US2122495A - Magnetron oscillator - Google Patents

Magnetron oscillator Download PDF

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Publication number
US2122495A
US2122495A US24060A US2406035A US2122495A US 2122495 A US2122495 A US 2122495A US 24060 A US24060 A US 24060A US 2406035 A US2406035 A US 2406035A US 2122495 A US2122495 A US 2122495A
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US
United States
Prior art keywords
anode
cathode
plates
oscillations
signal
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
US24060A
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English (en)
Inventor
Herbert J Scott
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.)
AT&T Corp
Original Assignee
Bell Telephone Laboratories Inc
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
Priority to BE468271D priority Critical patent/BE468271A/xx
Application filed by Bell Telephone Laboratories Inc filed Critical Bell Telephone Laboratories Inc
Priority to US24060A priority patent/US2122495A/en
Priority to GB12688/37A priority patent/GB468271A/en
Priority to FR812051D priority patent/FR812051A/fr
Application granted granted Critical
Publication of US2122495A publication Critical patent/US2122495A/en
Anticipated expiration legal-status Critical
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
    • H03—ELECTRONIC CIRCUITRY
    • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
    • H03B9/00—Generation of oscillations using transit-time effects
    • H03B9/01—Generation of oscillations using transit-time effects using discharge tubes
    • H03B9/10—Generation of oscillations using transit-time effects using discharge tubes using a magnetron

Definitions

  • This invention relates to oscillation generators and particularly to high frequency oscillationv generators of the so-called magnetron type wherein magnetic and electrostatic elds are employed to control the ilow of electrons between a cathode and an anode disposed Within an envelope or container.
  • One of the objects of this invention is to protect such an envelope from destructive bombardment by electrons.
  • Another object of this invention is to influence the output oscillations of a high frequency oscillation generator and to obtain greater efliciency of operation thereof.
  • Another object of this invention is to con- 2c trol or stabilize the frequency of the oscillations generated by a magnetron oscillator.
  • a magnetron oscillator may comprise circuits including a tube containing a suitable gas at a suitable pressure and also containing an electronemitting cathode element and an anode element comprising one or more anode plates, and means for producing a magnetic field transverse to the path of electrons between the cathode and anode structure.
  • the magnetic eld may be unidirectionally produced by an electromagnet having an iron core to concentrate the magnetic eld and may be adjustable to produce a glancing incidence of electrons with respect to the anode.
  • the tuned output circuit or antenna may be of any suitable type and if desired, of critical length with respect to the wave-length of the waves developed thereon.
  • the output power may be increased or the filament current required to produce a given output power may be reduced.
  • the auxiliary electrode structure may be in the form of one or more metal plates of suitable size disposed endwise of or at or adjacent the ends of the cathode-anode structure along the axis of the magnetic field.
  • the metal end plates may be built into the structure of the tube and disposed within the glass envelope or they may be attached to the outside or inside of the glass envelope.
  • Signal responsive potentials may be applied to the end plate structure to modulate the radio frequency output of the oscillator in accordance with such signals.
  • 'Ihe output oscillations may be modulated in accordance with signals not only through the plate structure alone, such as the anode plate structure or the end plate structure or other auxiliary electrode structure, but also through the magnetic iield alone, or by a combination of magnetic iield and plate modulation from the same signal current source wherein the signal currents from the same or common source may be so adjusted in phase and magnitude as to reduce distortion in the modulated oscillations.
  • a mechanical vibratile element in the form of a piezoelectric quartz crystal may be employed if desired, as by coupling with the output circuit or in connection with one or more of the plate electrodes, to control or stabilize the frequency of the oscillations generated by the magnetron oscillator in accordance with a frequency characteristic, fundamental or harmonic, of the crystal.
  • one of the anode plates may be maintained at constant potential and the potential of another anode plate may be modulated in accordance with signals, thereby leaving full voltage on at least one anode plate.
  • This arrangement may be utilized to render the circuit more stable and less likely to stop oscillating.
  • Fig. 2 is a sectional end view of the envelope, cathode, anode, and auxiliary electrode structure of Fig. 1;
  • Fig. 4 is a diagram showing another modification of a magnetron oscillator
  • the bridge 44 is connected at its midpoint 46 with the positive terminal of an adjustable source'of direct current in the form of a battery 48.
  • the negative terminal of the battery 48 is connected with the midpoint 33 of the transformer 32.
  • the battery 48 is adapted to furnish a high positive voltage to the anode plates I4 and I'u. Under proper conditions of heating of the cathode I2 and suitable potential applied to the anode plates I4 and I6 from the source 48 and proper adjustment of the strength of the magnetic field from the field coil I8, oscillations of the desired frequency or wave-length may be set up in the tunable output circuit 40, 42, and 44.
  • Auxiliary electrode structure in the form of a pair of equal size rectangular-shaped end plates 50 and 52 disposed at right angles to the axis of vthe cylindrical anode I4, I6 and suitably polarized from a battery 54 is provided to control or influence the electron flow between the cathode I2 and the anode plates I4 and I6 by producing an axial component of motion of the electrons with respect to the axis of the tube system Ii), I2, I4, and I 6.
  • the auxiliary electrodes 50 and 52 are disposed endwise of or at or adjacent the ends of the cathode and anode structure I2, I4, and I6 and may be built into the tube structure and disposed within the glass envelope I8.
  • the end plates 50 and 52 may be constructed of any suitable conductive material and may be attached to the outside or inside of the glass envelope Ill,
  • the end plates 50 and 52 When the end plates 50 and 52 are suitably polarized as from a battery corresponding to the battery 54, they may operate as electrostatic means to increase the space charge of the electron discharge device I and to increase the output power of the oscillating system. For example, when the system is oscillating and delivering power to the load circuit 40, 42, and 44, if the voltage from the source 54' applied to the auxiliary end plates U and 52 is made of suitable positive value with respect to the filament I2, an increase of radio frequency output power delivered to the load circuit of the magnetron oscillator may be obtained.
  • 1 oscillating at a wave-length of 1.5 meters may have a potential of the order of 1000 volts applied to the anode plates I4' and I6 from the source 48, suitable magnetic eld strength from the winding I8, and a voltage from the source 54 applied to the auxiliary end plates 58 and 52 of the order of several hundred volts with respect to the filament I2. It will be understood that the values of voltage applied from the source 54 to the end plates 50 and 52 may be adjusted to secure the optimum value of increased output power in the load circuit 40, 42, and 44.
  • the end plate auxiliary electrodes 50 and 52 are maintained at a moderately high negative potential, for example, of the order of 200 volts with respect to the filament I2, the electrons are turned back and repelled and destructive bombardment or sputtering of the ends II and I3 of the glass envelope I8 by electrons may be prevented. Such bombardment may take place at diametrically opposite parts I I and I3 of the tube I0 in a line corresponding very roughly to the axis of the magnetic field.
  • the end plates 50 and 52 suitably polarized may be utilized to protect the glass envelope I Il from such bombardment and sputtering.
  • Means may be provided for modulating in accordance with signals the radio frequency output oscillations of the magnetron oscillator shown in Fig. 1.
  • the modulating potentials may be supplied to the end plates 56 and 52 through a circuit including the conductors 55 and 51, a transformer 58, an audio frequency amplier 60, an audio frequency transformer B2, a telephone transmitter or microphone 64 and a battery 86.
  • Signals, such as voice signals, impressed upon the telephone transmitter 64 supply corresponding potentials to the auxiliary electrodes 50 and 52 and operate to f modulate the radio frequency output of the oscillation generator.
  • the modulating potentials may be impressed not only upon the end plates 50 and 52 alone as described, but also upon the magnetic field producing winding I8 by means of a circuit including the conductors 6l and 68 and a condenser 69 thereby to produce a combined simultaneous plate and magnetic eld modulation from the same or common signal source 64.
  • amplitude relations of the modulation potentials supplied from the common signal source 64 to the end plates 50 and 52 and to the winding I8 may be so adjusted, as by means of the variable inductance 58 and the variable condenser 89, as to reduce signal distortion by producing a linear relation between the change in amplitudes of the radio frequency modulation and the signal voltage modulation thereby to secure straight line amplitude modulation of the radio frequency oscilla- The phase and magnitions at a region where substantially no frequency modulation occurs.
  • the radio frequency output oscillations may be modulated through the magnetic field alone as by impressing the signal modulated voltages upon the winding I8 over the circuit including the conductors 6T and 68 and the condenser 69.
  • the end plates 50 and 52 may at the same time be utilized as hereinbefore described for producing an axial component of motion the electrons for theseveral purposes mentioned.
  • Fig. 2 shows a sectional end View of the auxiliary electrode and cathodeanode structure of Fig. l. It will be understood that the end plate electrodes 50 and 52 may be of circular or rectangular shape or other suitable shape and dimensions.'
  • Fig. 3 shows a modification of the system shown in Fig. 1.
  • the space discharge device inciuding the cathode I2, anode plates I4 and I6 and end plates 50 and 52 as shown is similar to that shown in Fig. 1.
  • An alternative modulation connection is shown in Fig. 3 wherein modulating potentials varying in accordance with signals may be supplied to the end plates 50 and 52 from the telephone transmitter 64 by means of a transformer 'te having a midpoint 'l2 of one of its windings connected with the battery 54.
  • the modulating potentials may be impressed not only upon the end plates 50 and 52,y but also upon the magnetic field producing winding I8 by means of a circuit including the conductors 61 and 68 and the condenser 69 to produce simultaneous plate and magnetic field modulation from the same source 64.
  • the radio frequency oscillations may be modulated in accordance with signals through the magnetic eld alone over the circuit including the conductors 61 and 68 and the condenser 60.
  • FIG. 3 An alternative tunable output circuit is shown in Fig. 3 which comprises a variable condenser 80 connected in parallel circuit relation with a winding 82 having a midpoint 84 connected with the battery 40 and connected to ground through a condenser 06.
  • the tunable output circuit 80, 82 is .connected with the anode plates I4 and I6 through the conductors 8
  • a mechanical vibratile element in the form of a piezoelectric quartz crystal having electrodes 92 and 94 may be coupled through a winding 96 to the winding 82 for controlling or stabilizing the frequency of the oscillations generated the tunable output circuit 80, 82.
  • Additional circuits or devices, such as amplifier tubes, may be provided as indicated at 08.
  • Figs. 4 and 5 show a multiple plate magnetron oscillator tube
  • rTwo of the plates namely, anode plates
  • the negative terminal'of the battery 48 is connected with the midpoint 33 of the transformer winding ⁇ 32 as in Fig. 1.
  • 06 are also oppositely disposed with respect to each otherand are interspaced between the anode plates
  • I6, may supply positive voltage of suitE able value to the modulating plates
  • a piezoelectric quartz crystal 00 may be connected, if desired, with the'anode plates
  • 22 may be employed in connection with a magnetic iield producing winding
  • 24 may be energized from a battery
  • 22 produce a magnetic field in a direction transverse to the path of electrons between the cathode I2 and the anode plates
  • the magnetic field-producing means illustrated is of the air core type like that shown in Fig. 1.
  • 60' has its negative terminal connected to ground at
  • the radio frequency output of the magnetron oscillator shown in Fig. 6 may be modulated by signals impressed on the transmitter or microphone 64.
  • the modulation system shown is of the constant current type modified to change the potential on the anode plate
  • 10 which may be used to amplify signal currents from the transmitter 64
  • 12 adapted to transmit audio frequency currents from the amplifier
  • 14 adapted to transmit audio frequency currents from the amplifier
  • 00 is therefore maintained at constant potential and the potential of the anode plate
  • Combined plate and magnetic field modulation in accordance with signals may be obtained by impressing the signal modulated potentials or currents upon the magnetic eld producing winding I8 by means of a circuit including a conductoi1
  • the modulating potentials from the common source 64 may be so adjusted in phase and magnitude as to reduce distortion by suitable adjustments in the variable inductance
  • radio frequency oscillations of the desired frequency may be set up in the tunable output circuit 220 and modulated in accordance with telephone or telegraph signals impressed on a signal responsive circuit as a circuit including the telephone transmitter or microphone 64, the battery 66, the transformer 62 and the audio frequency amplifier 60.
  • the radio frequency output oscillations may be modulated through the magnetic field alone by impressing modulating voltagesvarying in accordance with signals upon the winding 236 that produces the magnetic iield.
  • the winding 236 may be connected with the circuit of microphone 64 by means of conductors 250 and 252 and a condenser 254. Signals such as speech impressed on the microphone 64 produce signal currents which may be amplified by the amplifier 60 and introduced into the winding 236 by means of the conductors 250, 252 and the condenser 254 to impress modulating voltages varying in accordance with the signals upon the winding 236 thereby to inuence the magnetic field produced by the winding 236 to modulate the oscillations generated in accordance with the signals impressed on the microphone 64.
  • Plate modulation alone on both anode plates 204 and 206 of the oscillation generator of Fig. '1 may be obtained by coupling the signal source 64 with the anode plates 204 and 206 by means of a transformer 260 and disconnecting the magnetic field winding 236 from the signal source 64.
  • modulating voltages Varying in accordance with telephone signals on the microphone 64 are impressed on both anode plates 204 and 206 thereby to modulate the oscillations generated in accordance with signals.
  • Combined plate and magnetic field modulation of oscillations generated may be obtained with the system shown in Fig. '7 wherein modulating voltages varying in accordance with signals in the same or common signal circuit 64 may be impressed not only upon the winding 236 which produces the magnetic eld, but also upon the anode plates 204 and 206 thereby to produce a combined simultaneous plate and eld modulation of oscillations generated in accordance with signals impressed on the same source 64.
  • Fig. 9 shows a modification of Fig. '1, like reference characters indicating similar parts.
  • a winding 259 energized by a battery 262 controlled by a variable resistance 264 produces a magnetic field in the iron core
  • Apparatus for generating signal-modulated oscillations including a space discharge device having a cathode, an anode disposed around said cathode and auxiliary electrode plate structure disposed adjacent the opposite ends of said 'cathode and anode, magnetic eld producing means, a common source of signal currents, and modulatingmeans responsive to said common source for simultaneously influencing said magnetic eld and said auxiliary end plate structure and including reactance means for controlling the relative phase and magnitude of the signal currents supplied to said eld producing means with respect to the signal currents supplied to said auxiliary end plate structure from said common source for modulating the amplitude of said oscillations in linear relation with respect to the amplitude of said signal currents whereby distortion in said modulated oscillations is reduced.
  • Apparatus for generating signal-modulated oscillations including a space discharge device having a cathode, anode structure and auxiliary plate structure disposed concentrically with respect to said cathode, magnetic field producing means, a common source of'signal currents, and means simultaneously responsive to said common source of signal currents for applying said signal currents tofsaid magnetic eld producing means and said auxiliary plate structure for modulating said oscillations in accordance with said signal currents, and reactance means connected with said last-mentioned means for controlling the relative phase of the signal currents applied to said field producing means With respect to the signal currents applied to said auxiliary plate structure for modulating the amplitude of said oscillations in linear relation with respect to the amplitude of said signal currents of said source.
  • Apparatus for generating high frequency oscillations including a space discharge device having cathode and anode structure, a plurality of auxiliary electrodes, means including magnetic means influencing said device, a tunable output circuit connected with said anode structure for generating oscillations, piezoelectric means, and means including a circuit separate from said output 'circuit operatively connecting said piezoelectric means with said plurality of auxiliary electrodes for stabilizing the frequency of said oscillations.
  • Apparatus for generating signal-modulated oscillations including a space discharge device having a pair of oppositely disposed electrodes and another .pair of oppositely disposed auxiliary electrodes, a linear cathode disposed between said pairs of electrodes, means for producing a magnetic eld substantially in the direction of the axis of said linear cathode, a tunable output circuit and a source of potential operatively connected with said first-mentioned pair of electrodes, piezoelectric means operatively connected with one pair of said pairsof electrodes for stabilizing the frequency of said oscillations, a source of signal currents, and means connecting said source with said magnetic eld producing means and with at least one of said electrodes for modulating said oscillations in accordance with said signal currents, said connecting means including reactive means adjusting the phase and magnitude of said signal currents to modulate without distortion the amplitude of said oscillations in accordance with the amplitude of the signal currents in said source.
  • Apparatus for generating oscillations including a space discharge device having a cathode, a plurality of anode plates and auxiliary electrode structure, an oscillatory circuit connected with said anode plates for g-enerating oscillations, means for producing a magnetic field in the space between said cathode and anode plates, a source of constant potential, piezoelectric means connected with said auxiliary electrode structure for stabilizing the frequency of said oscillations, means for maintaining one of said anode plates at the potential of said source and for applying signal potentials to another of said anode plates for modulating said oscillations in accordance with said signal potentials.
  • Apparatus for generating oscillations including a space discharge device having a cathode, two pairs of oppositely disposed quarter cylindrical electrode plates surrounding and concentric with said cathode, means for producing a magnetic eld between said cathode and electrode plates, means including an oscillatory circuit connected with one pair of said pairs of plates for generating oscillations, a piezoelectric device, and an auxiliary circuit separate from said oscillatory circuit and connecting said piezoelectric device with another pair of said pairs of plates for controlling the frequency of said oscillations, and means for applying signal potentials to at least one of said electrode plates for modulating said oscillations in accordance with said signal potentials.
  • Apparatus for generating oscillations including a space discharge device having a cathode, two pairs of oppositely disposed quarter cylindrical spaced electrodes surrounding said cathode, means for producing a magnetic eld between said electrodes and said cathode, means for causing one pair of said pairs of electrodes to generate high frequency oscillations, and means for applying signal potentials to another pair of said pairs of electrodes to modulate said oscillations in accordance with said signal potentials.

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US24060A 1935-05-29 1935-05-29 Magnetron oscillator Expired - Lifetime US2122495A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
BE468271D BE468271A (OSRAM) 1935-05-29
US24060A US2122495A (en) 1935-05-29 1935-05-29 Magnetron oscillator
GB12688/37A GB468271A (en) 1935-05-29 1936-05-05 Improvements in or relating to electrical oscillation generators
FR812051D FR812051A (fr) 1935-05-29 1936-05-28 Perfectionnements aux générateurs d'oscillations électriques

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Application Number Priority Date Filing Date Title
US24060A US2122495A (en) 1935-05-29 1935-05-29 Magnetron oscillator

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US2122495A true US2122495A (en) 1938-07-05

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BE (1) BE468271A (OSRAM)
FR (1) FR812051A (OSRAM)
GB (1) GB468271A (OSRAM)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2493706A (en) * 1948-03-30 1950-01-03 Gen Precision Lab Inc Electronic switch
US2500328A (en) * 1945-03-27 1950-03-14 Raytheon Mfg Co Pulsed oscillator of the magnetron type
US2648772A (en) * 1949-02-15 1953-08-11 Raytheon Mfg Co Magnetron control circuits
US2774941A (en) * 1952-11-14 1956-12-18 Raytheon Mfg Co Communication systems
US2817820A (en) * 1952-12-31 1957-12-24 Raytheon Mfg Co Frequency-modulated communication systems
US2925523A (en) * 1957-02-12 1960-02-16 Sylvania Electric Prod Wave generator

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2500328A (en) * 1945-03-27 1950-03-14 Raytheon Mfg Co Pulsed oscillator of the magnetron type
US2493706A (en) * 1948-03-30 1950-01-03 Gen Precision Lab Inc Electronic switch
US2648772A (en) * 1949-02-15 1953-08-11 Raytheon Mfg Co Magnetron control circuits
US2774941A (en) * 1952-11-14 1956-12-18 Raytheon Mfg Co Communication systems
US2817820A (en) * 1952-12-31 1957-12-24 Raytheon Mfg Co Frequency-modulated communication systems
US2925523A (en) * 1957-02-12 1960-02-16 Sylvania Electric Prod Wave generator

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BE468271A (OSRAM)
FR812051A (fr) 1937-04-29
GB468271A (en) 1937-07-01

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