US2161087A - Oscillator of the magnetron type - Google Patents

Oscillator of the magnetron type Download PDF

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Publication number
US2161087A
US2161087A US54862A US5486235A US2161087A US 2161087 A US2161087 A US 2161087A US 54862 A US54862 A US 54862A US 5486235 A US5486235 A US 5486235A US 2161087 A US2161087 A US 2161087A
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US
United States
Prior art keywords
oscillator
tube
voltage
oscillations
frequency
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
US54862A
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English (en)
Inventor
Posthumus Klaas
Lindern Carl G A Von
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 US2161087A publication Critical patent/US2161087A/en
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Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03C—MODULATION
    • H03C1/00—Amplitude modulation
    • H03C1/28—Amplitude modulation by means of transit-time tube
    • H03C1/30—Amplitude modulation by means of transit-time tube by means of a magnetron
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J25/00—Transit-time tubes, e.g. klystrons, travelling-wave tubes, magnetrons
    • H01J25/50—Magnetrons, i.e. tubes with a magnet system producing an H-field crossing the E-field
    • H01J25/52—Magnetrons, i.e. tubes with a magnet system producing an H-field crossing the E-field with an electron space having a shape that does not prevent any electron from moving completely around the cathode or guide electrode
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J25/00—Transit-time tubes, e.g. klystrons, travelling-wave tubes, magnetrons
    • H01J25/64—Turbine tubes, i.e. tubes with H-field crossing the E-field and functioning with reversed cyclotron action
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K7/00—Modulating pulses with a continuously-variable modulating signal

Definitions

  • This invention has reference to an oscillator in which the frequencyof the oscillations generated depends to a marked extent on the voltages supplied to the electrodes of its electron dis- .5.' charge tube. It is a feature of our invention that the characteristic curve of modulation exhibits discontinuities, due to the superposition upon a variable modulating wave of another wave of predetermined frequency.
  • An example of such an oscillator is of the magnetron type comprising two or more pairs of anodes connected to. an output impedance in such manner that the alternating potential of each anode is in opposite phase with the alternating potential of the adjacent anode and in which the intensity-of the field is higher than the critical value.
  • Such an oscillator is capable of generating oscillations the frequency of which depends on the voltage supplied, to the anodes.
  • Fig. 2 shows diagrammatically an embodiment 3 of the invention
  • Fig. 3 is a graph illustrating the theory of the invention.
  • the high frequency current iw is plotted as a function of the anode voltage Va.
  • the anode voltage Va is plotted as a function of the anode voltage Va.
  • oscillations are continuously generated by the circuit arrangement described.
  • a modulation voltage is applied, according to prior art practice,
  • the modulation depth is limited to the ratio ef.'fc in which e is the mean value between the values cc and cg.
  • a further example of an oscillator in which the frequency of the oscillations generated depends on the voltages supplied to the electrodes and in which the characteristic curve of modulation exhibits discontinuities is in a Barkhausen-Kurz oscillator.
  • the modulation is effected by intermittently bringing about at one or more electrodes a potential variation during a series of time intervals the length of which depends on the instantaneous Value of the amplitude of the modulating oscillations.
  • Fig. 2 shows an oscillator 1 of the kind described.
  • the anode voltage is supplied from the source 2 to one or more electrodes of the oscillator I via a resistance 3 and a discharge tube 4 is connected in parallel with the series connection of the source of anode voltage 2 and the resistance 3.
  • the grid circuit of the tube 4 includes a series connection of the source of voltage 5 in which medium frequency oscillations are generated and a microphone 6 in which the oscillations to be modulated are generated.
  • I designates a low frequency modulating voltage generated in the microphone and supplied to the grid of the tube 4 and 8 is the result of the superimposition of this voltage generated in the microphone and the medium frequency alternating voltage from the source 5.
  • This frequency of the source 5 is not critical but is preferably higher than the highest modulating frequency occurring. In order to avoid distortion, the maximum amplitude of the medium frequency voltage is made equal to or higher than the maximum amplitude of the low frequency modulating voltage.
  • the resulting voltage designated by 8 is supplied to the grid of the tube 4 which does not allow current to pass until the voltage amplitude supplied to the grid is equal to or higher than the voltage the value of which is designated by the horizontal line 9.
  • a blocking bias source may be provided in the input circuit between'the cathode and the grid of the tube 4. The tube 4 is therefore conductive during those time intervals which in Figure 3 are designated by thick lines.
  • the tube 4 is a so-called absorption tube the internal resistance of which has a substantially constant value when a grid bias equal to or higher than that designated by the horizontal line 9 is supplied. This ensures that during the time intervals in which the tube A is conductive the electrodes of the oscillator I have supplied to them such an anode voltage that the oscillator does not generate or only generates to a slight extent, whereas during the time intervals in which the tube 4 is non-conductive, the anode voltage at the electrodes of the oscillator I is such that oscillations having a constant amplitude are generated.
  • the anode voltage is preferably such that even when the tube 4 is conductive the oscillator keeps generating to a feeble extent, as in this case with the desired variation of the anode voltage the correct frequency is obtained at once. If, on the contrary, generating is entirely interrupted first, an undesired frequency may still become manifest.
  • the oscillations generated by the oscillator are emitted in the antenna connected to the oscillator periodically with a constant amplitude during a series of time intervals the length of which depends on the instantaneous value of the modulating voltages.
  • An oscillator having an electron discharge tube of the magnetron type andlhaving a plurality of anode elements and a cathode in circuit therewith, a source of potential and a resistor in series between the anodesand the cathode, and modulating means including a source of variable waves and a source of alternating current of predetermined frequency, and means including a second electron discharge tube connected to the oscillator tube circuit for causing the anode voltage applied to the oscillator to vary abruptly between a value which permits of generating oscillations at a substantially constant frequency and a value which permits of generating oscillations of only negligible intensity.
  • An oscillator having an electron discharge tube of the magnetron type and having a plurality of anode elements and a cathode in circuit therewith, asource of direct current potential and an impedance in series between the anodes and the cathode, a second electron discharge tube having a'space path in shunt with the space path of the oscillator tube, means including a microphone in series with a source of alternating current and agrid blocking bias source for varying the impedance of the second electron discharge tube, and means for so adjusting the amplitude of the alternating current component with respect to the modulating component arising in the microphone that said second tube'is caused to intermittently interrupt the oscillatory action of the first said tube by the absorption of energy through its space path.
  • a high frequency oscillator comprising anelectron discharge tube of the magnetron type, including a linear cathode-and a plurality of surrounding segmented anodes, a resonant circuit system connected across the anode segments, a source of operating potential and an impedance connected between the cathode and said resonant circuit system, means for rendering said oscillator substantially intermittent in itsoperation, said means comprising a discharge tube having a discharge path in shunt with the discharge path of said oscillator tube, and means including a source of low frequency modulation potentials superposed upon a source of intermediate frequency potentials, said means being applied to an input circuit for the second said discharge tube for alternately blocking said tube and ren-'- dering the same conductive, thereby to control the anode voltage-applied to'said oscillator over a range sufiicient-tocause said intermittent oscillatory operation.

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US54862A 1934-12-17 1935-12-17 Oscillator of the magnetron type Expired - Lifetime US2161087A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL448762X 1934-12-17

Publications (1)

Publication Number Publication Date
US2161087A true US2161087A (en) 1939-06-06

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Family Applications (1)

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US54862A Expired - Lifetime US2161087A (en) 1934-12-17 1935-12-17 Oscillator of the magnetron type

Country Status (5)

Country Link
US (1) US2161087A (de)
DE (1) DE679422C (de)
FR (1) FR798355A (de)
GB (1) GB448762A (de)
NL (1) NL42088C (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2440264A (en) * 1943-10-15 1948-04-27 Standard Telephones Cables Ltd Modulator system

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2440264A (en) * 1943-10-15 1948-04-27 Standard Telephones Cables Ltd Modulator system

Also Published As

Publication number Publication date
GB448762A (en) 1936-06-15
DE679422C (de) 1939-08-04
NL42088C (de)
FR798355A (fr) 1936-05-15

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