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Патент USA US2408063

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Patented 8 Sept. 24,’ l 946
Donald D. Grieg, Forest Hills, N. Y., assignor to
Federal Telephone and Radio Corporation,
Newark, N. J ., a corporation of Delaware
Application May 24, 1943, Serial No. 488,178
9 Claims. (Cl. 250—20)
This invention relates to radio receivers and
particularly to pulse translating means in radio
receivers and other electrical apparatus.
It has been proposed heretofore to transmit
pulses whose repetition rate or frequency varies
according to F. M. (frequency modulation) prin
ciple. That is,a train of pulses is modulated
as to their repetition rate according to the in
telligence to be conveyed thereby.
One of the objects of my present invention is
to provide a method and means for translating
pulses of varying repetition rate into equivalent
by repetition modulated pulses by either wire or
through space. Also it will be readily apparent
that F. M. carrier energy may be transmitted
and the intelligence conveyed thereby may be
?rst translated into pulses which vary in repe
tition rate according to the frequency modula
tion of, the carrier.
The output of the detector or other source of
pulses Of varying repetition rate is applied to a
local pulse generator M which preferably is ad
,justable to produce generated pulses having. a
desired displacement. The generator l4 may‘ be
time modulated pulses.
of any known construction in which the opera
Another object of my invention is to provide
tion can be controlled by synchronizing pulses.
a radio receiver adapted to detect and translate 15 By way of example, the generator may comprise
pulses of varying repetition rate into equivalent
a form of ‘relaxation oscillator such as a multi
time modulated pulses for demodulation in a
vibrator having a given mode of operation and
T. M. (time modulation) demodulator.
which is synchronizable by pulses occurring with;
According to my invention provision is made
in a given latitude of the operating frequency
for generating locally a train of pulses the time 20 thereof- Such a multivibrator may be arranged
displacement of vwhich is selected according to
whereby the repetition’ modulated pulses detected
the repetition modulation characteristics of the
control the operation thereof so as to vary the
pulses to be translated. This local generation of
generation for alternate pulses in accordance with
pulses may be performed by any one of several
the instant repetition rate of ' the modulated
methods whereby the generation may be synchro
pulses received.
nized' within a given latitude. The repetition
modulated pulses are used to resynchronize the
local pulse generator upon generation of alter
As a further example of a local pulse generator
the multivibrator may be associated with a re
nate pulses. That is to say, alternate pulses
locally generated are caused to coincide with the
occurrence of succeeding pulses of the train of
repetition modulated pulses, thereby translating
the instant frequency characteristic thereof into
a time displacement represented by the intervals
between succeeding pairs of pulses. The adjust
ment of the local pulse generator is such as to
provide a normal time displacement between the
generated pulses which is less than the minimum
repetition interval but greater than one-half the
ceiver of the triggering oscillator character sim
ilarly as'disclosed in the copending application of
E. Labin and myself, Serial No. 488,181, ?led May
24, 1943. As set forth in more detail in the afore
said copending application, the triggering oscil
lator, upon detection of a transmitted pulse, sets
7 up" an oscillation. ' The establishment of this os
' cillation, in accordance with the principles of
the present invention, triggers the multivibrator -
or synchronizes the multivibrator in accordance
with the reception of the transmitted pulse,
thereby initiating a new timing operation for the
maximum repetition interval of the repetition 40 multivibrator. The output of the multivibrator
modulated pulses.
is applied to the triggering oscillator to ‘increase
For a further understanding of the invention,
the sensitivity thereof and consequently vary the
reference may be had to the following detailed
blocking potential for the‘ oscillator.
description to be read in connection with‘ the
According to the present invention, the local
45 generator 14 is adjusted to repeat its operation
accompanying drawing, in which:
Fig. 1 is a block diagram of a radio receiver
before the reception of the next succeeding pulse
in accordance with my invention; and
of the train of repetition modulated pulses. The
Fig. 2 is a graphical illustration showing three
pulse output of the generator is applied to any
separate trains of signal pulses of di?erent repe
suitable T. M. demodulator l6, which for exam
tition rates.
50 ple, may be of the character disclosed in my afore
Referring to Fig. 1, the radio receiver therein
said application Serial No. 459,959.
shown is provided with a known detector l0 hav
The region of synchronization for the generator
ing an antenna l2 by which repetition modulated
precedes the operation thereof a given interval
pulses may be detected. It will be understood,
of time during which the generator may be trigg
of course, that intelligence may be transmitted 55 gered from one state of operation to another.
For repetition modulated pulses of a ?xed ampli
tude, this region of synchronization is depend
ent on the time constants of the pulse generator.
In Fig. 2 there is shown for purposes of illus
trating the principles of the invention, a series
of curves having the same time base. Curve (2
represents a series of locally generated pulses L
having a normal repetition rate T which may be
varied within limits of synchronization accord
this region to cover the degree of repetition modu
As previously described in connection with
pulse Bl the signal pulse DI synchronizes the
generator to produce a pulse DLI (curve e). The
generator operates normally thereafter to pro
duce’ impulse L4 displaced an interval .T. from
pulses DLI. The signal pulse D2 falling in syn
chronizing region S3 resynchronizes the gen
ing to the degree of frequency modulation of the 10 erator to produce pulse DL2 displaced from pulse
L4 by a time interval 152. This continues for all
train of pulses to be translated. The intervals
signal pulses having the repetition rate f2.
of time S preceding each of the pulses L repre
Curve g shows still another series of signal
sents the region of synchronization during which
pulses G having a repetition rate is. Curve h
the local pulse generator may be triggered by an
input pulse. In other words, it is in this region 15 illustrates the translation of the repetition modu
lated pulses G into equivalent time modulated
that should a repetition modulated pulse be ap
pulses in the manner previously described. It
plied to the generator the generator will be caused
will be noted that the interval of time is be
to change its timing of the pulse generation. It
tween pulses L1 and GL2 etc, corresponds to the
will be understood, of course, that the pulses L
of curve a will shift in occurrence in accordance 20 repetition rate is of the signal pulses G.
Comparing the translation of the signal pulses
with resynchronization thereof by an input
of the rates f1, f2 and f3 (curves b, d and g) with
pulse but that succeeding pulses L will occur
the time modulated pulses indicated by curves
thereafter at a time displacement of T until the
0, e and h, it will be clear that in accordance
generator timing is changed by another input
25 with my invention a translation of the intelli
Curve 1) represents one series of signal pulses
B having a repetition rate of T1. The translation
of the increment of intelligence represented by
this repetition rate is indicated by the pulses of
gence of the repetition modulated pulses into
equivalent time modulated pulses is performed.
Since ‘I have chosen‘, for purposes of illustration,
increasing repetition rates (that is, decreasing
periods) for the signal pulses B, D and G, it will
be clear that the time displacement of the cor
repetition pulse Bl falls within a synchronizing
responding time modulated pulses decreases pro
region S thereby synchronizing the generator for
portionately as indicated by the time intervals
operation to produce pulse BL! in timed relation
i1, i2 and is.
with pulse Bl. The mode of operation of the gen
The T. M. pulses thus produced by the trans
erator l4, however, is so chosen that it will pro 35
lation of the incoming signal pulses of varying
duce thereafter at the time interval T. its next
repetition rate are applied to the T. M. demodu
pulse LI before reception of the next signal pulse
lator 66. While the demodulator ‘l6 may be of
B2. The displacement between the pulses BL!
various constructions it preferably is of the char
and LI, therefore, is T according to the mode
of operation of the generator. The reception of 40 acter disclosed in my copending application Se
rial No. 459,959. This demodulation,-for example,
signal pulse B2 occurs within the synchronizing
preferably is of the character involving the gen
region SI preceding the next normal operation of
erating or synchronizing of an energy wave hav
the generator which is indicated by broken line
ing recurring inclined portions, the period of
22. It will be noted that the interval between
pulse B2 and the broken line 22 is less than the 45 which is comparable to the unmodulated time
spacing of the pulses. The wave and the pulses
region of synchronization SI of the generator.
are combined, the pulses being superimposed on
Therefore, the generator is resynchronized ac
the wave at points along the inclined portions
cording to the occurrence of the signal B2 to pro
thereof according to the time displacement of
duce pulse BL2 which is displaced from pulse
the pulses. This produces by threshold clipping
Ll an interval t1 different from interval T.
output pulse energy which varies in amplitude
Following the occurrence of signal E2 the gen
according to the time modulation of the input
erator operates normally to produce pulse L2. It
pulses which may be detected in the usual man
follows that the next succeeding pulse B3 which
falls within synchronizing region S2 will again
curve 0. The local generator is adjusted so that
resynchronize the generator to produce pulse 55
. BL3 which is displaced from pulse L2 by the same
time interval t1 occurring between pulses LI and
BL2. This control of the generator I4 continues
for the signal pulses having the repetition rate
f1. The increment of intelligence transferred by
"the repetition rate ii of the signal pulses B is
thus represented by the interval 221 between the
pairs of pulses Ll, BL2; L2, BL3; etc.
While I have shown and described the prin
ciples of my invention in connection with speci?c
apparatus, it is to be understood that the de
scription and illustration are given by way of
example only and not as limiting the scope of the
invention as set forth in the objects and the ap
pended claims.
I claim:
1. A method of translating repetition modu
lated pulses into equivalent time modulated pulses
Curve 11 shows another series of signal pulses
D having a repetition rate f2 the occurrence of 65 comprising generating pulsesaccording to a given
time displacement and using the successive pulses
which is shown as falling Within the region of.
of a train of repetition modulated pulses to be
synchronization S of the generator according to
translated for synchronizing the generation of
the operating condition of the generator as in
alternate ones of the generated pulses,
dicated by curve a. Since curve d represents a
2. The method de?ned in claim 1 wherein the
change in repetition rate, the ?rst signal pulse 70
given time displacement of the generated pulses
DI is shown for purposes of illustration, shifted
in absence of said synchronizing operation is se
relative to pulse Bl . The region of synchroniza
lected less than the minimum repetition interval
tion S indicated by the line 2!! (curve a) of course,
between the repetition modulated pulses.
includes the pulse DI since the mode of opera
3. The method de?ned in claim 1 wherein the
tion of the generator is so adjusted as to time
given time displacement of the pulses generated
in absence of said synchronizing operation is se
lected less than the minimum repetition interval’
but greater than one-half the maximum repeti
tion interval of said repetition modulated pulses,
adjacent said alternate pulses being displaced
therefrom according to the modulation of the
corresponding repetition modulated pulses, and
means for demodulating the time modulated
'7. A radio receiver having means to: detect
4. A system for translating repetition modu~'
repetition modulated pulses, means to translate
lated pulses into equivalent time modulated
the repetition modulated pulses into equivalent
pulses comprising means to generate pulses at a
time modulated pulses, the last named means in
repetition rate the time displacement of which is
less than the minimum repetition interval but 10 cluding means to generate pulses having a given
time displacement, means for synchronizing the
greater than one-half the maximum repetition
generation of alternate pulses in time relation
interval of the repetition modulated pulses,
with successive modulated pulses, and means for
means to apply to said generating means for
demodulating the time modulated pulses.
synchronizing control thereof the successive
8. In a‘ pulse system, a source of pulses, a pulse
pulses of the train of repetition modulated pulses 15
generator for producing discrete pulses at a given
to be translated, and said pulse generating means
repetition rate which is higher than the average
being adjustable to a mode of operation such
pulse repetition rate of said source, and means
‘ that each of the successive repetition modulated
apply the pulses of said source to said genera
pulses resynchronizes the pulse generating means.
5. The system de?ned in claim. 4 wherein the 20 tor to control the production of alternate ones of
said discrete pulses.
generating means is adjustable to produce the
‘9. A pulse system according to claim 8, wherein
pulses at a repetition rate having the desired .
the pulses of said source vary in repetition rate
relation according to the limits of the modula
between two given limits according to signal
tion of said repetition, modulated pulses.
6. A radio receiver having 'means to detect 25 modulation thereof, the resulting spaces between
successive discrete pulses produced by said gen
repetition modulated pulses, means to translate
erator corresponding substantially to the instan
the repetition modulated pulses-into equivalent
taneous repetition rate of the pulses of said source.
time modulated pulses with alternate pulses
equally spaced apart in time relation, the pulses
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