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US2582725A - Frequency changing circuit arrangement - Google Patents

Frequency changing circuit arrangement Download PDF

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Publication number
US2582725A
US2582725A US680964A US68096446A US2582725A US 2582725 A US2582725 A US 2582725A US 680964 A US680964 A US 680964A US 68096446 A US68096446 A US 68096446A US 2582725 A US2582725 A US 2582725A
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United States
Prior art keywords
circuit
cathode
frequency
anode
feedback
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Expired - Lifetime
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US680964A
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English (en)
Inventor
Strutt Maximiliaan Julius Otto
Ziel Aldert Van Der
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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
    • H03F1/26—Modifications of amplifiers to reduce influence of noise generated by amplifying elements
    • H03F1/28—Modifications of amplifiers to reduce influence of noise generated by amplifying elements in discharge-tube amplifiers
    • 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
    • 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
    • H03D7/10—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 different pairs of electrodes

Definitions

  • This invention relates to a circuit-arrangement for frequency-changing of electric oscillations by mixing them with locally generated oscillations, which comprises a discharge tube containing a cathode, an input electrode, an outlet electrode and one or more further electrodes having a positive bias, in which the (high-frequency) oscillations to be changed in frequency jointly with the local oscillations are supplied to the said input electrode and in which the frequencychanged (intermediate-frequency) oscillations are taken from the said output electrode.
  • the object of the invention is to provide means which permit a material reduction of the noise occurring in such circuit-arrangements.
  • This noise which particularly in the'transmission of feeble signals is a source of great trouble, is due, on the one hand, to spontaneous voltage fluctuations (Brown's movement of the electrons) in the circuits connected to the discharge tube and on the other to current fluctuations in the discharge tube itself.
  • the latter current fluctuations can be distinguished in emission-fluctuations (irregularities in the flow of emission of a cathode) and in subdivision-fluctuations (irregularities in the subdivision of the current between two or more electrodes having a positive bias).
  • the noise due to these two latter causes is referred to respectively as the cathode-noise and as the subdivision-noise.
  • the subdivisionnoise is, in general, considerably stronger than the cathode-noise. It may be observed in this connection that the subdivision-noise current in the anode circuit is equal and opposite to the subdivision-noise current in the screen-grid circuit. This is because an increase of the anode current owing to a variation of the subdivision of the current involves an identical decrease of the screen-grid current.
  • the subdivision-noise consequently becomes manifest as an alternating current which passes from the anode to the screen-grid, but which does not occur in that part of the cathode conductor which is common to the anode circuit and to the screen-grid circuit. Due to this, the signal-to-noise ratio with screen-grid tubes is materially higher in that part of the cathode conductor than in the anode circuit. 7
  • the circuit-arrangement described hereinbefore has the disadvantage that the required strong positive feedback makes it very difi'icult to avoid self-excitation when tuning through a wide frequency-range. It has been proposed before to obviate this disadvantage by using, at the same time, a negative (degenerative) feedback which compensates the action of the positive feedback so far as the tendency to self-excitation is concerned, but which does not disturb the favourable signal-to-noise ratio obtained by means of the positive feedback.
  • the latter requirement is fulfilled if the feedback voltage for the negative feedback is taken from the intermediate-frequency output current, because in this case all the noise components of the output current are reduced by the negative feedback to the same extent as the signal.
  • an oscillatory circuit coupled to the said circuit and tuned to the intermediate frequency may be included in the'circuit of the input electrode.
  • the feedback current or voltage is preferably taken from that portion of the cathode-conductor which is common to thecircuits of the output electrode and of the .said further electrodets) having a positive bias.
  • An intermediate-frequency feedback arrangement has, according to the invention, important advantages over the high-frequencyfeedbac'k arrangement proposed before.
  • the arrangement, according to the invention permits the employment of very stron feedback without danger of oscillation as the tuning frequency-of the circuit is varied. If the stability is, nevertheless, still insuflicient, or if the selectivity is excessively increased by I the positive 'afeedback, 2a
  • negativefeedback for the -,frequency-band occupied bythe intermediate-frequency oscillations maybe used at the-same time, the feedbackcurrent :or voltage for the negative feedback "being taken from the circuitof the output electrode.
  • This negative feedback permits eliminating, wholly or. in part, the effect-of the positivefeedback with regard to :the selectivity and the tendency to oscillation, while at the same time the favourable .signal-to-noise ratio-obtained by means of the positive feedback .is notidisturbed, because all the intermediate-frequency noisecomponents .in the output circuit are-reduced to the same extent as the signal by :the negative feedback.
  • the negative feedback is zpreferabiy aproportioned in such .manner that it fbIiIlgS about :a damping ;of the-said oscillatory mircu-it which is substantially equal to the negativerrilampingtproduced by the positive feedback.
  • .Asz may be assumed'to' bea'known, the conversion conductance; that is to. say itlieintermediatefrequencytsignal currentin:thercircuitofrthe output eelectm'dexper 'volt ofJhigh-frequency signal voltage attthe input .electrodais highly dependent-uponxthe amplitude of :the .local oscillations supplied'to the tube. :It. is thus found that if a high-frequency positive feedback is used a maximum signal-to-noiseratio is achieved in the output impedance'if theconversion conductance is chosenzto be low.
  • the high-frequency oscillations received by an aerial I are transmitted inductively to'an input oscillatory circuit 2, which in series with-ac0il3coupled to a local oscillator 4 (shown diagrammatically) is included in the input cir- .nected to ground in the usual manner via ithe parallel combination of a resistance .14 :and .:-a condenser l5, so'that a suitable negativebias for the control-grid -l .is obtained.
  • 'Apositive zbia-s is supplied to the'screenegrid 8 and'to thepanode 9 via resistances It .and H. Jointly with the source of voltage these resistances .are shunted by condensers l8 and I9 "which constitute a short-circuit both;for theyhigh-frequency. -and:for thepintermediate+frequencywoscillations.
  • This feedback has the .effect of materially increasin the signal-voltage :a-croze;s the output circuit Hl.
  • The*sub'division-noisepurrent which is set up by fluctuations ofthe subdivision of the currentbetweenthe screen-grid 8 and the anode 9, does not "pass, however, through the coil '20 *and is consequently not biassed by the feedback. This results in'a-material increase of the signal to-noise'ratio.
  • the anode circuit of the circuit-arrangement shown in the drawing includes a coil- 22 which is coupled to the circuit 2! in such sense as to secure a negaf-i tive feedback for the intermediate-frequency oscillations' This negative feedback has again the effect of'reducing the output voltage occurring across the circuit [0.
  • the coil 1'2 is included in the connection between thescreen-grid '8 and the anode 9, so that the sub-'5" division-noise currentpasses through the coil' 22, the subdivision-noise voltage is reduced to the same extent as the signal voltage, so that the favourable signal-to-noise ratio obtained by meansofrthe positive feedback is'not disturbed.
  • a tetrode is used to constitute the mixing tube.v
  • a tube having more electrodes for instance a pentode or a hexo'de may be used. It is, however, essential in connec tion with the efi'ect aimed at thatthe (high; frequency) oscillations to be changed and the localoscillations should be supplied to the same not any intermediate-frequency current passing;
  • An electric circuitarrangement for mixing a first wave and a second wave comprising. an electron discharge tube having cathode, control grid, accelerating and anode electrodes, first means intercoupling said control .grid and cathode electrodes and constituting a control gridcathode circuit, second means intercoupling said accelerating and cathode electrodes and constituting an accelerating electrode-cathode circuit, third means intercoupling said anode and cathode electrodes and constituting an anode-cathode circuit, an output circuit coupled to said anode, means to apply said first and second waves to said control grid to develop in said output circuit an intermediate frequency wave, an impedance element connected in common to said anode-cathode and said accelerating elec- I trode-cathode circuits, and means to couples'aid impedance element to said control grid-cathode circuit in regenerative relationship at saidintermediate frequency to apply said intermediate frequency wave to said control grid.
  • An electric circuit arrangement for mixing a first wave and a second wave comprising an electron discharge tube having cathode, control grid, accelerating and anode electrodes, first means intercoupling said control grid and cathode electrodes and constituting a control gridcathode circuit, second means intercouplingsaid accelerating and cathode electrodes and constituting an accelerating electrode-cathode circuit, third means intercoupling said anode and cathode electrodes and constituting an anode-cathode circuit, an output circuit coupled to said anode, means to apply said first and second waves to said control grid to develop in-.; said output circuit an intermediate frequency wave, an oscillatory circuit coupled in said control grid cathode circuit and tuned to the frequency of said intermediate frequency wave, an impedance element connected in common to said anodecathode and said accelerating electrode-cathode 6.. circuits, and means to couple said impedance element to said oscillatory circuit'in regenerative relationship at said intermediate frequency to apply said intermediatefrequency wave to
  • An electric circuit arrangement for mixing a first wave and'a second wave comprising an electron discharge tube having cathode, control grid, accelerating and anode electrodes, first means intercoupling said control grid and cath-' odeelectrodes and constituting a control gridcathode circuit, second means intercoupling said accelerating andcathode electrodes and constitutingan accelerating electrode-cathode circuit, third means intercoupling said anode and bathode electrodes andconstituting an anode-cathode circuit, an output circuit coupled to said anode, means to apply said first and second waves'to said control grid to develop in said output circuit an intermediate frequency wave,-a low'impedance oscillatory circuit coupled in said control'grid-cathode'circuit and tuned to the frequency'of said intermediate frequency wave, an impedance element connected in common to saidanode-cathode and said acceleratingelectrode-cathode circuits, and means to couple said impedance element to said oscill
  • An electric circuit arrangement for mixing a first wave and a second wave comprising an electron discharge tube having cathode; control grid, accelerating and anode electrodes, first means intercoupling said control grid and cathode electrodes and constituting a control gridcathode circuit, second means intercoupling said accelerating and cathode electrodes and constituting an accelerating electrode-cathode circuit, third means intercoupling said anode and cathode electrodes and constituting an anode-cathode circuit, an output circuit coupled to said anode, means to apply said first and second waves to said control grid to develop in said output circuit an intermediate frequency wave, a first impedance element connected in common to said anode-cathode and said accelerating electrodecathode circuits, means to couple said first impedance element to said control grid-cathode circuit in regenerative relationship at said intermediate frequency to apply said intermediate frequency wave to said control grid in positive feedback relationship, a second impedance element coupled in said anode-cathode circuit
  • An electric circuit arrangement for mixing a first wave and a second wave comprising an electron discharge tube having cathode, control grid, accelerating and anode electrodes, first means intercoupling said control grid and cathode electrodes and constituting a control gridcathode circuit, second means intercoupling said accelerating and cathode electrodes and constituting an accelerating electrode-cathode circuit, third means intercoupling said anode and cathode electrodes and constituting an anode-cath ode circuit, an output circuit coupled to said anode, means to apply said first and second waves to said control grid to develop in said output circuit an intermediate frequency wave, an oscillatory circuit coupled in said control grid- 7 cathode :circuit .and tuned :to the :frequency :of saidfintermediatelfrequency wave, a first impedance element.
  • r electriccircuit arrangement for mixing a first wave and a second wave, comprising an electron discharge tube having cathode, control, accelerating 'and' anode electrodes, first means intercoupling said control grid-and cathode-electrodes :and "constituting a control grid-cathode circuit, second means intercoupling said accelcrating and cathode electrodes and constituting an accelerating electrode-cathode circuit, third means intercoupling said anode and cathode electrodes and constituting an anode-cathode circuit,an output circuit coupled :to said-anode,

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Particle Accelerators (AREA)
  • Channel Selection Circuits, Automatic Tuning Circuits (AREA)
US680964A 1943-05-03 1946-07-02 Frequency changing circuit arrangement Expired - Lifetime US2582725A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL617647X 1943-05-03

Publications (1)

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US2582725A true US2582725A (en) 1952-01-15

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US680964A Expired - Lifetime US2582725A (en) 1943-05-03 1946-07-02 Frequency changing circuit arrangement

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US (1) US2582725A (es)
BE (1) BE455595A (es)
FR (1) FR903902A (es)
GB (1) GB617647A (es)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2753449A (en) * 1952-01-30 1956-07-03 Gail E Boggs Superheterodyne mixer with negative feedback for stabilizing conversion gain
US2828410A (en) * 1953-02-12 1958-03-25 Philips Corp Mixing circuit comprising a self-oscillating triode with intermediate-frequency feed-back
US2835797A (en) * 1953-11-28 1958-05-20 Philips Corp Circuit-arrangement for frequencytransformation of oscillations of very high frequency
US2859336A (en) * 1951-10-22 1958-11-04 Philips Corp Frequency conversion of signal oscillation without use of an auxiliary local oscillation
US3641441A (en) * 1969-11-13 1972-02-08 Motorola Inc Frequency conversion module including emitter follower mixer

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL105942C (es) * 1956-08-24

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB361351A (en) * 1930-08-15 1931-11-16 Graham Amplion Ltd Improvements in thermionic valve circuits as applied to radiotelephonic systems and apparatus
US2022085A (en) * 1931-12-14 1935-11-26 Hazeltine Corp Radioreceiver
US2032675A (en) * 1933-11-18 1936-03-03 Rca Corp Radio receiver
US2122283A (en) * 1937-03-09 1938-06-28 Rca Corp Frequency converter
US2151800A (en) * 1935-07-10 1939-03-28 Csf Oscillation device
US2202576A (en) * 1938-01-31 1940-05-28 Bendix Radio Corp Modulation system
US2302867A (en) * 1941-10-25 1942-11-24 Rca Corp Combined mixer and intermediate frequency stage

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB361351A (en) * 1930-08-15 1931-11-16 Graham Amplion Ltd Improvements in thermionic valve circuits as applied to radiotelephonic systems and apparatus
US2022085A (en) * 1931-12-14 1935-11-26 Hazeltine Corp Radioreceiver
US2032675A (en) * 1933-11-18 1936-03-03 Rca Corp Radio receiver
US2151800A (en) * 1935-07-10 1939-03-28 Csf Oscillation device
US2122283A (en) * 1937-03-09 1938-06-28 Rca Corp Frequency converter
US2202576A (en) * 1938-01-31 1940-05-28 Bendix Radio Corp Modulation system
US2302867A (en) * 1941-10-25 1942-11-24 Rca Corp Combined mixer and intermediate frequency stage

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2859336A (en) * 1951-10-22 1958-11-04 Philips Corp Frequency conversion of signal oscillation without use of an auxiliary local oscillation
US2753449A (en) * 1952-01-30 1956-07-03 Gail E Boggs Superheterodyne mixer with negative feedback for stabilizing conversion gain
US2828410A (en) * 1953-02-12 1958-03-25 Philips Corp Mixing circuit comprising a self-oscillating triode with intermediate-frequency feed-back
US2835797A (en) * 1953-11-28 1958-05-20 Philips Corp Circuit-arrangement for frequencytransformation of oscillations of very high frequency
US3641441A (en) * 1969-11-13 1972-02-08 Motorola Inc Frequency conversion module including emitter follower mixer

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Publication number Publication date
GB617647A (en) 1949-02-09
BE455595A (es)
FR903902A (fr) 1945-10-22

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