US2475064A

US2475064A - Ultra high frequency mixer circuit

Info

Publication number: US2475064A
Application number: US728144A
Authority: US
Inventors: Adelbert Van Weel
Original assignee: Hartford National Bank and Trust Co
Current assignee: Hartford National Bank and Trust Co
Priority date: 1944-08-08
Filing date: 1947-02-12
Publication date: 1949-07-05
Anticipated expiration: 1966-07-05
Also published as: GB643671A; FR942905A; DE807400C; NL69394C; BE467878A

Description

July 5, 1949. A. VAN WEEL ULTRA HIGH FREQUENCY MIXER CIRCUIT Filed F'eb. 12, 1947 A. VAN WEEL INVE NTO R MM7 'ACENT J oscillatory circuit 2, 2 as well as of the said in-phase circuit may be reduced, provided that the said impedances are adjusted to a correct" va1ue. This feed-back coupling may be enhanced te such extent that there are predued either escillations of a frequency corresponding te the frequency te which the push-pull oscillatory cir" cuit is tuned and which oscillations may be transmitted directly by the receiving aerial l l, er oscillations whose frequency corresponds te the frequency te which the in-phase circuit mentiened before is tuned and. which osciilations thereforemay be used as the local oscillatiens in the reception. It is even fundamentaliy pessible te preduce simultaneeusly the escillations te be transmitted and the local oscillatiens serving for the receptien, so that a transmissien and a reception can take place, and if desired simultaneeusly, without any swtching-ever operation. As a ru1e, hewever,it is desired te produce only one of thetwe oscillations. In this case one or more of the ieed-back impedances may adventageeusly be made inoperative by short-circuitingeras an alternative damping resistances may be includedin one of the circuits, (push-pull circuit, in-phase circuit), the construction being such thatthe preductien of either iecal oscillatiens er oscillations te be transmitted is aveided.

Now, accerding te the invention, the frequency of the oscillations te be transmitted and the frequency of the local oscillatiens are both established by theuse efthe box circuit E3 which has beenmentiened before. This box circuit comprises two inner cenductors I and 18' arranged symmetricaliy, tegether with four adjustable cencentrated capacities H, 12', 12' and E3. The box circuit has twe tunings, viz, one as the pushpulicircuit andthe ether as the in-phase circuit. By regulating the capacity 1 l it is possible to vary the frequency of the push-pull circuit,

whereas the frequency of the in-phase circuit may be adjusted by regulating thecapacity l3. With the adef the capacities 12 and H a correct symmetrical arrangement may beobtained. The anedes of the mixing systems are cennected te the box circuit in points A and A, the extent te which the mixing systems are coup1ed te the boxcircuit being in the first piace dependent en the p1aces of the points A'- and A and further on the values of the impedances 5, 8 and 8. Since, as a rule, the piaces of the points A' and. A are fixed once or 2111, the adjustment of the ceupling is effected solely with the aid of the said impedances. By a suitable cheice of these impedances it is possible fer the ceupling of the mixing systems with the box circuit-te be adjusted diferently fer each of the modes of escillation, ewing te which the extent ofstabilisation obtained fer the push-pull circuit is diierent frem that for the in-phase circuit.

the ceupling becomes strenger and the stabilisa= tien becomes lesssatsfactery.

If the impedance 5 is given a capacitative value, only the coupling fer the in-phase oscillation becemes 1ess streng and hence the stabilisatien becomes better (with an inductive value of the irnpedance 5 theceupling.becomes strenger, etc.). The extent of stabilisation of the two kinds of oscillation may therefore be fully controlled by a suitable choice of the three said impedances.

Fig. 2 shows a circuit arrangement fer receiving electrical ultrahigh-frequency oscillatiens in which in a similar manner use is made of a box circuit as in the circuit shewn in Fig. 1. In this case, however, the box circuit is used te improve the selectivity of the push-pull input circuit. For this purpose the dipole aerial I, I is cennected in points B and B" to the inner conducters H3, H1 of the box circuit, whereas the control grids of the mixing triodes 3, 3 are cennected in peints C and C te the said nner cenductors.

As befere, the local oscillatiens are produced by the circuit itselfandthis owing te the backcoupling by means oianinductance 0011 Hi cated between the junction of the two cathedes and the junction of twecendensers and 15' interpesed betweenthe anedes of the mixing systems 3 and 3. The frequency of the local osciliations is nowstabilised in a similar manner as in the circuit of Fig, 1, evenif the box circuit 9 is iocated between the contrel grids and the cathodes and not between the anodes and the cen trol grids of the mixing triodes.

Instead of cennecting the aerial directly te the box circuit in thepeints B, B, it is also possible for the aerial te be cennected, threugh small ca pacities, te the contro1 grids of the two tubes.

In a circuit which utilizes a box circuit te enhance the selectivity efthe input circuit, the box circuit may alternatively be arranged between the anodes asinthe circuits shown in Fig. 1. However, use is preferably made of a circuit arrangement of the kind shewn in Figu1e 2.

What I claim.isz

1. A mixing circuit for combining lecal oscii- 1atiens with high: frequency esciilations compris ing a pair of electron discharge tubes having first and-second input electredes and an output electrode, ene pair of corresponding input electredes being interconnected, an.input circuit cennected between the other..pair of corresponding electredes fer applying:the high frequency osciliatiens thereto in push-pull relation, an auxiliary circuit cennected between said interconnection and the electrical centerofsaidinput circuit fer applying 1ocal escillations tosaid.other pair of cerresponding electredes te cephasal relation, an

output circuit cennected between the output electredes of said tubes fer deriving the intermediate oscillationstherefrom, and -means te stabilize the mixing circuit fer said 1ocal and high frequency oscillations, said stabilizing means including an enclesedt tubular outer conductor, a pair of symmetrically disposed inner conducters cennected te one end ef said outer conductor, said outer conductor being cennected te an intermediate point in said auxiliary circuit, means cennecting said inner "cenducters 1espectively te the anedes of said tubes, a capacitance between said inner conductors having a value eiecting resenance at thefrequency of said high frequency escillations and a capacitance between said inner conductorsandsaid outer conductorhaving a. va1ue eiecting resonance at the frequency of-1ocal oscillations.

2. An arrangement, as Sset forth in claim 1, wherein said capacitance betweensaid inner conductor and said outer conductor is constituted by a pair of series-connected capacitors connected between the free ends of said inner conductors, and a capacitor connected between said outer conductor and the juncture of said series-connected capacitors.

3. A mixing circuit for combning local cscillations with high frequency oscillations to produce intermediate frequency oscillations comprising a pair of. electron discharge tubes each having a cathode, a grid and. an anode, means interconnecting said grids, a resonant input circuit tuned to the high frequencies osciilations and connected between the cathodes of said tubes for applying said oscillations thereto in push-pull relation, a first impedance connected between the electrcal center of said input circuit and. ground, a second impedance connected between said interconnection and ground, said first and second impedances in combination with said input circuit being tuned to the frequency of the local oscillations for applying same to said tubes in cophasal relation, an output circuit connected between said anodes for deriving the intermediate frequency oscillations thereirom, and means to stabilize the mixing circuit for said local and high requency oscillations including an enclosed tubular outer conductor, a pair of symmetrically disposed inner conductors connected to one end of said outer conductor, said outer conductor being connected to ground, means connecting said inner conductors respectively to the anodes of said tubes, a capacitance between said inner conductors having a value effecting resonance at the frequency of said high frequency oscillations and a capacitance between said inner conductors and said outer conductors having a value effecting resonance at the frequency of said local oscillations.

4. An arrangement, as set forth in claim 3, wherein said second impedance has a va1ue effecting positive feedback for said local oscillations to reduce the damping of the cophasal circuit.

5. An arrangement, as set forth in claim 3, further including an impedance element between ea-ch of said anodes and said output circuit, said elements having values efiecting positive feedback for said high frequency oscillations to reduce the damping of the push-pull circuit.

6. An arrangement, as set forth in claim 3, further including a pair of impedance elements each interposed between one of said anodes and one of said inner conductors, said elements having values eiecting positive feedback for said high frequency oscllations to produce self-oscillation in the push-pull circuit.

7. A transceiver system for mxing local oscillations with high frequency oscillations to produce intermediate frequency oscillations and for transmitting high frequency oscillations, said system comprising a pair of e1ectron dis-charge tubes each having a cathode, a grid and an anode, means interconnecting said grids, a resonant input circuit tuned to the high frequencies oscil1ations and connected between the cathodes of said tubes for applyng said oscillations thereto in push-pull relation, a first impedance connected between the electrical center of said input circuit and. ground, a second impedance connected between said interconnection and ground, said first and. second impedances in combination with said input circuit being tuned to the frequency of the local oscillations for applying same to said tubes in cophasal re1ation, an output circuit connected between said anodes for derivng the intermediate requency oscillations therefrom, means to stabilize the mixing circuit for said local and high frequency oscillations including an enclosed tubular outer conductor, a pair of symmetrically disposed inner conductors connected to one end of said outer conductor, said outer conductor being connected to ground, means connecting said inner conductors respectively to the anodes of said tubes, a capacitance between said inner conductors having a value effecting resonance at the frequency of said high frequency oscillations and a capacitance between said inner conductors and said outer conductor having a va1ue effecting resonance at the freequency of said local oscillations, said second impedance having a va1ue eiecting positive feedback or said local oscillations to reduce the dampng of the cophasal circuit, and. a pair of impedance elements each interposed between one of said anodes and one of said inner conductors, said elements having values effecting positive feedback for said high frequency oscillations to generate osciliations in the push-pull circuit.

ADELBER'I VAN WEEL.

REFERENCES CITED The following references are of record in the file of this patent: