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Патент USA US2405765

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Patented Aug. 13, 1946
, 2,405,765
UNITED STATESl PATENT OFFICE
2,405,765
RADIO REPEATER
J. Ernest Smith, Brooklyn, N. Y., assìgnor to Ra
dio Corporation of America, a corporation of
Delaware
Application February 12, 1942, Serial No. 430,527
30 Claims. (Cl. Z50-15)
f
Y
2
l
The present invention relates to radio re
peater or relay stations and,»more particularly,
to such stations as are adapted to utilize ultra
high frequency waves for relaying television or
similar signals.
In ordinary transmission parlance, a repeater
is considered to be an amplifier having an out
put signal frequency dependent upon the fre
quency of the input signal. Amplification of fre
quencies in the neighborhood of 500 megacycles
for a band width sufficient for high ñdelity tele
vision transmission is diñicult with many ampli
ñer tubes -available at the present time. To over- '
are obtained in accordance with the principles of
the present invention by providing a crystal con
trolled oscillator and another oscillator, mixing
the output of said oscillators or modulating the
output of one of the oscillators, either in ampli
tude or wavelength, by the other of the oscillators
and separating the sum and difference fre
quencies thus obtained. One of these frequencies
is mixed with an incoming band of frequencies
to obtain a signal at a comparatively low inter
mediate frequency Which may be conveniently
amplified without adversely affecting the width
of the band of the frequencies. The amplified
band of frequencies is then mixed with the other
come this difficulty, the ultra high frequency sig
nal is heterodyned to a lower frequency band, 15 of the sum and difference frequencies to convert
the band to a position in the radio frequency
amplified and heterodyned back to an ultra high
spectrum near that of the incoming band of fre
frequency band for retransmission. Further, the
quencies and, also, thus dropping out the effect
retransmitted band normally does not coincide
of any frequency drift in the local oscillator. The
with the received frequency band but is difier
entially spaced therefrom to avoid feedback be 20 converted band of frequencies is then transmit
tween the transmitting and receiving antennas
and their associated circuits. While the present
heterodyning practice permits satisfactory am
plification at ultra high frequencies, it intro
duces, at the same time, the necessity for fre
quency monitoring of the retransmitted signal
since its frequency is a function of the heterodyn
ing oscillator frequency. Moreover, if the relay
ted to the Succeeding amplifiers in the relay sys
tem.
’
The present invention will be more fully un
derstood by reference to the following detailed
description which is accompanied by a drawing
in which:
Figure 1 illustrates the frequency distribution,
in a portion of the radio frequency spectrum, of
system incorporates antennas having band
various frequencies used in an embodiment of
Widths sufficient for the simultaneous transmis 30 the invention; While
Figure 2 is a diagram in conventional block
sion of a video channel and an adjacent sound
or “cue” channel, it is possible for cross-talk to
formation of an embodiment of the invention;
result due to drift of the heterodyning frequencies
Figure 3 is a curve illustrating the operation
at one of the repeaters.
of a portion of Figure 2; and
An object of the present invention is to over 35 Figure 4 illustrates a modification of the em
come the foregoing difficulties and disadvantages.
bodiment of Figure 2, and a different order of
A further object of the present invention is
application of the operations of the invention.
to improve the frequency stability of radio relay
Reference will now be had to the drawing, Fig
equipment.
ure 1 shows the frequency spectrum arrangement
Another object of the present vinvention is the 40 wherein the incoming frequency fs is heterodyned
provision of a radio relay station which may be
with a local frequency (fc-fk) giving the low in
conveniently controlled and supervised from the
termediate frequency band (fs-fc-l-fk) lwhich
terminal stations of a relay system.
may be amplified with-out difliculty. The ampli
fied signal is then heterodyned with another
A further object of the present invention is the
provision of a relay system which will not require 45 local frequency (fc-l-fk), thus resulting in the fre
frequency monitoring at each of the interme
quency (J‘S-i-2fk) which is to be retransmitted.
The frequencies fc and fk from which the sum
diate repeater stations.
and difference frequencies are derived are locally
Still a further object of the present invention
produced by oscillation generators, that for fre
is the provision of a system of amplifying ultra
high frequency radio waves wherein the output 50 quency fk being crystal controlled. It will be
noted that the outgoing frequency (fs-l-Zfk) is
signal from the amplifier means is determined
independent of the oscillator frequency fc.
substantially only by the frequency of the in
The frequency ,fk may conveniently be of the
coming waves.
order of 10 megacycles and is, therefore, prefer
The foregoing objects and others, which may
appear from the following detailed description, 55 ably derived from a crystal oscillator. Its drift,
3
l
therefore, compared to the outgoing carrier fre
frequencies in the output of modulator I2. Dis
quency of the order of 500 megacycles is neg
criminator 22 may be a conventional frequency
modulation receiver incorporating a back-to
back discriminator and an amplitude detector.
The discriminator 22 should have a characteris
ligible.
n
'
In Figure 2 is shown an embodiment of the
invention for performing the operations outlined
above. Frequency fk is generated by crystal os
cillator I0 and applied to balanced modulator I2
in a push-pull relationship. Another frequency
fe generated by oscillator I4 vis applied to bal
anced modulator I2 in push-push relationship.Y 10A
This is a well known carrier suppression system -
of modulation and therefore needs no further
description.
The output frequencies from balanced modu
tic with respect to the frequencies (fc-fk) and
(fc4-jk) as shown in Figure 3, wherein curves 24
and 26 illustrate the frequency-output voltage
characteristics Vof the halves of the back-to-back
discriminator. It Will ibe seen that as long as the
frequency (fc-fk) and the frequency (fc4-fk)
cut curves 24 and 26 at points equally distant
from the cross over point the output potential is
A’zeroL A shift in either direction will result in
lator I2 consist substantially‘of two side" bands 15
` '
_a positive or negative resultant output potential.
This direct resultant output potential is arranged
only, namely, (fc-fk) and (fc-Hr). The fre
quency (fc-fk) is applied to converter I6 and»
- to be applied as a variable bias to oscillator I4
there heterodyned with an incoming signal` is
whereby the frequency fc is controlled in such
arriving from a preceding station by way -of-re
sense that the output frequencies of modulator
ceiving antenna RA, giving an intermediate fre 20 I2 are shifted in the desired direction.
quency (fs-fe-i-fk). This frequency may be am
In vFigure 4 is shown a modification of the
plified in a conventional amplifier I8 toV any
embodiment of Figure 2 wherein the balanced
desired extent. After` ainpliñcation the inter
modulator arrangement I2 of Figure 2 is not used.
mediate frequency signal is Vheterodyned with
In this figure the incoming frequency is shown
the component (fc-HJC) in converter 20 thus pro 25 as (fs-l-Zfk) , the output frequency of the embodi
ducing the output frequency (fs-l-Zfr). The out
ment of Figure 2. The discriminatory character
put frequency is applied to transmitting antenna
istics of ñlter networks 30 and 32 are relied upon
TA for retransmission to succeeding relay sta
to Aselect the first lower and upper side bands
tions'. The antennas RA and TA Lare preferably
(fc-fk) and (fc-Hr) resulting from a mixing of
of the directive type with their zonesof maxi 30 frequencies fc‘ and fk, in modulator 24, while re
jecting the frequency je and components of higher
mum response directed away from each other and
toward
relay stations.
„
‘
"
‘
It should be understood »that the frequency
components shown in Figures'l and 2 and spe
order. Since rather severe selectivity isl required
of Afilter networks Si? and 32 to discriminate
against the frequency fc while passing frequencies
cifically mentioned are those which are essential 35 (fc-fk)
to the operation of the system. Other modula
tion products would be present but selective cir
cuits in the system may be provided to discrimi
nate against them.> Therefore, in order to reduce
and (gfe-l-fk) for straight mixing or
amplitude modulation, the crystal oscillator out
put fk may be arranged to frequency modulate
in modulator 24 the frequency fe generated by
oscillator I4. The modulation index may be ad
the number of other modulation products a filter 40 justed to emphasize the ñrst of the side bands
3D is provided in the channel between converter
with respect to the frequency fe and higher order
2i) and modulator I2 and a filter 32 is provided
components. For example, if a modulation index
between converter I5 and modulator I2. These
of about 2.4 is used, the amplitude of frequency
filters assure that only a single frequency as indi
fc is reduced to zero and at the same time the
cated is fed tofeach converter. Then the output 45 maximum fundamental or first order side band
of converter I 6 may be arranged to pass only
amplitudes are obtained. The channel carrying
the desired difference frequency fs-fc-l-fk while
frequencies (fc-I-fk) and (fe-fk) may include an
discriminating, for example, against the sum fre
amplitude hunting transducer device if desired.
quency J‘s-l-fc-fk. Likewise, the output of con
While I have used a modulation index of 2.4 in
verter 2l) may be arranged to pass only the sum
order to illustrate the selective property of this
frequency fs-l-Zjk discriminating, for example,
type of modulation, it is to be clearly understood
against the difference frequency J‘S-Zfcv. In order
to illustrate the stability of the outgoing signal
that my invention is not limited to that value,
(fel-21%), suppose a frequency drift of 5 kilo
since under some circumstances` a modulation
index of about 1.8 may be preferable. A modu
cyclesis allowed crystal oscillator IQ. Theout
lation index of this order gives aA maximum ratio
going signal then has a maximum drift rof l0
kilocycles in 50 megacycles or .002 percentA which,
for all practical purposes, is negligible. >Obvi
of fundamental to carrier and fundamental to `
second order side band amplitudes. The ampli
fied intermediate frequency is fs-fc-I-jk, the same
ously, the method described above is equally» ap
as in the previous example.
plicable to an amplitude or to ¿a frequency modu
dyned with the other side band frequency (fc-__fr)
andthe Vupper beat frequency, which becomes
fs, selected for retransmission. The outgoing
frequencies of the Vrepeaters using alternate
orders of application of the >side band frequencies
lationA
system.
‘
_
Y
Y
»
The system asso far described insures ¿that Athe
retransmitted frequency band will not-drift'. Y,lt
It is then hetero
does not, however, maintain the frequency band
to be amplified, that is, the frequency (fs-fe-l-fe), 85 thus are alternately js and (fel-2jr) throughout
the system.
`
constant since this frequency is a function of jc.
Due to the difficulty of obtaining wide enough
While I have particularly described and illus
pass bands at low frequencies to vobviate the
tratedseveral modiiicationsof the present in
effect of this drift, according to a further aspect
vention, Vit should be distinctly understood that
of the present invention, automatic frequency 70 my invention is not limited thereto but’may be
control of oscillator I4 may be provided. Side
varied within the scope o_f the appended claims.
band clipping in amplifier I8 is thus prevented
l. In a’ radio relay system, a stationincluding
since the position 0f band (Ís-.fc-I-J‘k) is main
tained constant. This may be accomplished by
receiving and transmitting antennae, a low-fre
supplying discriminator unit 22, Aresponsive to the 75 quency oscillator of high frequency stability, an
2,405,765'
.
6,
other oscillator, modulator means for so com
bining the output of said oscillators that sum and
difference frequencies are generated, a first con
verter means for mixing one of said frequencies
with incoming high frequency energy from said
receiving antenna for obtaining a low interme-`
diate frequency, means for amplifying said in
termediate frequency, a second converter means
for mixing the other of said sum and difference
put energy at a high frequency adjacent the fre
frequencies With said amplified intermediate fre
lator that the Wavelength of Ythe output is modu- `
lated thereby, a first converter means for mix
quency to obtain output energy at a high fre
quency of said incoming energy and means for
applying said output energy to said transmitting
antenna for radiation.
6. In a radio system, a station including receiv
ing and transmitting antennas, a 10W frequency
oscillator of high frequency stability, another
oscillator, means for so applying the output of
said low frequency oscillator to said other oscil
quency adjacent the frequency of said incoming
energy and means for applying said output en
ergy to said transmitting antenna for radiation.
ing one output frequency with incoming high fre
other oscillator, modulator means for so combin
quency oscillator that sum and difference fre
quencies are generated, a ñrst converter means
quency energy from said receiving antenna for
obtaining a low intermediate frequency, means
for amplifying said intermediate frequency, a sec
2. In a radio system, a source of high frequency
ond converter means for mixing another of said
energy, a low frequency oscillator of high fre
output frequencies With said amplified interme
quency stability, another oscillator, modulator
diate frequency to obtain output energy at a high
means for so combining the output of said oscil- >
frequency adjacent the frequency of said incom
lators that sum and difference frequencies are
generated, a ñrst converter means for mixing one 20 ing energy and means for applying said output
energy to said transmitting antenna for radiation.
of said sum and difference frequencies with said
'7. In a radio relay system, a station including
first mentioned high frequency energy for obtain
receiving and transmitting antennae, a low fre
ing a low intermediate frequency, means for
quency oscillator of high frequency stability, an
amplifying said intermediate frequency, a second
other oscillator, modulator means fo-r so combin
converter means for mixing the other of said sum
ing the output of said oscillators that sum and
and difference frequencies with said amplified
difference frequencies are generated, a first con
intermediate frequency to obtain output energy
verter means for mixing one of said frequencies
at a high frequency adjacent the frequency of
With incoming high frequency energy from said
said source.
3. Ina radio relay system, a station including 80 receiving antenna for obtaining a 10W interme
diate frequency, means for amplifying said inter
receiving and transmitting antennae, a loW fre
mediate frequency, a second Converter means for
quency oscillator of high frequency stability, an
mixing the other of said sum and difference fre
other oscillator, modulator means for so com
quencies With said ampliñed intermediate fre
bining the output of said oscillators that sum and
difference frequencies are generated, a first con 35 quency to obtain output energy at a high fre
quency adjacent the frequency of Said incoming
verter means for mixing said difference fre
energy and means for applying said output energy
quency with incoming high frequency energy
to said transmitting antenna for radiation, means
from said receiving antenna for obtaining a 10W
equally responsive in opposite senses to said sumintermediate frequency, means for amplifying
said intermediate frequency, a second converter 40 and difference frequencies for obtaining a control
potential and means for applying said potential to
means for mixing said sum frequency with said
control the frequency of said other oscillator.
amplified intermediate frequency to obtain out
18. In a radio relay system, a station including
put energy at a high frequency adjacent the fre
receiving and transmitting antennae, a low fre
quency of said incoming energy and means for
quency oscillator of high frequency stability, an
applying said output energy to said transmitting
other oscillator, means for so modulating the fre
antenna for radiation.
s
quency of said other oscillator by said low fre
4. In a radio system, input and output circuits
quency oscillator that sum and difference fre
for high frequency energy, a low frequency oscil
quencies are generated, a first converter means
lator of high frequency stability, another oscil
for mixing one of said frequencies With incoming
lator, modulator means for so combining the out
high frequency energy from said receiving an
put of said oscillators that sum and difference
tenna for obtaining a low intermediate frequency,
frequencies are generated, a first converter means
means for amplifying said intermediate fre
for mixing said difference frequencies with high
quency, a second converter means for mixing the
frequency energy from said input circuit for ob
taining a low intermediate frequency, means for 55 other of said sum and difference frequencies with
said amplified intermediate frequency t-o obtain
amplifying said intermediate frequency, a second
output energy at a high frequency adjacent the
converter means for mixing said sum frequency
frequency of said incoming energy and means for
with said amplified intermediate frequency to
applying said output energy to said transmitting
obtain output energy at a high frequency adjacent
the frequency of the energy at said input circuit 60 antenna for radiation.
9. In a radi-o relay system, a station including
and means for applying said output energy to said
receiving and transmitting antennae, a low fre
output circuit.
quency oscillator of high frequency stability, an
5. In a radio relay system, a station including
otherV oscillator, means for so modulating the fre.
receiving and transmitting antennae, a low fre
quency oscillator of high frequency stability, an 65 quency of said other oscillator by said low fre
ing the output of said oscillators that side band
for mixing one of said frequencies with incoming
frequencies are generated, a first Converter means
high frequency energy from said receiving an
for mixing one of said side band frequencies with
incoming high frequency energy from said receiv 70 tenna for obtaining a low intermediate frequency,
means for amplifying said intermediate fre
ing antenna for obtaining a 10W intermediate fre
quency, a second converter means for mixing the
quency, means for amplifying said intermediate
other of said sum and difference frequencies With
frequecy, a second converter means for mixing
said amplified intermediate frequency to obtain
another of said side band frequencies With said
amplified intermediate frequency to obtain out 75 output energy at a high frequency adjacent the
2,405,765 1
7
incoming high frequency energy from said re
frequency of said incoming energy and means for '
applying said output energy to »said transmitting
antenna, for radiation, means Yequally responsive
ceiving antenna for obtaining a low intermediate
frequency, meansfor amplifying said intermedi
in opposite senses to said sum and difference fre- l
ate frequency, a second converter means for mix
quencies for obtaining a control potential and
means for applying said potential to control the
ing said difference frequency with said amplified
intermediate frequency to obtain output energy
at a high frequency adjacent the frequency of
said incoming energy and means for applying
10. In a radio relay system, a station including
said output energy to said transmitting antenna
receiving and transmitting antennae, a. low fre
quency oscillator of high frequency stability; ‘an 10 for radiation, means equally responsive in oppo
frequency of said other oscillator.
'
_
site senses to said sum and difference frequencies
for obtaining a control potential and means for
otherV oscillator, modulator means for so combin
ing the output of said oscillators that sum and
difference frequencies are generated, a first >con-
applying said potential to control the frequency
of said other oscillator.
verter means for mixing said difference frequency
14. In a radio relay system, a station including
with incoming high frequency energy from said 15
receiving antenna for obtaining a low interme
receiving and transmitting antennas, a'low fre
diate frequency, means for amplifying said inter
quency oscillator of high frequency stability, an
other oscillator, means for modulating the Wave
length of the output of said other oscillatorby
mediate frequency, a second converter means for
mixing said sum frequency with said amplified
intermediate frequency to obtain output energy 20 said low frequency oscillator, a first converter
at a high frequency adjacent the frequency of
means for mixing the first upper sideband fre
said incoming energy and means for applying said
quencies of the output of said modulator means
output energy to said transmitting antenna for With incoming high frequency energy from said
radiation, means equally responsive in opposite
receivingr antenna for obtaining a low intermedi
senses to said sum and difference frequenciesmfor Aa5 ate frequency, means for amplifying said inter
obtaining a control potential and means for ap
mediate'frequency, a second converter means for
plying said potential to control the frequency of
mixing the first lower sideband frequency of the
said other oscillator.
output of `said modulator means with said ampli
11. In a radio relay system, a station including
fied intermediate frequency to obtain output en-Á
receiving and transmitting antennas. Ya low fre 30 ergy'at a >high frequency adjacent the frequency
quency oscillator of high frequency stability, an
of said incoming energy and means for applying
other oscillator, means for frequencyA modulating
said output energy to said transmitting antenna
said other oscillator by said low frequency oscil
for radiation.
'
«
lator, thelmodulation index being such that the
15. In aV radio relay system, a station including
receiving and transmitting antennas, a low fre
sum and difference frequencies predominate in
the output. a first converter means for mixing
said difference frequency with incoming high fre
quency energy from said receiving antenna for
obtaining a low intermediate frequency, means
quency oscillator of high frequency stability, an
other oscillator, means for modulating the Wave
length of the output of said other oscillator by
said low frequency oscillator, filter means for sep
for amplifyingsaid intermediate frequency, a sec 40 arating the sum frequency and the difference fre
ond converter meansìfor mixing said sum fre
quency from the output of said modulator, a first
quency with said amplified Y intermediate fre
converter means for mixing one of said frequen
quency to obtain output energy at a high fre
cies with incoming high frequency energy from
quency adjacent the frequency of said incoming
said receiving antenna for obtaining a low inter
energy and means for applying said output en
mediate frequency, means for amplifying said in
ergy to said transmitting antenna for radiation.
termediate frequency, a second converter means
12. In a radio relay system, astation including
for mixing the other of said sum and differenceV
receiving and transmitting antennas, a low fre
frequencies `With said amplified intermediate fre
quency oscillator of high frequency stability, an
quency to obtain output energy at a high fre
other oscillator. means for frequency modulating _ 50 quency adjacent the frequency of said incoming
said other oscillator by said low frequency oscil
energy and means for applying said output en
ergyV to said transmitting antenna for radiation.
lator, the modulation index being such that the
sum and difference frequencies predominate in
16. A radio relay system including a plurality
Y the output, a ñrst converter means for mixing
said difference frequency with incoming high fre
of stations as set forth in claim l, alternate ones
65
qency energy from said receiving antenna for ob
taining a low intermediate frequency, means for
amplifying-said intermediate frequency, a second
converter means for mixing said sum frequency
with said amplified intermediate frequency to ob
tain- output energy at a high frequency adjacent
the frequency of said incoming energy and means
for applying saidv output energy to said transmit
ting antenna for radiation, means equallyY re
sponsive in opposite senses to said sum and dif
ference frequencies for obtaining a control poten
tial and means for applying said potential to con
trol the frequency of said other oscillator.
13. In a radioY relay system, a station including
receiving and transmitting antennas, a low fre
quency oscillator of high frequency stability, an
other oscillator, modulator means for so combin
ing the output of said oscillators that sum and
difference frequencies are generated, a first con
verter means for mixing said sum frequency with
of said stations utilizing said difference frequency
in said first converter and said sum frequency in
said second converter, the other stations of said
system having the order of application of said
(if)
sum and difference frequencies reversed.
17. A radio relay system including a plurality
of stations as set forth in claim 8, alternate ones
of said stations utilizing said difference frequency
in said first converter and said sum frequencyl in
said second converter, the other stations of said
system having the order of application of said
sum and difference frequencies reversed.
'
18. A radio relay system including a plurality
of stations as set forth in claim 9, alternate onesV
of said stations utilizing said difference frequency
in said first converter and said sum frequency in
said second converter, the other stations of said
system having the order of application of said
sum and difference frequencies reversed.
19. In a radio system, a source of high fre- ,f
_quency energy, a low frequency oscillator~ of _high f.
2,405,765
10
frequency stability, another oscillator, modulator
cludes generating a relatively low frequency local
means for so combining the output of said oscilla
wave, generating a local carrier wave, frequency
tors that sum and difference frequencies are gen
modulating the carrier Wave with the local Wave
erated, a converter means for mixing one of said
to such a degree that the carrier has substantial
sum and difference frequencies With said first
ly zero Value in the waves resulting from the mod
mentioned high frequency energy for obtaining a
ulation process in order to facilitate filtering of
low intermediate frequency and means for ob
side bands on either side of the carrier, filtering
taining a control potential from said low interme
a side band frequency resulting from the modula
diate frequency and means for utilizing said con
tion process, heterodyning the `wave to be con
trol potential to control the frequency of said 10 verted with the filtered side band, selecting a beat
wave resulting from the heterodyning process,
other oscillator.
20. In a radio system, a low frequency oscilla
heterodyning the beat to a high frequency, and
tor of high frequency stability, another oscillator,
utilizing the resultant high frequency Wave.
means for so applying the output of said low fre
26. The method of Wave conversion which in
quency oscillator to said other oscillator that the 15 cludes generating a local Wave, generating a local
Wavelength of the outputU is modulated thereby,
carrier Wave, frequency modulating the carrier
converter means for mixing one output frequency
with the local Wave to such a degree that the car
from said modulating means with other high fre
rier is reduced substantially to zero in the Waves
resulting from the modulation process in order to
quency energy to obtain a low intermediate fre
quency and utilization means for said low inter 20 facilitate filtering of side bands apart from the
mediate frequency.
carrier, filtering a side band frequency Wave ly
ing to one side of the carrier frequency, hetero
21. In a radio system, a station including a re
dyning a Wave to be converted with the filtered
ceiving antenna, a low frequency oscillator of
side band frequency wave, amplifying a beat Wave
high frequency stability, another oscillator,
means for so modulating the frequency of said 25 resulting from the heterodyning process, and
heterodyning the amplified beat with another side
other oscillator of said low frequency oscillator
band frequency filtered from the modulated
that sum and difference frequencies are gener
waves.
ated. converter means for mixingr one of said fre
quencies’ with incomingr high frequency energy
27. The method of converting modulated waves
from said receiving antenna for obtaining a low 30 of a given mean frequency to modulated waves
of another mean frequency which includes gener
intermediate frequency, utilization means for said
ating a local relatively high frequency carrier
intermediate frequency and means equally re
wave, generating a relatively low frequency Wave,
sponsive in opposite senses to said sum and dif
producing sum and difference frequencies with
ference frequencies for obtaining a control poten
tial and means for applying said potential to con 35 the locally generated Waves, successively hetero
clyning waves derived from the modulated Waves
trol the frequency of said other oscillator.
of given mean frequency with the said sum and
22. In a radio system, a station including a re
difference waves, and utilizing a beat Wave de
ceiving antenna, a low frequency oscillator of
rived from the last heterodyning process.
high frequency stability, another oscillator, means
for modulating the Wavelength of the output of 40
28. The method of converting modulated Waves
of given mean frequency to Waves of another
said other oscillator by said low frequency oscilla
mean frequency Which includes generating a local
tor, converter means for mixing the ñrst upper
carrier wave, generating a local constant fre
sideband frequencies of the output of said modu
quency modulating Wave, carrier suppression
lator means with incoming high frequency ener
gy from said reeceiving antenna for obtaining a 45 modulating the carrier with the 10W frequency 4
modulatingr Wave, ñltering the side bands result
low intermediate frequency, and means for am
plifying said intermediate frequency.
23. 'I'he method of Wave conversion Which in
ing from the modulation, heterodyning the mod
ulated Waves of mean frequency with one of the
side bands to produce a relatively low, readily am
cludes generating a relatively 10W frequency local
wave. generating a local carrier wave, frequency 50 plifiable modulated intermediate frequency wave,
amplifying the relatively 10W, readily ampliiiable
modulating the'carrier wave With the local Wave
intermediate frequency wave, and heterodyning
to such a degree that the carrier has substantially
the amplified intermediate frequency wave
zero value in the Waves resulting from the modu
lation process in order to facilitate filtering of
against the other filtered side band to produce
side bands on either side of the carrier, filtering a 55 the modulated waves of the desired mean fre
quency.
side band frequency resulting from the modula
tion process. heterodyning a wave to be converted
29. The method as defined in the claim 28
Which includes the step of utilizing a portion of
with the filtered side band, and utilizing a beat
wave resulting from the heterodyning process.
the carrier suppression modulated waves to con
24. The method of wave conversion which in 60 trol the frequency of one of the locally generated
Waves.
cludes generating a relatively 10W frequency local
Wave, generating another local Wave. frequency
30. The method of wave conversion which in
modulating said other local Wave With the first
cludes locally generating a pair of Waves of dif
mentioned local Wave to such a degree that the
ferent frequency, producing sum and difference
said other local wave has substantially zero value 65 frequency Waves from the locally generated
in the Waves resulting from the modulation proc
Waves, utilizing a portion of the sum and differ
ess in order to facilitate selection of one of the
ence Waves to frequency control the frequency
remaining modulation products, selecting a side
of one of the locally generated Waves, and suc
band frequency resulting from the modulation
cessively heterodyning waves derived from waves
process, heterodyning a wave to be converted
of one mean frequency with said sum and differ
ence frequency Waves to produce a Wave of dif
with the selected side band, and utilizing a beat
Wave resulting from the heterodyning process.
25. The method of wave conversion which in
ferent mean frequency.
J. ERNEST SMITH.
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