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US2216940A - Modulation - Google Patents

Modulation Download PDF

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Publication number
US2216940A
US2216940A US134375A US13437537A US2216940A US 2216940 A US2216940 A US 2216940A US 134375 A US134375 A US 134375A US 13437537 A US13437537 A US 13437537A US 2216940 A US2216940 A US 2216940A
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US
United States
Prior art keywords
cathode
modulation
frequency
electrodes
anode
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
US134375A
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English (en)
Inventor
Fritz Karl
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.)
Telefunken AG
Original Assignee
Telefunken AG
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 Telefunken AG filed Critical Telefunken AG
Application granted granted Critical
Publication of US2216940A publication Critical patent/US2216940A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • 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
    • H01J25/68—Tubes specially designed to act as oscillator with positive grid and retarding field, e.g. for Barkhausen-Kurz oscillators
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03C—MODULATION
    • H03C3/00—Angle modulation
    • H03C3/30—Angle modulation by means of transit-time tube
    • H03C3/32—Angle modulation by means of transit-time tube the tube being a magnetron

Definitions

  • This invention concerns amethod of and means for attaining oscillations modulated in particu- ⁇ lar in frequency in magnetron tubes and retarding iield generators.
  • the presentr invention relates to a modulation method employing short wave tubes more especially magnetron tubes and retarding field tubes with so-called end-plate electrodes.
  • the greater part ofthe electrons can be caused to only rub against the electrodes serving for the production of oscillation, instead ⁇ of impinging thereon.
  • This part of the electrons likewise contributes lto the production of oscillation, namely through innuence.
  • 'I'he electrons move along a screw line under ⁇ the in-l fluence of the electrical cross field, the axis of said screw line extending approximately parallel to the axis of the system, so that the electrons reach the positively biased so-called. end-plate electrodes only after describing several turns.
  • a variation of the elongations of the electrons necessitates a variation of ⁇ the constant, magnetic iield or a variation of the vmean acceleration'potential. For this reason, accelera- 55 tion ⁇ potential and magnetic field shall bemaintalned constant. There shall be obtained vonly a turningof lthe planes of the courses of the electrons relative to a position 'at rightangles to the cathode. This turning is accomplished through electrical cross iields which cannot exert any ac- 6 celerating force upon theelectrons.
  • e i 'I'he method according to Ithe invention is preferably carried out through the use of discharge tubes having main electrodes disposed concentrically to the cathode, and further auxiliary elecl0* trodes at the ends of the discharge system.
  • Ithe modulation is applied to the end-plate electrodes, which are highly negatively biased relative to the cathode, eitherin equal sense, or in push-pull. Conse- 15 quently, the electronswill be concentrated to a f greater or lesser degreel in the center of the discharge system, without change in their elongations or in the diameters of the courses they follow.
  • Figures land 2 represent known constructie of tubes having end-plate electrodes.
  • Figure 3 clearly indicates the relationship of frequency and amplitude of high frequency oscillations produced in accordance with the method lli: ofthe invention.
  • Figures 4 and 5 show examples of circuits utii iizing the idea of the invention.
  • Figure 1 is a discharge tube with -a single cylindrical anode A.
  • the cathode K is disposed in the axis of the cylinder.v
  • the modulation potentials are applied' only'to the end-plate electrodes. 'rnere is shown as abscissa the bias potential of the endfplate electrodes with respect to the cathode.
  • FIG. 3 the direct bias of the end-plate electrodes S is plotted as the abscissa.
  • the fre- ⁇ quency, variations and the lamplitude variations of the radio frequency oscillations generated are et also plotted as ordinates. 'It will be-recognized from this graphic representation that at 0 nega- "tivebias of the end-plate electrodes S and for all values of-negative bias to the left of 0, the radio frequency amplitude remains constant andsthat l only the frequency of the oscillations generated is varying.
  • Figure 4 shows a complete oscillatory circuit utilizing a split plate magnetron in a self excitation circuit.
  • the anodes A1 and A2 have impressed thereon in the known manner a highly positive bias potential U. applied across the oscillatory circuit O. 'I'he end-plates S receive a vnegative bias potential U. relative to the cathode.
  • alternating -potentials which vary in rhythm with potentials supplied from a modulation source M across a transformer T.
  • Figure 5 shows a circuit in which there is obtained an amplitude modulation for instance by influencing the plate potential, -and a countermodulation by influencing the potential of the end-plate electrodes.
  • item R designates the tube envelope and P are the poles of a magnet arrangement.
  • the tube which is used in a device according to Figure 5 is represented in Figure 1.
  • the numeral M shows that at this point a microphone or a modulation amplifier is intended to be connected.
  • Positively biased end-plate electrodes are best suited in magnetrons having a single part anode.
  • a generator of the magnetron tube type comprising a tube having an anode and a cathode, mean-s for applying a positive potential to said anode relative to said cathode, means for producing a magnetic field of constant strength at right angles to the path which the electrons would follow between said cathode and anode in the absence of said field, means connecting said anode and cathode in oscillation generating circuits, said tube also having.endplate electrodes, means for maintaining said end-plate electrodes negative a substantial amount relative to said cathode, means for varying the potential of said anode in accordance with modulating potentials to amplitude modula'te the oscillations generated, and means for varying the negative potential of said end electrodes in accordance with modulating potentials to produce corresponding variations in the frequency of the oscillations generated.
  • a tube device having a substantially linear cathode, an anode concentrically disposed with respect to the cathode, and an end-plate located at each end of said aforesaid electrodes with means for producing a magnetic field of substantially constant -strength in which said electrodes are disposed, means connecting said anode and cathode in an oscillation producing circuit, means for mainf taining said end-plates at high negative potential relative to said cathode, and means for applying modulating potentials to said end-plates comprising a direct connection between said endplates, and a transformer havinga secondary kwinding connected between said end-plates and said cathode, and a primary winding excited by modulating potentials, the values of said modulating potentials and high negative potential being such that said tube operates substantially within the negative portion of its end-plate-output characteristic, whereby the oscillations produced are varied in frequency in accordance with said applied
  • a tube device having a substantially linear cathode, an
  • anode concentrically disposed with respect to the cathode and an end-plate located at each end of said aforesaid electrodes with means for producing a magnetic field of constant strength in which said electrodes are disposed, means for maintaining said end-'plates at relatively high negative potential relative to said cathode, means for applying modulating potentials to said anode to producecorresponding variations in the amplitude of the oscillations generated, and means for applying modulating potentials to said endplates, to produce corresponding variations in the frequency of the oscillations generated'to compensate frequency variations inherently produced therein by applying said modulating potentials to said anode.
  • a system as recited in claim 3 wherein said means for applying modulating potentials to said end-plates includes a direct connection between said end-plates and a reactance on which said modulating potentials .are impressed connecting said end-plates to said cathodewhereby said end- ⁇ plates are modulated in phase.
  • said means for applying 4modulating potentials.to said y anode and to said end-plates comprises a transformer having a primary Winding excited by modulating potentials, a .first secondary winding having one terminal connected to -both of said end-plates and the other terminal connected to said cathode and a second secondary winding connected between said anode and cathode.

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  • Microwave Tubes (AREA)
US134375A 1936-04-16 1937-04-01 Modulation Expired - Lifetime US2216940A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE485806X 1936-04-16

Publications (1)

Publication Number Publication Date
US2216940A true US2216940A (en) 1940-10-08

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Family Applications (1)

Application Number Title Priority Date Filing Date
US134375A Expired - Lifetime US2216940A (en) 1936-04-16 1937-04-01 Modulation

Country Status (3)

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US (1) US2216940A (de)
GB (1) GB485806A (de)
NL (1) NL47569C (de)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2462137A (en) * 1946-02-26 1949-02-22 Raytheon Mfg Co Electron discharge device

Also Published As

Publication number Publication date
GB485806A (en) 1938-05-25
NL47569C (de)

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