US1350752A - High-frequency signaling - Google Patents

High-frequency signaling Download PDF

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Publication number
US1350752A
US1350752A US46643A US4664315A US1350752A US 1350752 A US1350752 A US 1350752A US 46643 A US46643 A US 46643A US 4664315 A US4664315 A US 4664315A US 1350752 A US1350752 A US 1350752A
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United States
Prior art keywords
high frequency
wave
low frequency
waves
oscillations
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
US46643A
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English (en)
Inventor
Bijl Hendrik Johannes Van Der
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AT&T Corp
Original Assignee
Western Electric Co Inc
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Filing date
Publication date
Priority to GB141732D priority Critical patent/GB141732A/en
Priority to NL15248D priority patent/NL15248C/xx
Application filed by Western Electric Co Inc filed Critical Western Electric Co Inc
Priority to US46643A priority patent/US1350752A/en
Priority to DEB92860D priority patent/DE361361C/de
Priority to FR513761A priority patent/FR513761A/fr
Application granted granted Critical
Publication of US1350752A publication Critical patent/US1350752A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03C—MODULATION
    • H03C1/00—Amplitude modulation
    • H03C1/16—Amplitude modulation by means of discharge device having at least three electrodes
    • H03C1/18—Amplitude modulation by means of discharge device having at least three electrodes carrier applied to control grid
    • H03C1/22—Amplitude modulation by means of discharge device having at least three electrodes carrier applied to control grid modulating signal applied to same grid

Definitions

  • This invention relates to signaling by high frequency electrical oscillations or waves along wires or through space, and more particularly it relates to a system for modulating high frequency oscillations in accordance with the frequency and amplitude variations of message waves to be transmitted, and its object is to effect this modulation I without destroying the quality characteristics of the message wave.
  • the invention provides for modulating feeble high frequency oscillations by impressing the currents of tele honic frequencies, together with the high requency oscillations, on the input circuit of a thermionic amplifier; and makes use of the fact that the amplification of a thermionic amplifier of the audion type depends upon the voltage impressed upon the grid or input circuit.
  • the amplifying power of the 'tube for the .high fre uency oscillations is caused to vary in aecor ance with the variations of the electromotive force of the telephonic waves of low frequency, the desired modulation is obtained, for there will be produced a high frequency wave the envelop of which is an accurate re reduction of the telephonic wave, and t is wave may then be further amplified to any required degree for effective radiation from an antenna.
  • Perfect modulation refers to such a variation in the amplitude of envelop of the high frequency wave that this envelop is an lating wave
  • the max1mum negative value of the low frequency input wave is made just sufficient to reduce the modulated high frequency oscillations to zero amplitude.
  • the line represent space current will be moved ual horizontal distances from both sides of and the amplifiqttion' at an instant willdepend uponthe t ofthe meteristie at which the mp is working; that is, upon the form of the low fmquencyvoltage curve, and will in fact be proportional to the of the characteristic at the point i new, highoscillations are also impressed upon the grid circuit, the high frequency current in the output circuit will depend in magnitude upon the amount of amplification, that is, upon the part of the characteristic at which the amplifier is working and therefore upon the form of the low frequency voltage curve.
  • the low frequency should be large compared with the high frequency input to the modu lator, in order that the amplifying power shall not change appreciably due to the high frequency oscillations, but shall be subject to the low frequency voltage only. From a theoretical standpoint the best value for the ratio is infinity, but of course this is not practical, and it has been found that a sufficiently good modulation can be secured if the low frequency voltage input is from three to ten times as large as the high frequency voltage input.
  • A is a thermionic amplifier comprising an evacuated vessel 2 which incloses the cathode 3, anode 4 and an auxiliary electrode 5.
  • Cathode 3 is heated to incandescence by the battery 6 and is maintained positive with respect to electrode 5 by means of battery 7.
  • the normal potential of the grid is therefore at some such point as M in Fig. 3, such that the most negative grid potential resulting from the low frequency modulating wave will be just suflicient to carry the space current to zero as at point B.
  • the space current flowing bet-ween cathode 3 and anode 4 may be supplied from a direct current generator 8 having in shunt with it a condenser 9 sufficiently high in capacity to afford a path of low impedance for both the low and high frequency currents.
  • the input circuit of the amplifier A includes the cathode 3, battery 7, potentiometer 10, secondary 11 of the oscillation transformer 12 and the electrode 5.
  • the primary 13 of transformer 12 is connected to a high frequency generator 14, which may be of any suitable type, such, for example, as that described in an application of Hartley, Serial No. 31,476, filed June 1, 1915.
  • a telephone transmitter 15 is connected in series with a battery 16 in the primary circuit of a transformer 17, whose sec ondary is connected to the potentiometer 10 in the input circuit of the amplifier.
  • the output circuit of the amplifier includes the anode 4, Winding 18 of the oscillation transformer 19, the condenser 9 and generator 8 in parallel, and the cathode 3.
  • the arrangement described serves simply to produce in this output circuit high frequency currents having substantially the same wave form as that produced by the generator 14, but of greater amplitude.
  • the electrode 5 When. however, telephonic electromotive forces are impressed on the input circuit by means of the transformer 17, the electrode 5 will be made more or less negative with respect to the cathode 3, as the telephonic wave fluctuates from a negative to a positive value.
  • This variation in the potential of the electrode 5 has the effect of varying the amplifying power of the amplifier in accordance with variations in the telephonic electromotive forces.
  • the amplification produced by the tube depends upon the relative values of the internal resistance of the tube and the external impedance into which it works, it may be considered that the variation in the potential of the electrode 5 has the effect of varying the impedance of the electron discharge path between cathode 3 and anode 4, and as this path is included in the output circuit of the amplifier, it follows that the impedance of the output circuit is varied in accordance with variations in the telephonic electromotive forces.
  • the winding 18 of the transformer 19 there will be produced in the winding 18 of the transformer 19 a high frequency current whose amplitude varies with the variation in amplitude of the impressed telephonic electromotive force, that is. the envelop of the high frequency wave will be an accurate reproduction of the telephonic wave.
  • the power value of the impressed telephonic wave shall be greater than that of the generated high frequency oscillations, it will. appear that the power value of the modulated high frequency waves produced in the transformcr 19.may Well be insufiicient for effective radiation from an antenna. In such case the power may be amplified to the degree required for radiation by means of some such arrangement as that described in patent to Arnold No. 1,129,942, March 2. 1915. ()n the other hand, it may well be that the high frequency oscillations have a fairly large power to start with. and in this case it may be necessary to amplify the telephonic power before impressing the two upon a common amplifier.
  • the transformer 17 is shown directly connected to a telephone transmitter 15, it is to be understood that this transformer may be connected to a telephone line and serve as a means for relaying. to a wireless antenna or other high frequency signaling system, telephonic or other messages received over long distance conductors. It is also evident that the arrangement shown is suitable for telegraphic transmission by simply substituting a telegraph key for the transmitter 15 and adding an interrupter of any desired frequency. It is evident also that although this invention is particularly well adapted for use in signaling systems, which constitutes the principal application for modulated currents. in its broader aspects the invention may be used wherever it is desired to modulate waves or periodic disturbances, regardless of the use which is to be made of the modulated current or the medium in which the disturbances are produced.
  • the method of modulating carrier waves which consists in generating carrier waves of substantially constant amplitude. and invariably amplifying the amplitude of said carrier waves in accordance with a signal.
  • the method of modulating carrier current which comprises generating a high frequency carrier wave of substantially constant amplitude, simultaneously 'generating a low frequency wave and variably amplifying the high frequency wave in accordance with said low frequency wave.
  • the method of modulation which comprises generating a current of high frequency, generating a current of relatively low frequency, impressing energy from each of these currents in series upon a circuit, generating space current and causing the energy impressed upon said circuit to vary said space current, said variations being of the frequency of said carrier current but having greater amplitudes, the amplification varying in accordance with the varia-' tions of said low frequency current.
  • the method of modulating high frequency carrier current which consists in producing a high frequency carrier wave, simultaneously producing a low frequency wave of greater amplitude than said high frequency Wave and variably amplifying said high frequency wave in accordance with said low frequency wave.
  • the method of modulation which consists in generating a high frequency wave, simultaneously generating a low frequency wave having an amplitude at least as great as that of said high. frequency wave and variably amplifying said high frequency wave in accordance with said low frequency wave.
  • the method of signaling which comprises generating a series of waves and subsequently simultaneously amplifying and modulating each of the waves in accordance with a signal.
  • a source of high frequency oscillations an amplifier having an input circuit and an output circuit, means for impressing said high frequency oscillations on said input circuit, a primary source of low frequency currents, and a path of variable impedance in said output circuit controllable by said low frequency currents.
  • a source of high frequency oscillations having an input circuit, and a primary source of low frequency currents connected with said input circuit whereby the amplification of said oscillations is made to vary in conformity with variations in said low frequency currents.
  • a thermionic amplifier having an input circuit, a source of high frequency oscillations connected with said input circuit, and a primary source of low frequency electromotive force also connected with said input circuit.
  • means for amplifying said oscillations comprising an evacuated vessel containing an electron-emitting cathode, an anode and an auxiliary electrode, an input circuit including said cathode and said auxiliary electrode, means for impressing said oscillations on said input circuit, and a connection between said low frequency current source and said input circuit in series with said means.
  • means for amplifying said oscillations comprising a thermionic repeater having an input circuit and an output circuit, a high frequency transformer having its primary connected to said generator and its secondary included in said input circuit, a low frequency transformer having its primary connected to said low frequency source and having its secondary connected to said input circuit in series with the secondary of said high frequency transformer.
  • a modulating system thecombination with a source of high frequency oscillations, of means for modulating said oscillations, said means comprising a device asymmetrically conducting for said high frequency oscillations and an impedance varying clcmcnt therefor, said means being free from contact resistance.
  • a source of high frequency oscillations In a high frequency signaling system, a source of high frequency oscillations. and a power amplifier having a curved characteristic for modulating and amplifying said oscillations in accordance with a signal.
  • a source of high frequency oscillations power amplifying means for modulating said oscillations and means for impressing said high frequency oscillations upon said amplifying means, the amplifying power of said means being substantially independent of the amplitude of the impressed high frequency oscillations.
  • a generator providing a source of high frequency oscillations, a source of signal oscillations, an asymmetrically conducting thermionic device having a constantly active source of electrons, an input circuit and an output circuit, means for impressing oscillations from both of said oscillation sources upon the input circuit of said thermionic device, and a high frequency transmission circuit associated with the output circuit of said device.
  • the method of producing modulated waves which comprises producing a carrier wave, amplifying said carrier wave and simultane'ously varying the amplification of said carrier wave so as to make it substantially proportional to the amplitude of a low frequency wave.
  • the method of producing modulated waves which comprises producing a carrier wave, amplifying said carrier wave and simultaneously controlling the amplification of said carrier wave substantially exclusively in accordance with slow. frequency wave.
  • the method of producing modulated waves which comprises impressing a carrier wave upon an amplifier to produce an amplified carrier wave and simultaneously impressin u on said amplifier another wave of muc arger amplitudethan said impressed carrier wave in order to control the l-magnitude of the amplified carrier 4r wave.
  • the method which comprises simultaneously subjecting a thermionic device having a variable amplifying power to the action of a high frequenc wave, and a low frequency wave, the ampiitude of the high frequency wave being insufiicient to cause considerable chan e in the amplifying power of said amp ifier and the amplitude of the low frequency wave being suflicient to cause lar e change in the amplifying.
  • a thermionic discharge device having a cathode, an anode and an impedance control element, an input circuit connected to said cathode and said impedance control element and an output circuit connected to said cathode and said anode, which method comprises impressing a high frequency electromotive force upon said input circuit, simultaneously impressing an electromotive force between said control element and said cathode, negatively directed with respect to said control element, and varying at a low fre uency rate the effective value of said negatively directed electromotive force.
  • the method of producing a 'modu- .lated wave which comprises impressing a carrier wave upon a thermionic amplifier having .a curved characteristic and simultaneously impressing upon said amplifier an electromotive force varying at a low frequency and of a magnitude within a range throughout which the curved characteristic is substantially parabolic.
  • means for producing a carrier wave means connected thereto for amplifying said carrier wave, means for producing a low frequency wave connected to said amplifying means and means associated therewith whereby the amplification of said carrier wave may be made substantially proportional to the amplitude of said low frequency wave.
  • Means for producing a carrier wave an amplifier connected to said means, an means for impressin upon said amplifier another wave of amp itude large compared with that of said impressed carrier wave in order to control the magnitude of the amplified carrier wave.
  • an amplifier having a variable amplifying power, a high frequency source and a ow frequenc source, means'conneeting said sources to said amplifier to simultaneously impress thereon high frequenc waves an .low frequency waves,
  • a thermionic discharge device having a cathode, an adode and an impedance control element, an input circuit connected to said cathode and said control element, an out ut circuit connected to said cathode an anode, a high frequency source connected to said input circuit, means for impressing a negative electromotive force upon said controlelement with respect to said cathode, and means for varying at a low 38.
  • a thermionic ampli- 'fier having a curved characteristic, means for impressing thereon a carrier wave, means for simultaneously impressing upon said amplifier an electromotive force varying at low frequency andflhaving an amplitude within a range throughout which said curved characteristic is substantially parabolic.

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  • Transmitters (AREA)
  • Selective Calling Equipment (AREA)
  • Amplifiers (AREA)
US46643A 1915-08-21 1915-08-21 High-frequency signaling Expired - Lifetime US1350752A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
GB141732D GB141732A (enrdf_load_stackoverflow) 1915-08-21
NL15248D NL15248C (enrdf_load_stackoverflow) 1915-08-21
US46643A US1350752A (en) 1915-08-21 1915-08-21 High-frequency signaling
DEB92860D DE361361C (de) 1915-08-21 1920-02-15 Anordnung zur Zeichenuebermittlung
FR513761A FR513761A (fr) 1915-08-21 1920-04-15 Perfectionnements dans les systèmes de signalisation électrique utilisant des courants à hautes fréquences

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US46643A US1350752A (en) 1915-08-21 1915-08-21 High-frequency signaling

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US1350752A true US1350752A (en) 1920-08-24

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US46643A Expired - Lifetime US1350752A (en) 1915-08-21 1915-08-21 High-frequency signaling

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US (1) US1350752A (enrdf_load_stackoverflow)
DE (1) DE361361C (enrdf_load_stackoverflow)
FR (1) FR513761A (enrdf_load_stackoverflow)
GB (1) GB141732A (enrdf_load_stackoverflow)
NL (1) NL15248C (enrdf_load_stackoverflow)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2415227A (en) * 1943-08-04 1947-02-04 William E Tenbrook Vegetable topper

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2776729B1 (en) 2011-11-07 2018-06-13 Magna Powertrain Inc. Torque transfer unit for an engine starting system

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2415227A (en) * 1943-08-04 1947-02-04 William E Tenbrook Vegetable topper

Also Published As

Publication number Publication date
DE361361C (de) 1922-10-11
GB141732A (enrdf_load_stackoverflow)
NL15248C (enrdf_load_stackoverflow)
FR513761A (fr) 1921-02-23

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