US2264608A - Means and method for relaying frequency modulated signals - Google Patents

Means and method for relaying frequency modulated signals Download PDF

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Publication number
US2264608A
US2264608A US313496A US31349640A US2264608A US 2264608 A US2264608 A US 2264608A US 313496 A US313496 A US 313496A US 31349640 A US31349640 A US 31349640A US 2264608 A US2264608 A US 2264608A
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United States
Prior art keywords
frequency
heterodyning
oscillator
current
low
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Expired - Lifetime
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US313496A
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English (en)
Inventor
Edwin H Armstrong
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Individual
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Individual
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Filing date
Publication date
Priority to BE473156D priority Critical patent/BE473156A/xx
Priority to NL68041D priority patent/NL68041C/xx
Priority to BE472677D priority patent/BE472677A/xx
Priority to NL67372D priority patent/NL67372C/xx
Priority to US313496A priority patent/US2264608A/en
Application filed by Individual filed Critical Individual
Priority to US358207A priority patent/US2275486A/en
Application granted granted Critical
Publication of US2264608A publication Critical patent/US2264608A/en
Priority to GB994/47A priority patent/GB623219A/en
Priority to GB999/47A priority patent/GB623221A/en
Priority to FR946096D priority patent/FR946096A/fr
Priority to FR946307D priority patent/FR946307A/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B14/00—Transmission systems not characterised by the medium used for transmission
    • H04B14/002—Transmission systems not characterised by the medium used for transmission characterised by the use of a carrier modulation
    • H04B14/006—Angle modulation

Definitions

  • relay transmitting systems There are two types of relay transmitting systems. In one the received signal is detected and converted into its original form, and this current is used to modulate the second transmitter. In the other the received radio frequency current is heterodyned to the frequency to be transmitted, amplified up and transmitted without ever being converted into the audio or other signaling current. In each type of relaying certain difliculties are encountered. In the first type reception would be carried out with a superheterodyne which can be readily designed to give the necessary selectivity to prevent interference from the transmitter, but which suffers from the fact that in the detection at the receiver and the remodulation of the local transmitter a certain amount of distortion is encountered. This. while hardly detectable in a single relay, eventually places a limit on the number of retransmissions which could be undertaken. In the second type reception would be accomplished without converting to audio, and the frequency to be transmitted would be produced by adding to, or subtracting from,
  • the incoming frequency a locally produced current which might be of the order of 400 k. c.
  • the desired frequency component would be selected out and transmitted and in this way the distortion incident to detection an modulation would be avoided.
  • the circuits required to select 65 the desired frequency for retransmission and the circuits required to protect the receiver from the effects of the transmitter would of necessity have to be extremely selective and consequently critical to adjust and maintain.
  • the present invention has for its object the provision of means whereby the difficulties of both types are overcome and the advantage of both retained.
  • the incoming signal is heterodyned down to some relatively low intermediate frequency at which the desired selectivity may be obtained, converted to a frequency which differs from the initial intermediate frequency by an amount equal to the difference between the received frequency and the frequency to be radiated and heterodyned up by the same amount by which it was initially heterodyned down.
  • both of these heterodyning currents are obtained from the same oscillating source so that any drift in the frequency of one current occurs simultaneously in the other.
  • Figs. I and II represent the complete relay system in which the apparatus shown in Fig. I will usually be separated from the apparatus of Fig. II by a distance of some hundreds of feet, Fig. 11 being located at the transmitter. While this is not essential under all conditions, where weak signals are to be relayed it is desirable and the arrangement of apparatus required for separated locations is, therefore, depicted.
  • I represents the receiving antenna connected through filter 2 to a balanced converter 3.
  • This converter is supplied with a heterodyning current of 41.8 megacycles as shown.
  • 4 represents a filter having a pass band sufilcientlywide to pass the .90lL- 1100 k. c. current produced by the interaction of the incoming 42.8 megacycles signal with a 100 k. c. deviation, and the fixed frequency of 41.8 megacycles.
  • 5, 6, I and 8 represent selective amplifiers, 9 a limiter for the 1000 k. c. current, It!
  • a filter ii an amplifier, and 12 a second filter connecting to a line I3.
  • the line l3 which terminates at l8 in Fig. II should preferably be a concentric or balanced line.
  • the heterodyning current of 41.8 megacycles this is initially derived from a current supplied over a line II from an oscillator at the other location at 10.45 megaeycles through an amplifier l5, through a doubler it which raises it to 20.9 megacycles and a second doubler H which supplies 41.8 megacycles current to the amplifier l8.
  • l9 represents the end of the line carrying the 1000 k. c. intermediate frequency current, 20 a band pass fliter, 2
  • a local oscillator 23, preferably Xtal controlled, excites an amplifier 24 which supplies the converter 22.
  • the output of the converter is supplied through a band pass filter 25 having a pass band of 1500-1700 k. c. to an amplifier 26 whose output is fed into a balanced converter 21.
  • the heterodyning current for this converter is obtained from a 10.45 megacycle oscillator 28 through an amplifier 29.
  • 34 represents a band pass filter of 200 k. 0. width and a midfrequency point of 12.05 megacycles.
  • 35 represents an amplifier for this frequency, and 36 a second converter.
  • This converter is supplied with a heterodyning current of 31.35 megacycles derived from the 10.45 megacycles source and raised to the 31.35 megacycles value by the tripler 32.
  • 33 represents an amplifier for this frequency.
  • 31 represents an amplifier for 43.4 megacycle output current of the converter 35, 38 the power amplifier, and 39 the antenna.
  • an amplifier 30 is excited by current derived therefrom, and supplied to a line 3
  • the method of relaying frequency modulated signals ,on slightly different wave lengths which consists in receiving the wave of the first length, heterodyning the received wave down to a low intermediate frequencyby a heterodyning current which is a higher harmonic of a given low frequency oscillator, converting the low intermediate frequency to another frequency whose difference therefrom is equal to the frequency difference between the received and transmitted waves, raising the last-named frequency to the frequency to be transmitted by adding to it successively the frequency of the fundamental and an appropriate harmonic of said given low frequency heterodyning oscillator and transmitting currents of the resulting frequency.
  • the method of relaying frequency modulated signals on slightly different wave lengths which consists in receiving the wave of the first length, heterodyning the received wave down to a low intermediate frequency by a heterodyning current which is a harmonic of a given low frequency oscillator, amplifying the currents of low intermediate frequency, converting the amplified currents of low intermediate frequency to an other frequency whose difference therefrom is equal to the frequency difference between the received and transmitted waves, raising the lastnamed frequency to the frequency to be transmitted by adding to said last named frequency energy controlled by said given low frequency heterodyning oscillator and transmitting currents of the resulting frequency.
  • the method of relaying frequency modulated signals on slightly different wave lengths which consists in receiving the wave of the first length, heterodyning the received wave down to a low intermediate frequency by a heterodyning current which is a harmonic of a low frequency oscillator generating a substantially constant frequency, amplifying the currents of low intermediate frequency, converting the amplified currents of low intermediate frequency to a second low frequency whose difference therefrom is equal to the frequency difference between the received and transmitted waves, filtering and amplifying the currents of the second low frequency, converting the amplified currents of the second low frequency to the frequency to be transmitted by adding to said last named frequency energy controlled by said low frequency heterodyning oscillator and transmitting currents of the resulting frequency.
  • Means for relaying frequency modulated signais on slightly different wave lengths comprising, in combination, a converting device, means for energizing said converting device by the received wave of the first length, a first low frequency oscillator, frequency multiplying means coupled to said oscillator for generating a harmonic of the oscillator frequency, means conmeeting said frequency multiplying means to the converting device whereby currents are generated therein of a low intermediate frequency, a second converting device having its input connected to the output of the first converting device, a second low frequency oscillator connected to the input of the second converting device and arranged to generate a frequency equal to the frequency difference between the received and transmitted waves, means coupled to the output of the second converting device for increasing the frequency of the currents therein to the frequency to be transmitted, said coupled means comprising means for generating a harmonic frequency of the first low frequency oscillator, and means for transmitting currents of the resulting frequency.
  • Means for relaying frequency modulated signals on slightly different wave lengths comprising, in combination, a converting device, means for energizing said converting device by the received wave of the first length, a first oscillator. frequency multiplying means coupled to said oscillator for generating a harmonic of the oscillator frequency, means connecting said frequency multiplying means to the converting device whereby currents are generated therein of a low intermediate frequency, a second converting device having its input connected to the output of the first converting device, a low frequency oscillator connected to the input of the second converting device and arranged to generate a frequency equal to the frequency difference between the received and transmitted waves, a third converting device connected to the second conlength, generating a fundamental frequency and a higher harmonic of such fundamental frequency, heterodyning the received wave down to a first intermediate frequency by a heterodyningcurrent of said higher harmonic frequency, generating a radio frequencywhich is equal to the frequency diflerence between the received and transmitted waves, increasing said first intermediate frequency to a substantially higher
  • the method-of relaying frequency modulated radio signals on slightly different wave lengths which consists in receiving the wave of the first'length, heterodyning the received wave down to a low intermediate frequency by a heterodyning'current which is a harmonic of'a given lowfrequency oscillator, ,raising the lowintermediate frequency to the frequency to be transmitted by adding thereto a plurality of frequencies, one frequency of said plurality being ,equal to thedifference between the frequencies of the received and transmitted waves and the remaining frequencies of said plurality being controlled by the said low frequency oscillator.
  • Means for relaying frequency modulated radio signals on slightly different wave lengths comprising, in combination, means for receiv ing the wave on the first length, a lowfrequency oscillator, means for generating harmonic fretermediate frequency by adding thereto said fundamental and said radio frequencies, increasing said higher intermediate frequency to the frequency to be transmitted by adding thereto at least a higher harmonic of said fundamental frequen y, and transmitting currents of the resulting frequency.
  • a system for retransmitting a frequency modulated wave at a frequency which difiers slightly from the frequency at which it comes in comprising means for heterodyning the incoming frequency down to a desired low intermediate frequency, means for heterodyning the low'intermediate frequency current upto the desired frequency of retransmission, a

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Radio Relay Systems (AREA)
US313496A 1940-01-12 1940-01-12 Means and method for relaying frequency modulated signals Expired - Lifetime US2264608A (en)

Priority Applications (10)

Application Number Priority Date Filing Date Title
BE472677D BE472677A (US06653308-20031125-C00199.png) 1940-01-12
NL67372D NL67372C (US06653308-20031125-C00199.png) 1940-01-12
BE473156D BE473156A (US06653308-20031125-C00199.png) 1940-01-12
NL68041D NL68041C (US06653308-20031125-C00199.png) 1940-01-12
US313496A US2264608A (en) 1940-01-12 1940-01-12 Means and method for relaying frequency modulated signals
US358207A US2275486A (en) 1940-01-12 1940-09-25 Means and method for relaying frequency modulated signals
GB994/47A GB623219A (en) 1940-01-12 1947-01-11 Means and method for relaying frequency modulated signals
GB999/47A GB623221A (en) 1940-01-12 1947-01-11 Means and method for relaying frequency modulated signals
FR946096D FR946096A (fr) 1940-01-12 1947-05-05 Procédé et dispositif servant à relayer les signaux modulés en fréquence
FR946307D FR946307A (fr) 1940-01-12 1947-05-07 Méthode et moyens de réception d'une onde de fréquence modulée

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US313496A US2264608A (en) 1940-01-12 1940-01-12 Means and method for relaying frequency modulated signals

Publications (1)

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US2264608A true US2264608A (en) 1941-12-02

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US313496A Expired - Lifetime US2264608A (en) 1940-01-12 1940-01-12 Means and method for relaying frequency modulated signals

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US (1) US2264608A (US06653308-20031125-C00199.png)
BE (2) BE473156A (US06653308-20031125-C00199.png)
FR (2) FR946096A (US06653308-20031125-C00199.png)
GB (2) GB623219A (US06653308-20031125-C00199.png)
NL (2) NL68041C (US06653308-20031125-C00199.png)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2476141A (en) * 1946-08-21 1949-07-12 Rca Corp Frequency shift keyer
US2501368A (en) * 1944-03-25 1950-03-21 Emi Ltd Frequency stabilized relay for frequency-modulated oscillations
US2514425A (en) * 1945-02-06 1950-07-11 Rca Corp Radio relaying
US2539474A (en) * 1945-05-23 1951-01-30 Int Standard Electric Corp Transmission over cables by means of frequency modulation

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2501368A (en) * 1944-03-25 1950-03-21 Emi Ltd Frequency stabilized relay for frequency-modulated oscillations
US2514425A (en) * 1945-02-06 1950-07-11 Rca Corp Radio relaying
US2539474A (en) * 1945-05-23 1951-01-30 Int Standard Electric Corp Transmission over cables by means of frequency modulation
US2476141A (en) * 1946-08-21 1949-07-12 Rca Corp Frequency shift keyer

Also Published As

Publication number Publication date
NL68041C (US06653308-20031125-C00199.png)
NL67372C (US06653308-20031125-C00199.png)
FR946096A (fr) 1949-05-23
GB623219A (en) 1949-05-13
FR946307A (fr) 1949-05-31
GB623221A (en) 1949-05-13
BE472677A (US06653308-20031125-C00199.png)
BE473156A (US06653308-20031125-C00199.png)

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