US2609495A - Push-pull mixing circuit arrangement - Google Patents

Push-pull mixing circuit arrangement Download PDF

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Publication number
US2609495A
US2609495A US695888A US69588846A US2609495A US 2609495 A US2609495 A US 2609495A US 695888 A US695888 A US 695888A US 69588846 A US69588846 A US 69588846A US 2609495 A US2609495 A US 2609495A
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United States
Prior art keywords
circuit
oscillations
push
incoming
frequency
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Expired - Lifetime
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US695888A
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English (en)
Inventor
Adelbert Van Weel
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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
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
    • H03F1/08—Modifications of amplifiers to reduce detrimental influences of internal impedances of amplifying elements
    • 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
    • H03D7/14—Balanced arrangements
    • H03D7/1416—Balanced arrangements with discharge tubes having more than two electrodes
    • 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
    • H04B1/163—Special arrangements for the reduction of the damping of resonant circuits of receivers

Definitions

  • This invention relates to-a mixing circuit arrangement in which the incoming oscillations are-supplied in push-pull arrangement and the local oscillations in single phase (in the same phase) to the input electrodes of two discharge systems each of which comprises at least one cathode, one input electrode and one output electrode.
  • Fig. 1 is a schematic circuit diagram of a prior art push-pull mixing system
  • Fig. 1 is substitution diagrams for the input circuit of the system in Fig. 1, I
  • Fig. 4 is a schematic circuit diagram of a first preferred embodiment of a mixing system in accordance with the present invention
  • Fig.5 is a schematic circuit diagram of a second preferred embodiment of the invention
  • Fig. 6 is a schematic circuit diagram of a third preferred embodiment of the invention.
  • Fig. 1 of the accompanying drawing represents a mixing circuit of this kind, which forms part i .capacities between the inductance coils L1 and L1" respectively and the antenna coupling coil Lo are represented by Co and Co" respectively.
  • the connecting point of coils L1 and L1" is earthed through a condenser C2 and connected through a resistance R1 to a supply (not represented) by which the control-grids of the triods -T and T" are suitably biassed.
  • the input capacities of the triodes T'and T" are denoted by C3 and Cs" respectively.
  • the cathodes of the triodes T1.,and T are jointly connected to earth through an inductance L2 which is coupled with a coil L3 inserted in the output circuit of a diagrammatically represented local oscillator O. Consequently by means of coil L2 the local oscillations are supplied by means of so-called cathode injection to theinput circuits of the triodes in such a manner that the local oscillations appear in the same phase, at the control-grids of the two triodes.
  • coils L42 and L4" are inductively coupled with a. second intermediate-frequency circuit Ls, Ce, from which the output voltage of the circuit is taken.
  • the junction of condensers C4 and C4" is connected to the cathodes of the two triodes in order to obtainan electric circuit having a low impedance in regard to anode currents having the oscillator frequency. Since the aforesaid circuit is par. ticularly suitable for frequency-transformation of ultra-short waves, the input resonant circuit L1", L1", C1 will usually be realized in the form of a Lecher system in practice. y
  • the present circuit exhibits the drawback that the input impedance of the triodes, represented by the capacity C3 and C3" respectively in the drawing, notably in receiving ultra-short'waves has only a small value, due to which the voltage having the oscillator-frequency andbeingset up between the control-grid and the cathodeof any of thetubes, usually becomes too small.
  • the input impedance of the triodes represented by the capacity C3 and C3" respectively in the drawing
  • the expression push-pull circuit is to be understood to mean the assembly of impedances available between two not directly interconnected input electrodes of the discharge systems, in which are flowing currents having the frequency of the. incoming oscillationsffthe expression input circuit of a discharge, system.
  • Thepush-pull circuit is generally tuned tofithe frequency of the incoming oscillations.
  • Fig. 2 represents the substitution diagram of the input circuits of the two mixing triodes. From this diagram it appears that the elements. L1,
  • L1", Ca, Ca constitute a Wheatstone bridge in.
  • each triode is a maxi: mumwhen series-resonanceoccurs in the circuit L1, C2,,L2', C3.
  • the circuit in question must consequently bev tuned to the oscillator frequency.
  • thecircuitsLi, C2 andLz, C3 eachpindividually to the oscillator frequency the radiation of the local oscillations can bereduced to'a minimum by the antenna D.
  • the inductance of coil L2 and the capacity of condenser C2 may bemade variable for this purpose and these elements may be adjusted in such a manner that, the radiation of the local oscillations by the antenna is-a minimum and the voltage having the oscillator frequency between the control grid andthe-cathode of each; triode is a maximum.
  • the invention is based on the realization that the aforesaid expedient--the tuningof the said circuit to: the frequency of the local,oscillations does-not lead completely to the result aimed at under all conditions, and this because the said single-phase circuit. is usually damped. too strongly. In, addition to the input damping, of the mixing tubes thisdamping is also to be ascribedto a negative backcoupling brought about by the capacitative anode load. In fact, the capacityof condensers C4 and 041 should not be chosen too high, since otherwise the impedance of the intermediate frequency circuit L4, L4", C4, 04'', would become too low.
  • the condensers C4 and C4" constitute a not negligible impedance in regard to the oscillator frequency, so that between the anode and cathode of any of thetriodes an anode, voltage having the oscillator frequency occurs, which leads in phaseby 90 with respect to the alternating control-grid volt"- age.
  • the said anode voltage involves a current through the anodecontrol-gridcapacity, which is in phase opposition in regard to the alternating control-grid voltage and consequently has a damping effect on the said circuit. It is pointed out in this respect that in a similar manner a damping isalso brought about of the input resonant circuit-L1, L1", C1 tuned tothef-requency of the incoming oscillations.
  • the invention has for its object an improvement of the circuit according to the above-identified copending applicatiomas a result of which the said drawbacksare avoided.
  • inventionuse is maderof a positive backcoupling i'nrregard to the localoscillations, as a. result. of
  • a particularly suitable embodiment of the invention is obtained by giving the positive backcouplingsuch .ahigh value as to produce the local oscillations in the saidcircuit.
  • the distinct oscillator O can be dispensed with, which yields a great simplification of the circuit.
  • Theback-coupling current or -voltage for the positive back-coupling is taken from a part of the output circuit in which appear both the local and the incoming oscillations, so that both the said'circuitand the input circuit of the arrangement are undamped in regard to the incoming oscillations.
  • the positive backcoupling thus ob- .tained. in regard to the incoming oscillations has the advantage that an improvement of the signalto-noise ratio is obtained.
  • the damping of said circuit is generally different. fromthe damping of the input circuit for the incoming oscillations, inter alia because the lastmentioned circuit is damped to a much higher degree by the antenna. Therefore it is advisable that the strength of the backcoupling for both kinds of, oscillations'should be madedifferent, which can be ensured by taking an additional back-coupling current or voltage from a part of the, output circuit in which appear eitherexclusively'the local oscillations or exclusively the incoming oscillations.
  • the positive back-coupling is obtained by making the impedance of the output circuit for the local oscillations and, if desired, also for the incoming oscillations substantially inductive.
  • inductances' may be inserted in parts of the output circuit in which appear both the local oscillations and the incoming oscillations, the'desired intensity difierence-of the back-coupling in regard to-both' kinds of oscillations being obtained by inserting one or more-capacities in a part of the outputcircuitin which appear either exclusively-the local oscillationsor exclusively the incomingoscillations;
  • the circuit represented in Figure 4 substantially corresponds to that shown in Figure l, but the condenser-C2 and the inductanceLz are ad justable to permit the said circuit to be tuned to theoscillator'frequency in the manner referred to above. Furthermore; according to the invention, the conductor through which the junction of the condensers C4 and C4 is connected to the cathode includes an inductance L1. Since in the said conductor exclusively acurrent having the oscillator frequency is flowing'a positive back-coupling in regard to the local oscillations is obtained as a result thereof.
  • Figure 5 represents a circuit arrangementin which use is made. at, the same time of aipo'sitive .coming oscillations.
  • the inductances of coils La and La" are preferably chosen in such a manner that the sigtates as arule a practically complete undamp-' ing of the input resonant circuit L1, L1", Ci. Since the input resonant circuit is comparatively strongly damped by the antenna D, D, whereas the local oscillations are acted upon only to a slight degree by the antenna, the required intensity of the back-coupling in regard to the incoming oscillations is generally greater thanin regard to the local oscillations, so that the backcoupling in regard to the local oscillations, which is caused by the coils Lsf and La", must be decreased.
  • this is effected by providing a condenser Cabetween the junction of the condensers C4 and C4 and the cathodes of the triodes;
  • the condenser C3 is exclusively traversed by a current having the oscillator frequency and consequently reduces the intensity of the backcoupling in regard to the local oscillations without acting on the back-coupling for the inoorning oscillations.
  • intensity of the back-coupling in regard to the local oscillations can be made variable.
  • the inductances of coils LB and Le may, moreover, be made variable or variable condensers may be connected in series with these coils.
  • Figure 6 represents a circuit arrangement ac-' cording to the invention, in which the input resonant circuit L1, L1, C1 is provided between the cathodes of the triodes T and T", the grids being jointly earthed across the inductance La.
  • the required reduction in intensity of the backcoupling in regard to the local oscillations can be achieved, similarly to the circuit shown in Figure 5, by providing a condenser Ca in parallel with the series connection of con- I QQCOEQQB den'sers C4 and C4" and by'reducing the capacity between the junction of the condensers C4 and C4" and the cathodes.
  • an additional damping resistance may "be inserted in the input circuit for one or both kinds of oscillations.
  • This damping resistance may, for instance, be provided in parallel with the condenser C1 when an additional damping for the incoming oscillations is necessary.
  • a damping resistance in series with the condenser C2 or with the inductance Lz may be provided for this purpose.
  • An arrangement for mixing an incoming wave with'local oscillat-ions'to produce an intermediate frequency signal comprising a pair of electron dischargetubes each having'a cathode el'ectrode,"a grid electrode and an anode,'a'first resonant circuitarrangedto apply the incoming wave in push-pull relation to one set or corresponding electrodes in said tubes, an output system including a second resonant circuit coupled to the anodes of said 'tub'e's to derive in push-pull relation the intermediate frequency signal there'- from, a third and series "resonant circuit coupled between the electrical midpoint of said first circuit and the other set of corresponding electrodes to apply local oscillations in cophasal relation to the grid electrodes of said tubes, and means to introduce positive backcoupling between the output system of said tubes and said third resonant circuit.
  • a mixing circuit as defined in claim 1 further characterized in that said means has a value at which the intensity of said positive backcoupling generates local oscillations in said mixing circuit.
  • An arrangement for mixing an incoming wave with local oscillations to produce an intermediate frequency signal comprising a pair of electron discharge tubes each having a cathode, a grid and an anode, a first resonant circuit arranged to apply the incoming wave in push-pull relation to the grids of said tubes, a second resonant circuit coupled to the anodes of said tubes to derive in push-pull relation the intermediate frequency signal therefrom, a third and series resonant circuit coupled between the electrical midpoint of said first circuit and the cathodes of said tubes to apply local oscillations in cophasal relation to the grids of said tubes, and means to efiect negative damping of said first and third resonant circuits, said means including an inductive impedance interposed between each of said anodes and said second resonant circuit to introduce positive backcoupling between the anode-cathode circuits or said tubes and said first and third resonant circuits.
  • ne a first e f le +re m nant circuit including a center tapped; inductance connected between said grids, said first circuit being; tuned to the incoming wave; to apnly same in push-pull relation to said; grid-s, a; second parallel-resonant-circuit' constituted by an inductor in parallel with a pair-of series connected condensers connected between the anodesof said tubes and tuned to the intermediate irequency radio frequency cholges interposed between the ends of said inductor and said condensers, a series-resonantcircuit connected be- Q tween the tap in said inductance and the cathodes of said tubesand tuned to the frequencycf local oscillations to app y same in cophasal relation to said grids, inductive feedback impedances interposed between eachanode and each choke to effect; negative.
  • An arrangement for mixing an incoming radio wave with local, oscillations to produce an mediate ir ueccr deca m rises a pair 1 n ermedia e, re uent? signal comprising anei of e ect on i h r tub ea h havin sca hode, agrid andan anode, a first parallel-resonant circuit includinga center-tapped inductanceconnected between said cathodes, said first circuit being; tuned to the incoming wave to apply same in push-pull relation, to said cathodes, a second parallel-resonant circuit constituted by an inductor in parallel with a pair of series connected condensers connected. between the anodes of said tubes and tuned to, the intermediate frequency,
  • radio frequency chokes interposed between the ends of said inductor and, said. condensers, a series-resonant circuitconnectedbctween the tap in said inductance and the grids of said tubes and tuned to the frequency of local oscillations to apply same cophasalrelation to said grids, inductive feedback impedances. interposed between each andoeand each choketo efifect negative damping of saidfirst parallel-resonant circuit and said series-resonant circuit, andanadditional inductive feedback impedance connected betweenthe junction of said series-connected condensers and the. grids of said tubes. to increase the negativedampingof said series resonant circuitto. the point resulting in the generation of local oscillations,

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Inductance-Capacitance Distribution Constants And Capacitance-Resistance Oscillators (AREA)
  • Superheterodyne Receivers (AREA)
  • Amplifiers (AREA)
US695888A 1943-03-27 1946-09-10 Push-pull mixing circuit arrangement Expired - Lifetime US2609495A (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
NL248352X 1943-03-27
NL130543X 1943-05-13
NL211043X 1943-10-21
NL91143X 1943-11-09

Publications (1)

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US2609495A true US2609495A (en) 1952-09-02

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US695890A Expired - Lifetime US2606284A (en) 1943-03-27 1946-09-10 Mixing circuit arrangement
US695889A Expired - Lifetime US2606283A (en) 1943-03-27 1946-09-10 Mixing circuit arrangement
US695888A Expired - Lifetime US2609495A (en) 1943-03-27 1946-09-10 Push-pull mixing circuit arrangement

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Application Number Title Priority Date Filing Date
US695890A Expired - Lifetime US2606284A (en) 1943-03-27 1946-09-10 Mixing circuit arrangement
US695889A Expired - Lifetime US2606283A (en) 1943-03-27 1946-09-10 Mixing circuit arrangement

Country Status (5)

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US (3) US2606284A (de)
CH (1) CH248352A (de)
DE (1) DE908868C (de)
GB (1) GB632658A (de)
NL (1) NL72257C (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3275951A (en) * 1963-08-01 1966-09-27 Joachim A Maass Ring modulator with large dynamic operating range

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2710315A (en) * 1950-11-03 1955-06-07 Ben H Tongue Wide-band amplifying system
US2788493A (en) * 1953-10-28 1957-04-09 Rca Corp Modulated semi-conductor oscillator circuit
US2802069A (en) * 1954-09-07 1957-08-06 Bell Telephone Labor Inc Amplifier with high frequency compensation
US2857511A (en) * 1956-03-02 1958-10-21 Ben H Tongue Balanced mixer
US3110863A (en) * 1959-09-21 1963-11-12 Vector Mfg Company Phase modulation transmitter

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1596102A (en) * 1924-12-24 1926-08-17 American Telephone & Telegraph High-frequency translating circuits
US1907624A (en) * 1930-05-13 1933-05-09 Csf Heterodyne system
US1968610A (en) * 1931-03-23 1934-07-31 Rca Corp Thermionic amplifying system
US2107395A (en) * 1933-12-13 1938-02-08 Schlesinger Kurt Radio receiving system
US2434474A (en) * 1941-01-28 1948-01-13 Hartford Nat Bank & Trust Co Circuit arrangement for ultra short waves
US2441452A (en) * 1941-01-31 1948-05-11 Hartford Nat Bank & Trust Co Frequency changing circuits
US2479537A (en) * 1942-12-30 1949-08-16 Gen Electric Detector-oscillator circuit for ultra high frequency receivers
US2483766A (en) * 1942-12-29 1949-10-04 Rca Corp Power converter system

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1396786A (en) * 1916-11-06 1921-11-15 Western Electric Co System for transmission of intelligence
US1767508A (en) * 1925-07-27 1930-06-24 Crosley Radio Corp Vacuum-tube circuits
US2088432A (en) * 1934-02-17 1937-07-27 Rca Corp Frequency converter circuit
US2169305A (en) * 1935-06-15 1939-08-15 Rca Corp Low-loss circuits
DE727990C (de) * 1939-10-06 1942-11-17 Habil Friedrich Vilbig Dr Ing Verfahren zur Beseitigung der durch Amplituden- und/oder Phasenverzerrung der beidenSeitenbaender hervorgerufenen Stoerungen einer mit Traegerfrequenz uebertragenen Nachricht
NL58327C (de) * 1940-12-05
BE470453A (de) * 1942-11-16

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1596102A (en) * 1924-12-24 1926-08-17 American Telephone & Telegraph High-frequency translating circuits
US1907624A (en) * 1930-05-13 1933-05-09 Csf Heterodyne system
US1968610A (en) * 1931-03-23 1934-07-31 Rca Corp Thermionic amplifying system
US2107395A (en) * 1933-12-13 1938-02-08 Schlesinger Kurt Radio receiving system
US2434474A (en) * 1941-01-28 1948-01-13 Hartford Nat Bank & Trust Co Circuit arrangement for ultra short waves
US2441452A (en) * 1941-01-31 1948-05-11 Hartford Nat Bank & Trust Co Frequency changing circuits
US2483766A (en) * 1942-12-29 1949-10-04 Rca Corp Power converter system
US2479537A (en) * 1942-12-30 1949-08-16 Gen Electric Detector-oscillator circuit for ultra high frequency receivers

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3275951A (en) * 1963-08-01 1966-09-27 Joachim A Maass Ring modulator with large dynamic operating range

Also Published As

Publication number Publication date
NL72257C (de)
US2606284A (en) 1952-08-05
CH248352A (de) 1947-04-30
GB632658A (en) 1949-11-28
DE908868C (de) 1954-04-12
US2606283A (en) 1952-08-05

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