US2530611A - Reactance tube circuit arrangement - Google Patents

Reactance tube circuit arrangement Download PDF

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Publication number
US2530611A
US2530611A US667446A US66744646A US2530611A US 2530611 A US2530611 A US 2530611A US 667446 A US667446 A US 667446A US 66744646 A US66744646 A US 66744646A US 2530611 A US2530611 A US 2530611A
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United States
Prior art keywords
tube
anode
reactance
reactance tube
cathode
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Expired - Lifetime
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US667446A
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English (en)
Inventor
Hepp Gerard
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Hartford National Bank and Trust Co
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Hartford National Bank and Trust Co
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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

  • the invention provides simple means therefor.
  • the starting-point is in this case the so-called reactance tube by which is meant a tube which is generally utilized in combination with a tuned system and which is controlled in suchmanner that it behaves with respect to the system as a more or less pure inductance or capacity.
  • the modulatin control voltage is impressed upon such a reactance tube so as to have a controlling effect and, after demodulation, part of the current which flows in this tube and which is modulated in amplitude by the control voltage is fed-back in counterphase to the tube.
  • the invention is particularly suitable for being applied inter alia to transmitters with frequency modulation.
  • Degenerative coupling of the modulation has previously been suggested for such transmitters but up to the present it has involved the drawback that the signal modulated in frequency had to be detected for this purpose. With the degenerative coupling the almost unavoidable distortion due to this frequency-detection is obtained in the transmitter.
  • the detection of the amplitude-modulated currents in the reactance tube may take place without any distortion and the circuit arrangement is simplified to such an extent that parasitic oscillations are not to be feared.
  • Fig. 1 I denotes a generator tube which may be connected arbitrarily.
  • a reactance tube 2 In parallel with the tuning circuit of the tube is connected a reactance tube 2 whose wiring diagram and operation are well-known and are therefore not described in detail.
  • the coil 3 connected to the anode of the tube 2; this coil is traversed by the anode current of the tube 2 but has so slight an impedance that it 2 does not have a noticeable influence on the operation of the reactance tube as such.
  • the coil 3 is coupled with a detector circuit which comprises a rectifier I of any type desired and'a resistance 8.
  • the voltage variations produced in this resistance are impressed in series but in counter-phase with the modulating voltage applied between terminals 8, 8, upon the grid of the tube 2. If there is no modulation, the tube 2 and the coil 3 are traversed by an alternating current whose frequency is equal to that of the generator and whose phase differs by about from that of the voltage across the generator circuit.
  • this alternating current in 2 and 3 is caused to vary in value so that in the circuit 5, l, 8 use may be made of an ordinary detector known for amplitude modulation. Across the ends of the resistance 8 there consequently occur the detected modulating voltages, which may be utilized for degenerative coupling.
  • the current which passes in consequence thereof through the coil 3 and whose phase may differ from that above referred to and which has in this case a harmful effect on the desired result should preferably also be taken into account.
  • This influence can, however. be easily neutralized, as is illustrated in Fig. 1, by causing a similar current to pass through a coil 4 which is likewise coupled with the coil 5 and which is connected to earth through the intermediary of a small condenser 6 of the same capacity as the capacity indicated in dotted lines.
  • the senses of coupling of the coils 3 and l with the coil 5 are, of course, taken opposite.
  • FIG. 2 Another method of avoiding the same drawback is illustrated in Fig. 2, in which event it is not the reactance tube 2 itself which is connected in parallel with the generator but a second tube l2 connected in cascade with the tube 2.
  • This series-connection is brought about in this case in the ordinary manner with the aid of an anode resistance Ill and a separating condenser
  • Ill an anode resistance
  • a separating condenser The whole of the current in the tube 2 and therefore in the coil 5 is now in the correct phase determined by the voltages applied to the grid of this tube whilst the voltage of the generator circuit, which is out of phase with respect thereto, is no longer applied to the anode of tube 2 but to that of tube I2 where it cannot influence the circuit 5, l, 8.
  • a circuit arrangement for linearly varying an admittance by means oi a periodic control voltage comprising a reactance tube having an anode, a control grid and a cathode, means to apply said control voltage to the control grid oi said tube to modulate the current flowing through said tube, means to derive a potential proportional to the amplitude variation oi the modulated current. and means to apply said potential to said control grid in opposition to said control voltage thereby to linearize the relationship between variations in the amplitude of said control voltage and said admittance variations.
  • a circuit arrangement for linearly varying an admittance by means of a periodic control voltage comprising a reactance tube having an anode, a control grid and a cathode, meansto apply said control voltage to the control grid oi said tube to modulate the current flowing through said tube, means to derive a potential proportional to the amplitude variations of the modulated current, means to apply said potential to said control grid in opposition to said control voltage,
  • a capacitive element having a capacity substantially equal to the anode-cathode capacity said tube, and means to pass a current through said capacitive element to neutralize the leakage of the anode-cathode'capacity of said tube.
  • a circuit arrangement for linearly varying an admittance by means of a periodic control voltage comprising a reactance tube having an anode, a control grid and a cathode, means to apply said control voltage to the control gridof said tube to modulate the current flowing through said tube, means to derive a potential proportional to the amplitude variations of the modulated current, means to apply said potential to said control grid in opposition to said control voltage, a transfer tube having an anode, a control grid and a cathode, and means to couple the anode of said reactance tube to the control grid of said transfer tube to eflect current flow through said tube to neutralize the leakage of the anode-cathode capacity of said reactance tube.
  • a circuit arrangement for frequency modulating a carrier wave comprising an oscillator circuit having an electron discharge tube to generate said carrier wave, a reactance tube having an anode, a control grid and a cathode, means to apply a voltage in phase quadrature with the voltage generated by said oscillator circuit to the control grid of said reactance tube, means to apply modulating potentials between the control grid and cathode of said reactance tube and to modulate the current flowing through said reactance tube.
  • means comprising a rectifier to derive a direct potential proportional to the amplitude variations of the modulated current, means to apply said direct potential in opposition to said modulating potentials, a capacitor having a capacity substantially equal to the anode-cathode capacity of said reactance tube, means to derive a current proportional to said modulating potentials, means to pass said current through said capacitor to neutralize the anode-cathode capacity of said reactance tube, and means to couple the anode of said reactance tube to said oscillator circuit.
  • a circuit arrangement for frequency modulating a carrier wave comprising an oscillator circuit having an electron discharge tube to generate said carrier wave.
  • a reactance tube having an anode, a control grid and a cathode.
  • a resistor, a first capacitor, a transiormer a primary winding, a secondary winding a a tertiary winding, said first resistor, said first cspacitor and the primary winding of said transiormer being connected in series between the control grid and the cathode of said reactance tube, a rectifier coupled to the secondary winding of said transformer, means to apply modulating potentials between the control grid and cathode of said reactance tube, a load resistor coupled to said rectifier to derive a direct potential proper tional to the.
  • a second ca pacitor having a capacity substantially equal to the anode-cathode capacity of said reactance tube, means to connect one end of saidtertiary winding to the end of said primary winding re mote from said anode, means to connect said second capacitor between the remaining end of said tertiary winding and the cathode oi said actance tube, means to couple said tertiary r ing inductively to said primary winding to i i a current in said tertiary winding to neutralize anode-cathode capacity of said reactance tube, and means to couple said reactance tube to said oscillator circuit.
  • a circuit arrangement for frequency modulating a carrier wave comprising an oscillator circuit having an electron discharge tube to generate said carrier wave, a reactance tube having an anode, a control grid and a cathode, a first resistor, a, first capacitor, said first resistor and said first capacitor being connected in series to couple the control grid of said reactance tube to said oscillator circuit to apply a voltage to said control grid in phase quadrature to the voltage generated in said oscillator circuit, a transformer having a primary winding and a secondary winding, a second resistor, means to connect said second resistor and the primary winding of said transformer in series between the anode and cathode of said reactance u means to apply modulating potentials between the control grid and cathode of said reactance tube, a rectifier coupled to the secondary winding of said transformer, a load resistor coupled to said rectifier to derive a direct potentialproportional to the voltage generated by said secondary winding, means to apply said direct potential in opposition to said modulating potentials.
  • modulating potentials to the control grid 15 of said reactance tube to modulate the current flowing through said reactance tube, means comprising a rectifier coupled to the anode of said reactance tube to derive a direct potential proportional to the amplitude of said modulating potentials, and means to apply said direct potential to the control grid of said reactance tube in phase opposition tosaid modulating potentials thereby to linearize the relationship between frequency deviations of said carrier wave and variations in said modulating potential.

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US667446A 1941-09-17 1946-05-04 Reactance tube circuit arrangement Expired - Lifetime US2530611A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL609970X 1941-09-17

Publications (1)

Publication Number Publication Date
US2530611A true US2530611A (en) 1950-11-21

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US667446A Expired - Lifetime US2530611A (en) 1941-09-17 1946-05-04 Reactance tube circuit arrangement

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US (1) US2530611A (en)van)
DE (1) DE862319C (en)van)
FR (1) FR885945A (en)van)
GB (1) GB609970A (en)van)
NL (1) NL67073C (en)van)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2279660A (en) * 1937-04-13 1942-04-14 Rca Corp Wave length modulation system
US2301907A (en) * 1941-07-24 1942-11-10 Collins Radio Co Frequency modulation distortion correction system
US2341243A (en) * 1940-07-18 1944-02-08 Rca Corp Wave length modulation
US2382436A (en) * 1943-08-18 1945-08-14 Bell Telephone Labor Inc Reactance tube circuit

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2279660A (en) * 1937-04-13 1942-04-14 Rca Corp Wave length modulation system
US2341243A (en) * 1940-07-18 1944-02-08 Rca Corp Wave length modulation
US2301907A (en) * 1941-07-24 1942-11-10 Collins Radio Co Frequency modulation distortion correction system
US2382436A (en) * 1943-08-18 1945-08-14 Bell Telephone Labor Inc Reactance tube circuit

Also Published As

Publication number Publication date
FR885945A (fr) 1943-09-29
NL67073C (en)van)
GB609970A (en) 1948-10-08
DE862319C (de) 1953-01-08

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