US2290159A - Frequency modulation system - Google Patents

Frequency modulation system Download PDF

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Publication number
US2290159A
US2290159A US313497A US31349740A US2290159A US 2290159 A US2290159 A US 2290159A US 313497 A US313497 A US 313497A US 31349740 A US31349740 A US 31349740A US 2290159 A US2290159 A US 2290159A
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United States
Prior art keywords
frequency
multiplying
path
current
currents
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Expired - Lifetime
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US313497A
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English (en)
Inventor
Edwin H Armstrong
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Individual
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Individual
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Priority to NL67371D priority Critical patent/NL67371C/xx
Priority to BE473157D priority patent/BE473157A/xx
First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=23215936&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=US2290159(A) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by Individual filed Critical Individual
Priority to US313497A priority patent/US2290159A/en
Application granted granted Critical
Publication of US2290159A publication Critical patent/US2290159A/en
Priority to GB995/47A priority patent/GB621228A/en
Priority to FR946097D priority patent/FR946097A/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03C—MODULATION
    • H03C3/00—Angle modulation
    • H03C3/02—Details
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03C—MODULATION
    • H03C3/00—Angle modulation
    • H03C3/02—Details
    • H03C3/09—Modifications of modulator for regulating the mean frequency

Definitions

  • This invention has for its object the elimination of disturbances-resulting from frequency changes in radio transmitting systems, particularly of the type described in my U. S. Patent #1,941,068 for producing Wide band frequency modulated signals.
  • the frequency modulated signal is produced.
  • the single figure illustrates the general arrangement of theapparatus which will be understood from the following desciiption.
  • An arrangement now in common use for producing a frequency modulated current of 100 k. c. deviation at approximately 40 megacycles consists of a crystal controlled oscillator having a frequency of 200 k. c., a phase shifting Vdevice therefor, and a series of frequency multipliers.
  • the frequency multiplication is usually accomplished in two steps, the first stage being up to some convenient multiple of the 200 k. c. from which it is heterodyned down to some relatively lower frequency that is a sub-multiple of the frequency to be radiated, and this in turn is multiplied up to the final Value. It has been common practice to multiply up to a frequency of 12.8 megacycles, which is then heterodyned down to some frequency in the vincinity of 900 k. c. This frequency is then in turn multiplied up to the vicinity of 40 megacycles. In a specific case for producing a 42 ⁇ megacycle wave a heterodyning current of l11.925 megacycles would be combined to produce a difference frequency of 875 k. c. which would them be multiplied 48 times to produce a 42000 kilocycle current. The total frequency multiplication amounts to 3072 times.
  • the heterodyning current would be produced by a second crystal oscillator. Any changes in the frequency of the initial oscillator'would produce a change in the diiierence frequency of the beat with the frequency of the second oscillator, the numerical change being increased some 64 fold due to the multiplication of the doublers E-I I.
  • the present invention proposes to eliminate this change by deriving the heterodyning frequency from the initial oscillator and subjecting it to the same number of multiplications as the current supplied to the converter I9 through th main path has had. This is accomplished in e following way. A part of the output of the oscillator I at 200 k. c.
  • a frequency modulation system comprising, in combination, a frequency converting device, means for generating electrical oscillations whose frequency is subject to minor variations, a rst circuit path connecting said generating means to said converting device and including means for multiplying the frequency of the oscillations generated, a modulating device connected to said circuit path for modulating the frequency of the currents therein in accordance with signals; a second circuit path connecting said generating means to said converting device and including means for multiplying the frequency of the currents generated by said generating means, said second circuit path also including means for generating electrical currents of substantially constant frequency and means for combining the currents of multiplied frequency in the second circuit path with said currents of constant frequency, and means connected to the output of said frequency converting device for transmitting the frequency modulated signal currents.
  • a frequency modulation system comprising, in combination, means for generating electrical oscillations, a first frequency converting device, a circuit connecting said converting device to said oscillation generator and comprising means for multiplying the frequency of the oscillations generated, a modulating device connected to said circuit for modulating the frequency of the currents therein, a second circuit connecting said converting device to said oscillation generator and comprising the series connection of a second frequency converting device and a device for multiplying the frequency of the oscillations generated by said oscillation generator, an oscillation generator connected to said second frequency converting device and arranged to generate current of a-frequency which is a submultiple of -the frequency to be transmitted, a frequency multiplying device connected to the output of said -rst frequency converting device and arranged to multiply the converted frequency up to that of the transmission frequency, and means for transmitting vcurrents of the transmission frequency,

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  • Magnetic Resonance Imaging Apparatus (AREA)
  • Stabilization Of Oscillater, Synchronisation, Frequency Synthesizers (AREA)
  • Amplitude Modulation (AREA)
  • Transmitters (AREA)
US313497A 1940-01-12 1940-01-12 Frequency modulation system Expired - Lifetime US2290159A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
NL67371D NL67371C (en(2012)) 1940-01-12
BE473157D BE473157A (en(2012)) 1940-01-12
US313497A US2290159A (en) 1940-01-12 1940-01-12 Frequency modulation system
GB995/47A GB621228A (en) 1940-01-12 1947-01-11 Frequency modulation systems
FR946097D FR946097A (fr) 1940-01-12 1947-05-05 Perfectionnement aux procédés de modulation en fréquence

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US313497A US2290159A (en) 1940-01-12 1940-01-12 Frequency modulation system

Publications (1)

Publication Number Publication Date
US2290159A true US2290159A (en) 1942-07-21

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ID=23215936

Family Applications (1)

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US313497A Expired - Lifetime US2290159A (en) 1940-01-12 1940-01-12 Frequency modulation system

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US (1) US2290159A (en(2012))
BE (1) BE473157A (en(2012))
FR (1) FR946097A (en(2012))
GB (1) GB621228A (en(2012))
NL (1) NL67371C (en(2012))

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2470892A (en) * 1942-11-25 1949-05-24 Hartford Nat Bank & Trust Co Stabilized frequency modulator
US2572958A (en) * 1947-08-19 1951-10-30 Tesla Nat Corp Method for increasing the deviation of frequency modulated oscillations
US2602159A (en) * 1946-06-14 1952-07-01 Collins Radio Co Frequency modulation generator
US2773125A (en) * 1953-10-12 1956-12-04 Esther M Armstrong Multiplex frequency modulation transmitter

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2470892A (en) * 1942-11-25 1949-05-24 Hartford Nat Bank & Trust Co Stabilized frequency modulator
US2602159A (en) * 1946-06-14 1952-07-01 Collins Radio Co Frequency modulation generator
US2572958A (en) * 1947-08-19 1951-10-30 Tesla Nat Corp Method for increasing the deviation of frequency modulated oscillations
US2773125A (en) * 1953-10-12 1956-12-04 Esther M Armstrong Multiplex frequency modulation transmitter

Also Published As

Publication number Publication date
GB621228A (en) 1949-04-06
NL67371C (en(2012))
BE473157A (en(2012))
FR946097A (fr) 1949-05-23

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