A. V. HAEFF ET AL FULSE TRANSMISSION SYSTEM

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP81-00120R000100050005-7
• Release Decision: RIFPUB
• Original Classification: K
• Document Page Count: 9
• Document Creation Date: December 20, 2016
• Document Release Date: July 26, 2000
• Sequence Number: 5
• Publication Date: July 24, 1951
• Content Type: CONT

Approved For Release 2007/09/21: CIA-RDP81-0012OR000100050005-7
July 24, 1951
A. V. HAEFF ET AL 2,555 61,363
PULSE TRANSMISSION SYSTEM
LOCAL
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CONTROL CONTROL 1DELAYCONTR
TUBE RECTIFIER AMPLIFIER
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FOLLOWER STORAGE
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1NVEN?ORS
ANDREW V. HAEFF
FRANKLIN H. HARRIS
BY
TORAGE
3 Sheets-Sheet 1
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MEMORY
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ERROR
SIGNAL
AMPLIFIER
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lftwrl~
July 24, 1951
A. V. HAEFF ET AL
PULSE TRANSMISSION SYSTEM
2,561,363
INVENTORS
ANDREW V. HAEFF
FRANKLIN H. HARRIS
BY
Approved For Release 2007/09/21: CIA-RDP81-00120R000100050005-7
 Approved For Release 2007/09/21: CIA-RDP81-0012OR000100050005-7
July 24, 1951
A- FROM MULTIVIB, 50 TOORIO OF TUBE 53
B- FROM MOLT,v,8. 9/ TO yIt/0 OF 77/BE S3'2
C- COMB/NATION OF A AND B AT rrR//,O C
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70 TO TUBE S5
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(Cogia,NATION OF O 44'O E/ ,
SATU RATI O N
CUT OFF -
ANDREW V. HAEFFPUBS
FRANKLIN H. HARRIS
BY
2,561,363
Approved For Release 2007/09/21: CIA-RDP81-0012OR000100050005-7
 Approved For Release 2007/09/21: CIA-RDP81-0012OR000100050005-7
Patented July 24, 1951
2,561,3163
UNITED STATES PATENT OFFICE
2,561,363
PULSE TRANSMISSION SYSTEM
Andrew V. Haeff, Washington, D. C., and
Franklin H. Harris, Accokeek, Md.
Application January 16, 1946, Serial No. 641,548
13 Claims. (Ci. 250-15)
(Granted under the act of March 3, 1883, as
amended April 30, 1928; 370 O. G. 757)
i 2
This invention relates to devices used to render which perform these functions, such as those
enermy radio echo object detecting and ranging described in greater detail in the copending ap-
equipment ineffective. plication of Andrew V. Haeff and Franklin H.
One of the important special applications of Harris, entitled: A Synchronizing System, Serial
radio echo object detecting and ranging equip- 5 Number 641,363 filed January 15, 1948, normally
ment is its use for the control of gun fire. In will utilize each received pulse from the enemy
such applications the radio echo equipment is radio location equipment to actuate an interfer-
designed to determine the range and bearing of ing pulse delayed so that it will include the next
target objects with greater accuracy than is nor- following echo pulse reflected from the target
mally possible with radio echo location equip- 10 object. Synchronization is maintained by gen-
ment intended for detection and search purposes erating error signals when discrepancies arise,
only. and using these error signals to alter the delay.
Efforts to render enemy radio echo location The effectiveness of these timing circuits is
equipment ineffective commonly consist of trans- impaired if, because of atmospheric conditions
mitting a suitably modulated interfering signal 15 or other reasons, one or more pulses from the
which either saturates one or more stages of the enemy radio echo location equipment is not re-
radio echo location receiver or renders the visual ceived. The aim of the present invention is to
presentation unintelligible. For the latter pur- obviate this impairment.
pose modulation with a form of random signal It is accordingly one object of this invention
containing a broad spectrum of frequencies up to 20 to continue the actuating of an interfering trans-
several megacycles, known as noise modulation, mitter at an established pulse repetition rate
has been found most effective. when the normal actuating signal is temporarily
The interfering signal must be tuned to or ap- interrupted.
proximately to the carrier frequency of the en- Another object of this inventuion is to provide
emy radio echo location equipment. To be effec- 25 a correction to the synchronizing circuits of an
tive, the interfering signal must be many decibels interfering transmitter when the pulse repetition
larger than the echo signal at the enemy radio rate of the enemy radio echo location equipment
echo location receiver. Also, the interfering decreases.
transmitter should be capable of being modulated A further object of this invention is to provide
with a signal containing relatively high frequen- 30 a means for returning' control to the basic syn-
cies. These three requisites therefore create the chronizing circuits when a large change occurs in
need for an interfering transmitter, tunable over the pulse repetition rate of the enemy radio echo
a broad range, capable of modulation up to sev- location equipment.
eral megacycles, and capable of delivering a large Other objects and features of the present in-
amount of power spread over its frequency spec- 35 vention will become apparent upon a careful con-
trum. If the interfering signal is to be contin- sideration of the following detailed description
uous, the design of such a transmitter involves when taken together with the accompanying
the use of special power tubes which are not drawings, in which:
readily available. Fig. 1 is a block diagram of the interference
An alternative method is to transmit the inter- 40 transmitting system of which this invention is a
fering signal in suitably timed pulses. Such a part;
method, described in greater detail in the copend- Fig. 2 is a block diagram of the basic circuits
ing application of Andrew V. Haeff, Serial Num- used ;in timing the pulses and the pertinent cir-
ber 641,549, filed January 16, 1946, entitled: cuits of the invention;
Pulse Generation System permits substantial 43 Fig. 3, partly in schematic form, shows the
peak power output from tubes with low average basic timing circuits, the circuits which continue
power capacities. Its use is based on the premise operation during temporary interruptions of the
that for the protection of individual targets from received signals, and the circuits which provide,
enemy fire control radio echo location equipments the correction to the synchronizing circuits when
it is sufficient ' to generate interfering signals 50 the pulse repetition rate changes;
which will be received by these equipments only Fig. 4 is a diagram, partly schematic, of the
in the immediate proximity of the echo signal, circuits which return control to the basic syn-
so as to render impossible ascertainment of the chronizing circuits when a large change occurs
exact position of the target object. in the pulse repetition rate; and
With this alternative method, timing circuits 55 Fig. 5 shows a series of wave shapes useful in
are required which will cause an interference explaining the various circuits which provide the
pulse to be transmitted at such times that they correction.
will include echo pulses and which will maintain The interference transmitting system of which
this synchronization regardless of changes in the the present invention is a part, and which is de-
enemy. pulse repetition rate. Timing circuits 00 scribed in detail in the Haeff application supra,
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receives radio pulses of enemy origin and utilizes
them to actuate pulses after a suitable interval
which in turn actuate a transmitter. In order
that the output of transmitter will not reactuate
the system, means are provided whereby a por-
tion of the transmitter output neutralizes the
transmitter signal received by the receiver
antenna.
Specifically, and in accordance with the ar-
rangement shown in Fig. 1, the pulses trans-
mitted by the enemy radio are received by
antenna 10 of a directional type, amplified by
preselector II, and converted to signals of-an
intermediate frequency by beating with the out-
put of local oscillator 15 in mixer 12. These
intermediate frequency signals then are amplified
In intermediate frequency amplifier section 13,
demodulated in detector 14, and further amplified
in differential amplifier and video amplifier 16,
the output of which is applied to cathode ray
indicator tube IT and to the delay pulser 22.
For each trigger pulse received from the video
amplifier I6, the delay pulser 22 applies an actu-
ating pulse to modulator 25 after a suitable delay.
Modulator 25 in turn actuates transmitter 24, the
output of which Is radiated through a separate
directional antenna 23. The delay occasioned by
delay pulser 22 is such that the actuating pulse
from the delay pulser overlaps the next succeed-
ing pulse received from the enemy.
The cathode ray indicator tube 17 and its
associated circuits are used in adjusting the
pulser 22 to the enemy pulse repetition rate.
A small portion of the output of transmitter 24
is fed through attenuator 18 to mixer 16 where it
is converted to the intermediate frequency by
beating with the output of local oscillator 15.
This signal is amplified in intermediate frequency
amplifier section 20, demodulated in detector 21
and applied to differential amplifier 18. Dif-
ferential amplifier 16 is arranged, in a manner
described in the Haeff application supra, so that
the signal originating in leakage radiation cou-
pling between the receiving and transmitting
antennas 10 and 23 respectively and applied from
detector 14 is neutralized by the signal applied
from detector 21. Accordingly, when the channel
containing detector 21 is operative, only the
pulses received from the enemy radar and a small
residue of the interference pulses are passed to
delay pulser 22 and cathode ray tube IT.
The interrelation of the pertinent circuits con-
tained in the delay pulser is shown in Fig. 2. The
timing and duration of the interference pulse is
determined in the channel comprising a series
of timing pulse generators shown in this embodi-
ment as multivibrators 31, 84, and 35. Multi-
vibrator 31 is a one-shot multivibrator the period
of which is controlled both mechanically (by ad-
justing the resistance or capacitance of the grid
circuit of the normally conducting tube) and by
the voltage applied from the control tube 49.
Multivibrators 34 and 35 are also one-shot multi-
vibrators the periods of which may be adjusted.
Multivibrator 81 Is triggered by the pulse signal
received from the enemy, which is applied at
input 80, and the trailing edge of the output of
this multivibrator triggers multivibrator K. The
trailing edge of the output of multivibrator 34
in turn triggers multivibrator 85. The combined
periods of multivibrators 31 and 34 determine
the time elapsing between the reception of the
first pulse from the enemy and the start of the
interference pulse which is to obscure the echo
from the next succeeding pulse from the enemy.
4
Multivibrator 85 determines the duration of the
interference pulse.
Multivibrator 89, which is another one-shot
multivibrator with an adjustable period, is used
6 in the automatic delay control circuits presently
to be described. This multivibrator is also trig-
gered by the trailing edge of the output from
multivibrator 34. The total of the periods of
multivibrators 31, 34, and 39 is made equal to
10 the interval between pulses received from the
enemy.
The timing in the system as above described
would be adequate if no changes occurred in the
pulse repetition rate of the enemy radio echo
15 location equipment. For the possibility that such
changes will occur, it is desirable to provide means
whereby the system automatically adjusts itself
to such changes. The mixing network 38, auto-
matic delay control amplifier 42, the delay control
20 rectifier 41 and the control tube 40 perform this
function. Positive pulses of equal amplitude are
applied from multivibrators 31, 34, and 39 to mix-
ing network 88. Since the combined periods of
these three multivibrators are equal to the in-
25 terval between enemy pulses at the initial pulse
repetition frequency, the output of the mixing
network is a steady direct current voltage as long
as the enemy pulse repetition frequency remains
constant. If, however, the enemy pulse repeti-
80 tion frequency is increased, part of the output of
multivibrator 39 will overlap the start of the posi-
tive pulse from multivibrator 81, and positive
pulses will appear in the output of mixing network
38. Similarly, if the enemy pulse repetition rate
35 Is decreased, negative pulses will appear in the
output of the mixing network. The automatic
delay control rectifier 41 operates to convert
these positive or negative pulses into steady sig-
nals which are applied to the grid of delay con-
40 trol tube 40.
The period of multivibrator 81 (see Fig. 3) is
determined in part by the potential to which the
grid of its normally conducting tube is returned.
This potential is determined by the delay control
45 tube in such a way that the period of multivi-
brator 31 is decreased if positive pulses are ap-
plied to automatic delay control amplifier 42 and,
conversely, is increased if negative pulses are ap-
plied to automatic delay control amplifier 42.
60 This action tends to keep the system synchro-
nized with the enemy pulse repetition rate.
The timing and synchronizing system which
has been described above, and which is described
in greater detail in the Haeff and Harris appli-
55 cation supra, will be adequate provided there is
no interruption, due to atmospheric or other con-
ditions, in the reception of signals from the enemy
radio echo location equipment. When such in-
terruptions do occur, as has been mentioned pre-
60 viously, the effectiveness of the system will be im-
paired. The circuits represented by the remain-
ing blocks in the Fig. 2 circuit representation
are to prevent this impairment.
If the pulse repetition rate of the enemy equip-
65 ment remains the same, and if adequate recep-
tion of signals from the enemy is somehow inter-
rupted, it is necessary that the system continue
to be triggered at the proper intervals during the
TO interruption. The trailing edge of the output
from multivibrator 39 coincides in time with the
reception of the next succeeding signal from the
enemy for the established pulse repetition rate.
Consequently, the trailing edge of the output from
7 mlultivibr tqr 38 14 used to actuate the memory
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trigger tube 52 which in turn applies the required
trigger pulse to the input of multivibrator 81.
It is necessary that the memory trigger tube 52
be operative only for a short interval after sig-
nals from the enemy equipment cease entirely; 5
otherwise, the memory feed back channel would
continue the system in operation for an indefi-
nite period. Consequently, memory trigger tube
52 must be supplied with an enabling voltage
which is present only while and immediately after 10
the enemy equipment is in operation. Multivi-
brator 50 is a one shot multivibrator triggered by
the signals received from the enemy at input 80.
The output pulses from multivibrator 50 are fil-
tered in the enabling voltage holding circuit 51 15
to provide the required enabling voltage for mem-
ory trigger circuit 52.
If, while the memory circuit is in operation, the
enemy pulse repetition rate is increased, the au-
tomatic delay control circuits will operate in the 20
normal manner to return the system to synchro-
nization, since the next received signal from the
enemy will trigger multivibrator 31 before the
memory trigger pulse from memory trigger tube
52 is generated. When the memory trigger pulse 25
is generated, it will be applied to multivibrator
31 at a time in the cycle of the latter when it will
have no effect.
If, however, the enemy pulse repetition rate
decreases while the memory circuit is in opera- so
tion, the memory circuit, as described above,
would trigger the system before the next suc-
ceeding signal from the enemy was received, and
accordingly, the automatic delay control circuits
would be prevented from maintaining synchro- 36
nization. Consequently, when this situation
arises, error signals must be applied to the mixing
network 38 from some adjunct of the memory
circuit itself. Moreover, the adjunct must dis-
tinguish between enemy signals arriving late and 40
enemy signals not arriving at all. Multivibrator
31 which is activated by either the enemy signal
or the memory circuit, and multivibrator 50 which
is activated by the enemy signal only, both apply
signals to the memory cathode follower 53. If
these signals coincide, no error signal is gener-
ated; however, if the signal from multivibra-
tor 31 arrives first, an error signal is generated
which is stored in a capacitor resistor network
54 having a suitable time-constant. Then, if the
enemy signal only is late, when this signal is re-
ceived, the output from multivibrator 50 applies
the error signal remaining in the storage network
54 to the error signal amplifier 55. From the
error signal amplifier 55 it is applied as a nega-
tive pulse to the mixing network 38, actuating
the automatic delay control circuits. If, however,
no enemy signal corresponding to the cycle un-
der consideration arrives, the stored error sig-
nal expires according to the time-constant char-
acteristics of network 54, and the memory circuits
operate normally without actuating the auto-
matic delay control.
It has been found that with the memory cir-
cuits in operation, the synchronizing circuits are
not as responsive to sudden changes in the enemy
pulse repetition rate as they are without the
memory circuits in operation. In particular, if
the enemy pulse repetition rate is switched to a
significantly different value, there is the possi-
bility that the system will stabilize itself in such
a way that only some submultiple of the enemy
pulses Is covered. For this possibility, means are
provided to disable the memory circuits when
enemy signals are not being covered by the in- fig
6
terfering pulses. A signal corresponding to the
interfering pulse from multivibrator 35 and the
signal received from the enemy are both applied
to squelch triode 66. If the latter signal occurs
during the interval of the former, there is no
output from the squelch triode 56. If, however,
an enemy signal does not occur during the in-
terval of the former, it causes the squelch triode
56 to apply a short pulse to multivibrator 50.
This short pulse applied to multivibrator 60 pre-
vents this multivibrator from being actuated by
the enemy signals. When multivibrator 50 is
not actuated, the enabling voltage holding cir-
cuit 51 does not provide the enabling voltage to
the. memory circuit. Accordingly, the memory
circuits are rendered inoperative and the ad-
justment in the timing is made directly by the
automatic delay control circuits.
For a more detailed description of the memory
circuit and some of its associated circuits, refer-
ence is now made to Fig. 3. Multivibrator 31 is
triggered by means of a trigger tube, not shown,
the signal from which is applied at terminal TO.
The trailing edge of the output from multivi-
brator 31 in turn triggers multivibrator 34, and
the trailing edge of the output from multivi-
brator 34 triggers multivibrator 39. A negative
pulse is obtained from the cathode terminals 71
of this one shot cathode coupled multivibrator,
which pulse is differentiated by capacitor 12 and
resistor 73 for application to the grid of the
memory trigger tube 52.
Switch 15 determines whether or not the
memory circuits are to be operative. When
switch 15 Is open, the cathode of memory trig-
ger tube 52 is returned to the positive side of the
power supply, and the tube remains non-con-
ducting regardless of signals applied to the grid.
When switch 75 is closed, the cathode potential
is determined by the voltage divider comprising
resistor 14 and resistor 76. The potential deter-
mined by this voltage divider is sufficient to hold
the tube cut off in spite of signals applied to its
grid from the differentiated output; of multivi-
brator 39, unless a positive grid bias is obtained
from the enabling voltage holding cathode fol-
lower 51. If a positive grid bias is obtained from
the enabling voltage holding cathode follower 51,
the short positive pulse occassioned in the dif-
ferentiator circuit by the trailing edge of the out-
put of multivibrator 39 causes memory trigger
tube 52 to be momentarily conducting. Memory
trigger tube 52 has a common plate load resistor
with the normally non-conducting tube of mul-
tivibrator 31. Accordingly, when the former
tube is rendered conducting, multivibrator 31 is
actuated according to well known multivibrator
principles, and the system is maintained in op-
eration even if for some reason the signal ex-
pected from the enemy radio echo location equip-
ment is not received.
The enabling voltage holding cathode follower
5I maintains an enabling grid bias for the mem-
ory trigger tube for an interval long enough to
permit the memory channel to operate through
short interruptions in the reception of enemy
signals, but not to operate indefinitely. This
cathode follower is actuated by multivibrator 59
which is in turn actuated by trigger tube 17. Sig-
nal pulses of positive polarity received from the
enemy radio echo location equipment are applied
to the grid of trigger tube 77. The cathode po-
tential and thus the threshold sensitivity of tube
77 is determined by the position of the tap on
potentiometer 18. Tube 17 has the same plate
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load resistor as the normally non-conducting
tube of multivibrator 60; consequently, this mul-
tivibrator is actuated when tube 11 is rendered
conducting by the enemy signals.
A positive pulse is taken from the plate of the 6
normally conducting tube of multivibrator 50
and applied through a coupling network com-
prising capacitor 79 and resistor 80 to the grid
of enabling voltage holding cathode follower 51.
The load of this cathode follower, comprising re- 10
sistor 81 and capacitor 82 in shunt, filters the
positive pulse output, and a suitable direct cur-
rent voltage is applied as bias from the cathode
of tube 51 to the grid of memory trigger tube 52.
The period for which this bias is retained after 16
enemy signals are no longer received is deter-
mined by the time constant of the circuit com-
prising resistor 81 and capacitor 82.
8
signal on the grid of- tube 55 is shown as wave-
form F on Fig. 5.
The cathode of tube 55 is maintained at a
potential determined by the voltage divider com-
prising resistors 98 and 94. As will be apparent
from Fig. 5 F this potential is such that tube 55
Is held cut off except when the stored error signal
and the pulse from multivibrator 50 operate in
combination to raise the potential of the grid.
Thus the tube is not rendered conducting if the
enemy signal is received when it is expected and
is not rendered conducting if the enemy signal
is not received at all, but is rendered conducting
if the enemy signal is received late.
When tube 55 conducts, a negative pulse is
obtained from its plate and applied to the mix-
ing network 88 which actuates the automatic de-
lay control circuits in the manner described in
tion to the automatic delay control circuits when 20, For a more detailed description of the circuits
the enemy pulse repetition rate decreases, two which return control to the automatic delay con-
signals are applied to the memory cathode fol- trol circuits when the interfering pulse is found
lower 53. to be not covering the echo signal effectively, re-
A negative pulse is obtained from the normally ference is now made to Fig. 4.
non-conducting tube of multivibrator 50 and 25 Short positive pulses coincident with the re-
applied through capacitor 88 and resistor 89 to ception of enemy signals are applied from input
the grid of tube 53. This signal is shown as wave- 80 to the grid of the squelch tube 56. Negative
form A on Fig. 5 and its leading edge coincides pulses are also applied to this grid from the nor-
with the reception of the enemy signal. Also, a mally non-conducting tube of multivibrator 85
positive pulse is obtained from the plate of the 80 through capacitor I01 and resistor 102. The lat-
normally conducting tube of multivibrator 81, is ter negative pulses coincide in time with the
differentiated by capacitor 85 and resistor 86, and interference pulses; consequently, when the
is applied through resistor 87 to the grid of tube enemy signals are being properly included the
53. This signal is shown as waveform B on Fig- positive pulses from input 30 occur within the
ure 5, and the leading edge of the positive pulse 85 negative pulses from multivibrator 35.
corresponds to the time of triggering the system, The cathode potential of tube 56 is determined
either by the enemy signal or by the memory by the voltage divider comprising resistors 103
circuit. and 104. This potential is such that the tube
The combination of these two signals is shown remains cut off while no signal is applied to its
as waveform C in Fig. 5. When the system is 40 grid and while the positive pulses from input 80
properly synchronized, the two leading edges are offset by the negative pulses from multivibra-
coincide (as is shown in the first two cycles of tor 85. If, however, the received signals are not
waveform C), and no significant positive signal is properly included, the two signals to the grid of
applied to the grid of tube 53. If, however, the tube 56 arrive separately; and the positive pulses
enemy signal is delayed or is not received, the 45 from input 80 render the tube conducting.
positive pulse occasioned by the leading edge of When tube 56 conducts, a negative pulse is
the output from multivibrator 31 does appear as applied from its plate through the coupling net-
a positive signal (as is shown in the third cycle work comprising capacitor 105 and resistor 106 to
of waveform C). the grid of the normally nonconducting tube of
The cathode of tube 58 is connected to ground 50 multivibrator 50. This pulse arrives simul-
through resistor 91 and resistor 80. Resistor 91 taneously with the trigger signal from trigger
is a large resistor; consequently, in the quiescent tube 11 and prevents the multivibrator from being
condition very little current flows through the actuated. When the multivibrator is not ac-
tube. When a positive signal such as that shown tuated, the enabling voltage holding cathode fol-
for the third cycle of waveform C is applied to 55 lower does not maintain an enabling voltage for
the grid of tube 53, a substantial increase in cur- the memory trigger tube 52; and, accordingly
rent occurs and capacitor 92 charges according the memory channel is inoperative. With the
to a relatively short time constant. At the ter- memory channel inoperative, the automatic delay
mination of this signal, the voltage developed control, circuits assume full control of the tim-
across capacitor 92 is sufficient to cut tube 53 off; 60 ing.
consequently the capacitor discharges according Although only a certain and specific embodi-
to a much larger time constant. The voltage at ment of the invention has been shown and de-
the cathode of tube 58 (the high potential side scribed, we are fully aware of the many modi-
of the storage network comprising resistor 91 and flcations thereof. Therefore this invention is not
capacitor 92) is shown as waveform D on Fig. 5, 65 to be limited except insofar as is necessitated
The higher voltage observed for the third cycle by the spirit of the prior art and the scope of
is, in effect, the error signal, and it is applied as the claims.
enabling bias to the grid of the error signal am- In the appended claims the words "received
plifler tube 65. pulse" are construed to mean any pertinent ac-
A positive pulse is obtained from the plate of the 70 tuating signal, and the words "transmitted
normally conducting tube of multivibrator 50 if pulse" are construed to mean any pertinent out-
and when the enemy signal arrives. This pulse, put signal.
which is shown as waveform E on Fig. 5, is ap- The invention described herein may be manu-
plied through capacitor 79 and the storage net- factured and used by or for the Government of
work to the grid of tube 55 also. The composite 76 the United States of America for governmental
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Durposes without the payment of any royalties terval; a second one shotOmultivibrator initiated
thereon or therefor. into operation by the output of the delay means.
What is claimed is: the second one shot multivibrator and the delay
1. A method of recurrently transmitting pulses means in combination establishing the expected
in dependency on a series of recurrent received interval between successive received pulses;
pulses comprising the steps of receiving the re- vacuum tube means connected to the capacitor
current pulses, initiating a timing period on re- means operative in response to the enabling volt-
ceipt of a pulse, terminating the timing period age to reinitiate operation of the delay means in
before the receipt of the next pulse, transmitting coincidence with the trailing edge of the output
a pulse signal responsively to the termination of 10 of the second one shot multivibrator, the vacuum
the timing period, recurrently generating a series tube means being rendered capable of operation
of timing pulses at the average recurrence period by the enabling voltage.
of a preceding number of received pulses follow- 6. A method of generating an error signal
ing each received pulse by the same timing period, when the repetition rate of a first series of
and initiating transmission of a periodic pulse in 1s periodic pulses decreases but not when pulses of
response to a timing pulse in the event of failure the first series of pulses are omitted, which com-
to receive a recurrent pulse. prises the steps of generating separately second
2. Apparatus for receiving periodic pulses and periodic pulses which are initially coincident
transmitting other periodic pulses in response to with the first pulses, of polarity opposite to that
the received pulses comprising time delay means I0 of the first pulses, and initially at the recurrence
becoming operative responsively to a received rate of a preceding number of the first pulses;
pulse, pulse transmitter means initiated into op- and generating an output error signal when
eration after a time delay by the delay means, pulses of the first and second series both occur
timing pulse generator means operative to supply but not simultaneously.
timing pulses at the average recurrence rate of a u 7. A method of generating an error signal
preceding number of received periodic pulses, and when the repetition rate of a first pulsed signal
means responsive to the timing pulse generator decreases but not when pulses of this first pulsed
means operative to initiate operation of the time signal are omitted, which comprises the steps of
delay means in the event of brief interruption in generating separately a second pulsed signal
the reception of periodic pulses. '0 which is initially coincident with the first signal,
3. Apparatus for receiving periodic Pulses and of polarity opposite to that of the first signal, and
transmitting other periodic pulses in response to having the initial repetition rate of the first sig-
the received pulses comprising time delay means nal; mixing the first signal and the second signal
operative responsively to a received pulse, pulse to neutralize the signals when corresponding
transmitter means initiated into operation after SS pulses of both signals occur simultaneously and
a time delay by the delay means, pulse generating to form a third signal when it pulse of the first
means initiated into operation by the output of signal occurs later than the corresponding pulse
the delay means, the pulse generating means and of the second signal or does not occur; storing
the delay means in combination establishing the the third signal for a suitable period; and apply-
expected interval between successive received 40 ing the third signal as an error signal if and when
of the first pulsed signal occurs within
pulses; and means responsive to the trailing edge a that pulse period.
of the output of the pulse generating means
which reinitiates operation of the time delay 8. A means for obtaining error signals when
means. the repetition rate of a first pulsed signal de-
4. Apparatus for receiving periodic pulses and 45 creases but not when random pulses of this first
transmitting other periodic pulses in response to signal are omitted, which comprises; means gen-
the received Pulses comprising time delay means erating a second pulsed signal nitially coinci-
operative responsively to a received pulse, pulse dent with the first pulsed signal, said second
transmitter means initiated into operation after signal being of polarity opposite to that of the
a time delay by the delay means, a first pulse s0 first signal and having the initial repetition rate
generating means initiated into operation by the of the first signal; means mixing the first signal
received pulses; means converting the output of and the second signal to neutralize the second
the first pulse generator means into a direct cur- signal when corresponding pulses of both sig-
rent enabling voltage; capacitor means retain1jig nals occur simultaneously and to form a third
the enabling voltage for a holding interval; a s6 signal when a pulse of the first signal occurs later
second pulse generating means initiated into op- than the corresponding pulse of the second sig-
eration by the delay means, the second pulse gen- nal or does not occur; means storing the signal
erating means and the delay means in combina- for a suitable interval; and means applying the
tion establishing the expected interval between third signal as an error signal if and when a
successive received pulses; and means reinitiating 60 pulse of the first signal occurs within the interval.
the delay means into operation from the trailing 9. A means for obtaining error signals when
edge of the output of the second pulse generating the repetition rate of a negative pulsed signal de-
means, the reinitiating means being rendered creases but not when random pulses of this nega-
operative by the enabling voltage. tive signal are omitted, which comprises; means
5. Apparatus for receiving periodic pulses and generating separately a positive pulsed signal
transmitting other periodic pulses in response to which is initially coincident with and has the
the received pulses comprising, time delay means initial repetition rate of the negative signal;
operative responsively to a received pulse; pulse mixing means combining the two signals; a ca-
transmitter means initiated into operation after pacitor connected with the mixing means to have
a time delay by the delay means; a first one shot 70 its charge increased when a positive pulse is not
multivibrator initiated into operation by the re- neutralized by a negative pulse, said capacitor
ceived pulses; rectifier means converting the out- being arranged to retain a substantial part of
put of the first one shot multivibrator into a the increase in charge for a finite period after
direct current enabling voltage; capacitor means the termination of the positive pulse occasioning
retaining said enabling voltage for a holding in- , g the increase in charge; means directly responsive
Approved For Release 2007/09/21: CIA-RDP81-0012OR000100050005-7
 Approved For Release 2007/09/21: CIA-RDP81-0012OR000100050005-7
11
to each negative pulse generating a simultaneous
positive pulse; and a vacuum tube amplifier hav-
ing a tube with anode, cathode and grid elec-
trodes, the grid bias of the vacuum tube amplifier
being determined by the voltage across the ca- 5
pacitor, the grid of the vacuum tube amplifier
receiving the simultaneous positive pulses, the
cathode potential of the vacuum tube amplifier
holding the amplifier cut off except when the
simultaneous positive pulses are applied while 10
the capacitor is suitably charged, the error sig-
nal being obtained from the output of the
amplifier.
10. Apparatus for receiving periodic pulses and
transmitting other periodic pulses in response to' 15
the received pulses so that each transmitted pulse
includes in time the next succeeding received
pulse and so that the transmission of pulses con-
tinues through brief interruptions in the received
pulses, which comprises; time delay means oper- 20
ative responsively to a received pulse; pulse trans-
mitter means initiated into operation after a time
delay by the delay means; pulse generator means
operative to supply timing pulses at the average
recurrence rate of a preceding number of re 25
ceived periodic pulses; means responsive to the
timing pulses operative to initiate operation of
the time delay means in the event of brief inter-
ruption in the reception of the periodic pulses;
means generating a first pulsed control signal re-
sponsively to the trailing edges of the timing
pulse; means generating a second pulsed control
signal responsively to the received pulses, said
second signal being of polarity opposite to that
of said first signal; means mixing the first signal
and the second signal to effectively neutralize the
first signal when corresponding pulses of both
signals occur simultaneously and to form a third
signal when a pulse of the second signal occurs
later than the corresponding pulse of the first
signal or does not occur; means storing the third
signal for a suitable interval; means applying
the third signal as an error signal if and when
a pulse of the second signal occurs within the
interval; and circuit means operative responsively
to the error signal to adjust the time delay means
to maintain synchronization.
11. Apparatus for receiving periodic pulses and
transmitting other periodic pulses in response to
the received pulses so that each transmitted pulse -50
includes in time the next succeeding received
pulse and so that the transmission of pulses con-
tinues through brief interruptions in the received
pulses, which comprises; time delay means oper-,
ative responsively to a received pulse; pulse trans-
mitter means initiated into operation after a
time delay by the delay means; pulse generator
means operative to supply timing pulses at the
average recurrence rate of a preceding number
of received periodic pulses; means responsive to
the timing pulses operative to reinitiate operation
of the time delay means in the event of brief in-
terruption in the reception of the periodic pulses;
means generating a positive pulsed control signal
with leading edges coincident with the trailing
edges of the timing pulses; means generating a
negative pulse control signal responsively to the
received pulses; mixing means combining the two
control signals; a capacitor connected with the
mixing means to have its charge increased when
12
means directly responsive to each negative pulse
generating a simultaneous positive pulse; a vac-
uum tube amplifier having a tube with anode,
cathode and grid electrodes, the grid bias of the
amplifier being determined by the voltage across
the capacitor, the grid of the amplifier receiving
the simultaneous positive pulses, the cathode
potential of the amplifier holding the amplifier
cut off except when the simultaneous positive
pulses are applied while the capacitor is suitably
charged; and circuit means responsive to the out-
put of the amplifier adjusting the time delay
means to maintain synchronization.
12. Apparatus for receiving periodic pulses and
transmitting other periodic pulses in response
to the received pulses so that each transmitted
pulse includes in time the next succeeding re-
ceived pulse and so that the transmission of
pulses normally continues through brief interrup-
tions in the received pulses, which comprises
time delay means operative responsively to re-
ceived pulses; pulse transmitter means initiated
into operation after a time delay by the delay
means; control circuit means operative to gen-
erate error signals when the recurrence rate of
the received pulses changes; means responsive
to the error signals to adjust the time delay
means to restore-synchronization; means gener-
ating an enabling voltage responsively to the
received signals; means rendered operative by the
enabling voltage for reinitiating into operation
the time delay means in the event of interrup-
tions in the received pulses; means generating
negative pulses coincident with the transmitted
pulses; means mixing said negative pulses with
the received pulses in positive polarity; and an
amplifier receiving the output of said mixing
means, said amplifier being responsive only when
the received pulses do not occur within the in-
terval occupied by the negative pulses, the output
of the amplifier rendering the enabling voltage
generating means inoperative.
13. A system for transmitting pulses in a se-
lected time relationship to received recurrent
pulses comprising, a receiver system operative to
receive and amplify recurrent pulse signals, a
delay pulse generator connected to the output of
said receiver system operative to provide trans-
mitter keying signals each bearing a selected time
displacement from each received pulse signal,
signal sustaining means operative to initiate op-
eration of the delay pulse generator to sustain
production of transmitter keying signals upon
momentary interruption of received signals, and
transmitter means operative to transmit an out-
put pulse responsive to each transmitter keying
signal.
ANDREW V. HAEFF.
FRANKLIN H. HARRIS.
a positive pulse is not neutralized by a negative
pulse, said capacitor being arranged to retain a
substantial part of the increase in charge for a
finite period after the termination of the posi-
tive pulse occasioning the increase in charge;
REFERENCES CITED
The following references are of record in the
file of this patent:
UNITED STATES PATENTS
Number Name Date
2,266,401 Reeves ------------- Dec. 16, 1941
2,272,070 Reeves -------------- Feb. 3, 1942
2,402,916 Schroeder ---------- June 25, 1946
2,402,917 Miller ------------- June 25, 1946
2,413,932 Sziklai -------------- Jan. 7,1947
2,415,359 Loughlin ------------ Feb.4,1947
2,418,127 Labin --------------- Apr. 1, 1947
2,419,548 Grieg -------------- Apr. 29, 1947
Approved For Release 2007/09/21: CIA-RDP81-0012OR000100050005-7