US2207933A - Tuned ultra high frequency amplifier - Google Patents

Tuned ultra high frequency amplifier Download PDF

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Publication number
US2207933A
US2207933A US136038A US13603837A US2207933A US 2207933 A US2207933 A US 2207933A US 136038 A US136038 A US 136038A US 13603837 A US13603837 A US 13603837A US 2207933 A US2207933 A US 2207933A
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US
United States
Prior art keywords
circuit
tube
resistance
cathode
tuned
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
US136038A
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English (en)
Inventor
Mountjoy Garrard
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.)
RCA Corp
Original Assignee
RCA Corp
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
Application filed by RCA Corp filed Critical RCA Corp
Priority to US136038A priority Critical patent/US2207933A/en
Priority to CH200859D priority patent/CH200859A/de
Application granted granted Critical
Publication of US2207933A publication Critical patent/US2207933A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/50—Amplifiers in which input is applied to, or output is derived from, an impedance common to input and output circuits of the amplifying element, e.g. cathode follower
    • H03F3/52—Amplifiers in which input is applied to, or output is derived from, an impedance common to input and output circuits of the amplifying element, e.g. cathode follower with tubes only
    • 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

Definitions

  • Electron discharge tube amplifiers have a control grid-cathode resistance, the input resistance of the amplifier tube; which decreases rapidly .as the operating frequency increases.
  • an'electro-n dischargetube which exhibits an input resistance of several megohms in'the standard broadcast range of 500 to 1500 kc., may have its input resistance magnitude reduced to just a few hundred ohms at very high frequencies.
  • an electron dischargetube is 'used to amplify the alternating current .voltage' developed across a parallel resonant circuit, the input resistance of the tube is shunted across :the resonant circuit.
  • . ing eifect on Accordinglyit may be stated that it is one of resonant circuit being disposed in the cathode circuit of the tube whereby at resonance it has a substantially infinite impedance arranged in series with the control grid to cathode resistance of the tube, the tube input resistance being relatively high at resonance and having little dampthe preceding resonant input circuit.
  • Still other objects o-f'the invention are gen-- erally to improve the efiiciency of operation of tuned ultra high frequency amplifier circuits, and more especially to provide such a circuit with maximum selectivity and with the utilization of minimum additional circuit elements.
  • the novel features which I believe to be characteristic of my invention are set forth in particularity in the appended claims; the invention there is shown an ultra high frequency amplifier circuit which includes at least two resonant cir-' cuitsv coupled in cascade by an electron discharge tube-T.
  • the source of signal energy A may be of any well known type. For example it may be a grounded antenna circuit, a loop antenna; an ultra high radio frequency distribution line; or an antenna'of the dipole type.
  • the signal collector A is coupled, as at M, to the coil L1 of the resonant input circuit I of the amplifier tube T.
  • a condenser C1 In shunt with the 0011 L1 there is connected a condenser C1, and it is denoted as variable so that the circuit lmay beadjusted in tuning over a relatively wide frequency range if such adjustment is-desired.
  • the frequency range' may be, for example, such as to include the ultra high radio frequencies of the order of 50 megacycles. It is to be clearly understood that. this frequency value is. merely given for, illustrative purposes; stated interms of meters, the signal wave range may be such as .to-receive waves as short as 0.1 meter. Generally speaking the signal wave range is that in which the control grid to cathode resistance of tube T has. an appreciable damping efiect on the input circuit l.
  • control grid 2 of tube T is connected to the high alternating Potential side-of circuit I.
  • the cathode 3 is con nected to a point of relatively fixed radio fre-; quency potential, as ground, througha path which includes coil L2 and condenser 5.
  • the latter has a low impedance to the ultra high frequencies to be amplified; it is in shunt with resistor 4 functioning as the grid bias resistor.
  • the resistor 4 may have a magnitude of 1000 ohms, and is in series between the low potential side of coil L2 and the low potential side of input circuit i.
  • variable condenser C2 is in shunt with coil L2 to provide the second tuned circuit s'; the rotor of condenser 4 is connected to ground so that the rotors of condenser C1 and 02 may be operated by a common grounded shaft, designated by the dotted line 6.
  • the signal voltage e2 developed across circuit 4' is impressed between the input electrodes of a following tube.
  • the latter may be another amplifier. or a detector tube.
  • the plate, or anode, I of tube T is connected to a positive point on voltage source B; the negative terminalof the latter being connected to the grounded side of self-bias resistor 4.
  • the circuits I and 4' are shown arranged for tuning to a common operating carrier frequency.
  • the circuits I and 4' may be fixedly tuned to a desired frequency.
  • the signal voltage e1 developed across circuit I is amplified by tube T; the amplified voltage e2 is utilized in any desired-manner.
  • the selectivity of circuit I is greatly improved over what it would have been with circuit 4' disposed in the anode circuit in the conventional manner.
  • the input resistance r (shown in dotted line in the figure) would exert a very high damping effect on circuit I, and thus greatly reduce its selectivity. This follows from the fact that at the operating ultra high frequencies, the resistance 'r has a small value. Since this resistance would be in shunt across circuit I, the equivalent series resistance in the circuit 1 is high; an inverse relation existing between the shunt resistance and its equivalent series value.
  • an amplifier of the type including a tube provided with at least a cathode, control grid and anode, a resonant circuit connected between the grid and a point of relatively fixed potential, said circuit being tuned to a carrier frequency at which the grid to cathode resistance of the tube sub- 2.
  • a resonant circuit connected between the grid and a point of relatively fixed potential, said circuit being tuned to a carrier frequency at which the grid to cathode resistance of the tube sub- 2.
  • said circuit being tuned to a carrier frequency at which the grid to cathode resistance of the tube substantially damps the resonant circuit, a direct current source connected between the anode and said point, a second resonant circuit, tuned to said carrier frequency, connected between the cathode and said pointthereby substantially minimizing said damping effect, and means for impressing carrier voltage developed across the second circuit upon an output circuit, said second resonant circuit including a coil in series with a resistor between the cathode and said point, and means for bypassing: current of carrier frequency around said resistor, said resistor establishing the grid at a desired negative bias.
  • an amplifier of the type including a tube provided with at least a cathode, control grid and anode, a resonant circuit connected between the grid and a point of relatively fixed potential, said circuit being. tuned to a carrier frequency at which the grid to cathode resistance of the tube substantially damps the resonant circuit, a direct current source connected between the anode and said point, a second resonant circuit,tuned to said carrier frequency, connected between the cathode and said point thereby substantially minimizing said damping effect, means for impressing carrier voltage developed across the second circuit upon an output circuit, each of said resonant circuits being parallel resonant, and-meansfor tuning said resonant circuits over a rangebf ultra high frequencies.
  • an amplifier of the type including 'a'tube and a parallel resonant circuit connected between the control grid and cathode of the tube, said circuit being tuned to a frequency lying in the ultra high frequency range, thecontrolgrid to cathode resistance of the tube being sufficiently small at said frequency to greatly damp said circuit, and a second parallel resonant circuit, tuned to said frequency, arranged in the space current path of said tube and connected between said control grid and cathode in series'with said first resonant circuit thereby substantially to minimize said damping effect of said resistance and maintainhigh selectivity of said amplifier.
  • an amplifier of the type including'a tube and aparallel resonant circuit connected between the control grid and cathode of. the tube, said resonant circuit thereby substantially to minimize said damping effect of said resistance and maintain high selectivity of said amplifier, and I means for impressing high frequency voltage developed across the second resonant circuit upon 5 a utilization network.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Amplifiers (AREA)
US136038A 1937-04-10 1937-04-10 Tuned ultra high frequency amplifier Expired - Lifetime US2207933A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US136038A US2207933A (en) 1937-04-10 1937-04-10 Tuned ultra high frequency amplifier
CH200859D CH200859A (de) 1937-04-10 1938-04-08 Hochfrequenzverstärker mit mindestens zwei kaskadengeschalteten und mittels einer Verstärkerröhre gekoppelten, auf die gleiche Frequenz abgestimmten Schwingungskreisen.

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US136038A US2207933A (en) 1937-04-10 1937-04-10 Tuned ultra high frequency amplifier

Publications (1)

Publication Number Publication Date
US2207933A true US2207933A (en) 1940-07-16

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ID=22470970

Family Applications (1)

Application Number Title Priority Date Filing Date
US136038A Expired - Lifetime US2207933A (en) 1937-04-10 1937-04-10 Tuned ultra high frequency amplifier

Country Status (2)

Country Link
US (1) US2207933A (de)
CH (1) CH200859A (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2658958A (en) * 1949-07-16 1953-11-10 Wilcox Gay Corp Negative feedback frequency response compensation amplifier system
US3394319A (en) * 1964-05-26 1968-07-23 Zenith Radio Corp Video band-pass control

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE742713C (de) * 1940-01-04 1943-12-09 Fernseh Gmbh Schaltanordnung zur Daempfungsaenderung eines Schwingungskreises

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2658958A (en) * 1949-07-16 1953-11-10 Wilcox Gay Corp Negative feedback frequency response compensation amplifier system
US3394319A (en) * 1964-05-26 1968-07-23 Zenith Radio Corp Video band-pass control

Also Published As

Publication number Publication date
CH200859A (de) 1938-10-31

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