US2760067A - Electric discharge tube - Google Patents

Electric discharge tube Download PDF

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Publication number
US2760067A
US2760067A US251351A US25135151A US2760067A US 2760067 A US2760067 A US 2760067A US 251351 A US251351 A US 251351A US 25135151 A US25135151 A US 25135151A US 2760067 A US2760067 A US 2760067A
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United States
Prior art keywords
grid
control
anode
grids
tube
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Expired - Lifetime
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US251351A
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English (en)
Inventor
Adrianus Johannes Wilhel Marie
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Hartford National Bank and Trust Co
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Hartford National Bank and Trust Co
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Publication date
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
    • H03D3/00—Demodulation of angle-, frequency- or phase- modulated oscillations
    • H03D3/02—Demodulation of angle-, frequency- or phase- modulated oscillations by detecting phase difference between two signals obtained from input signal
    • H03D3/22—Demodulation of angle-, frequency- or phase- modulated oscillations by detecting phase difference between two signals obtained from input signal by means of active elements with more than two electrodes to which two signals are applied derived from the signal to be demodulated and having a phase difference related to the frequency deviation, e.g. phase detector
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J19/00—Details of vacuum tubes of the types covered by group H01J21/00
    • H01J19/02—Electron-emitting electrodes; Cathodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J21/00—Vacuum tubes
    • H01J21/02—Tubes with a single discharge path
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2893/00—Discharge tubes and lamps
    • H01J2893/0001—Electrodes and electrode systems suitable for discharge tubes or lamps

Definitions

  • This invention relates to a device for detecting frequencymodulated signals comprising an electric discharge tube, to the control grids of which tube two auxiliary signals produced from an incoming signal are applied.
  • the strength of these auxiliary signals depends upon the intensity of the incoming signal.
  • These auxiliary signals also have a phase-displacement relative to each other which is proportional to the deviations in frequency of the incoming signal from a definite center frequency.
  • the electric discharge tube comprises at least four grids including the two control grids, to each of which oneof the auxiliary signals is supplied and each of which is adapted to pass or check completely and anode current of given strength (saturation current).
  • the second and fourth grid being used as control grids and the third grid being a screen-grid.
  • the fifth and, as the case may be, sixth grid act as second screen grid and as suppressor grid.
  • the customary attempts are directed to choosing the setting of such a tube or constructing the tube in such manner as to render the mutual conductance of the two control-grids as high as possible at the working point.
  • the device operates satisfactorily even with weak incoming signals.
  • cording to' the invention in an electric discharge tube Patented Aug. 21, 1956 Ice grids, suitable for use in a device for detecting, frequencymodulated signalgforwhich purpose two auxiliarysignals are produced, of which the strength depends upon the intensity of the incoming signal, whilst the two auxiliary signals exhibit a relative phase-displacement proportionalv to the deviations of the frequency of the incoming, signal from a given frequency, which auxiliary signals are eachsupplied to a control-grid of the tube, and.
  • the mutual conductance of the two control grids of the tube in the proximity of the working point is low, and more particularly lower than the saturated anode current expressed in milliamps divided by 4 volts.
  • This is obtained to a high degree by winding, the control-grids with a variable pitch, these two grids being preferably arranged in the tube and constructed in such manner that at least two parts of the second controlgrid which exhibit openings of different sizes with respect to one another, are located opposite a part of the first control grid exhibiting openings of a definite size.
  • a decrease in mutual conductance is also obtainable by making use of inverse feedback from the anode circuit of the tube. This means may be used in combination with the particular construction of the tube.
  • the length of the cathode over which it is coated with electronemitting material is small e; g. 1 to 10 mms.
  • the positive voltages applied to the remaining screen-grids present in the" tube should likewise be comparatively 10WviZiAO volts at the' utmost.
  • an accelerator grid is placed between the cathode and the firstj control grid, which accelerator grid may be connected to a screen grid and is consequently also supplied with a positive voltage of 40 volts at the most.
  • this first grid is preferably less than 5 times the wire diartie'ter.
  • a suppressor grid which may be connected to the cathode.
  • the pitch of this suppressor grid may be chosen to be so great that the positive anode field engages through this grid in such manner that a positive potential is set up in the plane of this grid so that a separate positive screen-grid is no longer required between the second control-grid and the anode.
  • FIG. 1 represents a circuit-arrangement
  • Figs. 2, 3, 4, 5, 6', 7, 8 and 9 show graphs illustrating the operation of a known device and of a device accordingto the invention.
  • Fig. 10 shows the arrangement of the two control grids.
  • Fig. 11 is a cross-section of a discharge tube
  • Figs. 12 and 1-3 are detail views of such a tube which is par-- ticularly suitable for use in a device according. to the invention.
  • the reference numeral 1 designates the receiving device of the frequency-modulated incoming signal, by which device the incoming signal is converted into two
  • the pitch of auxiliary voltages on the conductors 2 and 3 which, for example, with non-modulated incoming signals, exhibit a phase-displacement of 90. With a fully modulated incoming signal this phase-displacement of the auxiliary signals varies, for instance, between 60 and 120.
  • These auxiliary signals are supplied to the two control grids of tube 4 and the low-frequency modulation is separated and further amplified at 5.
  • the control grids are connected, through the conductor 6, to the chassis by way of the coupling member in the receiving device 1.
  • inverse feedback from the anode lead of tube 4 may be used to reduce the mutual conductance.
  • the conductor 6 is connected to a point of a voltage divider 41 placed between the anode and the chassis, as is indicated in Fig. 1.
  • the tube 4 operates with a saturated anode current so that the control voltages 9 and (Fig. 2) enclosing the cross-hatched area 8, produce current pulses 8' in the anode circuit, which pulses are independent of the amplitude of the signals 9 and 10 if this amplitude has a sufiiciently high value. Consequently the average strength of the anode current depends upon the duration of the pulses 8' passed simultaneously by the two control grids. In this event the tube should be set exactly at the center (point 7) of the control range.
  • the IaVg characteristic curve in Fig. 4 will exhibit the form of line 16.
  • the device With the same incorrectness of the control-grid voltage adjustment, the device will, for instance, be set to point 15. In this event the deviation of the anode-current deviation is small with respect to the anode current upon correct adjustment. Consequently, the aforesaid phenomenon is liable to occur only to a small degree so that no troublesome amplitude-modulation detection will occur.
  • an Ia-Vg characteristic curve according to line 17 in Fig. 5, with which the mutual conductance at both sides of the working point is zero over a given area, is very advantageous. This may, for instance, be achieved by means of twoparts control grids, each part of each control-grid supplying one half of the saturated anode current.
  • variable pitch should be distributed in a definite manner over the length of the control-grids.
  • construction of the second control-grid should be closely matched to that of the first one.
  • a grid having a pitch gradually varying throughout its length would yield a curved characteristic as shown in Fig. 6, wherein both the bend at the lower end and that at the top of the characteristic curve is large.
  • the attempts will have to be directed to making the bends as acute as possible as indicated by line 16 in Fig. 4.
  • the parts with the largest and with the smallest openings of each of the control grids must be longer, whereas the parts exhibiting openings of medium size must be shorter.
  • Fig. 7 shows a number of Ia-Vgz characteristic curves of the first control-grid g2 at different voltages on the second control grid g4.
  • the characteristic curve a is obtained at zero potential or a positive potential of the second control grid, and with ever increasing negative potentials of g4, the lines b, c, d and e must be obtained to ensure a satisfactory operation of the device.
  • FIG. 10 A very suitable construction and position of the two control grids is shown in Fig. 10, in which the length of the two control grids g2 and g4 is plotted vertically, the parts exhibiting different openings being designated I to IV. From this it appears that the second control grid exhibits a comparatively complicated distribution of its openings. Alternatively, a somewhat simpler distribution may be chosen, provided that a part exhibiting openings of a given size of the first control-grid is faced by at least two parts with diflferent openings of the second control-grid.
  • a tube according to the invention may be constructed as follows (Fig. 11).
  • a cathode 18 coated with electron-emitting material over a length of 1 to mms. is surrounded by four or more grids 19, 21, 22, 23, an anode 24 and, a suppressor grid 25.
  • the first grid 19 is oval so that the supporting rods are more spaced from the cathode than the active part of this grid.
  • the remaining grids may also be oval, and the anode may be circular-cylindrical.
  • rods 26 as shown in Fig. 12 are provided which are preferably connected to the cathode.
  • the accelerator grid 19 is connected to the screen grid 22 and given a low positive potential of less than 40 volts, the rod-shaped electrode 26 reducing the current to the accelerator grid 19.
  • the reduction of current might also be achieved if the cathode 18, according to Fig. 13, is coated with electron-emitting material 30 only opposite the active grid parts and the parts of the supporting rods 20 of the accelerator grid 19 facing the cathode are coated with insulating material 31.
  • the following electrode-construction may be used.
  • Example I With the use of a cathode sprayed over a comparatively great length (8 to 10 mms.):
  • wire diameter 80 ;, pitch 0.2 mm.
  • First control-grid variably wound 40% of the length, pitch 0.8 mm. (I in Fig. 10)
  • a circuit arrangement for detecting a frequency modulated wave having frequency deviations about a given center frequency comprising an input circuit including means to derive from said wave first and second signals, said second signal having a phase displacement relative to the first signal proportional to the deviation of said Wave from said center frequency, an electric discharge tube exhibiting a mutual conductance lower than its saturated anode current in milliamperes divided by four volts at the working point thereof and comprising means including a cathode, an accelerating anode, a first control grid, a screen grid, a second control grid and an anode arranged in that order to produce an anode current of given saturation value in said tube, means applying one of said signals to the first control grid and the other of said signals to the second control grid, said first control grid having a winding with at least two different pitches each extending over a given length portion thereof, said second control grid having at least two portions radially aligned with each given length portion of said first control grid, said two portions of said second control grid having windings of

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Particle Accelerators (AREA)
  • Microwave Tubes (AREA)
US251351A 1947-09-03 1951-10-15 Electric discharge tube Expired - Lifetime US2760067A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL266765X 1947-09-03

Publications (1)

Publication Number Publication Date
US2760067A true US2760067A (en) 1956-08-21

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ID=19781765

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Application Number Title Priority Date Filing Date
US251351A Expired - Lifetime US2760067A (en) 1947-09-03 1951-10-15 Electric discharge tube

Country Status (7)

Country Link
US (1) US2760067A (fr)
BE (1) BE484647A (fr)
CH (1) CH266765A (fr)
DE (1) DE826760C (fr)
FR (1) FR988495A (fr)
GB (1) GB679176A (fr)
NL (1) NL71107C (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE969436C (de) * 1951-04-26 1958-06-04 Lorenz C Ag Anordnung zur Demodulation frequenz- oder phasenmodulierter Schwingungen

Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2050474A (en) * 1935-01-31 1936-08-11 Rca Corp Electric discharge modulating system
US2086271A (en) * 1934-07-04 1937-07-06 Telefunken Gmbh Electron discharge device
US2090218A (en) * 1935-06-25 1937-08-17 Hygrade Sylvania Corp Electron discharge device
US2134407A (en) * 1937-02-12 1938-10-25 Philips Nv Electron discharge device
US2145368A (en) * 1934-12-27 1939-01-31 Rca Corp Amplifier tube and circuit
US2228980A (en) * 1938-09-27 1941-01-14 Telefunken Gmbh Electron discharge device
US2235498A (en) * 1940-01-11 1941-03-18 Rca Corp Electron discharge device
US2286337A (en) * 1937-11-27 1942-06-16 Telefunken Gmbh Negative feedback circuit
US2343263A (en) * 1942-05-06 1944-03-07 Hazeltine Corp Carrier-signal frequency detector
US2379764A (en) * 1942-06-06 1945-07-03 Rca Corp Frequency modulation detection
US2441254A (en) * 1945-08-04 1948-05-11 Remco Electronic Inc Symmetrical space charge tube
US2460062A (en) * 1945-11-23 1949-01-25 Philco Corp Grid controlled electron tube

Patent Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2086271A (en) * 1934-07-04 1937-07-06 Telefunken Gmbh Electron discharge device
US2145368A (en) * 1934-12-27 1939-01-31 Rca Corp Amplifier tube and circuit
US2050474A (en) * 1935-01-31 1936-08-11 Rca Corp Electric discharge modulating system
US2090218A (en) * 1935-06-25 1937-08-17 Hygrade Sylvania Corp Electron discharge device
US2134407A (en) * 1937-02-12 1938-10-25 Philips Nv Electron discharge device
US2286337A (en) * 1937-11-27 1942-06-16 Telefunken Gmbh Negative feedback circuit
US2228980A (en) * 1938-09-27 1941-01-14 Telefunken Gmbh Electron discharge device
US2235498A (en) * 1940-01-11 1941-03-18 Rca Corp Electron discharge device
US2343263A (en) * 1942-05-06 1944-03-07 Hazeltine Corp Carrier-signal frequency detector
US2379764A (en) * 1942-06-06 1945-07-03 Rca Corp Frequency modulation detection
US2441254A (en) * 1945-08-04 1948-05-11 Remco Electronic Inc Symmetrical space charge tube
US2460062A (en) * 1945-11-23 1949-01-25 Philco Corp Grid controlled electron tube

Also Published As

Publication number Publication date
BE484647A (fr)
FR988495A (fr) 1951-08-28
NL71107C (fr)
GB679176A (en) 1952-09-17
DE826760C (de) 1952-01-03
CH266765A (de) 1950-02-15

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