US2582673A - Circuit arrangement for wave length modulation - Google Patents

Circuit arrangement for wave length modulation Download PDF

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Publication number
US2582673A
US2582673A US683696A US68369646A US2582673A US 2582673 A US2582673 A US 2582673A US 683696 A US683696 A US 683696A US 68369646 A US68369646 A US 68369646A US 2582673 A US2582673 A US 2582673A
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United States
Prior art keywords
tube
grid
modulating
circuit
reactance
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Expired - Lifetime
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US683696A
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English (en)
Inventor
Boelens Willem Wigger
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Hartford National Bank and Trust Co
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Hartford National Bank and Trust Co
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03C—MODULATION
    • H03C3/00—Angle modulation
    • H03C3/10—Angle modulation by means of variable impedance
    • H03C3/12—Angle modulation by means of variable impedance by means of a variable reactive element
    • H03C3/14—Angle modulation by means of variable impedance by means of a variable reactive element simulated by circuit comprising active element with at least three electrodes, e.g. reactance-tube circuit

Definitions

  • the phase-rotating network consists as a rule of an ohmic resistance and a reactan-ce, or which olements the one is located between the anode and the control grid and the other between the trol grid and the cathode whilst the impedance the control grid is large relatively to that oi the other element,
  • circuit-arrangement with wattless feed-back use is made of a similar phaserotating network of which the one element is of a discharge tube and the other, which has a considerably smaller impedance, is conhecte d between the anode and the cathode of this tube whilst between the control grid and the cathode I of the element provided between the anode and connected between the anode and the control grid there exists a virtual reactance which isinversely i proportional to the slope of the tube.
  • the modulating oscillations are supplied to a control electrode 01 the reactance tube for example to the previously mentioned control grid or to a second control grid, so that the slope of the reactance tube varies in the rhythm of the modulating oscillations.
  • a virtual reactance Whose value varies in the rhythm of the modulating oscillations.
  • phase modulation may be realized by including the said virtual reactance in a p a et ns ne work; to. which h oscination to be mo u ated a e su p ed,
  • the reactance tube is a linear function of the instantaneous value of the modulating oscillations.
  • the latter condition implies that the characteristic which represents the anode current of the reactance tube as a function of the voltage or the control grid to which the modulating oscillations are supplied, should he an exactly square function if the oscillations in be modulated are supplied to the same control grid, a d a e a tl linea function if the o il a ion o be d l a supplied to a second control grid.
  • Discharge tubes with an exactly square or linear characteristic are generally not available in pracrtice, so that in the case of modulation there occurs nearly always a certain distortion. It is lgnown obtained are combined in anti-phase with the i i his me hod ha th drawback "that the desired modulation without distortion is only obtained if the detection of the modulated oscillations takes place without any distortion. The latter requirement leads in map,-
  • a feedback for the modulating oscillations is utilized in the reactance tube in such a sense and with such an intensity that the instantaneous value of the frequencyor phase-displacement brought about by the modulation is always proportional or at least approximately proportional to the instantaneous value of the modulating oscillations.
  • Fig. l is a schematic diagram of a circuit arrangement for wave length modulation according to the invention.
  • Fig. 2 is a schematic diagram of an alternate embodiment of the invention.
  • Fig. 1 represents a circuit-arrangement for frequency modulation wherein the oscillations to be modulated are generated by an oscillator tube 1 which is connected for this purpose in three-point connection to 'an oscillatory circuit, which consists-of an inductance coil 2 and a condenser 3. That portion of the oscillatory circuit 2, 3 which is located between the anode and the cathode of the tube i has connected in parallel with it a reactance tube 4 constructed as a pentode whilst in parallel with the remainder of the said oscillatory circuit is connected the seriesconnection of a separating condenser 5, an ohmic resistance 5 and a condenser l.
  • the condenser 5 forms a short-circuit for the oscillations to be modulated whilst the resistance 6 is large relatively to the impedance of the condenser 1 and forms, jointly with the latter, a phase-rotating network by which a phase-displacement of approximately 90 is brought about.
  • the voltage set up across the condenser l which voltage is out of phase by approximately 90 with respect to the voltage across the circuit 2, 3, is supplied to the control grid of the tube 4 so that for the oscillations to be modulated this tube behaves as a reactance.
  • the value of the reactance formed by the tube 4 is controlled in the rhythm of the modulating oscillations by supplying these oscillations via terminals 8 and 9 and a high-frequency reactance coil I 0 to the control grid.
  • the oscillations modulated in frequency are taken via terminals H and H. from that portion of the circuit 2, 3 which is located between the anode and the cathode of the tube I.
  • the static characteristic may be represented by a function of the shape wherein the exponent n is more than 2.
  • the static, characteristic can be represented by a similar power function with an exponent less than 2, use should be made of positive feedback.
  • negative feedback for the modulating oscillations isobtainedby-means of a resistance l3 which is included in the cathode lead of the reactance tube 4 and which, for the frequency of the oscillations to be modulated, is preferably shunted by a condenser M.
  • th circuit arrangement according to the invention also differs from the known circuitarrangements with negative feedback in that in the case under consideration it is possible to ascertain an exactly determined value of Be With which the characteristic approximates the desired square shape with the greatest exactitude whereas such is not the case with larger or lower values of Rk.
  • the value of R ⁇ : which is utilized in accordance with the invention, is generally considerably smaller than in the known amplifying circuit-arrangements with negative feedback, and this'to such an extent that SR10.5.
  • the desired negative feedback may also be obtained by incorporating an ohmic resistance in the screen grid circuit or, when a triode is utilized as the reactance tube, in the anode circuit. In those cases in which positive feedback is required, this may be obtained in the known manner by coupling the circuit of one of the current-carrying electrodesby means of a transformer to the control grid circuit.
  • Fig. 2 represents a circuit-arrangement according to the invention wherein the reactance tube 5 is constructed as an hexode.
  • the oscillations to be modulated are supplied to the inner control grid whereas the modulating oscillations are supplied to the outer control grid.
  • the dynamic characteristic which represents the anode current as a function of the voltage of the outer control grid, has a linear or at least an approximately linear course. Since the cathode current .does not comprise a component with the frequency of the modulating oscillations, the incorporation of a resistance in the cathode lead would not lead to the purpose in view.
  • means of a resistance included in the anode ulating an electric wave comprising means to generatesaid electric wave, a reactance tuoe cuit coupled to said generating means and comprising an electron discharge tube having a plurality of electrodes, means to apply modulating potentials to said reactance tube to wavelength modulate said wave, means comprising an impedance element coupled to one of the electrodes of said discharge tube to derive a voltage proportional to the amplitude of said modulating potentials, and means to combine said voltage and said modulating potentials, said impedance element having a negligible impedance value at the frequency of said electric wave and a given impedance value at the frequency of said modulating potentials thereby to produce wave length modulation of said electric wave proportional to the instantaneous
  • a circuit arrangement for wave length modulating an electric wave comprising means to generate said electric wave, a reactance tube circuit coupled to said generating means and comprising an electron discharge tube having a cathode, a gride and an anode, means to apply modulating potentials to the grid of said reactance tube to wave length modulate said wave, means comprising an impedance element coupled to the cathode of said discharge tube to derive a voltage proportional to the amplitude of said modulating potentials, and means to apply said voltage to the grid of said reactance tube, said impedance element having a negligible impedance value at the frequency of said electric wave and a given impedance value at the frequency of said modulating potentials whereby the resultant value of anode current of said reactance tube is propor-' tional to the square of the value of voltage applied to the grid thereby to produce wave length modulation of said electric wave proportional to the instantaneous amplitude of said modulating potentials.
  • a circuit arrangement for wave length modulating an electric wave comprising means to generate said electric wave, a reactance tube circuit coupled to said generating means and comprising an electron discharge tube having a cathode, a grid an anode, the static characteristic of said electron discharge tube being represented by a power function having an exponent greater than 2, and means to apply modulating potentials to the grid of said reactance tube to wave length modulate said Wave, means to .derive a voltage proportional to the amplitude of said modulating potentials, means to apply said voltage to the grid of said reactance tube, and a resistor interposed in the anode-cathode circuit of said tube and having a resistance value at most equal to the value one-half divided by the transconductance of said tube thereby to pro- .duce wave length modulation of said electric wave proportional to the instantaneous amplitude of said modulating potentials.
  • a circuit arrangement for wave length modulating an electric wave comprising means to generate said electric wave, a reactance tube circuit comprising an electron discharge tube having a cathode, a first grid, a second grid, a screen grid and an anode, means to couple said generating means to one of the grids of said reactance tube, means to apply modulating potentials to the other of the grids of said reactance tube to wave length modulate said wave, and means including a resistance element coupled to said screen grid to derive a negative feedback voltage proportional to the amplitude of said modulating potentials, said resistance element having a resistance value at which the resultant wave length modulation of said electric wave is proportional to the instantaneous amplitude of said modulating potentials.
  • a circuit arrangement for wave length modulating an electric wave comprising means to generate said electric wave, a reactance tube circuit comprising an electron discharge tube having a cathode, a first grid, a screen grid, a second grid and an anode, the static characteristic of said electron discharge tube being represented by a power function having an exponent greater than 1, means to couple said generating means to the first grid 'of said reactance tube, means to apply modulating potentials to the second grid of said reactance tube to wave length modulate said wave, means to derive a voltage proportional to the amplitude of said modulating potentials, means to apply said voltage to the screen grid of said reactance tube, and a resistor interposed in the screen grid-cathode circuit of said tube and having a resistance value at which the resultant value of anode current of said reactance tube is linearly proportional to the voltage applied to the said second grid thereby to produce wave length modulation of said electric wave proportional to the instantaneous amplitude of said modulating potentials.
  • a circuit arrangement for wave length modulating an electric wave comprising means to generate said electric Wave, a reactance tube circuit comprising an electron discharge tube having a cathode, a first grid, a screen grid, a second grid and an anode, the static characteristic of said electron discharge tube being represented by a power function having an exponent greater than 1, means to couple said generating means to the first grid of said reactance tube, means to apply modulating potentials to the second grid of said reactance tube to wave length modulate said wave, means to derive a voltage proportional to the amplitude of said modulating potentials.

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  • Inductance-Capacitance Distribution Constants And Capacitance-Resistance Oscillators (AREA)
  • Ac-Ac Conversion (AREA)
  • Amplitude Modulation (AREA)
US683696A 1943-02-25 1946-07-15 Circuit arrangement for wave length modulation Expired - Lifetime US2582673A (en)

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Application Number Priority Date Filing Date Title
NL241543X 1943-02-25

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US2582673A true US2582673A (en) 1952-01-15

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US (1) US2582673A (en(2012))
BE (1) BE454503A (en(2012))
CH (1) CH241543A (en(2012))
DE (1) DE864413C (en(2012))
FR (1) FR902171A (en(2012))
GB (1) GB625268A (en(2012))

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2728891A (en) * 1950-04-15 1955-12-27 Emi Ltd Modulation circuit arrangements
US2858436A (en) * 1953-12-14 1958-10-28 Gen Electric Automatic frequency control system

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE872228C (de) * 1951-09-18 1953-03-30 Telefunken Gmbh Schaltung zur Modulation von Hochfrequenzschwingungen
JPS6042393Y2 (ja) * 1980-01-24 1985-12-26 シチズン時計株式会社 クオ−ツ腕時計の防水リユウズ装置

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2279660A (en) * 1937-04-13 1942-04-14 Rca Corp Wave length modulation system
US2323598A (en) * 1941-01-07 1943-07-06 Rca Corp Variable signal response network
US2361658A (en) * 1942-10-26 1944-10-31 Rca Corp Sound recording and reproducing system
US2382436A (en) * 1943-08-18 1945-08-14 Bell Telephone Labor Inc Reactance tube circuit
US2383848A (en) * 1943-02-25 1945-08-28 Rca Corp Reactance control circuit
US2394427A (en) * 1942-11-09 1946-02-05 Rca Corp Wave length modulation

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2279660A (en) * 1937-04-13 1942-04-14 Rca Corp Wave length modulation system
US2323598A (en) * 1941-01-07 1943-07-06 Rca Corp Variable signal response network
US2361658A (en) * 1942-10-26 1944-10-31 Rca Corp Sound recording and reproducing system
US2394427A (en) * 1942-11-09 1946-02-05 Rca Corp Wave length modulation
US2383848A (en) * 1943-02-25 1945-08-28 Rca Corp Reactance control circuit
US2382436A (en) * 1943-08-18 1945-08-14 Bell Telephone Labor Inc Reactance tube circuit

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2728891A (en) * 1950-04-15 1955-12-27 Emi Ltd Modulation circuit arrangements
US2858436A (en) * 1953-12-14 1958-10-28 Gen Electric Automatic frequency control system

Also Published As

Publication number Publication date
GB625268A (en) 1949-06-24
CH241543A (de) 1946-03-15
DE864413C (de) 1953-01-26
FR902171A (fr) 1945-08-21
BE454503A (en(2012))

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