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Патент USA US2412986

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Dßç. 24,
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v2,412,986
BEACON SYSTEM
Filéd March 1o, 1945
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INVEN TOR.
»LEO/V H/MMEL ,
BY
Patented Dec. 24, 1946
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2,412,986
UNITED STATES PATENT oFFicE
2,412,986
BEACON SYSTEM
Leon Himmel, Bronx, N. Y., assignor to Federal
Telephone and Radio Corporation, New York,
N. Y., a corporation of Delaware
Application March 10, 1945, Serial N o. 582,051
9 Claims.
(Cl. Z50-11)
1
2
This invention relates to directive radio sys
tems and more particularly to such systems for
use in guiding beacons, localizing, radio ranging
and the like.
The invention is in the nature of an improve
ment on the type of system shown in U. S. Pat
those parts of a complete radio guiding or locating
system are shown as are necessary to an under
standingof the inventive concept. It will be un
derstood therefore, that the disclosure of said
Patent No. 2,293,694 shall form _part of the pres
ent disclosure.
ent No. 2,293,694 to A. Alford, granted August
In Fig. 1 of the drawing, there are shown three
25, 1942, although in certain of its aspects the
directive antennae, I, 2 and 3, which may be in
invention is capable of use in other types of di
the form of vertical dipoles, and each -of which
rective radio systems.
10 may be tuned by the associated adjustable trans
A principal object of the invention is to provide
mission line sections 4, 5 and 6. Antenna I, which
an improved course localizing arrangement by
may be termed the “carrier antenna” is located
means of radiation patterns and wherein the pos
between the antennae 2 and 3 which may be
sibility of »course identification is materially in
termed “side-band antennae.” Antenna I is fed
creased.
.
with radiant energy from the high frequency car
Another object is to provide a course defining
rier source 'I over one diagonal of a hybrid bridge
or localizing system using a radiation pattern of
arrangement 8. As shown, source 1 is connected
the snif-table lobe type, wherein the individual
to
one end of said diagonal through a suitable
lobes are identified by respective modulation fre
quencies and the chances of relative error in fol 20 carrier power amplifier 9, and the other end of
said diagonal is connected to the source 1.through
lowing the course are reduced by applying the
another power amplifier I 0 which is arranged
identfying modulations to a common modu
-to be modulated at audio frequency as described
lator.
hereinbelow.
Another object is :t0 provide a course deñning
or localizing system employing an vantenna array
comprising a so-called carrier antenna and a
plurality of “side-band” antennae spaced there
from, and wherein the side-band antennae are
keyed at a predetermined rate so that the re
spective side-band radiation patterns `are modu
lated at identifying audio frequencies. In this
way, the possibility of error resulting from a
dissimilarity in separate modulation tubes is
avoided.
'
The energy from the two amplifiers is applied
. to the bridge in phase. Energy from source 'I
is also supplied >to the side-band antennae 2 and
3 over respective transmission lines II, I2, which
are fed from the opposite diagonal of .the bridger
through a switching device or link relay I3, ar
30 ranged to be operated at any desired keying rate
so as alternately to reverse the relative phase of
the energy feeding antennae 2 and 3. The car
rier is substantially balanced out at the lower
terminal
of bridge 8 so that only the side-band
A feature of the invention relates to a direc 35
energy reaches antennae 2 and 3. The antennae
tive radio system employing a radiation pattern
2 and 3 are fed at 180 degrees phase opposition by
of the ‘shiftable lobe type for defining an “on
reason of the transposition I4.
course” region, wherein the shifting of the lobe
The eiîect of the carrierantenna and the al
is controlled by a switching device which also
phase reversal of the side-band an
acts to apply lobe identifying modulations to 40 Iternating
tennae coupling is to provide a field pattern in
a common modulator .to control the “off-course”
ñeld pattern.
Further objects and advantages will be apparent
from a consideration `of the following detailed
descriptions and the appended claims, and from 45
the appended drawing illustrating one preferred
form of the invention.
`
Fig. 1 shows in schematic form a course local
izing or guiding system embodying principles of
the invention.
`
‘
Fig. 2 is a, schematic representation of a typical
receiver and indicator arrangement that may be
used with the system of Fig. 1.
Inasmuch as the invention relates to systems of
the general shape of a directed beam which os
clllates to either side of a common symmetry
line which defines the course or directivity path
to be marked.
In accordance with the present invention, in
addition to the alternating switching of the lobes
of the field pattern, each lobe is identified by a
corresponding low or audio frequency signal
which may be in ,the form of an audio frequency
50 modulation. For this purpose, the switching re
lay I3, in addition to the normal switching con
tacts (not shown) for controlling the energy sup~
plied lines I I and I 2, is also provided with a mov
Athe type shown in U. S. `Patent No. 2,293,694, only 55 ing contact arm I5 and a cooperating pair of
fixed contacts I 6, I1. 'Contacts ‘I6 and I'I are
:2,412,986
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4
3.
supplied with respective low or audio frequency
signals, e. g., 90 and 150 C. P. S., through respec
tive filters I8, i9, which in turn are supplied with
ing both the audio frequency signals into the
common amplifier modulator this difficulty is
avoided.
What is claimed is:
90 and 150 C. P. S. signals from a common low
l. A directive radiant pattern system compris
frequency oscillation source 20. Source 20 may Ul ing means to develop in space a field pattern
be of any well-known kind which is capable of
generating simultaneously with the requisite sta
bility, the 90 and 150 C. P. S. signals. If desired,
Ithe source 20 may .take the form of twoA oscil
lators of 120 and 30 C. P. S. which are mixed in a
suitable common mixer tube or device to produce
the upper and lower beat frequencies of 150 and
90 C. P. S. Whichever method is used to pro
duce the audio frequency signals, these signals
should be so adjusted that they are of substan
tially the same amplitude when applied to con~
tacts I6 and l1.
Contact arm l5 is connected to amplifier l0 so
as to subject the carrier passing through the am
pliñer to an amplitude modulation in any well
known manner. The net result is that the radi
having off-course side-band lobes and an on
course carrier lobe deñning a desired course,
means to phase reverse said side-band lobes at
predetermined rates, and means to modulate the
energy in said lobes at respective but different
low frequencies and in timed relation with the
phase reversal.
2. A system according' to claim l in which the
means to modulate said energy comprises a sin
gle modulator upon which both the low frequency
modulating voltages are impressed.
3. A directive radiant pattern system compris
ing a set of three antennae, a high frequency car
rier source, means to apply carrier energy from
said source to one antenna, means to excite the
other antennae in phase opposition under control
of the carrier energy, means to control the latter
excitation alternately, and means to modulate at
imposed on it a square wave of frequency con
trolled bythe relay f3. Thus, on one side of 25 a plurality of distinctive low frequencies the ex
citation of said other antennae.
the course, a square wave modulated with one
4. A directive radiant pattern system compris
frequency, e. g., 90 C.
S., will exist. On the
ation pattern as seen from one side will be a
modulated high frequency envelope having super
other side of the course a square wave modulated
with the other frequency, e. g., 150 C. P. S., will
exist.
Any Well-known form of radio receiver may
be used aboard the moving craft which is to be
guided. It may consistof a radio receiver 2l
whereby the two audio frequency modulations of
90 and 150 C. P. S. may be detected and amplified
ing a first radiator, a pair of radiators spaced
from the first radiator on opposite sides thereof,
said pair of radiators being arranged for exci
tation in phase opposition, a common source of
high frequency energy for all said radiators, a
four-armed bridge network, means connecting
said pair of radiators in phase opposition to an
_apex of said network, means connecting the op
and applied to the control elements of the well
known crossed pointer indicator 22. In accord
ance with standard practise, the output of the
posite apex of said network to the first radiator,
indicator needle.
rendering the excitation of said pair of radiators
means connecting said source cophasally to the
other two apexes of said network, means to modu
late at distinctive low frequencies the energy sup
receiver is shunted by a condenser 23, e. g., 1000
mfd., so as to provide a steady indication b-y the 40 plied to one of said other apexes, and means for
The overall effect, therefore,
alternately effective in identifying a course line
will be the same as if the two audio frequencies
defined by the overlapping ñeld patterns from
were on simultaneously. It will be understood, of
all said radiators.
course, that the invention is not limited to an
5. A directive radiant, pattern system of the
equal timed switching of the antennae 2 and 3. _.
type having a central radiant acting member,
For example, the switching may be effected in
other radiant acting members spaced from the
accordance with conventional “AN” practise so
that when the craft is on course, a Vcontinuous'sig
nal is produced in the aural signal device 24.
When the craft is to one side of the course the ,
signal will be keyed at the characteristic A rate,
while at the other ide of the craft the signal
will be keyed at the characteristic N rate. Like
wise, if desired, the audio frequencyr modulators
may be applied to amplifier 9 instead of to ampli- ,
fier id.
One of the advantages of the system as above
described is that the timing or operation of the
relay i3 does not affect the marker course. Thus
central member to pro-duce overlapping fields hav
ing distinctive signal characteristics in each of
two directions to define a path in space, a carrier
source, a hybrid bridge network having two diag
onals, means connecting the end of one diagonal
to the said central member, connecting means
between the other end of said one diagonal and
said other members to excite said other members
in phase opposition, a switching device in said
connecting means for rendering said other mem- -
bers alternately effective in identifying a course
line defined by the overlapping field patterns from
if the relay stays on one side more than on the Gil all said members, a pair of amplifiers connected
to said source, one amplifier being connected to
other, while it will cause the proportion of side
one end of the second diagonal of the bridge, the
bands present at each side of the course to change,
other lamplifier being connected to the opposite
it will not affect the course at all. This will be
end
of said second diagonal, and means to modu
apparent since the energy from side-band radi
late one of said amplifiers alternately by distinc
ators 2 and 3 is null along the course line.' The
tive low frequency signals.
.
.
v _`
eíect of unequal timing will merely cause ,the sen
6. A directive radiant pattern system of the
sitivity upon _departure from course to be greater
type .having a central radiator and side-band
on one side than on the other.
Furthermore,
radiators which are excited from a common car
since only one power amplifier, namely amplifier
rier 'source through a hybrid bridge network to
lil, is modulated, the operating conditionshare 70
produce overlapping ñelds having distinctive sig
not changed for each modulating frequency. If
nal characteristics `in each of two directions de
the two frequencies were applied to separate
ñning a path in space, characterizedby the novel
modulators it would be extremely' difficult to
`features that the opposite ends of onediagonal
insure that at all times the two modulators main-rV
of said bridge are connected through respective
tain the same electrical characteristics. -By feed 75
5
6
power amplifiers to the carrier source, and means
to said network for rendering the side-band an
are provided for modulating one of said ampli
tennae alternately effective at a predetermined
ñers by a plurality of distinctive low frequency
succession, means to develop two low frequency
signals in alternating succession.
signals of substantially the same amplitude, and
7. A directive radiant pattern system according
means for applying said low frequency signals to
to claim 6 in which the central radiator is con
one of said ampliñers alternately under control
nected to one end of the other diagonal of the
of said switching means to modulate the output
bridge and the other end of said other diagonal
of said ampliñer.
is connected through a switching relay to said
9. A system as claimed in claim 8 in which said
10 switching means is keyed in accordance with pre
side-band radiators.
8. In a system of the character described, an
determined distinctive code signals which pro
antenna array comprising a carrier antenna, a
duce a continuous signal along the course to be
pair of side-band antennae spaced from the car*
marked but which produce individual code `sig
rier antenna, a source of carrier energy, a plu
nals on opposite sides of the course, and said 10W
ralìty of paths connected to said Isource each in 15 frequency signals identify the respective sides of
cluding a separate carrier amplifier, a hybrid
the course.
bridge network connecting said amplifiers to said
LEON HIMMEL.
antenna array, a switching device also connected
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