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Патент USA US2110278

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March 8, 1938.
2,110,278
R. c. SHAW
TRANSLATING CIRCUIT
Filed April 14, 1932
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Patented Mar. 8, 1938
‘ 2,110,27
STATES
PATENT orrlcs
2,110,278
TRANSLATING CIRCUIT
Robert 0. Shaw, Red Bank, N. J., assignor to Bell a ‘ 7
Telephone Laboratories, Incorporated, New
York, N. Y., a corporation of New York
Application April 14, 1932, Serial No. 605,243
‘20 Claims. (Cl. 178—44)
This invention relates to systems for the trans
point. The balanced circuit‘Lz may be coupled
lation of electrical energy and more particularly to another balanced circuit associated with wind
to signaling systems operating at radio fre
ing 9 of transformer T,. such as the input of a
quencies.
push-pull ampli?er; or circuit L2 may, for ex
To maintain the two sides of an electrical cir
ample, comprise an open wire transmission line
cuit in balanced relation with respect to ground connected to the members of a horizontal
is a problem frequently encountered in the de
double-V, or diamond-shaped, antenna or of a
sign of high frequency signaling systems. It is a similar balanced radiating structure. The un
particularly difficult problem to meet where the balanced circuit L1, likewise, may comprise a
10 frequencies are of the order of those employed
transmission line of open wire, or other type, or
in short wave radio transmission. The slightest‘ merely a connection to adjacent apparatus.
unbalance in the output circuit of a push-pull
Between the terminals 0, d, of the balanced cir
ampli?er, for example, may be su?icient to create cuit is connected a linear conductor 3, the
a “singing” condition that will render the am
terminals of which are represented as a and b.
15 pli?er useless. Where, also, an antenna of
Shielding the conductor 3 is a tubular conductor
balanced type is to be connected to a remote
4, which is grounded preferably at a plurality of
transmitter or receiver through a transmission points. The connections between the terminals
line, one side of which is grounded, it is desirable, of conductor 3 and the terminals of circuit L2 are
though for a different reason, that the balanced made of the, same length l and preferably are
2O condition remain undisturbed. One of the chief balanced physically with respect to ground, so
sources of unbalance in such systems is in the that the electrical balance at terminalsc, d is
device used to couple the balanced circuit to a not affected.
.
circuit that is not electrically balanced with re
The length of conductor 3 is critically related
spect to ground.
to the frequency of the waves which are to be
An object of the present invention is to couple transmitted, or more accurately, to the length
25
25
an unbalanced or grounded circuit to a balanced
of the waves as they are transmitted through
I circuit without disturbing the balance of. the
latter.
In accordance with the invention, the trans
the conductor.
As an approximation, the length
of conductor 3 may be one-half wave length or
any odd multiple thereof, or symbolically,
30 formation from a balanced circuit to .an un
(Lei
balanced. circuit is eiiected by taking advantage
of the changes in phase that a wave transmitted
along a conductor undergoes. The nature of the
present invention will more fully appear in the
following description of several speci?c embodi
ments which are illustrated in the three ?gures
of the accompanying drawing.
In the accompanying drawing, Figure 1 shows
where n is an integral number and A is the wave
length.
Where conductor 3 is thus proportioned it is
apparent that the phase of a wave transmitted
from terminal 0 of. the balanced circuit and
through conductor 3 to terminal b of the latter,
a device for coupling an unbalanced circuit to a
will be altered exactly one-half cycle with respect
balanced circuit.
Figure 2 shows a different embodiment of the
to a similar wave transmitted directly from
terminal d of the balanced circuit to terminal b.
Since, then, the phases of the voltage waves ap
invention.
Figure 3 shows still another embodiment of the
invention.
Referring to Fig. 1, there is shown a device
providing for the bilateral translation of elec
trical waves between an unbalanced circuit L1
and a balanced circuit L2. The unbalanced cir
cuit is represented as a coaxial conductor pair
comprising a central conductor l and a grounded,
tubular return conductor 2 surrounding the cen
tral conductor and effectively shielding it. The
balanced circuit shown comprises a pair of ordi
nary conductors connected to winding 8 of trans
55 former T, winding 8 being grounded at its center
30
pearing at the respective terminals 0, d, of the
balanced circuit are exactly opposite, it, follows
that the waves transmitted through the two sides
45
of the circuit to point b will be in phase with
respect to any external load connected between
point b and ground. Because of the phase re
versal in conductor 3, point b is effectively at the
same potential withreference to both terminals
of the balanced circuit.
Any circuit connected ,
to point b, therefore, will have the same effect
on the two sides of. the balanced circuit and the
balance of the latter will notbe affected. Cir
cuit L1, being connected between point b and 55
2
" 2,110,278
I
V
‘
ground accordingly has no unbalancing eftfect'on ' V'Thislmay be seen from Fig. 1, where E repre- sents the voltage across' the unbalanced circuit
circuit L2 with which it is coupled.
1 The bilateral character of’ the coupling circuit ' and I, the current therein. Going into the bal- '
is believed to require but j little discussion. ' anced.‘ circuit the current I divides and produces
in that circuit a circulating current. of 1/2.
Voltage variations‘createdr between point b'and ‘ The
voltages E producedacross both halves of
ground by waves in line Lnar'e' transferred to
the balanced circuit are added in phase, resulting
points c 'andd and the'terminalsof winding _8. ~ in
a total of 2E. ' The’ impedance of the balanced
The reversalrrinrphase occurring. in conductor.’ 3
circuit therefore appears as
results in thephasefopposi't'ioh of the 'waves at
10
-
v10
the respective terminals of’ winding'8 which is
necessary for the translationiof waves through: ,_
V
the transformer.
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.orfour times the-impedance (E/I) of‘the an;
».
_ Fig-'2‘ illustrates an embodiment of the inven
balanced-circuit. The tuned: circuits» are also
' tion‘as utilized ior coupling the output circuit of . useful, in correcting small phase .di?erences that
15'
;a balanced‘ or ‘ push-pull. ampli?er; :to Ian
may exist at'the terminals of the balanced cir
. balanced circuit such a'sz'a coaxial ciomiuct‘orv : cui't. 'By slight yariations'in the length of the
transmission line L1. In thisgcaser'the separate .conductor l3, likewise, impedance and phase -'
conductor 3 of critical length? shown in Fig.- -1 .dissymfmetries of the system maybe compensated .
is omitted and the terminals. c and d of. the bale‘v
20 anced circuit areconnected directly-to the point
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for.
'
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The combinationof coaxial conductor line and
20f
b and ‘the unbalanced circuit connectedfthereto. ~
' Therequired phase changeis obtainedby'making, balanced openfwire line‘illustratedin Fig. 3 may
be’us'edg-forexample, where a'balanced or sym-'
"the-conductor bc electricallyv longer than 'con- .
metricaliantenna array is to be. connected to‘ a
'ductor 1 bd by an amQunt'equivaIent ‘to one-half
a wave length or an odd‘multiple ‘thereof.
Thus, v
'
if the length‘ bd be represented by ‘l, the
length
‘he
must
be,
'
_
,,
‘
_
_
_
,
remoteiradio' station; _ The v open wire line i pro
: vides animpedance match for theantenna, while '
‘ the coaxial conductor line provides an e?lciently '
shielde‘d transmission path, to the‘ station.
.
' Although‘ the invention has been described with.
reference to "specific embodiments and applica
7 i The embodiment:- of "thei‘invention- shown "in 'tions of it, it is to be understood that the in
' .Fig. ._3-.has certain advantages “over the; systems.‘ vention is limited only by the scope and- spirit ;
hereinbetore described, jparticularlye with regard ‘ of the appended claims.
to compactness, ?exibility and’ accurate matching 1 "What is claimed is:
'Y 1. In a high frequency transmission system, ‘a
_of the impedances of the: connected circuits.‘ J It
is ‘similar; to . the system shown fin Fig. ._,1'- with the. ' circuit balancedto ground, a circuit one side of‘ .
substitution" of e l a UQ-shaped conductor. l3 for" ‘which is grounded," and leads from the terminals‘ '
the linear conductor 3 of the-‘latter ?gure and r of said balanced circuit'tothe ungrounded side
of said second mentioned circuit, the electrical
nections, ac‘and 'bd'... Arrangingconductor l3 . lengths of said ‘leads di?eringfrom each other
40 in the-form of a U or long, 'narrowiloop does f by an odd number of-half-wave lengths of, the -,
not materially alter its effectiveness ‘as a‘ phase 7 waves transmitted therethrough. ' " r
2. In a high'frequency transmission system, a
shifting device and‘ it hasthe advantage'that the
’ terminals needi‘not. be widely separated. from circuit balanced to ground,’a circuit one side of
with‘ the insertion of tuned'circuits in the com
Moreo'ver‘the over-all ‘dimensions '
which is. grounded, and connections from the
are reduced, :With fa. straight conductor as‘ in ,
terminals of said balanced circuit to the un-.
. each other,
Fig. 1, ‘a length‘ of, the order OfthlI‘tYfGBt would
' be required» in a system operating at ?fteen meg
acycles per second, whereas therlength" ‘ofthe'
grounded side of’said second mentioned circuit, ~ ‘
and means in said connections for reversing the
relative phases’ of 'vwavestransmittedr, theree‘
to
I space required may be reduced to approximately .
In ‘a 'high frequency transmissionsystem, a
half the amount by using the _ U construction. '
circuit balanced to ground, a‘ conductor ‘having 1 ‘ ‘
In any, of these cases an unshielded conductor
through.
V
.
.
_
van electrical lengthequivalent to .an- odd num
ber of‘ half-wave lengths of‘ the waves transmit
sible by providing short-circuiting- connections ted, symmetrical connections from the termi- ;
nals of said balanced circuit to .the terminals of across. the loop at di?erent"points',i'these con
may alternatively beemployed. ‘1
~
,
V
.
_
Operation at different frequencies is made pos
nections being selectivelycompleted by 'means of
said conductor, andra circuit connected between
remotely controlled switches l5, l6. Thegéxact;
location of the'short-circuiting connections may
be adjusted from" time to time to accommodate,
. 4. vIn a'high frequency transmission system, a
' balanced circuit, an unbalanced. circuit, means
one terminal'of said conductor and ground.
GO changing load conditions;
'for couplingisaid
lation comprising
_Terminals ,a and b of conductor l3 are con
nected to intermediate‘ points of inductance coils 7 of. said balanced
‘ ‘2| a-ndlll, respectively, the adjacent terminals balanced circuit,
circuits‘in energy transfer re
connections from the terminals
circuit to one side of said un
the ‘relative electrical lengths
of'rwhicharev grounded. CondensersIC1 and C2
of said connections being such that the balance ‘
of said'?rst mentioned circuit is maintained. 7
23; respectively,rof the. respective coils ‘20 and
- '5.‘ In a high frequency transmission system, a
are connected’ between ground and‘taps 22 and
2|. The terminals c, ‘d of the balanced line In. balanced circuit, an unbalanced circuit, and/
means‘for coupling said circuits in energy trans
. are symmetrically connected to taps on the two
coils; .The tuned circuits comprising condensers vferrelatlon comprising connections from the '
C1 and C2‘ and coils Y20 and ‘2I’perm'it an ad- - terminals of said balanced circuit to onefside
of said unbalanced circuit, one- of saidconnec- _
justm'ent‘of, the» impedance ratio or the trans
forming system. "Without such" adjustment‘ an tions including a phase reversing device ‘compris
impedance-ratio or 1:4 is obtained; looking ‘from ' , ing a conductor greater in length than the short
thev unbalanced circuitto the balanced circuit.‘ est distance between its terminals. '
2,110,278
6. A combination in accordance with claim 4,
comprising means for adjusting the relative ef
ul
3
respect to ground potential, means for providing
di?erent frequencies.
a circuit coupling arrangement between said un
symmetrical and symmetrical circuits, said means
comprising conductor leads from the terminals
of said symmetrical circuit to the ungrounded
7. In a high frequency transmission system, a
balanced circuit, an unbalanced circuit, and
side of said unsymmetrical circuit, the electrical
lengths of said conductor leads differing from
means for coupling said circuits comprising con
nections from said balanced circuit to said un
each other by an odd number of half wave lengths
of the waves transmitted therethrough.
balanced circuit, the electrical lengths of said
connections being substantial and different by
16. In a high frequency coupling arrangement 10
comprising a circuit which is normally unsym
metrical with respect to ground potential, a sec
ond circuit which is normally symmetrical with
respect to ground potential, means forv providing
a symmetrical circuit coupling arrangement be 15
tween said unsymmetrical and symmetrical cir
cuits, said means comprising concentric conduc
tors, at least one of said conductors being ground
ed and branched, the difference in the geometric
length of said branch lines being differently
fective geometrical lengths of said connections
to adapt said coupling means for operation at
in
‘
an amount such that the balance of said ?rst
mentioned circuit is preserved.
8. A combination in accordance with claim 7,
in which said connections consist of conductors.
9. In a high frequency transmission system, a
circuit substantially balanced with respect to
ground, a circuit unbalanced with respect to
ground, and means coupling said circuits in en
ergy transfer relation, said coupling means com
prising a ?rst connection from a point on one
side of said balanced circuit to a point in said
unbalanced circuit, a second connection from a
point on the other side of said balanced circuit
25 to a point in said unbalanced circuit, said con
nections differing in electrical lengths by an
amount corresponding to the di?erence in phase
between said respective points on said balanced
circuit and ground.
30
10. In a‘ high frequency transmission system,
a balanced circuit and an unbalanced circuit and
means for coupling said circuitsv together com
prising connections from said balanced circuit
vto a common point on said unbalanced circuit,
CO 921 the electrical lengths of said connections differ
ing by an amount su?icient to introduce the phase
change required to maintain the electrical balance
of said balanced circuit.
11. A combination in accordance with claim 10
40 in which said coupling includes means effective
to match the impedances of said balanced and un
balanced circuits.
12. A combination in accordance with claim 10
comprising means for suppressing radiation from
said coupling connections.
13. A combination in accordance with claim 10
in which each of said connections comprises the
inner conductor of a coaxial pair, the outer con
ductor of each pair being grounded at a plurality
of points.
14. In combination, a circuit balanced with
respect to ground, a circuit unbalanced with re
spect to ground and means for coupling said
circuits in energy transfer relation comprising
a conductor connected across said balanced cir
cuit, said conductor being electrically and physi
cally symmetrical with respect to ground and
said balanced circuit, and a connection from said
unbalanced circuit to a point on said conductor
60 that is an odd number of half wave-lengths
farther from one end of said conductor than
from the other end.
15. In a high frequency coupling arrangement
comprising a circuit which is normally unsym
65 metrical with respect to ground potential, a
second circuit which is normally symmetrical with
chosen so as to compensate for the unsymmetrical
circuit. arrangement.
17. In a high frequency coupling arrangement
comprising a circuit which is normally unsym
metrical with respect to ground potential, a sec
ond circuit which is normally symmetrical with
respect to ground potential, means for providing
a symmetrical circuit coupling arrangement be
tween said unsymmetrical and symmetrical cir
cuits, said means comprising concentric conduc
tors, at least one of said conductors being ground
ed and branched, the difference in length of said
branches being such as to compensate for the
unsymmetrical circuit arrangement.
18. In a high frequency coupling arrangement
comprising a circuit which is normally unsym
metrical with respect to ground potential, a sec
ond circuit which is normally symmetrical ‘with
respect to ground potential, means for providing
a symmetrical circuit coupling arrangement be
tween said unsymmetrical and symmetrical cir
cuits, said means comprising concentric conduc
tors, at least one of said conductors being ground
ed and branched, the di?erence in length of said
branches being an uneven number of half waves
so as to compensate for the unsymmetrical cir
cuit arrangement.
19. In a high frequency transmission system,
a circuit substantially balanced with respect to
ground, a circuit unbalanced with respect to 50
ground, and means coupling said circuits in en
ergy transfer relation comprising a connection
from a point in said balanced circuit to a point
in said unbalanced circuit and a connection from
a point of different phase in said balanced cir
cuit to a point in said unbalanced circuit, the
electrical lengths of said connections differing
by an amount sufficient to introduce the phase
change required to maintain the electrical bal
ance of said balanced circuit at the frequency of 60
transmission.
20. A combination, in accordance with claim 19,
in which at least the electrically longer of said
connections comprises the inner conductor of a
coaxial pair.
ROBERT C. SHAW.
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