US2208142A - Amplitude and frequency modulation receiver - Google Patents

Amplitude and frequency modulation receiver Download PDF

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Publication number
US2208142A
US2208142A US253730A US25373039A US2208142A US 2208142 A US2208142 A US 2208142A US 253730 A US253730 A US 253730A US 25373039 A US25373039 A US 25373039A US 2208142 A US2208142 A US 2208142A
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United States
Prior art keywords
frequency
amplitude
carrier
oscillation
oscillations
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US253730A
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English (en)
Inventor
Tuxen Otto
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Telefunken AG
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Telefunken AG
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Publication date
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Publication of US2208142A publication Critical patent/US2208142A/en
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
    • H03D5/00—Circuits for demodulating amplitude-modulated or angle-modulated oscillations at will

Definitions

  • a distortion free demodulation of oscillations whether modulated in amplitude or frequency can be obtained without any switching means in that the received oscillation containing the carrier and the side bands is multiplicatively mixed with an oscillation having the same frequency as the arriving carrier and a phase displacement of approximately 45 relative to said carrier.
  • the oscillation received by the antenna A and amplified in the high frequency amplifier H is mixed in the mixer stage M with the oscillation of the local oscillator O.
  • the constant intermediate frequency obtained in the output is amplified by the intermediate frequency amplifier Z.
  • a part of the amplified oscillation is used across the vernier'tuning means S for the automatic frequency control of the oscillator thus serving for maintaining accurately constant the intermediate frequency.
  • Another part of the amplified intermediate frequency is passed across the filter F (quartz filter for instance) which filters out of the arriving band the intermediate frequency carrier without substantially altering its phase.
  • the filtered carrier eventually amplified separately receives in the phase shifting means P a phase displacement of 45 whereafter it is mixed multiplicatively with the unfiltered intermediate frequency in the multiplicative demodulator D.
  • the demodulator may consist of a. multi-grid tube having two control grids separated by a screen grid. There is applied to the one control grid the filtered-out carrier displaced in phase by 45 and to the other grid the total intermediate frequency oscillation including the side bands. The produced audio frequency is applied to the loudspeaker L across the audio frequency amplifier N. l
  • Inplace of the filter F the filtering of the carrier may be done by means of an oscillator which oscillates in the intermediate frequency and is actuated by the arriving carrier.
  • a side band may also be displaced relative to the carrier.
  • the receiver is also suited for the reception combination.
  • a system for demodulating wave energy "modulated in frequency or in amplitude and comprising a carrier and sidebands means for pro- 7 'ducing oscillations of a frequency equal to the frequency of said carrier and of a substantially fixed phase having a phase which differs from the carrier phase by a phase displacement which is nearer to an odd multiple of 45 than an even multiple of 45, and means for combining and demodulating said oscillations and sidebands.
  • means for receiving Wave energy comprising a carrier and side-bands resulting from amplitude or frequency modulation means connected with said first named means and excited by the carrier only of said received wave energy for producing oscillations synchronized as to frequency with said carrier oscillations, means connected with said second named means for adjusting the phase of said produced oscillations to a phase which differs from the carrier phase by a phase displacement which is nearer to an odd multiple of 45 than an even multiple of 45, and means connected with said last named means and with said first named means for combining said oscillations with received carrier and side-band energy and demodulating the energy resulting from said OTTO TiiXEN.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Superheterodyne Receivers (AREA)
  • Noise Elimination (AREA)
US253730A 1938-02-21 1939-01-31 Amplitude and frequency modulation receiver Expired - Lifetime US2208142A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE507896X 1938-02-21

Publications (1)

Publication Number Publication Date
US2208142A true US2208142A (en) 1940-07-16

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ID=6546860

Family Applications (1)

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US253730A Expired - Lifetime US2208142A (en) 1938-02-21 1939-01-31 Amplitude and frequency modulation receiver

Country Status (3)

Country Link
US (1) US2208142A (fr)
FR (1) FR850517A (fr)
GB (1) GB507896A (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2562703A (en) * 1947-12-26 1951-07-31 Gen Electric Multiple channel radio receiving system

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2562703A (en) * 1947-12-26 1951-07-31 Gen Electric Multiple channel radio receiving system

Also Published As

Publication number Publication date
FR850517A (fr) 1939-12-19
GB507896A (en) 1939-06-22

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