US2473318A - Phase or frequency modulation - Google Patents

Phase or frequency modulation Download PDF

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Publication number
US2473318A
US2473318A US767117A US76711747A US2473318A US 2473318 A US2473318 A US 2473318A US 767117 A US767117 A US 767117A US 76711747 A US76711747 A US 76711747A US 2473318 A US2473318 A US 2473318A
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United States
Prior art keywords
frequency
oscillations
heterodyning
phase
modulated
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Expired - Lifetime
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US767117A
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English (en)
Inventor
Weighton Donald
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Pye Electronic Products Ltd
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Pye Ltd
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Publication date
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03C—MODULATION
    • H03C3/00—Angle modulation

Definitions

  • the present invention relates to a method of phase or frequency modulation.
  • the method of phase or frequency modulation consists in heterodyning master oscillator oscillations with frequency modulated oscillations, and then heterodyning the beat oscillations (comprising either the summation ordifference components) with the frequency modulated oscillations, and in submitting the frequency modulated oscillations in one .of the channels leading to the second heterodyning stage to the action of a phase shifting device or network.
  • the method consists in heterodyning master oscillator oscillations with frequency modulated oscillations, and then heterodyning the beat oscillations with the frequency modulated oscillations, the frequency modulated oscillations submitted to the first heterodyning, or the beat oscillations or frequency modulated oscillations submitted to the second heterodyning also being submitted to the action of a phase shifting device or network.
  • the arrangement for carrying out the method consists of a master oscillator A, which may be crystal controlled, and
  • I an unstabilised oscillator 13 which is frequency modulated by a capacitor valve or similar device.
  • the outputs from both oscillators are fed into a first frequency changer C, which may comprise a valve, and the summation components in the output are selected.
  • the selected signal is thus frequency modulated about a mean equal to the sum of the frequencies of the master and modulated oscillators.
  • This signal is applied to a phase shifting deviceor network D which may consist of a balanced transmission line or, more conveniently, of an artificial network representing such a line. Thereby the voltage appearing across the termination of the network D undergoes a phase shift which is a linear function of the frequency whilst the amplitude is independent of the frequency.
  • the signal is, therefore, now phase modulated at the desired modulation frequency, in addition to thefrequency modulation derived from the modulated oscillator B.
  • This frequency modulation may be removed by heterodyning the signal again with the output from the modulated'oscillator B by means of a second frequency changer 'E, and selecting the difference component.
  • phase shift introduced is determined by the frequency excursions of the modulated oscillator B and the characteristic of the phase shifting network D, so thatby making this a sufficiently long balanced line, the phase shift may be increased to any desired magnitude.
  • the output from the second frequency changer E may be fed to one or more frequency multi pliers F.
  • the arrangement may be used as a frequency modulator by the introduction of a suitable distorting network in the modulationcircuit prior to the modulated oscillator B.
  • the arrangement may be modified by introducing the phase shifting network D between the frequency modulated oscillator B and the first frequency changer C, or alternatively, between the frequency modulated oscillator B and the second frequency changer E.
  • the chief advantages of the method according to this invention are its inherent freedom from amplitude modulation and the absence of any theoretical limit to the modulation index. This may be increased to any desired magnitude thus avoiding the necessity for a large number of free quency multiplying stages in the design of a transmitter.
  • Method of wave modulation which comprises heterodyning master oscillations of substantially constant frequency with frequency modulated oscillations, heterodyning the resultant beat oscillations with the frequency modulated oscillations, applying a phase shift which is a linear function of frequency to the frequency modulated oscillations prior to the second-mentioned heterodyning. and selecting a desired product of said second heterodyning.
  • Method of phase modulation which comprises heterodyning master oscillations of substantially constant frequency with frequency modulated oscillations, heterodyning the. resultant beat oscillations with the frequency moduconstant frequency with lated oscillations, applying a phase shift which; a linear function of frequency tothe frequency modulated oscillations prior to the second-memtioned heterodyning, and selecting a product of said second heterodyning having the original master oscillation in accordance with of the original frequency modulated oscillations. 4.
  • Method of wave modulation which comprises frequency modulated in phase I heterodyning master-oscillations of substantially constant frequency with frequency modulated os cillations, applying a phase shift which is a linear function of frequency to the resultant beat oscillations, heterodyning the beat oscillations with the frequency modulated oscillations, and selecting a desired productof the second-mentioned heterodyning.
  • Method of wave modulation which comprises heterodyning master oscillations of substantially constant frequency with frequency modulated oscillations, selecting the summation beat oscilby said heterodyning, applying lations produced the modulation in frequency a phase shift which is a linear function of frequency to said beat oscillations, heterodyning the product of said phase shift with said 'frequency modulated oscillations, and selecting the difference component from the product of the second-mentioned heterodyning,
  • Method of wave modulation which comprises applying a phase delay which is a linear function of frequency to frequency modulated oscillations, heterodyning master oscillations of substantially the delayed frequency modulated oscillations, heterodyning the resultant beat oscillations with undelayed frequency 1 modulated oscillations, and selecting a desired product of the second-mentioned heterodyning.
  • heterodyning master oscillations of substantially constant frequency with the delayed frequency modulated 7 beat oscillations from the product of said heterodyning heterodyning the selected beat oscillations withundelayed frequency modulated oscillations, and selecting the difference component of the product of the second-mentioned heterodyning.
  • Method of wave modulation which comprises heterodyning master oscillations of substantially constant frequency with frequency modulated oscillations, heterodyning the resultant beat oscillations with frequency modulated oscillations delayed in phase as a linear function of frequency, and selecting a desired product of the secondmentioned heterodyning.
  • Method of wave modulation which comprises heterodyning master oscillations of substantially constant frequency with frequency modulated oscillations, selecting the summation beat oscillations from the product of said heterodyning, heterodyning the summation beat oscillations with frequency modulated oscillations altered in phase as a linear function of frequency, and selecting the difference component from the product of the second-mentioned heterodyning.

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  • Stabilization Of Oscillater, Synchronisation, Frequency Synthesizers (AREA)
  • Oscillators With Electromechanical Resonators (AREA)
US767117A 1939-12-22 1947-08-07 Phase or frequency modulation Expired - Lifetime US2473318A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB32760/39A GB534955A (en) 1939-12-22 1939-12-22 Improvements in or relating to phase or frequency modulation

Publications (1)

Publication Number Publication Date
US2473318A true US2473318A (en) 1949-06-14

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US767117A Expired - Lifetime US2473318A (en) 1939-12-22 1947-08-07 Phase or frequency modulation

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US (1) US2473318A (fr)
FR (1) FR932587A (fr)
GB (1) GB534955A (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2568132A (en) * 1948-05-21 1951-09-18 Tesla Nat Corp Phase modulated signaling system and method
US2677806A (en) * 1949-03-29 1954-05-04 Radio Electr Soc Fr Phase-modulated piezoelectric crystal oscillator system
US3017583A (en) * 1958-06-06 1962-01-16 Raytheon Co Large angle rf phase shifters
US3263019A (en) * 1964-03-18 1966-07-26 Hurvitz Hyman Randomization of phases and frequencies of musical spectra
WO2022221076A1 (fr) * 2021-04-15 2022-10-20 The Regents Of The University Of California Marquage de spin artériel ultra-rapide avec marquage à sélectivité de vitesse à bande étroite (nb-vs)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB707027A (en) * 1952-03-24 1954-04-07 Gen Electric Co Ltd Improvements in or relating to arrangements for supplying phase modulated electric oscillations

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1964522A (en) * 1929-06-13 1934-06-26 Harold M Lewis Phase control system
US2335934A (en) * 1942-06-10 1943-12-07 Rca Corp Phase modulation

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1964522A (en) * 1929-06-13 1934-06-26 Harold M Lewis Phase control system
US2335934A (en) * 1942-06-10 1943-12-07 Rca Corp Phase modulation

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2568132A (en) * 1948-05-21 1951-09-18 Tesla Nat Corp Phase modulated signaling system and method
US2677806A (en) * 1949-03-29 1954-05-04 Radio Electr Soc Fr Phase-modulated piezoelectric crystal oscillator system
US3017583A (en) * 1958-06-06 1962-01-16 Raytheon Co Large angle rf phase shifters
US3263019A (en) * 1964-03-18 1966-07-26 Hurvitz Hyman Randomization of phases and frequencies of musical spectra
WO2022221076A1 (fr) * 2021-04-15 2022-10-20 The Regents Of The University Of California Marquage de spin artériel ultra-rapide avec marquage à sélectivité de vitesse à bande étroite (nb-vs)

Also Published As

Publication number Publication date
FR932587A (fr) 1948-03-25
GB534955A (en) 1941-03-24

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