US2251629A - Parasitic oscillation elimination - Google Patents
Parasitic oscillation elimination Download PDFInfo
- Publication number
- US2251629A US2251629A US345768A US34576840A US2251629A US 2251629 A US2251629 A US 2251629A US 345768 A US345768 A US 345768A US 34576840 A US34576840 A US 34576840A US 2251629 A US2251629 A US 2251629A
- Authority
- US
- United States
- Prior art keywords
- circuit
- frequency
- undesired
- inductance
- conductor
- 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
Links
- 230000010355 oscillation Effects 0.000 title description 32
- 230000003071 parasitic effect Effects 0.000 title description 14
- 230000008030 elimination Effects 0.000 title description 4
- 238000003379 elimination reaction Methods 0.000 title description 4
- 239000004020 conductor Substances 0.000 description 29
- 230000003472 neutralizing effect Effects 0.000 description 8
- 238000013016 damping Methods 0.000 description 7
- 239000003990 capacitor Substances 0.000 description 6
- 208000028659 discharge Diseases 0.000 description 5
- 230000001939 inductive effect Effects 0.000 description 5
- 230000001747 exhibiting effect Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000006386 neutralization reaction Methods 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000008520 organization Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
Images
Classifications
-
- 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
- H03F1/12—Modifications of amplifiers to reduce detrimental influences of internal impedances of amplifying elements by use of attenuating means
- H03F1/13—Modifications of amplifiers to reduce detrimental influences of internal impedances of amplifying elements by use of attenuating means in discharge-tube amplifiers
Definitions
- My invention relates to high frequency circuits and more particularly to means for damping undesired oscillations in such high frequency circuits.
- a pair of electron discharge devices lb and H are connected to operate in balanced or push-pull relation to amplify a wave from a source, not shown, which wave appears across an input inductance l2.
- the amplified wave is impressed across an output inductance I3 and is eventually utilized in a load circuit, not shown.
- the ends of the inductance I2 are connected respectively to the control electrodes [4 and of the devices 10 and II.
- the cathodes It and [1 are connected to ground.
- the central point of the inductance I2 is connected through a choke coil I8 and a source [9 terelectrode and circuit capacities, resonate with the inductance 12 at the frequency of the wave impressed thereon.
- the anodes 23 and 24 thereof are connected to opposite ends of the inductance 13, respectively through conductors 38 and 39;
- a condenser 25 is connected fromthe anode 23 to ground and a second condenser 26 is connected from the anode 24 to ground.
- These two condensers in series, together with unavoidable interelectrode and circuitcapacities, resonate with the inductance 13 at the frequency of the wave impressed on the inductance l2;
- the central point of the inductance 131's connected through a choke coil 21 and a source 28 of anode potential, by-passed by a condenser 29,to ground.
- triode electron discharge devices are commonly used which require neutralization.
- Conventional neutralizing means including a pair of condensers 38 and 3
- condenser 30 is connectedfrom the anode 23 througha conductor 32 to the control electrode l5 of the discharge device I I. Similarly the condenser 3
- the conductors 32 and 33 may have an inductance resonant with the interelectrode capacities in the devices ID and Hand withinductance and capacity in other portions of the circuit at a frequency or frequencies, near or in the band of frequencies within which it is desired to operate the amplifier.
- Parasitic oscillation may, of course, be produced at any frequency determined by circuit conditions. Such undesired or parasitic oscillations may completely destroy the usefulness of the amplifier if the oscillations are strong, or may result in spurious radiations and reduced useful output if the oscillations are weak. For satisfactory operation, parasitic oscillations must be completely eliminated.
- parasitic oscillations occurring in the neutralizing circuit are at frequencies substantially higher than the operating frequency.
- resistors 34 and 36 and their associated condensers 35 and 31 series resonant at the parasitic frequency and connected in shunt to conductors 32 and 33, there is substantially no damping at the operating or power frequency, yet the circuit may be critically damped at the frequency of undesired oscillations.
- such a series resonant combination of resistance and capacity may be connected in shunt to some other portion of a circuit resonant at an undesired frequency, such other portion being, for example, an anode conductor 38 or 39, or a portion of the choke coil I8 or 21, or a surface or portion of a neutralizing condenser 33 or 3
- Fig. 2 there is illustrated apparatus similar to that of Fig. l in which such a series combination of resistance and capacity is connected in shunt to a portion of the anode circuit.
- the devices Hi and II respectively have screen electrodes 40 and 4!, in addition to anodes 23 and 24, cathodes l6 and I7, and control electrodes I4 and 15. These screen electrodes minimize capacitive reaction between the anodes 23 and 24 and the control electrodes hi and I5. gether and through a source 42 of potential to ground and are respectively by-passed to ground through respective condensers 43 and 44.
- are frequently utilized to avoid the necessity of neutralization.
- a series combination of a capacitor 45 and a resistor 43 is connected in shunt to the conductor 38, and a similar series combination of a capacitor 41 and a resistor 48 is connected in shunt to the conductor 39.
- the capacitor 45 They are connected tois adjusted to resonate at the undesired parasitic frequency with the inductance of the resistor 46, which exists due to its finite length.
- the series combination of capacity and resistance being series resonant, presents a pure resistance at the undesired frequency in the parasitic oscillation circuit. This resistance 4'6 may be adjusted to produce critical damping of the undesired parasitic oscillation, so that such oscillation is effectively eliminated.
- capacitor 41 and resistor 43 are similarly made series resonant, so that it likewise presents a pure resistance at the undesired parasitic frequency in shunt to the conductor 39.
- the resistance 43 also may be adjusted to produce critical damping in the circuit for the parasitic oscillation.
- Radio apparatus comprising a circuit in which oscillations of an undesired frequency tend to exist, said circuit including a conductor of finite length, which thereby exhibits inductance, across which such oscillations appear, and a resistance and a capacitor serially connected between spaced points on said conductor, said resistance, due to its finite length, being inductive and being resonant at said undesired frequency with said capacitor, whereby a pure resistance is presented between said spaced points at said undesired frequency effectively to damp said oscillation.
- an electron discharge device having an anode, a cathode, and a control electrode, a circuit connected between said anode and control electrode and including a conductor of substantial length, said circuit having a tendency to break into oscillation at an undesired frequency, said conductor due to its length having substantial inductance, and a series combination of resistance and capacity connected in shunt to said conductor, said resistance being inductive due to its finite length and being resonant at said undesired frequency with said capacity effectively to damp the oscillation in said circuit.
- An electron discharge amplifier including a circuit which tends to oscillate at an undesired frequency, a portion of said circuit being a conductor of finite length whereby it is inductive, and a series combination of resistance and capacity connected in shunt to said conductor, said resistance also being inductive due to its finite length and being series resonant at said undesired frequency with said capacity effectively to damp said oscillation.
- said neutralizing means including a conductor of substantial length, the inductance of which tends to resonate with other portions of said amplifier at an undesired frequency, and means in shunt to said conductor for damping oscillations of said undesired frequency, said means comprising a series combination of resistance and capacity, said resistance being of finite length and exhibiting inductance, and said capacity being of such value with respect to said inductance as to resonate therewith at said undesired frequency effectively to damp said neutralizing means.
- an electron discharge amplifier device having an anode and a pair of control electrodes, said anode and one of said control electrodes being adjacent each other, a circuit through said anode and said adjacent control electrode including a conductor of finite length which thereby exhibits inductance, said circuit tending to oscillate at an undesired frequency, and a series combination of a resistor and a condenser in shunt to said conductor, said resistor having finite length and exhibiting inductance and said condenser being resonant therewith at said undesired frequency effectively to damp said circuit.
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Oscillators With Electromechanical Resonators (AREA)
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
BE448814D BE448814A (sv) | 1940-07-16 | ||
US345768A US2251629A (en) | 1940-07-16 | 1940-07-16 | Parasitic oscillation elimination |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US345768A US2251629A (en) | 1940-07-16 | 1940-07-16 | Parasitic oscillation elimination |
Publications (1)
Publication Number | Publication Date |
---|---|
US2251629A true US2251629A (en) | 1941-08-05 |
Family
ID=23356395
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US345768A Expired - Lifetime US2251629A (en) | 1940-07-16 | 1940-07-16 | Parasitic oscillation elimination |
Country Status (2)
Country | Link |
---|---|
US (1) | US2251629A (sv) |
BE (1) | BE448814A (sv) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2530636A (en) * | 1944-11-03 | 1950-11-21 | Hartford Nat Bank & Trust Co | Push-pull high-frequency amplifying apparatus |
US4379463A (en) * | 1981-04-13 | 1983-04-12 | Camp International, Inc. | Multicentric knee cage |
-
0
- BE BE448814D patent/BE448814A/xx unknown
-
1940
- 1940-07-16 US US345768A patent/US2251629A/en not_active Expired - Lifetime
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2530636A (en) * | 1944-11-03 | 1950-11-21 | Hartford Nat Bank & Trust Co | Push-pull high-frequency amplifying apparatus |
US4379463A (en) * | 1981-04-13 | 1983-04-12 | Camp International, Inc. | Multicentric knee cage |
Also Published As
Publication number | Publication date |
---|---|
BE448814A (sv) |
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