US2523209A - Method of and means for the modulation of ultrashort waves - Google Patents

Method of and means for the modulation of ultrashort waves Download PDF

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Publication number
US2523209A
US2523209A US684819A US68481946A US2523209A US 2523209 A US2523209 A US 2523209A US 684819 A US684819 A US 684819A US 68481946 A US68481946 A US 68481946A US 2523209 A US2523209 A US 2523209A
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United States
Prior art keywords
magnetron
wave
modulation
anode
cathode
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Expired - Lifetime
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US684819A
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English (en)
Inventor
Gutton Henri
Ortusi Antoine Jean
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Thales SA
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CSF Compagnie Generale de Telegraphie sans Fil SA
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    • 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

Definitions

  • This invention is directed to improvements in or relating to methods of and means for the modulation of ultra-short waves in a guide or on a feeder by means of space charge valves such as a magnetron, brake field valve and the like.
  • space charge valves such as a magnetron, brake field valve and the like.
  • Figure 1 illustrates diagrammatically .a device of a transmitter feeding a system radiating through the intermediary of a feeder coupled to a resonator i Fig. 2 re'presents the variations of'the edemcient of transmission of the wave corresponding to' the detuning dof'the resonator;
  • Fig. 3 illustrates, corresponding to a potential Vofthe'ano'de, 'va'riati'on curves of the transmission coe'fiicienfi'for different "values of the magnetic field;
  • the curve representing the coeflicient of transmission of the wave'as a function of the detuning d of the resonator therefore assumes the form illustrated in"Fig. 2. It shows all the more pointedly that "the looser the'coupling of'the resonator to the feeder, 'so-the coefficient of transmission may pass from a value very close to 1, at A, to a value very close'to '0, at B, and'this all themore suddenly the greater the modification of the capacity C of the resonator about the resonance.
  • the preceding group comprises curves that are almost linear, thus permitting very important ratesof modulation of the order of Without appreciable distortion to be obtained.
  • the modulator magnetron may be of comparatively small capacity, so that its impedance remaining large athigh frequencies of modulation, it permits, without appre ciable attenuation, the-modulation of, for example, very rapid television signals.
  • a particularly important advantage of the system according to the present invention is that the magnetron modulates the transmitter without absorbing energy.
  • the characteristics of Fig. 3 have, in fact, all been drawn for potentials very much below the potential necessary to unblock the valve and practically the anode current never exceeds 1 milliarnpere.
  • the invention provides a double modulator the principle of which is as follows:
  • the transmitter is charged on two feeders, or two electromagnetic guides, in such manner that each of these transmits half the energy. Symmetrically there are coupled two resonators on each of these guides. The capacities of these resonators each comprise a magnetron the anode potential of which is modulated. The first magnetron receives the modulated potential to be transmitted and the second a complementary potential in such manner that the sum of these two potentials remains constant. Under these conditions, the transmitter supports a constant charge.
  • the methods which permit these two complementary modulations to be obtained are, furthermore, numerous; for example, a transformer the secondary of which has a central point earthed, may be used for the transmission of telephonic signals; or, again, an amplification may be made in push-pull, etc.
  • one or other of the complementary modulations may be transmitted indifferently to the radiator; if it is a question, on the contrary, of the transmission of television signals, only the wave correctly modulated can be used to transmit to the aerial.
  • the complementary modulated wave is eliminated by terminating the guide which transmits it by its characteristic impedance; this can be effected either by a radiator fitted to the extremity of the guide, which radiator radiates the energy. in a direction other than that of the receiver, or by a resistance fitted at the extremity of the guide.
  • this method of modulation may be utilized with other kinds of valves, in which the capacity in high frequency between two electrodes undergoes variations when the potential of one of the electrodes varies as compared with the other.
  • the magnetron can be replaced by a valve with brake field; there exists, as a matter of fact, in this valve, as in the magnetron, a space charge capable of resonating at a definite frequency; the eiTect produced by causing the potential of the retarding plate or that of the accelerating grid to vary, is similar to that observed with the magnetron.
  • the transmitter E (Fig. 4), for example, a velocity modulation valve, is coupled to a guide G of rectangular section which can only transmit the wave H01 on the frequency of the transmitter. Coupling takes place by a radiating aerial in the interior of a guide element closed on one side by a piston P, and on the other side by a suitable slot F. The whole is fitted in such manner that the transmitter is charged under the desired conditions.
  • the preceding guide is separated into two guides I and 2, by the interposing of a metallic partition Q. Arrangements are made so that there should be no reflection on the incident wave on this discontinuity. This may be accomplished by annulling the reflection by a suitable adaptor D. Half the incident energy then circulates in each of the guides l and 2.
  • the anode potentials of the two magnetrons Mrand M2 on which are superposed the modulation potentials are produced by means of two conducting wires f1, f2 (Fig. 6) arranged normally to the elastic field q and connected respectively to the two electrodes of the condenser S; these wires f1 and f2 emerge furthermore from the guide through an insulator.
  • Fig. 6 represents a section of Fig. 4, which section is made perpendicularly to the plane of the latter, at the level of the condenser S.
  • the branch l of the guide (Fig. 4) which has received the modulation suitable to be transmitted is terminated by the radiator K, which is an electromagnetic horn adapted by a suitable corrector D1; whilst the branch 2 which receives the complementary modulation from I, is terminated by a resistance R adjusted by means of a slot F1 and a piston P1 suitably actuated.
  • the transmitter not being modulated, its stability of frequency remains very high, and its point of operation can be chosen under the best conditions; in general it will therefore be useless to pilot it.
  • the modulation may be very rapid, since it is only limited in the direction of high frequencies by the capacity of the electrodes of the modulatorpit will thus be possible for example to pass television signals.
  • the modulation band will not have to pass into the circuits of the high frequency generator which consequently may preserve great supertension favorable to output and to the stability of the generator wave.
  • the modulator does not absorb the energy coming from the transmitter; it can thus be of small dimensions and consequently of very low cost price.
  • the energy furnished by a single generator can be delivered into a large number of feeders or of guides, and modulate in a totally independent manner on each of these guides. This may be utilized to produce a multiplex having a large number of paths.
  • a system for the modulation of an ultrahigh frequency Wave comprising a generator of the said wave, a transmission guide for said Wave, a transmission line connected laterally to the said guide, a magnetron including an anode and cathode, connections between said magnetron and said line, the characteristics of the said line and of the said magnetron being chosen in such a way that their aggregate resounds on the frequency of the said wave, means connected with the said magnetron for varying the direct voltage between the anode and cathode of the said ma netron means for applying a continuous potential beween the anode and the cathode of said magnetron, regulated in such a way that the latter is in the blocked state, and means for applying a variable potential in series with the said con tinuous potential, said variable potential being regulated in such a way as to maintain the tube in the blocked state.
  • a system for the modulation of an ultrahigh frequency wave comprising a generator of the said wave, a transmission guide for said wave, a transmission line connected laterally to the said guide, a magnetron comprising a cathode, an anode concentric with the cathode, and a magnetic field directed along the common axis of the said anode and of the said cathode, means for varying the voltage between the anode and the cathode of the said magnetron, means connected with the said magnetron for giving to the said magnetic field a value slightly different from the value which determines the electronic resonance of the space charge of the magnetron on the frequency of the wave to be modulated, means for applying a continuous potential between the anode and the cathode of said magnetron, regulated in such a Way that the latter is in the blocked state, and means for applying a variable potential in series with the said continuous potential, said variable potential being regulated in such a way as to maintain the tube in the blocked state.
  • a system for the modulation of an ultrahigh frequency wave comprising a generator of the said wave, a transmission guide for said wave, a conductive wall separating the said guide into twoother guides, a transmission line, connected laterally to one of said two guides, a magnetron connected with the said line, and comprising a cathode, an anode concentric with the cathode, and a magnetic field directed alongthe common axis of the said anode and of the said cathode, another transmission line connected laterally to the second guide, another magnetron connected with the said lin and comprising a cathode, an anode concentric with the cathode, and a magnetic field directed along the common axis of the said anode and of the said cathode, means connected with the said magnetrons for giving to the said magnetic fields values slightly different from the values which determine the electronic resonance of the space charges of the magnetrons on the frequency of the waves to be modulated, and means connected with the said magnetrons for applying between their electrodes modulation
  • a system for the modulation of an ultrahigh frequency wave comprising a generator of the said wave, a transmission guide for said wave, a transmission line connected laterally to the said guide, a magnetron including an anode and cathode, connections between said magnetron and said line, the characteristics of the said line and of the said magnetron being chosen in such a way that they conjointly resonate at the frequency of said wave, means for applying a continuous potential between the anode and the cathode of said magnetron regulated in such a way that the latter is in the blocked state, means for applying a variable potential in series with the said continuous potential, said variable potential being regulated in such a way as to main tain the tube in the blocked state, means for establishing a magnetic field parallel to the cathode and means for regulating said field in such a way that it is slightly different from the field determining the electronic resonance of the space charge on the wave to be modulated.
  • a system for the amplitude modulation of an ultra-high frequency wave comprising in combination a generator for supplying an ultrahigh frequency wave, a transmission guide for said wave, a circuit tunable to this wave composed of a transmission line coupled laterally to the said guide and a magnetron including a cathode, an anode concentric with the cathode, and a magnetic field directed along the common axis of the said anode and the said cathode, means for applying a continuous potential between the anode and the cathode of said magnetron, regulated in such a way that the latter is in the blocked state, means for applying a variable potential in series with the said continuous potential, said variable potential being regulated in such a way as to maintain the tube in the blocked state, and means for regulating said magnetic field in such a way that it is slightly different from the field determining the electronic resonance of the space charge on the wave to be modulated.
  • a circuit tunable to the said wave coupled laterally with said guide, a magnetron in this circuit comprising a cathode and an anode surrounding it, means for introducing a magnetic field between said cathode 7 and anode, means for energizing-the said mag,- REFERENCES CITED matron an of said means being adjusted so as to
  • the following references are of-reco r d in the maintain the magnetron in a, blocked state, me of this patent; means for applying the modulating voltage between said anode and cathode the amplitude of 5 UNITED STATES PATENTS which is adjusted so as to maintain the mag- Number Name Date netron in said blocked condition, the said mag- 2,106,770 Southworth et a1.

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  • Microwave Tubes (AREA)
  • Radar Systems Or Details Thereof (AREA)
  • Control Of Motors That Do Not Use Commutators (AREA)
US684819A 1945-02-06 1946-07-19 Method of and means for the modulation of ultrashort waves Expired - Lifetime US2523209A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR843431X 1945-02-06

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US2523209A true US2523209A (en) 1950-09-19

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US (1) US2523209A (es)
BE (1) BE462983A (es)
CH (1) CH254414A (es)
DE (1) DE843431C (es)
FR (1) FR994840A (es)
GB (1) GB611931A (es)
NL (1) NL69798C (es)

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2106770A (en) * 1938-02-01 Apparatus and method fob receiving
US2121737A (en) * 1933-07-24 1938-06-21 Rca Corp Variable reactance modulator circuit
US2196392A (en) * 1934-11-28 1940-04-09 Rca Corp Ultra high frequency oscillator system
US2211003A (en) * 1938-01-29 1940-08-13 Rca Corp Radio signaling system
US2223058A (en) * 1936-12-23 1940-11-26 Lorenz C Ag Arrangement for modulating highfrequency oscillations
US2293945A (en) * 1938-12-22 1942-08-25 Emi Ltd Modulating system
US2393414A (en) * 1942-09-25 1946-01-22 Rca Corp Modulation system for ultra high frequency waves

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2106770A (en) * 1938-02-01 Apparatus and method fob receiving
US2121737A (en) * 1933-07-24 1938-06-21 Rca Corp Variable reactance modulator circuit
US2196392A (en) * 1934-11-28 1940-04-09 Rca Corp Ultra high frequency oscillator system
US2223058A (en) * 1936-12-23 1940-11-26 Lorenz C Ag Arrangement for modulating highfrequency oscillations
US2211003A (en) * 1938-01-29 1940-08-13 Rca Corp Radio signaling system
US2293945A (en) * 1938-12-22 1942-08-25 Emi Ltd Modulating system
US2393414A (en) * 1942-09-25 1946-01-22 Rca Corp Modulation system for ultra high frequency waves

Also Published As

Publication number Publication date
NL69798C (es)
FR994840A (fr) 1951-11-22
BE462983A (es)
DE843431C (de) 1952-07-07
CH254414A (fr) 1948-04-30
GB611931A (en) 1948-11-05

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