US2406839A - Impedance matching device - Google Patents

Impedance matching device Download PDF

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Publication number
US2406839A
US2406839A US426455A US42645542A US2406839A US 2406839 A US2406839 A US 2406839A US 426455 A US426455 A US 426455A US 42645542 A US42645542 A US 42645542A US 2406839 A US2406839 A US 2406839A
Authority
US
United States
Prior art keywords
circuit
oscillator
impedance
modulator
grid
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
US426455A
Other languages
English (en)
Inventor
Labin Emile
James H Nye
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.)
STC PLC
Federal Telephone and Radio Corp
Original Assignee
Standard Telephone and Cables PLC
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 BE472158D priority Critical patent/BE472158A/xx
Application filed by Standard Telephone and Cables PLC filed Critical Standard Telephone and Cables PLC
Priority to US426455A priority patent/US2406839A/en
Priority to GB20749/43A priority patent/GB600188A/en
Application granted granted Critical
Publication of US2406839A publication Critical patent/US2406839A/en
Priority to FR941511D priority patent/FR941511A/fr
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
    • H03C1/16—Amplitude modulation by means of discharge device having at least three electrodes
    • H03C1/18—Amplitude modulation by means of discharge device having at least three electrodes carrier applied to control grid
    • H03C1/20—Amplitude modulation by means of discharge device having at least three electrodes carrier applied to control grid modulating signal applied to anode
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H11/00—Networks using active elements
    • H03H11/02—Multiple-port networks
    • H03H11/28—Impedance matching networks
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H2/00—Networks using elements or techniques not provided for in groups H03H3/00 - H03H21/00
    • H03H2/005—Coupling circuits between transmission lines or antennas and transmitters, receivers or amplifiers
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H2/00—Networks using elements or techniques not provided for in groups H03H3/00 - H03H21/00
    • H03H2/005—Coupling circuits between transmission lines or antennas and transmitters, receivers or amplifiers
    • H03H2/006—Transmitter or amplifier output circuits
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K3/00—Circuits for generating electric pulses; Monostable, bistable or multistable circuits
    • H03K3/78—Generating a single train of pulses having a predetermined pattern, e.g. a predetermined number
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K3/00—Circuits for generating electric pulses; Monostable, bistable or multistable circuits
    • H03K3/80—Generating trains of sinusoidal oscillations
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K7/00—Modulating pulses with a continuously-variable modulating signal

Definitions

  • This invention relates to an improved form of impedance matching arrangement and in particular to means for adjustably matching the apparent input impedance of a radio frequency oscillator to the output impedance of a modulator feeding the oscillator.
  • The. invention contemplates particular application in the case of impulse modulators and transmitters of the nature disclosed in the copendingapplica-tion of Emile Labin, Serial No. 406,499, filed August 12, 1941, and entitled Pulse transmitters. These devices are particularly adaptable to radio locator equipment.
  • vIt is an object of the invention to provide an improved form of impedance matching device.
  • Another object is to provide relatively simple means for adjusting aradio frequency oscillator to give maximum output when supplied with high voltage impulse energy.
  • the said drawing depicts schematically an impulse modulator and radio frequency oscillator circuit embodying features of the invention.
  • high voltage pulses of short duration may be generated from a relatively low D. C. voltage in somewhat the following manner.
  • the basic circuit involved includes a relaxation oscillator having inductive feedback and an R. C. time con stant circuit in the filament return. Operation depends upon establishinga high current in a coil in the plate circuit of the relaxation oscillator and rapidly interrupting this current. The resultant discharge of the coil into the load presented by a radio frequency oscillator may then develop a peak voltage which is on the order of five times the magnitude of voltage applied to the relaxation oscillator. In forms shown in the said application it is this large voltage which serves as plate supply for the radio frequency oscillator. I
  • the impulse generator or modulator includes a pair of triodes I0, I I having all circuits connected in parallel, an inductance L2 in the plate circuit inductively coupled through a coil L1 to the input or control grid circuit, and resistance and capacitance time constant elements [2, l3, and I4 across the input circuit.
  • the plate supply voltage, as impressed between terminals 15 and [6, may be on the order of one fifth the peak voltthe maximum voltage obtainable across the plate coil L2 and substantially to eliminate oscillations in the grid circuit-thus assuring regularity of the pulsing cycle.
  • the radio frequency oscile lator includes two triodes I9, 20 connected in push-pull.
  • the filament, grid, and plate circuits of tubes l9 and 20 are tuned by balanced line structures 2
  • input is supplied from across inductance L2 in the modulator to short circuiting member 26 of the radio frequency oscillator plate circuit, and output may be derived from an inductive coupling 21 with the plate tuned circuit 23.
  • the output impedance of the modulator should equal or substantially approximate the apparent input impedance of the radio frequency oscillator (looking into the oscillator from inductance L2).
  • this impedance be essentially resistive so as to be substantially independent of frequency.
  • the magnitude of this resistance R should correspond to the critical damping resistance of coil L2, as defined by the relation e where C represents the total stray capacitance in parallel with inductance L2, and L is the inand to provide some means for adjusting the os cillator in actual operation.
  • This subsequent adjustment of the oscillator may be effected by controlling the bias of oscillator tubes l9 and 20, as by varying the grid bias resistor 28.
  • tubes l9 and 2'9 have abnormally large filaments for relatively high emission during the periods of transmitting impulses, i. e. when the radio frequency oscillator is in OS- cillation.
  • the grid characteristic is of an extremely critical nature with respect to bias variation for optimum oscillation conditions.
  • the magnitude of resistor 28 is relatively small so that the bias may be relatively stablethus permitting use of the desired gridcharacteristic.
  • nitude should. be kepta'slow as possiblet'o: ensure maximum power output and minimum power loss in this resistor.
  • an impulse transmitter comprising an impulse modulator feeding a radiof'requency oscillator having vacuum tube means including cathode, grid, and anode circuits and a substantially resistive impedance in the anode-cathode circuit, the method of matching the impedance of the oscillator to that of the modulator which comprises varyingsaid impedance in the anode-cathode circuit untilmaximum output is obtained from the oscillator.
  • man impulse transmitter comprising an impulse modulator feeding a radio frequency oscillator having vacuum tube means including a cathod circuit, a grid circuit, and an anode circuit, the output of said modulator being in said anode circuit, and said cathode circuit having resistance therein, the method of obtaining. maximum output from the oscillator which comprises adjustably varying said resistance, whereby the apparent impedance of said anode circuit may be varied Without appreciably changing. conditions in said grid circuit.
  • An impulse transmitter comprising an impulse generator and a radio frequency oscillator, said generator including a Vacuum tube having an electron emissiv electrode, a control electrode, and an electron receiving electrode, an inductance, a source of energy, means connecting said source and saidinductance in series between said receiving electrode and another electrode of said tube, a coupling coil inductively coupled. to said inductance, a timing circuit, and means com necting saidcoil and said circuit in series between said control electrode and said emissive electrode, said oscillator including vacuum tube means including a cathode circuit, a grid circuit, and an anode circuit, said anode circuit being. coupled across said inductance, said grid circuit including biassing means, and said cathode circuit including relatively high emission cathode means and adjustable resistance means.
  • said generator including a Vacuum tube having an electron emissiv electrode, a control electrode, and an electron receiving electrode, an inductance, a source of energy, means connecting said source and saidinductance in
  • An impulse transmitter comprising an impulse mcdulator and aradio frequenc oscillator, said oscillator including vacuum tube means having an anode circuit to ground, a cathode circuit to' ground, a, grid circuit to ground, and means coupling said anode circuit to said modulator, said grid circuit having a biasing resistance means, said cathode circuit having an adjustable resistance means adjustment of which operates to vary the" impedance of the anode circuit. for impedance matching with respect to the modulator impedance while negligibly affecting the grid biasing adjustment.

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  • Inductance-Capacitance Distribution Constants And Capacitance-Resistance Oscillators (AREA)
  • Magnetic Resonance Imaging Apparatus (AREA)
US426455A 1942-01-12 1942-01-12 Impedance matching device Expired - Lifetime US2406839A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
BE472158D BE472158A (ru) 1942-01-12
US426455A US2406839A (en) 1942-01-12 1942-01-12 Impedance matching device
GB20749/43A GB600188A (en) 1942-01-12 1943-12-10 Impulse modulating arrangements for radio frequency oscillators
FR941511D FR941511A (fr) 1942-01-12 1947-02-14 Appareils adaptateurs d'impédances

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US426455A US2406839A (en) 1942-01-12 1942-01-12 Impedance matching device

Publications (1)

Publication Number Publication Date
US2406839A true US2406839A (en) 1946-09-03

Family

ID=23690874

Family Applications (1)

Application Number Title Priority Date Filing Date
US426455A Expired - Lifetime US2406839A (en) 1942-01-12 1942-01-12 Impedance matching device

Country Status (4)

Country Link
US (1) US2406839A (ru)
BE (1) BE472158A (ru)
FR (1) FR941511A (ru)
GB (1) GB600188A (ru)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2508751A (en) * 1945-11-10 1950-05-23 Cutler Hammer Inc Oscillator circuit for high-frequency dielectric heating
US2520174A (en) * 1943-08-05 1950-08-29 John J Slattery Transmitter biasing circuit
US2585007A (en) * 1948-01-19 1952-02-12 Edward H Guboff Oscillator circuits for use in diathermy

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2520174A (en) * 1943-08-05 1950-08-29 John J Slattery Transmitter biasing circuit
US2508751A (en) * 1945-11-10 1950-05-23 Cutler Hammer Inc Oscillator circuit for high-frequency dielectric heating
US2585007A (en) * 1948-01-19 1952-02-12 Edward H Guboff Oscillator circuits for use in diathermy

Also Published As

Publication number Publication date
BE472158A (ru)
FR941511A (fr) 1949-01-13
GB600188A (en) 1948-04-02

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