US2171678A - Superheterodyne receiver - Google Patents

Superheterodyne receiver Download PDF

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Publication number
US2171678A
US2171678A US188842A US18884238A US2171678A US 2171678 A US2171678 A US 2171678A US 188842 A US188842 A US 188842A US 18884238 A US18884238 A US 18884238A US 2171678 A US2171678 A US 2171678A
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US
United States
Prior art keywords
frequency
oscillation
intermediate frequency
auxiliary
oscillations
Prior art date
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
Application number
US188842A
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English (en)
Inventor
Weyers Theodorus Josephus
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.)
Koninklijke Philips NV
Original Assignee
Philips Gloeilampenfabrieken NV
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Philips Gloeilampenfabrieken NV filed Critical Philips Gloeilampenfabrieken NV
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Publication of US2171678A publication Critical patent/US2171678A/en
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Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/06—Receivers
    • H04B1/16—Circuits
    • H04B1/30—Circuits for homodyne or synchrodyne receivers

Definitions

  • the present invention relates to homodyne circuits used in receivers operating on the superheterodyne principle.
  • the said isochronism is obtained by the generator which produces the auxiliary oscillation being controlled in dependence on the difference between the received carrier oscillation and the auxiliary oscillation by the two oscillations to be rectified and the interference oscillations thus obtained influencing the local generator.
  • 0 1 schematically shows a receiving system embodying the present invention
  • Fig. 2 shows a characteristic of the network IU of Fig. 1.
  • Fig. 1 shows a receiver of the superheterodyne type to which the above-mentioned principles are applied.
  • the receiving channel contains a highfrequency amplifier I capable of being tuned to the signals to be received, a first detector 2 with a local oscillator 3, an intermediate frequency amplifier 4, a second detector 5, a low-frequency amplifier 6; and, in addition, an auxiliary 05- 5 cillator l which is coupled to the second detector 5 and which serves to generate the auxiliary oscillation having the same frequency and phase as the intermediate frequency carrier oscillation of the signal received by the amplifier 4. Due to fading, or to partial suppression of the carrier Wave of the signal, which suppression has occurred in the transmitter, the percentage modulation of the signal supplied to the first detector 2 is momentarily, or constantly, higher than 100%.
  • the intermediate frequency carrier wave is separated by a filter 8, and by means I of a frequency multiplier 9 with a subsequent oscillatory circuit l0, an even harmonic, for example the second, is derived from the intermediate frequency carrier wave and supplied to a rectifier II.
  • This harmonic is brought in the rectifier H to interference with a corresponding even harmonic of the oscillation produced by the auxiliary oscillator I, by the latter oscillation being supplied to a frequency multiplier l2 and the desired harmonic being then selected by means of an oscillatory circuit l3 tuned to it.
  • a beat oscillation is thus set up in the output circuit of the rectifier H, and is used for controlling in well-known manner the frequency of the auxiliary oscillator (for example, by altering the inductance or capacity of the oscillatory circuit of the auxiliary oscillator or by altering the electrode voltages of the discharge tube serving for the generation of the auxiliary oscillation) in such manner that the auxiliary oscillation set up is fed to the second detector 5 in isochronism with the intermediate frequency carrier oscillation.
  • Fig. 2 shows the phase constant of the most simple kind of high-pass filters indicated by the dotted curve. Below the cut-off frequency T1 the phase constant has the value 2 and above the same, in the transmitting range of the filter, this value approaches to zero With increasing frequency.
  • the path of this curve shows that when a high-pass filter is substituted for the oscillatory circuits l0 and 13 respectively of Fig.
  • the non-pass range there may be in the non-pass range two attenuation peaks occurring at frequencies slightly higher than, and slightly below, the frequency of the intermediate frequency carrier oscillation so that, also, in the case of variations of this frequency a high attenuationof the intermediate frequency carrier oscillation always occurs in the output circuit of the frequency multiplier.
  • highpass filters use may be made of band-pass filters having one or more attenuation peaks in the nonpass range.
  • a method of homodyne reception which includes heterodyning signals with local oscillations to produce signals of intermediate frequency, producing local oscillations of said intermediate frequency, combining the intermediate frequency signals with the intermediate frequency oscillations, deriving higher even harmonics from each of said intermediate frequency signals and intermediate frequency oscillations, combining the derived harmonics to produce energy of a beat frequency, rectifying said energy of beat frequency, and controlling the phase and frequency of said intermediate frequency oscillations with the rectified energy.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Superheterodyne Receivers (AREA)
  • Noise Elimination (AREA)
US188842A 1937-03-30 1938-02-05 Superheterodyne receiver Expired - Lifetime US2171678A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE491437X 1937-03-30

Publications (1)

Publication Number Publication Date
US2171678A true US2171678A (en) 1939-09-05

Family

ID=6544280

Family Applications (1)

Application Number Title Priority Date Filing Date
US188842A Expired - Lifetime US2171678A (en) 1937-03-30 1938-02-05 Superheterodyne receiver

Country Status (4)

Country Link
US (1) US2171678A (enrdf_load_stackoverflow)
BE (1) BE427232A (enrdf_load_stackoverflow)
FR (1) FR835862A (enrdf_load_stackoverflow)
GB (1) GB491437A (enrdf_load_stackoverflow)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2738380A (en) * 1950-02-07 1956-03-13 Murray G Crosby Exalted-carrier television receiver
US2828414A (en) * 1953-01-21 1958-03-25 Bell Telephone Labor Inc Demodulation of vestigial sideband signals
US2976409A (en) * 1956-10-19 1961-03-21 Hazeltine Research Inc Detector circuit
US3510776A (en) * 1966-02-16 1970-05-05 Motorola Inc Fm tone signal receiving circuit

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2738380A (en) * 1950-02-07 1956-03-13 Murray G Crosby Exalted-carrier television receiver
US2828414A (en) * 1953-01-21 1958-03-25 Bell Telephone Labor Inc Demodulation of vestigial sideband signals
US2976409A (en) * 1956-10-19 1961-03-21 Hazeltine Research Inc Detector circuit
US3510776A (en) * 1966-02-16 1970-05-05 Motorola Inc Fm tone signal receiving circuit

Also Published As

Publication number Publication date
BE427232A (enrdf_load_stackoverflow)
FR835862A (fr) 1939-01-05
GB491437A (en) 1938-09-01

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