US2194512A - Combined oscillator-detector circuits - Google Patents

Combined oscillator-detector circuits Download PDF

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Publication number
US2194512A
US2194512A US162274A US16227437A US2194512A US 2194512 A US2194512 A US 2194512A US 162274 A US162274 A US 162274A US 16227437 A US16227437 A US 16227437A US 2194512 A US2194512 A US 2194512A
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United States
Prior art keywords
grid
circuit
oscillator
frequency
signal
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
US162274A
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English (en)
Inventor
Travis Charles
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
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Filing date
Publication date
Priority to NL38790D priority Critical patent/NL38790C/xx
Priority claimed from US668231A external-priority patent/US2153778A/en
Priority to FR771600D priority patent/FR771600A/fr
Priority to DER90463D priority patent/DE632327C/de
Priority to GB12343/34A priority patent/GB423772A/en
Application filed by RCA Corp filed Critical RCA Corp
Priority to US162274A priority patent/US2194512A/en
Application granted granted Critical
Publication of US2194512A publication Critical patent/US2194512A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03D—DEMODULATION OR TRANSFERENCE OF MODULATION FROM ONE CARRIER TO ANOTHER
    • H03D7/00—Transference of modulation from one carrier to another, e.g. frequency-changing
    • H03D7/06—Transference of modulation from one carrier to another, e.g. frequency-changing by means of discharge tubes having more than two electrodes
    • H03D7/10—Transference of modulation from one carrier to another, e.g. frequency-changing by means of discharge tubes having more than two electrodes the signals to be mixed being applied between different pairs of electrodes
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
    • H03B5/00—Generation of oscillations using amplifier with regenerative feedback from output to input
    • H03B5/08—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance
    • H03B5/10—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance active element in amplifier being vacuum tube

Definitions

  • An object of the present invention is to provide application Serial No. 642,544, filed Nov. 14, 1932,
  • the local voltage generated may be maintained suboscillator circuit includes 'coil II and variable stantially constant.
  • condenser 12 by which the oscillation frequency A still further object is to provide a combined may be adjusted to produce any desired beat oscillator detector, which may for example be the frequency.
  • This circuit may be connected in a first detector of a superheterodyne receiver, in known manner to the oscillator control grid I 35 which there is substantial freedom from frequency through a condenser ID, a suitable grid leak redrift.
  • sistor 9 being provided and connected to grid l
  • Another object of the invention is to further and the cathode C.
  • the normal steady bias of neutralize the capacity existing between the plate the grid 4 may be provided in known manner by and a grid of a vacuum tube having a plurality a resistor 'l'connected between cathode C and of grids, including a screen grid. Still other obground, resistor I being shunted by a condenser 8. 20
  • the plate 6 may be connected to a constant skilled in the art as the description thereof voltage source of abou 250 Vo t owa proceeds.
  • parallel circuit comprising coil I6 and condenser Circuit arrangements showing embodiments of H, the latter of which may be adjustable to tune the invention are illustrated in the accompanying he p ate Circuit t0 t e desired beat q y, drawings in which: which may be, for example, 175 kilocycles.
  • FIG. 1 and 2 show a vacuum tube having a oscillator'anode electrode 2'is shown connected to plurality of grids arranged as a combined oscilthe 250 volt source through a resistor l4, shunted lator and detector; by a condenser l5, and a tickler coil I3 which is Figs. 3 and 4 show circuits embodying my ininductively coupled to coil ll.
  • This coupling be- 30 vention in connection with a combined oscillator tween coils l3 and l l provides the'necessary feeddetector having five grids; and 7 back of energy to the grid circuit l ll2, to cause Fig. 5 shows a circuit similar to that of Fig. 1 the tube to generate oscillations.
  • the screen with a neutralizing arrangement according to my grids 3 and 5 may be connected together coninvention. ductively either within, or without, the tube, and 35
  • This invention relates in general to circuit armay have a steady positive voltage of 50 to 100 rangements useful in connection with a Vacuum volts applied thereto from any desired voltage tube having several grids as disclosed in the ap- Source (not Shown) y 3 lead e T can plication filed in the name of J. C. Smith on Jan. be of the well-known 2A7 type.
  • a tunable input circuit consisting bias on grid 4 was changed from -3 volts to cut- 50 of secondary 22 and variable condenser i8, is conon (about -30 to 35 volts) nected to the signal control grid 4, the lead 20
  • the circuit arrangement shown in Fig. 2 is connected to the opposite side of coil 22 being essentially the same as that of Fig.
  • tickler coil i3 is also included in tector of the receiver as shown, for example, in the circuit of plate 6 so thatthe platecurrent of the tube flows through it, in addition to the current of oscillator anode electrode 2.
  • tickler coil 28 in the plate circuit, of one third the number of turns of tickler coil I3, it was found that the oscillation strength and frequency remained substantially constant, as the bias on signal grid 4 was changed over a substantial voltage range.
  • the oscillator control grid I was of the sharp cut-off type wherebyless voltage was required to produce the desired oscillation strength, whereas, grid 4 was constructed to give remote cut-off or producea result similar to that of a variable mu tube.
  • Figs. 3 and 4 I have shown the intermediate frequency tuned circuit I 6, ll inductively coupled to a secondary 24 tuned to the intermediate frequency by a condenser 25.
  • This circuit maybe connected as the input circuit of an intermediate frequency amplifier 21, being connected to the grid 26 thereof.
  • For broadcast reception circuits Hi, I! and 24, 25 are preferably tuned to 175 kilocycles, or any other desired beat frequency.
  • this frequency condenser I2 is initially adjusted so that the oscillation frequency is higher, or lower, than the incoming signal frequency by an amount equal to the desired beat frequency.
  • Iam enabled by this invention to prevent detuning of the receiver due to change, or drift, in the oscillator frequency caused by change in the grid bias of the signal control grid 4. Also,
  • FIG. 5 A further aspect of the invention is disclosed in Fig. 5 where the circuit shown is generally similar to that of Fig. 1.
  • a neutralizing circuit has been added, as shown, comprising CN and a coil 29 inductively coupled to coil 22.
  • Coil 29 may consist of a few reversed turns wound around the low potential end of the radio frequency secondary coil 22.
  • a capacity of about one quarter micro-microfarad (0.25) exists between plate 6 and grid 4, and it is the purpose of the neutralizing circuit shown to neutralize this ca pacity.
  • the load in the plate circuit is essentially capacitive.
  • the effective plate circuit capacity is always less than the physical capacity I!
  • a neutralizing condenser of fixed value may be used; that is, the circuit is not one requiring individual adjustment of the neutral izing condenser for each individual receiver.
  • resistor l4 having a value of approximately 20,000 ohms.
  • a combined oscillator and detector comprising a vacuum tube having an oscillator grid, anode electrode a signal control grid, a screen grid mounted on each side of said signal control grid, a cathode and a plate, a circuit tunable to the incoming signal frequency connected to said signal control grid, a tunable oscillator circuit connected between said oscillator grid and cathode, a circuit connected to said anode electrode and including a feedback con, nection to said oscillator circuit to cause said tube to generate oscillations of a frequency higher than the incoming signal frequency by a desired beat frequency, means for applying a positive voltage to said screen grid, a plate circuit including a circuit tuned to said beat frequency and means to prevent reaction of said last named circuit on said circuit tuned to the signal frequency due to thecapacity coupling between said plate and said signal control grid.
  • reaction preventing means comprises a condenser and coil connected in series, said coil being inductively coupled to thesignal tuned circuit and a conductive connection between one side of said condenser and lthe plate of said tube.
  • an electron discharge tube having at least a cathode and an output electrode, an oscillator grid, an oscillator anode and I a signal grid being disposed in the electron stream betweensaid cathode and output electrode, said signal grid being disposedbetween the oscillator anode and said output electrode, a signal input circuit connected between the cathode and signal grid, 2.
  • a resonant circuit tuned to a predetermined local oscillator frequency, respectively coupling the oscillator anode and oscillator grid, an intermediate frequency circuit connected to said output electrode,'means reactively coupling the output electrode and said local oscillation frequen'cy'resonant circuit, and means for establishing said signalgrid at a predetermined negative direct current potential with respect to the cathode.
  • an electron discharge tube having at least a cathode and an output electrode, an oscillator grid, an oscillator anode and a signal grid being disposed in the electron stream between said cathode and output electrode, said signal grid being disposed between the oscillator anode and said output electrode, a signal input circuit connected between the cathode and signal 7 grid, a network, including a resonant circuit tuned to a predetermined local oscillator frequency, reactively coupling the oscillator anode and oscillator grid, an intermediate frequency circuit connected to said output electrode, means I local oscillation amplitude.
  • an automatic gain control means for increasing the negative bias on the signal grid of the tube as the received signal amplitude increases and the feedback from each of said electrodes-being pro- 'portioned to maintain substantially constant oscillation amplitude as said negative bias varies.
  • a superheterodyine receiver including a combined local oscillator-first detector network em ploying a tube provided with oscillator and mixer sections, said oscillator section including a grid electrode and an anode electrode and said mixer section including a signal grid and an output electrode, automatic volume control means for varying the bias of the signal grid, and means providing a" radio frequency energy feedback from each of the oscillator anode and the mixer output electrode to the oscillator grid electrode, and said feedbacks being relatively proportioned to render the oscillation strength and frequency substantially independent of the signal grid bias variation.
  • said mixe sectionsignal grid being constructed to have a remote cut-off characteristic, and said oscillator section grid has a sharp cut-ofi characteristic.
  • an oscillator-detector circuit comprising a tube provided with oscillator section electrodes and detector section electrodes, said detector section including a signal input electrode and an output electrode, a source of signals coupled to the signal input electrode of the detector section, a local oscillation circuit coupled to the oscillator electrodes to produce oscillations of a frequency diiiering'from the signal frequency by an interquency energy feedback between the output electrode of the detector section and the said oscillation circuit, and means for varying the direct current voltage of said signal input electrode thereby to control the amplitude of the intermediate frequency energy.
  • a detector-oscillator system using a'tube provided with oscillator section electrodes and detector section electrodes, said detector section including input electrodes and an output electrode, a source of signals coupled to the input electrodes of the detector section, a local oscillation circuit-coupled to the oscillator electrodes,
  • a beat frequency output circuit coupled to the mediate frequency, means providing radio fredetector section output electrode, means feeding back radio frequency energy from the said output electrode to said oscillation circuit, and automatic gain control means responsive to an increase in signal amplitude for decreasing the CHARLES TRAVIS.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Inductance-Capacitance Distribution Constants And Capacitance-Resistance Oscillators (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Stabilization Of Oscillater, Synchronisation, Frequency Synthesizers (AREA)
US162274A 1933-04-27 1937-09-03 Combined oscillator-detector circuits Expired - Lifetime US2194512A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
NL38790D NL38790C (xx) 1933-04-27
FR771600D FR771600A (fr) 1933-04-27 1934-04-10 Montages de circuits
DER90463D DE632327C (de) 1933-04-27 1934-04-24 Roehrenschaltung unter Verwendung einer Roehre mit mehreren Gittern
GB12343/34A GB423772A (en) 1933-04-27 1934-04-24 Improvements in or relating to thermionic valve arrangements
US162274A US2194512A (en) 1933-04-27 1937-09-03 Combined oscillator-detector circuits

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US668231A US2153778A (en) 1933-04-27 1933-04-27 Circuit arrangement
US162274A US2194512A (en) 1933-04-27 1937-09-03 Combined oscillator-detector circuits

Publications (1)

Publication Number Publication Date
US2194512A true US2194512A (en) 1940-03-26

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Family Applications (1)

Application Number Title Priority Date Filing Date
US162274A Expired - Lifetime US2194512A (en) 1933-04-27 1937-09-03 Combined oscillator-detector circuits

Country Status (5)

Country Link
US (1) US2194512A (xx)
DE (1) DE632327C (xx)
FR (1) FR771600A (xx)
GB (1) GB423772A (xx)
NL (1) NL38790C (xx)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2774867A (en) * 1952-06-14 1956-12-18 Hazeltine Research Inc Frequency modulation detector having fixed output frequency converter

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1035218B (de) * 1952-09-10 1958-07-31 Telefunken Gmbh Schaltungsanordnung zur Erzeugung eines leistungsstarken Frequenzspektrums

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2774867A (en) * 1952-06-14 1956-12-18 Hazeltine Research Inc Frequency modulation detector having fixed output frequency converter

Also Published As

Publication number Publication date
DE632327C (de) 1936-07-06
NL38790C (xx)
FR771600A (fr) 1934-10-12
GB423772A (en) 1935-02-07

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