US2725468A - Superheterodyne receiving circuit - Google Patents

Superheterodyne receiving circuit Download PDF

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Publication number
US2725468A
US2725468A US296215A US29621552A US2725468A US 2725468 A US2725468 A US 2725468A US 296215 A US296215 A US 296215A US 29621552 A US29621552 A US 29621552A US 2725468 A US2725468 A US 2725468A
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United States
Prior art keywords
circuit
oscillator
grid
frequency
anode
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Expired - Lifetime
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US296215A
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English (en)
Inventor
Dammers Bernhardus Gerhardus
Uitjens Abraham Gert Wilhelmus
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Hartford National Bank and Trust Co
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Hartford National Bank and Trust Co
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B15/00—Suppression or limitation of noise or interference
    • H04B15/02—Reducing interference from electric apparatus by means located at or near the interfering apparatus
    • H04B15/04—Reducing interference from electric apparatus by means located at or near the interfering apparatus the interference being caused by substantially sinusoidal oscillations, e.g. in a receiver or in a tape-recorder
    • H04B15/06—Reducing interference from electric apparatus by means located at or near the interfering apparatus the interference being caused by substantially sinusoidal oscillations, e.g. in a receiver or in a tape-recorder by local oscillators of receivers
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
    • H03D7/00—Transference of modulation from one carrier to another, e.g. frequency-changing
    • H03D7/06—Transference of modulation from one carrier to another, e.g. frequency-changing by means of discharge tubes having more than two electrodes
    • H03D7/08—Transference of modulation from one carrier to another, e.g. frequency-changing by means of discharge tubes having more than two electrodes the signals to be mixed being applied between the same two electrodes

Definitions

  • the invention relates to superheterodyne receiving circuits of the kind in which use is made of a mixing tube acting as an oscillator by reason of an inductive coupling between an inductor of a tuned local-oscillator circuit in the circuit of a current-conveying electrode of the mixer and a feedback coil included in the circuit of a controlgrid of the tube, the intermediate-frequency oscillations being taken from an impedance included in the anode circuit of the mixer. If the incoming signal oscillations and the local oscillations produced by the mixer itself occur on the same control-grid the mixer acts as an additive mixer.
  • Additive mixing circuits in general and self-oscillating additive mixers in particular have a limitation in that it is difiicult to prevent undue coupling between the circuit tuned to the local oscillations and the aerial circuit, so that there is always a certain radiation of the local oscillations from the aerial.
  • a screen-grid tube is employed as a mixer and the screen-grid has a certain voltage of the frequency of the'local-oscillations, as is the case with several known arrangements, there is a further limitation in that the conversion conductance is compara tively low. This is due to the fact that the voltages of local-oscillator frequency occurring at the anode and at the screen-grid are in phase opposition to the local-oscillator voltage at the control grid, so that dc-mixing occurs.
  • the invention has for its object to mitigate these disadvantages.
  • a superheterodyne receiver in which use is made of a mixing tube acting as an oscillator by reason of an inductive coupling between an inductor of a tuned local-oscillator circuit in the circuit of a current-conveying electrode of the mixer, and a feedback coil included in the circuit of a control-grid of the tube, the intermediate-frequency oscillations being taken from an impedance included in the anode circuit of the tube, is characterized in that the incoming signal oscillations are supplied to a tapping point, for example the centre, of the feedback coil and the said current-conveying electrode is connected to a tapping of the inductor of the circuit tuned to the local-oscillator frequency.
  • the screen-grid is preferably connected, for highfrequency currents, to the second-mentioned tapping.
  • a very advantageous circuit-arrangement is that in which both the screen-grid and the anode operate as oscillator electrodes and are connected to the said tapping.
  • Fig. 1 shows a first embodiment
  • Fig. 2 shows a slightly modified embodiment.
  • Fig. 1, 1 designates an aerial circuit which is inductively coupled with an input circuit 2, tunable to the frequency to be received.
  • the circuit 2 is connected to earth at one end and is connected at the other end through the parallel combination of a resistor 3 and a capacitor 4 to the centre of a coil 5.
  • One end of the coil 5 is directly connected to the first control-grid 9 of a mixer 6 and the other end is connected to earth through the parallel combination of a resistor 13 and a capacitor 14.
  • the elements 3 and 4 operate as a grid leak and a grid capacitor respectively for the tube 6 which acts as an additive mixer.
  • the coil 5 is inductively coupled with the coil 17 of a circuit 17, 18, 19 tuned to the local-oscillator frequency and acts as a feedback coil.
  • capacitor 18 is a tuning capacitor gauged to the capacitor of circuit 2 whilst the capacitor 19 which is fixed or semi-variable, is a padding element to obtain a substantially constant frequency difierence between the oscillator circuit and the input circuit.
  • the two halves of the coil 5 constitute a bridge-circult in conjunction with the parallel combination of the resistor 13 and the capacitor 14 and with the input impedance of the tube 6, to which the said parallel combination is equivalent. If the bridge is balanced, no oscillations of the local-oscillator frequency should occur across the circuit 2 and thus the aerial circuit.
  • the voltage of oscillator frequency at the said positive electrode of the tube is lower, sfothat de-rnixing is reduced, whilst at the same time the symmetry of the inductor 17 with respect to the feedback coil 5 is improved. 4
  • the anode 8 of the rnixer 6 is cor'lriec'ted to a circuit 15, tuned to intermediate frequency and forming with a second tuned circuit 16 an intermediate-frequency bandpass filter,,a s well as to the 'said tapping 24 of the inductor oithe oscillator circuit and at the same time interconnected screen-grids 1Q and 12 Within tube 6 are connected through a capacitor 20 to the said tapping.
  • the son grids are, "moreover, connected through a supp y 'res stor l l to the positive terminal er the supply source.
  • the aridde is fed th'rough 'the lower part of the coil 17 and through resistor 23 from the "sam source, Capacitor, 22pmvides a high-frequency earth connection for the lower end of 17.
  • the two screen-grids operate, together with the anode, as oscillator electrodes for the local oscillation, which has the additional advantage that automatic gain control may be obtained ⁇ in a simple manner by means of a control grid 11 placed between the two screen-grids.
  • the control-grid has, at the most, asugnufy negative voltage with respect to the cathode 7.
  • the controlvoltage may be fderived, in known manner, frbrn the in'terr'nediate-freqiiency signal so that it varies with the mean carrier-amplitude thereof,
  • the c ol-vol tage exerts substantially no ihflue'n'ce on thef' a ration of the tiihe, "since the grid 11 "opr es 'as adiswanting grid an the total cathode current remains enhstantially constant duriifg control.
  • Fig. 2 shoi'rv's a second embodiment, gu'i'shed from that shown in Fig 1 i'nthat the set grids and am nes-Linda are connected to th ,tap'pi g 24 at the inductor 17, the anode 'o f the t'ube being cenkcted thr'odh the intermediate-frequency circuit 4 to the live (i. e. unearthed) end of the circuit tuned to the local frequency.
  • the screen-grids may be connected to the upper end of the said circuit and the anode alone to a tapping of the coil.
  • sion conductance is obtained and the radiation of the 'os'cilla'tion's from the aerial, atlef ast the medium-wave region, may be readily reduced to below the perr nissible limit.
  • a co'nverterjfor combining anincomingele ctric wave with local oscillations to produce an inter1 nediate-frequency wave comprising an electron discha'r'g'e tube havi a c thode, a, ,cg rq usr d atecreeu grid electrode and an anode electrode, means to generate local oscillations ctricaily coniii 7.- :1

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Power Engineering (AREA)
  • Superheterodyne Receivers (AREA)
  • Inductance-Capacitance Distribution Constants And Capacitance-Resistance Oscillators (AREA)
US296215A 1951-07-02 1952-06-28 Superheterodyne receiving circuit Expired - Lifetime US2725468A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL698397X 1951-07-02

Publications (1)

Publication Number Publication Date
US2725468A true US2725468A (en) 1955-11-29

Family

ID=19808952

Family Applications (1)

Application Number Title Priority Date Filing Date
US296215A Expired - Lifetime US2725468A (en) 1951-07-02 1952-06-28 Superheterodyne receiving circuit

Country Status (4)

Country Link
US (1) US2725468A (fr)
DE (1) DE968562C (fr)
FR (1) FR1059342A (fr)
GB (1) GB698397A (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL183196B (nl) * 1953-11-28 M & T Chemicals Inc Werkwijze voor de bereiding van een preparaat ten gebruike voor celvormige vinylchloridepolymeren, werkwijze voor de bereiding van vinylchloridehomo- of copolymeren, alsmede gevormd voortbrengsel, verkregen onder toepassing van een dergelijk preparaat, resp. geheel of ten dele bestaande uit een aldus bereid vinylchloridehomo- of copolymeer.
NL183474B (nl) * 1953-12-09 Festo Maschf Stoll G Inrichting voor het lageren van een zuigerstang in een cilinderdeksel bij pneumatische of hydraulische werkcilinders.

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB285130A (en) * 1926-11-09 1928-02-09 Richard Leonard Howard Flander Improvements in or relating to portable or semi-portable selfcontained wireless receiving apparatus
FR673718A (fr) * 1928-08-25 1930-01-18 Radiomodulation par les lampes à faible capacité intérieure
US1972189A (en) * 1929-09-25 1934-09-04 Radio Patents Corp Radioreceiver
US2034513A (en) * 1933-04-01 1936-03-17 Rca Corp Combined detector oscillator circuit
US2049777A (en) * 1933-07-21 1936-08-04 Rca Corp Oscillator-detector
US2051177A (en) * 1935-02-13 1936-08-18 Radio Patents Corp Electron coupled circuit

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR591694A (fr) * 1925-01-15 1925-07-16 Etablissements Ducretet Soc D Dispositif changeur de fréquence
USRE19765E (en) * 1931-12-14 1935-11-26 Badioreceiveb

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB285130A (en) * 1926-11-09 1928-02-09 Richard Leonard Howard Flander Improvements in or relating to portable or semi-portable selfcontained wireless receiving apparatus
FR673718A (fr) * 1928-08-25 1930-01-18 Radiomodulation par les lampes à faible capacité intérieure
US1972189A (en) * 1929-09-25 1934-09-04 Radio Patents Corp Radioreceiver
US2034513A (en) * 1933-04-01 1936-03-17 Rca Corp Combined detector oscillator circuit
US2049777A (en) * 1933-07-21 1936-08-04 Rca Corp Oscillator-detector
US2051177A (en) * 1935-02-13 1936-08-18 Radio Patents Corp Electron coupled circuit

Also Published As

Publication number Publication date
FR1059342A (fr) 1954-03-24
DE968562C (de) 1958-03-06
GB698397A (en) 1953-10-14

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