixed
capacitive elements B and 1_
The movable capacitive elements 8 and 9, which
are in capacitive relation., respectively,y with the
fixed capacitive elements 6, and l, are connected
together through a compact bunched helical in
ductive element I0 of the type described hereto
fore. Operating potentials for the anodes of the
'2,408,896
ytwo triodes 24, 25 are provided from any suitable
source, not shown, and applied to the respective
electrodes through suitable isolating resistors 3l,
6
The gauging of the four swítchesis indicated in
the drawings by the dash line 60.
The supplementary coupling `capacitors are
connected in the same manner as described here
`
A mixer or converter stage includes a 'double Ul tofore in the circuit of Figure 1. The capacities
ci, c2 are indicated by dash lines between the
triode 34 having the two anodes thereof con
32 and 33.
nected together and connected to the primary of
an intermediate frequency transformer 36. The
cathode is connected to ground. The control
electrodes of the two triodes of the double triode
34 are each connected to one end of separate
resonant circuits comprising second low band in
ductors I5’ and I6’ respectively connected in
series with second high band inductors I1’ and
I8' and resonant lines 4' and 5’. The resonant
B., F. amplifier and converter tuned circuits.
Similar capacities c3, c4, also shown in dash lines,
indicate coupling between the converter and
oscillator tuners. The two coupling capacitors
Il, i2 are connected between the tube ends of
the resonant circuits of the R. F. amplifier and
converter in the same manner as indicated in the
circuit of Figure l, Similar capacitors II’ >and
i3’ couple between the tube ends of the resonant
circuits of the converter and oscillator tubes.
lines 4' and 5' are inductively coupled to the res
Referring to Figure 4, a preferred mechanical
onant lines 4 and 5 of the radio frequency am
construction
employing the several features of
pliñer anode circuit. The resonant lines 4', 5'
the invention comprises a plurality of variable
are tuned by a second tuning unit 6', 1', 8', 9',
capacitive elements indicated by reference nu
I0', of the type described heretofore, which is 20 merals
conforming to the equivalent elements of
serially connected to the lines 4', 5', and with the
the circuit of Figure 3. The inductive elements
corresponding low band and high band inductors
I5, I 0', Iü” are shown as small helical inductors
I5', I5', Il', I8'. A grounded center-tapped re
secured between the rotatable capacitor plates
sistor network 31, 38 is connected between the
8, I9, 8', 9', 8", 9", respectively. The low band
common terminals of the inductive elements I5',
inductors are shown as small substantially rigid
I1' and I6', I3', to provide a d-c grid return
helices I5, I6, i5', I5', I5" and I6”. rI‘he high
circuit for the balanced converter.
band inductors are shown as similar small sub
An ultra high frequency oscillator includes a
stantially rigid helices I1, I8, I1', I8', I1", i8"
double triode 44 having its cathode connected to
which are supported between the lower contacts
ground through a cathode resistor 45 and cathode ~
capacitor 46. The grid circuit of the oscillator
is comprised of a single turn loop 41 terminating
in the two control electrodes and having its cen
ter-point grounded through a grid resistor 48.
The anode circuit of the push-pull oscillator in- ‘
cludes a third tuning unit 6", 1", 8", 9", I0"
serially connected with corresponding lines 4",
5” and low band and high band inductors I5",
I6", I1", I8". Anode potential is applied to the
two anodes through anode resistors 49, 50.
The three tuning units described heretofore
may be ganged as indicated by the dash lines 5I.
The balanced oscillator circuit is coupled to the
converter input circuit by means of mutual in
ductive coupling between the tuned resonant lines
in any manner known in the art, It should be
understood that the constants of the circuits will
be so selected that the desired intermediate fre
quency may be derived from the converter anode
circuit.
For example, the several tuning capacitors may
be of a conventional type providing a capacity
range of the order of from one to ten micro
micro-farads. Circuits of the type described have
been constructed to provide suitable tuning over
ranges extending from 90 to 130 megacycles and
130 to 230 megacycles. These ranges could be
extended readily by proper selection of circuit
constants, and by adapting the constructional
features to the desired frequency ranges in a
manner well known in the art.
|The three resonant circuits may be matched,
or the low frequency limits thereof extended, by
means of variable capacitors 53, 54 and 55 con
nected respectively in shunt with the correspond
ing tube ends of the resonant circuits. Similarly,
band switching of the three resonant circuits is
obtained by means of three four-pole, two posi
tion wafer type switches 56, 51 and '58 which
selectively short-circuit the several low band in
ductors I5, I6, I5', I5', I5" and I6"_ The three
switches 56, 51 and 58 may be ganged together
and ganged to a band switch 59 adapted to
iorten the grid loop 41 of the oscillator circuit.
of the corresponding wave band switches and one
end of the corresponding resonant lines 4, 5, 4', 5',
4", 5”, respectively. It should be noted that the
low band helices are secured directly to the cor
responding band switch terminals to minimize
residual circuit reactances and provide conven
ient support. The band switches 58, 51, 58 may
be the conventional wafer type band switch em
ployed in commercial multiband tuners wherein
the various switch wafer elements are insulated
from each other. The various fixed capacitor
plates B, 1, 5', 1', 5", 1" may be secured to
insulating base supports ’53, E5 for convenient
mounting to the receiver chassis, not shown.
Similarly, the band switches 56, 51, 58 may be
supported in any convenient manner by the re
ceiver chassis and provided with a suitable actu
ating mechanism, not shown. The supplemen
tary tuning capacitors 53, 54, 55 and the sup
plementary coupling capacitors II, I2, II', I2’
are indicated schematically to simplify the draw
ings.
lln practice, these capacitors should be the
small tubular type well known in the art.
Shielding, of the type indicated by the frag
mentary shield portion 55, may be employed in
accordance with recognized shielding procedure
between any of the tuned circuits requiring iso
lation. It should be understood that inductive
coupling between the various resonant circuits
may be adjusted by adjusting the position and
size of the shields isolating said circuits.
Thus the invention described comprises im
provements of the invention described in appli
cant’s copending application identified hereto
fore, wherein multiband tuning is provided at
microwave frequencies, and novel capacitive
coupling is included to supplement the inherent
inductive coupling between a plurality of circuit
tuning elements, thereby to provide substantially
uniform band width throughout the tuning range ’
and substantially constant reaction between said
coupled circuits.
I claim as my invention:
1. Ultra-high-frequency apparatus including a
plurality of inductively coupled tuning circuits
lmoeras@
8
each comprising a pair of resonant lines and ad
justable means for tuning said lines, a plurality
of coupling capacitors, and means connecting said
capacitors between the resonant lines of different
von said lines to vprovide predetermined'micro
ones of said coupled circuits at predetermined
points on said lines to provide predetermined
including a. plurality of inductively coupled tun
ing circuits each including, in combination, a pair
of resonant lines, a pair of adjustable capacitive
wave coupling between said circuits throughout
the tuning range of said circuits.
5. Multiband ultra-high-frequency apparatus
`coupling between said circuits throughout the
tuning range of said circuits.
elements each having at least a fixed electrode
2. Multiband microwave apparatus including a
plurality of inductively coupled microwave tuning
vand a movable electrode, an inductive element
circuits each comprising a pair of resonant lines
and adjustable means for tuning said lines, a
plurality of coupling capacitors, a plurality of
loading inductors, means for selectively and
the inductance of one of said resonant lines.
having an inductance at least of the order of
' means connecting said inductive element between
said movable electrodes of said capacitive ele
ments, means connecting one extremity of each
of said resonant lines to a different one o1' said
iixed electrodes of said capacitive elements, a.
utilization device, means connecting the remain
ing ends of said lines to said utilization device,
simultaneously interposing one of said loading
inductors in each of said resonant lines to change
the tuning waveband thereof, and means con
necting said capacitors between the resonant lines
of different ones of said coupled circuits at pre
and means for adjusting simultaneously the
determined points on said lines to provide pre 20 capacity of all of said capacitive elements to vary
determined microwave coupling between said cir
cuits throughout the tuning range of said circuits.
3. Ultra-high-frequency apparatus including a
plurality of inductively coupled tuning circuits
simultaneously the effective series inductive and
capacitive reactance of all of said circuits; a plu
rality of loading inductors, means for selectively
and simultaneously interposing one of said load
ing inductors in each of said resonant lines to
each comprising a pair of resonant lines and ad
justable means for tuning said lines, a plurality
change the tuning waveband thereof, a plurality
of coupling capacitors, and means connecting said
of coupling capacitors, and means connecting
capacitors between the resonant lines of diii’erent
said capacitors between the resonant lines of
ones of said coupled circuits at points on said
diiîerent ones of said coupled circuits at prede
lines corresponding to the regions of voltage anti 30 termined points on said lines to provide prede
nodes at the limits of said circuit tuning ranges
termined coupling between said circuits through
to provide predetermined coupling between said
out said tuning bands.
'
circuits throughout said tuning range of said
6. Multiband microwave apparatus including
circuits.
a plurality of inductively coupled microwave tun
4. Multiband microwave apparatus including
ing circuits each including a pair of inductive
a plurality of inductively coupled microwave tun
ing circuits each comprising a pair of resonant
lines and adjustable means for tuning said lines,
a plurality of coupling capacitors, a plurality of
elements `and adjustable means for tuning said
circuits, a plurality of coupling capacitors, a.
plurality of loading inductors, means for selec
tively interposing said loading inductors in each
loading inductors, means including separate 40 of said tuning circuits to change the tuning
waveband thereof, and means connecting said
ductors for selectively and simultaneously inter
capacitors between said inductive elements of dif
short-circuiting means shunting each of said in
posing one of said loading inductors in each of
ferent ones of said coupled circuits to provide
said resonant lines to change the tuning wave
predetermined
microwave coupling between said
band thereof, and means connecting said capaci 45 circuits throughout the multiband tuning range
tors between the resonant lines of diiîerent ones
of said circuits.
of said coupled circuits at predetermined points
l
~
ALFRED H. TURNER.
Документ
Категория
Без категории
Просмотров
0
Размер файла
736 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа