RADIO REPEATING SYSTEM

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP81-00120R000100050020-0
• Release Decision: RIFPUB
• Original Classification: K
• Document Page Count: 5
• Document Creation Date: December 20, 2016
• Document Release Date: July 26, 2000
• Sequence Number: 20
• Publication Date: March 29, 1960
• Content Type: CONT

Approved For Release 2007/09/21 : CIA-RDP81-0012OR000100050020-0
March 29, 1960
E. M. DELORAINE ET AL 2,931,031
RADIO REPEATING SYSTEM
T U N E R HRt
TCK/NR
'PL /FIER
TUN/N!4
CONTROL
MIXING
CIRCUIT
TRANS-
MITTER
INVENTORS
SOMON0 M. MORAINE
BY EN~ eu
ATTORNEY
CONTROL
MAMM/TTE
SCANN/NR
RECEIVER
1~q
Approved For Release 2007/09/21 : CIA-RDP81-0012OR000100050020-0
 Approved For Release 2007/09/21 : CIA-RDP81-0012OR000100050020-0
March 29, 1960
Filed Aug. 28, 1942
A9--j-
CONTROL
CIRCUIT
CONTROL
TRANBMIT7
EDMONDNI % DECOR A/Ni
HENRI
R. ?U,s/bN/ES
BY
ATTORNEY
E-
M. DELORAINE ET AL 2,931,031
RADIO REPEATING SYSTEM
2 Sheets-Sheet 2
Approved For Release 2007/09/21 : CIA-RDP81-0012OR000100050020-0
 Approved For Release 2007/09/21 : CIA-RDP81-0012OR000100050020-0
NOW "IF
united States Patent Offince
2,931,031,
RADIO REPEATING SYSTEM
Edmond M. Deloraine, New York, and Henri G. $u-
signies, Forest Hills, N.Y., assignors to International
Telephone and Telegraph Corporation, a corporation
of Maryland
Application August 28, 1942, Serial No. 456,498
6 Claims. (Cl. 343--10)
2,931,031
Patc;rted Pd.ar. Z0,1060'
2
:operate some form of distance detecting apparatus 19
that obstacles may be readily detected at the receiver,
Such obstacle detection apparatus is commonly used for
the location of ships or aircraft. A purpose of the
present invention is to provide apparatus simulating the
reflection effects of ships or aircraft so that an enemy
station of the form shown in Fig. I cannot readily locate
the position of the craft.
At an intercepting station 5 which may be located on
board one of the ships of -a convoy or a bomber plane
or at some fixed land station is provided a scanning re-
ceiver 7. This scanning receiver operates continuously
to tune receiver 7 over a band of frequencies so that
the pulses sent out by transmitter 2 may be readily de-
tected. Any known form of frequency scanning receiver
may be provided, for example, the receiver may be of
the type generally disclosed in the copending application
of Emile Labin, Serial No. 451,302, filed July 17, 1942,
entitled "Radio Transmission and Monitoring System,"
now Patent No. 2,412,991. The indications of the shape
and frequency of the pulse may be determined by indi-
cator 8 in the output of receiver 7. Upon determination
of the frequency of the obstacle locating apparatus buoy-
ant mobile craft such as the propeller float 10 or the
balloon 20 may be released. In both of these arrange+
ments are provided repeater equipments 11 and 21 re-
spectively, tuned to the frequency of the signals from
transmitter 2. At the repeater, signals from transmitter
2 are received on antennae 12 and 22, respectively, and
are retransmitted after a suitable delay from antenna ele-
ments 13 and 23, respectively. These signals will ap-
pear at the receiver 3 as pulses simulating reflective im-
pulses in accordance with the system described in the
previous invention, application Serial No. 436,846.
However, should the tuning or spacing of pulses from
transmitter 2 be changed the repeated pulses from 10 and
20 would no longer properly simulate the reflection im-
pulses. Accordingly, at interceptor station 5 we provide
a control transmitter 9 which serves to transmit control
signals to adjust the tuning of repeaters 10 and 21 upon
change of tuning of transmitter 3. To accomplish this,
tuning adjusters 14 and 24 are provided at repeaters 10
and 20 to receive the signals from the control transmitter
8 and adjust the tuning of the repeater in any well known
manner to the desired frequency. To facilitate the con-
trolof the tuning, repeated signals from 11 and 21 may
be received at scanning receiver 7 and compared on indi-
cator 8 with the pulses from transmitter 3. From the
comparison of these pulses the desired adjustment of
control transmitter 9 is accomplished so that tuners 14
and 24 may be properly adjusted.
Many different forms of remote tuning control for
adjusting a transmitter or receiver are known and any
of these known systems may be utilized in the devices 10
and 11. However, in order to give a better understand
ing of the invention, a few types of repeater systems are
illustrated in Figs. 2, 3 and 5.
Turning to Fig. 2, the repeater equipment is shown as
consisting of the heterodyne receiver 30 preferably of the
self blocking type so that it will block itself for a prede-
termined-period of time upon receipt of a signal. Such a
receiver equipment used in a repeater is disclosed in the
copending application of E. M. Deloraine and E. Labin,
entitled "Radio Guiding Method and System," filed
August 28, 1942, Serial No. 456,500, now Patent No.
2,441,956. This blocking should be of sufficient dura-
This invention relates to radio systems and more 15
particularly to radio systems for falsely simulating the
reflection characteristics of extensive conductive bodies
with respect to an arriving succession of impulses. In
our previous copending application, Serial No. 436,846,
filed March 30, 1942, entitled "Radio Repeater," is dis- 20
closed an arrangement wherein a repeater mounted on a
mobile unit such as a balloon or a raft is used to receive
from and retransmit to signals from an obstacle detecting
system to produce a false simulation of a large conduc-
tive body. In systems such as described in the above- 25
mentioned application, the repeater apparatus must be
previously tuned to the carrier frequency of the obstacle
detection system since no control is retained over the
equipment once it has been released.
It is a principal object of this invention to provide 30
remotely located reflection simulating apparatus and re-
mote control equipment for adjusting the receiving char-
acteristics of the repeater system.
It is a further object of this invention to provide a
system for comparing the signals transmitted from a radio 35
obstacle detection arrangement with the signals trans-
mitted from a false simulation system to determine nec-
essary adjustments and then to transmit remote control
signals to produce the desired adjustments.
It is a still further object of our invention to provide 40
a system for continuously controlling the tuning or other
characteristics of a remotely located repeater so that it
will continuously follow changes in frequency or other
characteristics of a transmitting system of an obstacle
detection arrangement. 45
It is a still further object of our invention to provide
repeater systems capable of continuous operation over a
relatively wide variable frequency band.
A better understanding of our invention and the objects
and features thereof may be had by reference to the 60
accompanying drawings, in which;
Fig. 1 schematically illustrates a complete radio system
in accordance with this invention with the circuits in
.block diagram;
Fig. 2 is a block circuit diagram of one form of 55
repeater suitable for use in the system of Fig. 1;
Fig. 3 is a block circuit diagram of still another form
of repeater for use in the system of Fig. 1;
Fig. 4 is a set of curves serving to explain the opera-
tion of the system of Fig. 3; 60
Fig. 5 is _a block circuit diagram of still another form
of repeater in accordance with our invention; and
Fig. 6 is a block circuit diagram of an alternative
control arrangement for use in connection with the sys-
tem of Fig. 1. 65
Turning first to Fig. 1, the obstacle detecting apparatus
receiver 3. The transmitter 2 is normally adapted to
transmit a series of relatively widely spaced pulses which
after reflection. from a conductive body, are. received on 70
receiver 3. The output of receiver 3 is normally used to'
nals transmitted from transmitter 31 of an adjacent re-
peater so that the system will not start to sing. A blocjkirig
amplifier 32 may be provided to block the receiver at all
times - while transmitter 31 is in operation when self
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8,031,081
3 4
blocking is not provided. Blocking for a period of time Circuit 47 is capacitively reactive and has an Impedance
greater than that needed for its own transmitter may be curve illustrated by C of Fig. 4 adjusted by means of
desirable because of signals repeated from other simulat- condenser 49. Circuit 48 is inductively reactive and
ing stations. Accordingly, it is preferable to provide for has an impedance curve L, Fig. 4, controlled by means
blocking of the receiver a sufficient length of time to 5 of variable inductance 50. As a consequence the re-
assure that signals from other closely spaced mobile re- ceived signal at 46 will be applied over circuits 47 and
peaters are not effective in the system. If the mobile re- 48 to control relays 45 and 44, respectively. If the
peaters are widely spaced one from another the repeated signal is not at the center point indicated by line A of
signals will generally be too weak to trigger the receiver Fig. 4 then one of the relays 444 or 45 will predominate
since the field of the repeater transmitter is relatively 10 the other causing closure of switch 43 in the correspond-
weak. ing direction. The energy in relay 45 will predominate
Tuning control 33 is provided and preferably consists if the frequency is lower than indicated at A and 44 will
of a means for supplying beating frequency to receiver 30 predominate if the energy is higher in frequency than
to reduce the received signals to a suitable intermediate indicated at A. Accordingly, switch 43 will be moved
frequency. This intermediate frequency is then ampli- 15 into a position to operate motor 42 until balance is re-
fied in intermediate frequency amplifier 34 delayed for stored by the operation of variable condenser 49 and
a desired time in delay circuit 35 and then applied to a inductance 50. In this way oscillator 41 will be tuned
mixing circuit 36 where the signal is also mixed with en- to the proper frequency for repeating the signals.
ergy from tuning control 33 to restore it to the original It should be understood that motor 42 instead of op-
received frequency. From mixing circuit 36 the energy 20 erating an oscillator for beating with the received signals
is applied to repeater transmitter 31 and is rebroadcast. in repeater 40 may, if desired, directly operate the tuning
The rebroadcast pulse is preferably of such an amplitude of the repeater. It is clear that with the arrangement
as to simulate reflection from a ship or other extensive of Fig. 3, the repeater will be tuned to the desired fre-
reflecting surface. quency and this adjustment in tuning may be made to
Preferably, the energy from the control transmitter 9 25 follow any changes in the enemy transmitted frequency
is on an ultra high frequency wave band so that the con- as long as the variation does not exceed the response
trol signals will not serve as a guiding radiation for range of the system. At the same time, once the re-
enemy craft to indicate the location of the observation peater leaves the control area of the control transmitter
station. When these ultra short waves are used, control the system will remain tuned to the last frequency at
of the repeaters, if they are floating on the water, will not 30 which it was operated. Thus, if there is no change in
be possible beyond a distance determined by the curva- the energy signal the repeater may serve to interfere with
ture of the earth. This will probably be not more than their distance determining apparatus long after it is out
8 to 15 miles on the surface of the sea. However, when of the range of the control station.
balloons are used as shown at 20 in Fig. 1 control may In Fig. 5 is illustrated an alternative type of repeater.
be maintained for a much greater distance because of the 35 In this system the repeater 51 may be similar to that dis-
higher elevation of the repeaters. In such cases it may closed in Figs. 2 and 3 or may be of any variable tuning
be desirable to broadcast directly from control trans- type. The transmitted control signal may consist of a
mitter 9 a frequency for beating with the received signals carrier modulated with two different frequency signals
at 30 to produce the desired intermediate frequency. which may be alternatively applied to tune the repeater
Since the control frequency, however, is generally much 40 up or down in frequency. The receiver detector 52
higher than the transmitted signal it may be necessary to serves to receive the control signals and to detect this
transmit the control beating frequency as a modulation signal to derive therefrom control frequencies. These
of a high frequency carrier. In this case tuning control two frequencies derived at the output of receiver de-
means need be only a detector for detecting the carrier tector 52 are applied over selectively tuned circuits 53,
frequency so as to produce the desired beat frequency for 45 54 to tuning control means 55. Tuning control means
application to the receiver 30 and mixing circuit 36. If 55 may consist of a motor such as shown in Fig. 3 or
the beat frequency is transmitted directly then tuning any other suitable remote control apparatus, such as a
control 33 may be merely a broad band amplifier for step-by-step switch or other tuning circuits commonly
amplifying this signal before application to receiver 30 used in remote control receiver tuning. If the signal
and transmitter 31. 60 coming over circuit 53 predominates, the tuning will be
Although the direct transmission of a control inter- in one direction, while if the signal is such as to be ap-
mediate frequency may be provided as described above plied primarily over circuit 54, the repeater will be tuned
this system has the drawback that once the repeater has in the opposite direction. Thus, the tuning of the re-
traveled out of the control area of the control station peater may be permanently accomplished so that should
it will no longer function since no beating frequency will 55 the repeater leave the controlled area it will still re-
be supplied. It may be, therefore, preferable to provide main in operation.
means for tuning an oscillator in accordance with trans- In Fig. I the control station is shown with separate
mitted signals so that the repeaters will continue to op- and independently controlled receiver and transmitter
,crate at the frequency at which they are last tuned even units. Accordingly, in this arrangement the adjustment
after they have left the control range of the interceptor 80 of the control transmitter for remotely controlling the
station. For this purpose a system such as shown in tuning. of the receivers must depend upon manual ad-
Fig. 3 may be used. The repeater station 40 may be justment of the control transmitter 9. If it is desired to
similar to that illustrated in Fig. 2 with the receiver in- follow closely the tuning of the enemy transmitter, it
termediate frequency amplifier delay circuit and retrans- may be difficult to adjust manually the control transmit-
mitter. A control or tuning oscillator is provided at 41. 65 ter at a sufficiently high rate of speed. Accordingly,
This oscillator 41 produces the beat frequency for con- at the control station an arrangement such as illustrated
trol of the repeater in the manner described in connec- in Fig. 6 may be provided. In this system a broad band
tion with Fig. 2. The oscillator, however, is tuned by receiver is shown at 60 which is preferably of sufficient
means of a motor 42 driven in either of two directions range to cover the normal frequencies to be used by the
by means of a reversing switch 43. Reversing switch 70 enemy. This broad band receiver may serve to produce
43 is operated in its two positions by means of balanced a control frequency dependent upon the frequency re-
.relays 44, 45 controlled by the signals from the control ceived and operate a control circuit 62 which may, for
receiver 46. example, comprise a control circuit similar to that shown
To facilitate the control of the modulator, the output in Fig. 3. This control circuit 62 will then operate con-
of receiver 46 is coupled to two circuits 47 and 48. 75 trol transmitter 63 to tune it to the desired frequency for
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 Approved For Release 2007/09/21 : CIA-RDP81-0012OR000100050020-0
Now 1"&V1
2,931,031
transmitting signals to the repeated apparatus. Trans- means comprises a system Gfcrr supplying energy differ-
mitter 63 may be a high frequency carrier transmitter ing from sarid application carrier to said frequency by receiver said and said mix-
intermediate
modulated by a controlling frequency which is adjusted frequency fo
in accordance with the signals received in receiver 60. ing circuit, and said remote control transmission means
Furthermore, if desired, control circuit 62 may be of 5 comprises a variable frequency source for transmitting
some type which is adjusted in some other way by means energy to said tuning means.
of the signals received at 60. 4. A system according to claim 1 wherein said re-
While we have described the system throughout as peater comprises a heterodyne receiver, an intermediate
an arrangement for adjusting the tuning of repeaters, it frequency system, a mixing circuit for raising said inter-
is clear that other controls such as adjustment of the 10 mediate frequency to the carrier frequency and a trans-
shaping of the repeated signal may be operated as well mitter for transmitting said signals, and said tuning means
by the remote control system herein described. Also comprises a system for supplying energy differing from
the control transmission period may be adjusted by re- said carrier frequency by said intermediate frequency
mote means in the manner similar to that described for application to said receiver and said mixing cir-
above. It is clear that any control which may be 15 cuit, and selective means for selecting a given character-
manually operated at a repeater station may be remotely ized wave for adjusting said system to the desired fre-
positioned by the system outlined in the present applica- quency, and said remote control transmission means com-
tion. Furthermore, the system has been described prises means for transmitting radio frequency energy with
throughout without reference to the number of pulses given characteristics to control said selective means.
retransmitted. It is clear that, if desired, the system 20 5. A system according to claim I wherein said re-
may be made to transmit a plurality of delayed impulses peater comprises a heterodyne receiver, an intermediate
in the manner disclosed in the copending application frequency system, a mixing circuit for raising said inter-
of Edmond M. Deloraine and Henri G. Busignies, Serial mediate frequency to the carrier frequency and a trans-
No. 453,668 filed August 5, 1942, entitled "Radio Receiv- mitter for transmitting said signals, and said tuning means
ing and Transmitting System." 25 comprises a system for supplying energy differing from
While we have described particular embodiments of said carrier frequency by said intermediate frequency
our invention in order to fully explain the operation of for application to said receiver and said mixing circuit,
the system, it should be distinctly understood that this and means continuously responsive to a control wave of
description is given merely by way of illustration and is given characteristics for controlling said tuning means,
not intended to limit the scope of the invention as de- 30 said remote control transmission means being provided
fined in the appended claims. with a control circuit responsive to said pulses received
What is claimed is: at said analyzing means for givin to 1. Apparatus for simulating the reflection character- waves the desired controlling ha acteristic said transmitted
istic of an extensive conductive body with respect to an 6. A method of simulating the reflection characteris-
arriving succession of pulses incoming at a predetermined 35 tic of an extensive conductive body with respect to an
carrier frequency which comprises repeater means re- arriving succession of pulses incoming at a predetermined
motely positioned from said conductive body for receiv- carrier frequency, by means of a repeater having tunable
ing said succession of pulses and transmitting impulses transmitter and receiver parts thereof, said repeater means
in response thereto, tuning means at said repeater means being remotely positioned from said conductive body,
for coordinating the tuning of the transmitter and re- 40 comprising receiving and retransmitting said succession
ceiver means of said repeater means, and tuning control of pulses at said repeater means, transmitting tuning con-
means remotely positioned from said repeater means for trol signals from a point remotely positioned with respect
adjusting said tuning means to said predetermined car- to said repeater, tuning the transmitter and receiver means
rier frequency whereby the pulses retransmitted from said of said repeater to a predetermined frequency in response
repeater means have characteristics corresponding to the 45 to said control signals, and adjusting said repeater tun-
pulses reflected from said extensive conductive body, ing in response to said signals to said predetermined
thereby providing a simulation of the reflected pulses. carrier frequency, whereby the retransmitted pulses from
2. Apparatus according to claim 1, further compris- said repeater means have the same carrier frequency Char-
ing a receiver means adjacent said control means for re- acteristics as the pulses reflected from said extensive con-
ceiving the succession of pulses and determining the 80 ductive body.
carrier frequency thereof, and means operatively asso-
ciating said receiver means and said control means. References Cited in the file of this patent
3. A system according to claim I wherein said re-
peater comprises a heterodyne receiver, an intermediate UNITED STATES PATENTS
frequency system, a mixing circuit for raising said in- 66
termediate frequency to the carrier frequency and a
transmitter for transmitting said signals, and said tuning
2,014,518
Beverage --------------
1
2,076,361
Beverage --------------- Apr.
6, 1937
2,134,716
Gunn ----------------- Nov. 1, 1938
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