US2363918A - Reactive electron discharge circuits - Google Patents

Reactive electron discharge circuits Download PDF

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Publication number
US2363918A
US2363918A US450498A US45049842A US2363918A US 2363918 A US2363918 A US 2363918A US 450498 A US450498 A US 450498A US 45049842 A US45049842 A US 45049842A US 2363918 A US2363918 A US 2363918A
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United States
Prior art keywords
frequency
anode
cathode
inductance
control electrode
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Expired - Lifetime
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US450498A
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English (en)
Inventor
James F Wilcox
Edwin W Kenefake
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General Electric Co
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General Electric Co
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Filing date
Publication date
Priority to BE471687D priority Critical patent/BE471687A/xx
Application filed by General Electric Co filed Critical General Electric Co
Priority to US450498A priority patent/US2363918A/en
Priority to GB11151/43A priority patent/GB564504A/en
Application granted granted Critical
Publication of US2363918A publication Critical patent/US2363918A/en
Priority to FR938600D priority patent/FR938600A/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03C—MODULATION
    • H03C3/00—Angle modulation
    • H03C3/10—Angle modulation by means of variable impedance
    • H03C3/12—Angle modulation by means of variable impedance by means of a variable reactive element
    • H03C3/14—Angle modulation by means of variable impedance by means of a variable reactive element simulated by circuit comprising active element with at least three electrodes, e.g. reactance-tube circuit

Definitions

  • Such resonant circuits whose operating frequency may be readily adjusted, are used to produce frequency modulated carrier waves, the adjustably tuned circuit being the frequency controlling ciruit of an oscillator. It has been found that one of the advantages of frequencymodulation is attained when th'e amount of frequency shift of the carrier wave is greater than the highest frequency of the modulating signal.
  • an ordinary audio signal may contain components up to about 5000 cycles making it desirable to shift the frequency ofthe carrier wave about 25,000 cycles from its mean frequency in either direction.
  • Fig. 1 signals from a microcircuit including a discharge device ll, the resonant circuit being maintained in oscillation by a discharge device I2, and such frequency modulated oscillations being amplified through a power amplifier *I3 and .impressed on a power line I4 through a coupling condenser l5.
  • the cathode I6 of the oscillating discharge device l2 is grounded, the control electrode Il thereof is connected through a grid leak resistance
  • the intermediate cap 221s connected to less than about twenty times the highest frequency component of the signal to be transmitted the usual type of adjustable frequency tuned circuit is not capable of shifting the frequency of the carrier wave sumciently to give the large frequency swing desired. For example, with a carrier wave of 50 kilocycles, as frequently used for carrier current transmission, a 3% swing in either direction would be about 1500 cycles in either di rection. If the highest frequency component of' the signal to be transmitted were only 3,000 cycles, with such a low ratio of the highest signal frequency tothe ⁇ carrier frequency swing, a low I signal to noise vratio results.
  • the anode 23 .of the device l2 is coupled through a suitable coupling condenser 24 to the amplifier I3.
  • Discharge current for the device l2 is supplied from the positive terminal of a source 25 of operating potential, whose negative terminal y is grounded through an intermediate tap 26 of the inductance 20 between the tap 22 and'terminal 28 of the inductance.
  • the tap 26. is bypassed to ground by a bypassing condenser 2l for high frequency currents.
  • the discharge device ll, ⁇ which controls the resonant frequency of the tunedcircuit including the inductance 20 and condenser ⁇ 2 I, has an anode 38 connected to that terminal of the inductance 20 opposite the terminal 28.
  • -of device II is connected to ground through a biasi ing resistance 32 in parallel with the bypassing condenser 33.
  • the rst, or control, electrode 34 is connected to ground through a pair of resistances 35 and 36, connected in series, and through the microphone I0.
  • the second or screen electrode 31 of the device I I is connected to cathode 3
  • the control electrode 34 ofthe device I I is excited with a voltage which is out of phase with the voltage across the tuned circuit 20, 2
  • may be made to differ in phase by exactly 90 from the alternating potential across condenser 2
  • the reactance of condenser 42 should besubstantial at the frequency of signals from microphone I0 to avoid undesirable attenuation thereof.
  • a curve 50 illustrates the relation between the instantaneous signal potential from microphone I0 and the resulting frequency deviation of the carrier wave generated by the device I2.
  • the instantaneous signal potentials in volts are plotted as abscissae, and the resulting frequency deviations in kilocycles as ordinates. as zero, the carrier frequency was actually 88.5 kilocycles and the ⁇ instantaneous signal potential 3.87 volts.
  • th'e frequency of the carrier wave was changed linearly about 5 kilocycles in either direction. The total linear frequency change thus produced was more than 11 percent of the'average carrier frequency.
  • an autotransformer arrangement such as that in Fig. 1 including the inductance 28, is utilized to produce a wide linear frequency swing in response to a modulating potential, it is desirable that amplitude modulation of the frequency modulated carrier wave be minimized.
  • an alternating potential be applied to the control electrode 34 of device II which has a component in phase with the alternating potential between taps 22 and 28 of the inductance'20, a regenerative or degenerative effect is produced upon the tuned oscillator circuit through the action of current flowing through the anode 30 controlled in accordance with the alternating potential on the control electrode 34.
  • This regenerative or degenerative action results in the production of amplitude modulations of the oscillating potential maintained in the tuned circuit 20, 2
  • phase shiftlist ing network including condensers 40 and 4
  • Our invention may be utilized to modulate the frequency of any carrier wave, such as for a radio transmitter, over a very wide frequency band. It may, in fact, be utilized to take a large reactive current from any source of alternating potential, where such a reactive current is desired.
  • an oscillator including an lllectron discharge device having an anode and a A suitable bypassing condenserl 42A is connected 'u control electrode connected to opposite terminals At the frequency deviation indicated ⁇ of a resonant circuit to excite oscillations therein, said resonant circuit including a winding, a second electron discharge device having an anode, a cathode and a control electrode, a second winding connected in series with said winding and comprising therewith an autotransformer, said autotransformer having its end terminals connected between the anode and cathode of said second discharge device.
  • said autotransformer means for supplying .to the control electrode of said second discharge device oscillations having such phase relations to oscillations on the anode of said second discharge device that a reactive current flows between the anode and cathode thereof and through said autotransformer, and means for supplying a variable'unidirectional potential to the control electrode of said second electron discharge device to vary said reactive current and thereby to control the tuning ofsaid resonant circuit and the frequency of oscillations excited therein by said iirst discharge device, said autotransformer increasing the reactive effect of ⁇ said second electron discharge device upon said resonant, circuit and extending the range of said frequency variations.
  • a source of alternating po ⁇ tential means for taking'from said source an adjustable reactive current, said means comprising an electron discharge device having an anode, a cathode, and a control electrode so connected across said source that a reactive current ows between said anode and cathode and the impedance of said device between said anode and cathode simulates a reactance
  • means comprising a step-up autotransformer interposed between said source and said device, said autotransformer having its end terminals connected between said anode and cathode and an intermediate portion thereof connected across said source thereby to increase the reactive e'ect of said device on said source, and means to modulate the current between said anode and cathode in accordance with a varying electromotive force thereby to modulate the reactive current drawn -by said device from said source in accordance with the variation's of said electromotive force.
  • a source of alternating potential a reactance device comprising an inductance and arranged to take a reactive current from said'source, means for impressing potential from said source across a portion of said inductance, an electron discharge device having -an anode, a cathode and a control electrode, said anode and cathode being connected to electrically spaced points of said inductance includingV appreciably more of said inductance than said portion thereof, and phase shifting means for impressing alternating potentials from said source between said control electrode and said cathode in displaced time-phase relation with respect to the alternating potential between said anode and cathode.
  • a source of alternating potential a reactance'device comprising, an inductance and arranged to take a reactive current from said source, means for impressing potential from said source across a portion of said induct.. ance, an electron discharge device having an anode, a cathode and a control electrode, saidV anode and cathode being connected across a second portion of said inductance greater than and including said rst portion, and means comprising a reactance and a resistance connected serially across said rst portion of said inductance for impressing between said control electrode and said cathode an alternating potential derived from said source of potential and displaced in time-phase relation withA respect thereto, said means comprising a connection between said control electrode and a point between said reactance and resistance.
  • an oscillator including an electron discharge device having an anode and a control electrode connected to opposite terminals of a resonant circuit to excite oscillations therein, said resonant circuit including a winding, a second electron discharge device having an anode, a cathode and a control electrode, a second winding connected in series with said winding and comprising therewith an autotransformer, said autotransformer having its end terminals connected between the anode and cathode of said second discharge device, and phase shifting means connected to derive from said resonant circuit and apply to the control electrode of said second electron discharge device an alternating voltage in substantially quadrature relation with respect to the voltage of said resonant circuit thereby to effect the iiow of ⁇ a reactive current through said second electron discharge device and said autotransformer and to minimize any tendency of said connected in series with said iirst inductance, an oscillator including an electron discharge device having an anode and a control electrode connected to opposite terminals of a re
  • electron discharge device having an anode, a cathode and control electrode, means for impressing alternating potential from said tuned circuit between said control electrode and cathode in displaced time-phase relation with respect to the .phase of the alternating potential of said source, means for connecting said anode and cathode to the electrically remote terminals of said inductance, whereby the auto-transformer action oi' said inductance increases the reactive eiifect of said discharge device and a component of said alternating potential between said control electrode and cathode in phase with the alternating potential of said tuned circuit tends to produce amplitude modulation of said alternating potential onsaid tuned circuit, and means for increasing the time phase relation of alternating potential between said control electrode and cathode with-respect to the timev phase of the alternating potential across said tuned circuit'sub-A stantially to a quarter wave of said alternating potential to minimize such amplitude modulation.
  • a variable frequency oscillation generator comprising an inductance, a condenser connected across a portion of said inductance and forming 'with said portion a tuned circuit. means for maintaining an electrically intermediate point of said portion of said inductance. at a xed potential, means for maintaining oscillations in said tuned circuit.
  • an electron discharge device having an anode, a cathode and a control electrode, said anoder being connected to a rst terminalof said inductance electrically spaced from said tuned portion and said cathode being maintained at a second fixed potential and connected to a second terminal of said inductance and means for impressing an alternating potential between said control electrode and cathode in displacedl comprising a resistance and reactance serially connected in shunt to said tuned circuit, said control electrode being connected between said relactance and resistance, said reactance at the resonant frequency of said tuned circuit being so related to said 'resistance that the alternating potential impressed thereby between said control 5 is minimized.

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  • Ac-Ac Conversion (AREA)
  • Amplifiers (AREA)
US450498A 1942-07-11 1942-07-11 Reactive electron discharge circuits Expired - Lifetime US2363918A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
BE471687D BE471687A (sr) 1942-07-11
US450498A US2363918A (en) 1942-07-11 1942-07-11 Reactive electron discharge circuits
GB11151/43A GB564504A (en) 1942-07-11 1943-07-09 Improvements in and relating to electron discharge circuits
FR938600D FR938600A (fr) 1942-07-11 1946-09-02 Perfectionnements aux circuits comprenant un tube à réactance

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US450498A US2363918A (en) 1942-07-11 1942-07-11 Reactive electron discharge circuits

Publications (1)

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US2363918A true US2363918A (en) 1944-11-28

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US450498A Expired - Lifetime US2363918A (en) 1942-07-11 1942-07-11 Reactive electron discharge circuits

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US (1) US2363918A (sr)
BE (1) BE471687A (sr)
FR (1) FR938600A (sr)
GB (1) GB564504A (sr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2472769A (en) * 1945-03-07 1949-06-07 Rca Corp Signaling system
US2530165A (en) * 1946-09-20 1950-11-14 Hartford Nat Bank & Trust Co Circuit for frequency control
US2858436A (en) * 1953-12-14 1958-10-28 Gen Electric Automatic frequency control system
US2890417A (en) * 1957-05-27 1959-06-09 Sanders Milton Frequency modulation system
US3868856A (en) * 1973-04-25 1975-03-04 Nasa Instrumentation for measurement of air-craft noise and sonic boom

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2472769A (en) * 1945-03-07 1949-06-07 Rca Corp Signaling system
US2530165A (en) * 1946-09-20 1950-11-14 Hartford Nat Bank & Trust Co Circuit for frequency control
US2858436A (en) * 1953-12-14 1958-10-28 Gen Electric Automatic frequency control system
US2890417A (en) * 1957-05-27 1959-06-09 Sanders Milton Frequency modulation system
US3868856A (en) * 1973-04-25 1975-03-04 Nasa Instrumentation for measurement of air-craft noise and sonic boom

Also Published As

Publication number Publication date
BE471687A (sr)
FR938600A (fr) 1948-10-19
GB564504A (en) 1944-09-29

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