US2222423A - Neutralized amplifier circuit - Google Patents

Neutralized amplifier circuit Download PDF

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Publication number
US2222423A
US2222423A US289420A US28942039A US2222423A US 2222423 A US2222423 A US 2222423A US 289420 A US289420 A US 289420A US 28942039 A US28942039 A US 28942039A US 2222423 A US2222423 A US 2222423A
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US
United States
Prior art keywords
circuit
cathode
impedance
neutralized
tubes
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Expired - Lifetime
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US289420A
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English (en)
Inventor
Rahn Ernst
Willwacher Erwin
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Telefunken AG
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Telefunken AG
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Publication date
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Publication of US2222423A publication Critical patent/US2222423A/en
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
    • H03F1/08—Modifications of amplifiers to reduce detrimental influences of internal impedances of amplifying elements
    • H03F1/14—Modifications of amplifiers to reduce detrimental influences of internal impedances of amplifying elements by use of neutralising means
    • H03F1/16—Modifications of amplifiers to reduce detrimental influences of internal impedances of amplifying elements by use of neutralising means in discharge-tube amplifiers

Definitions

  • 'I"ne invention is concerned with a neutralized amplifier circuit scheme especially suited for ultra-short waves.
  • This circuit arrangement offers the advantage over others known in the 5 prior art that in the presence of unvaried neutralization, that is to say, with perfect freedom from reaction between output circuit and input circuit, it is possible to bring about in a controlled manner either de-attenuation (regenerlO ation) or damping in the amplifier tube.
  • de-attenuation de-attenuation
  • damping damping in the amplifier tube.
  • This provides ways and means for insuring far higher amplification or a substantially better stabilization of the circuits together with an avoidance of stray .or interfering oscillations.
  • Neutralization that is, freedom from reaction between input and output circuit of a tube arrangement is practiced as a general rule by the aid of bridge schemes.
  • bridge schemes do not always insure freedom from feedback, that is to say, freedom from reactions produced by the plate circuit upon the grid filament path or circuit.
  • the object of the invention is to act upon the feed back under proper conditions of measured control or regu- 95 lation so that, as a result, the circuit organization may be either regenerated or damped to a desired degree, while neutralization as hereinbefore defined will be fully preserved.
  • Two tubes are used according to the invention of which one, if desired, is not heated or replaced by an impedance simulation.
  • the plates of these tubes are inter-connected directly and the grids by way of the input circuit, while, .on
  • Figure 1A shows the equivalent circuit of Fi ure 1.
  • Fig. 1 shows a frequency doubler circuit organization comprising the heated tubes l and 2, the input circuit 3, the output circuit 4 and the cathode circuits 5 and 5'. These cathode circults consist preferably of tunable Lecher-Wire lines. According to the invention, the junction point of the two cathode circuits is joined with a variable tap of the output coil 4.
  • the bridge scheme corresponding to Fig. 1 is represented in Fig. 1a, where G! and G2 the points where the grids are in the two tubes; E is the grounding terminal and A the anode terminal.
  • the rest of the reference numerals are the same as in Fig. 1.
  • Regeneration (or de-attenuation) is particularly favorable since it applies to the doubled frequency, with the result that the whole circuit scheme is regenerated for the useful or signal frequency while its properties are unaltered for the fundamental.
  • the operation of the variable connection of the cathode circuit with the output circuit is predicated upon the fact that a grid alternating potential regulable both as to size and phase is produced, it being advantageous not only to shift the slider or tap, but also to tune the cathode circuit.
  • Fig. 1 operates with two distinct cathode circuits 5 and 5, though as shown in Fig. 2 the same could be replaced also by a single cathode circuit 5. In this instance, however, the cathodes must be connected by way of an impedance, with the cathode circuit being connected with an intermediate point or tap of this impedance as can be seen also from Fig. 2.
  • Fig. Z'tube 2 is not heated or if the same is replaced by a tube simulation, then, while the circuit arrangement remains otherwise the same, the identical effect is obtainable as with a heated tube. All that happens is that the "frequency doubler action is absent, in fact, that amplification at a frequency of 1:1 is produced. Also in this case where a neutralized one-tube circuit scheme is concerned, it is advantageous to insure controllable regeneration or damping, while neutralization is preserved. . If, finally, the tube simulation consists of inductances rather than capacitances, so that merely the impedance ratio of the various impedances occurring in the tube is simulated, there results a circuit arrangement of the kind shown in Fig.
  • the circuit arrangement distinguishes itself merely from the other schemes insofar as the output circuit is not constituted by the inductance 4, but by the inductance 2 which is split at the ratio of the tube capacity reactances, that is, the part above the tap is to the part below as Cpg is to Cgk.
  • the circuit for putting out or taking off the useful or signal energy is designated by 6 in Fig. 3.
  • the input circuit 3 is situated between the grid and the point of symmetry of inductance 2.
  • this circuit organization really represents a balanced bridge in which adjustment of the feedback is feasible without essentially afiecting the bridge It willbe understood, however, that this circuit organization is not perfectly independent of the wavelength since the bridge comprises both capacities and inductances. However, for reduced wavebands this disadvantage may be readily tolerated.
  • circuit schemes here shown and discussed represent merely the underlying principle of the .circuit arrangements, for all direct current circuits, biasing potentials, etc. have been omitted,
  • a neutralized amplifier circuit for ultrashort Waves comprising a pair of tubes each having a cathode, a grid and an anode, an input circuit connected between the grids of said tubes, a direct connection between the anodes, an output impedance connected between said direct anode connection and the input circuit, an impedance connected between the cathodes, an adjustable tap on said output impedance, and a connection from an intermediate point on said cathode impedance to said adjustable tap.
  • a neutralized amplifier circuit for ultrashort waves comprising a pairof tubes each having a cathode, a grid and an anode, an input circuit connected between the grids of said tubes, a
  • a neutralized amplifier circuit for ultrashort waves comprising a pair of tubes each having a cathode, a grid and an anode, a tunable input circuit connected between the grids of said tubes, a direct connection between the anodes, an output impedance having one end connected to said direct anode connection and the other end to a point of symmetry of the input circuit, a variable impedance connected to each of the cathodes, and a connection from the junction point of the two cathode impedances to an adjustable tap on the output impedance, said adjustable tap controlling the degree of regeneration.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Microwave Amplifiers (AREA)
  • Amplifiers (AREA)
US289420A 1938-07-06 1939-08-10 Neutralized amplifier circuit Expired - Lifetime US2222423A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE217087X 1938-07-06
DE2281345X 1939-08-24

Publications (1)

Publication Number Publication Date
US2222423A true US2222423A (en) 1940-11-19

Family

ID=32094487

Family Applications (2)

Application Number Title Priority Date Filing Date
US289420A Expired - Lifetime US2222423A (en) 1938-07-06 1939-08-10 Neutralized amplifier circuit
US379068A Expired - Lifetime US2281345A (en) 1938-07-06 1941-02-15 Neutralized short wave amplifier circuit

Family Applications After (1)

Application Number Title Priority Date Filing Date
US379068A Expired - Lifetime US2281345A (en) 1938-07-06 1941-02-15 Neutralized short wave amplifier circuit

Country Status (5)

Country Link
US (2) US2222423A (fr)
CH (1) CH217087A (fr)
DE (1) DE728657C (fr)
FR (2) FR868037A (fr)
GB (1) GB530936A (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1002398A (fr) * 1946-09-20 1952-03-05 Radio Ind Perfectionnements apportés aux systèmes amplificateurs
US2648727A (en) * 1949-10-04 1953-08-11 Crosley Broadeasting Corp Push-pull wide band amplifier

Also Published As

Publication number Publication date
US2281345A (en) 1942-04-28
GB530936A (en) 1940-12-24
FR868037A (fr) 1941-12-12
DE728657C (de) 1942-12-02
FR51537E (fr) 1942-10-05
CH217087A (de) 1941-09-30

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