US1946274A - Method of signaling - Google Patents

Method of signaling Download PDF

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Publication number
US1946274A
US1946274A US520309A US52030931A US1946274A US 1946274 A US1946274 A US 1946274A US 520309 A US520309 A US 520309A US 52030931 A US52030931 A US 52030931A US 1946274 A US1946274 A US 1946274A
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United States
Prior art keywords
spectrum
wave
phase
circuit
circuits
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Expired - Lifetime
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US520309A
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English (en)
Inventor
Chireix Henri
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Thales SA
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Cie Generaie De Telegraphie
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03C—MODULATION
    • H03C1/00—Amplitude modulation
    • H03C1/52—Modulators in which carrier or one sideband is wholly or partially suppressed
    • H03C1/60—Modulators in which carrier or one sideband is wholly or partially suppressed with one sideband wholly or partially suppressed

Definitions

  • n COS u 4 an designating the amplitude of the component of pulsation Sin and of phase displacement qbn.
  • the normal telephonic modulation caused by any transmitter or emitter of pulsation w and of amplitude A may be expresed by:
  • a cos wfll-l- K COS n n) ⁇ Km being in that case the degree of depth of modulation expressed in percent of the pulsation 911.
  • the first term representswhat is called the carrier wave
  • the second term the upper spectrum or band
  • the third term the lower spectrum or band.
  • the present invention which is known as the Chireix system, discloses one method of overcoming the aforementioned difliculty.
  • a first great difficulty to be solved consists, there being given a spectrum of currents to produce, starting out from this spectrum, another spectrum identical with the first with respect to the respective amplitudes an but representing currents shifted in phase by 90, this to hold true even for the very low frequencies.
  • This problem can only be solved approximately, but in accordance with the modes of realization furnished by the invention, the solution obtained may be as close as desired.
  • Figures 1 and 2 illustrate two circuit schemes in accordance with the present invention of obtaining a current in quadrature with the applied current, but having the same amplitude.
  • Figures 3 to 5 illustrate detailed methods of obtaining two currents in quadrature with respect to each other from a source of applied current over a wide range of frequencies.
  • Figures 6 and 7 illustrate two embodiments for use in arrangements such as those illustrated in Figures 1 to 5 for suppressing the carrier and one of its associated side bands without the use of filter circuits.
  • FIG 8 illustrates, in schematic form, the essential elements or" a complete system embodying the principles of the present invention wherein reference characters in the boxes represent the numbers of the figures which are shown in detail in the other circuit arrangements.
  • circuit of Figure 1 comprising, connected in series with an inductance L, a condenser C, a resistance r and a second resistance r.
  • the input potential E is supplied by the conductors 1 and 1' between L and C on the one hand and between 1' and r on the other hand; the output potential e is collected between the conductors 2 and 2' connected respectively between L and r on the one hand and between C and 1" on the other land; in this circuit, for all the frequencies here considered, the resistances r and r are small compared with the inductive and capacitative impedances. If the circuit resonates at the pulsation we and if 1*:1" the potential collected between 2 and 2' is:
  • the telephonic currents being supplied by 1, 1, there is obtained in ab a potential in quadrature with E, of an amplitude at being a certain coefiicient due to the device Q1.
  • a portion in phase of the potential E is then added another tension furnished by the transformer T.
  • This potential is produced by the potential ab having traversed a device P1 identical or similar to Q1. It is of the form and in phase with E, since it has been subjected to a double phase shift of
  • the transformer T furnishes likewise a potential which is impressed on a device Q2 similar to P1 and Q1 and which reproduces at e a potential of the form:
  • these two potentials may be rendered quite equal to each other over a large range of frequencies.
  • circuit arrangement must be done in the manner as to prevent any shunting at the outgoing end of the phase displacing circuits, and for instance by means of relay tubes, as indicated in Figure 4, which may be understood without further description, the letters and numbers of reference designating the same elements or terminals.
  • FIG. 5 A variant of Figure 4 is given in Figure 5. This variant has the purpose to prevent phase displacements which may be introduced by the transformers if these latter are not constructed correctly.
  • Two high frequency potentials in quadrature are branched off the line 1, 1 by means of two tuned circuits I and II, the circuit II obtaining tubes or groups of tubes, connected in opposition.
  • the grids of the symmetrical circuit III are fed by means of conductors 7, 7' which are on the other end connected to the two armatures of condenser 11 of the tuned circuit I, provided with two seif-inductances, one, 9, being the coupling means with the self-inductance 10 of the tuned circuit II.
  • the condenser 12 of this second tuned circuit are branched the two conductors 8, 8' which feed the grids of the symmetric circuit IV.
  • potentials impressed on the circuits III and IV are modulated, for instance according to the system called anode control system or system with constant current, by the outputs coming from the lines 2, 2 and 3, 3' of Figures 4 or 5.
  • a particularly interesting application of the method and devices according to the invention resides in broadcasting.
  • the suppression of one of the lateral bands is the means, all other things being otherwise equal, to place in one and the same frequency band twice as many transmissions. It permits, besides, the reduction in half of the shifting band of the receivers and accordingly, due to a more pronounced syntony, the reduction of the influence of the atmospheric strays.
  • the circuit of Figure 6 would be simply inserted between two stages of high frequency amplification without further complications. For the same reasons the antenna may be tuned closer since the frequency spectrum is reduced by half.
  • the present invention is particularly useful in various types of short wave systems, especially in multiplex telegraph and telephone communication systems operating either on a code basis or any other suitable basis.
  • the following example relates to a telephone communication system and is merely mentioned as an illustration, not as a limitation.
  • the frequencies of the first telephonic transmission P may be written symbolically for a given instant as EP; likewise the frequencies of the second 2Q.
  • the spectra are the same, they are the ones of the voice.
  • the spectrum 2P may be transposed to the spectrum E(F+P) or then again to the spectrum 2(F-P), F being a frequency of the order of several thousands per second, so as to separate the new spectrum Z(F+P) or Z(FP) from the spectrum 2Q.
  • the short-wave transmitter by a spectrum of frequencies or a band of frequencies A e, the spectrum A comprising:
  • These communications may be separated by filters and rendered intelligible after demodulation by heterodynes of 4000 and 5000 periods per second.
  • a circuit arrangement for obtaining a wave presenting a phase angle of 90 degrees with reference to an applied wave spectrum while preserving substantial equality of amplitude relation throughout the frequency range between currents of each frequency in the obtained wave and the applied spectrum including a bridge arrangement comprising four elements of which two adjacent elements are respectively an inductance and a capacity, and two others two equal resistances, the value or" each or" said resistances being greatly difierent from each of the said pair of impedances, means for applying the wave spectrum to two opposite apices of the bridge, and means for collecting the phase-displaced wave at the other two apices of. said bridge.
  • Circuit arrangement adapted to obtain from a given wave spectrum two wave spectrums, one presenting the sad e phase angle as the original wave spectrum, and the other waves spectrum presenting phase angle of 90 degrees, these two wave spectrums being of like amplitudes, comprising a plurality of circuits associated with the source of current, one of said circuits containing in cascade an even number of phasedisplacing circuits causing the change in phase of 90 degrees, and means for superposing the output currents of these latter phase displacing circuits in a common or joint circuit, another of said plurality of circuits associated with the source of current containing in cascade an odd number of the said phase-shifting circuits, and means adapted to superpose the output currents of these latter circuits in another common or joint circuit.
  • a radio frequency source a radio frequency source
  • a radio communication circuit arrangement adapted to derive from said source two waves presenting a relative phase displacement of 90 degrees, two symmetric circuits passed respectively by each of said waves, means of modulation of the output currents of these circuits respectively by currents of like amplitude, but of a phase displaced 90 degrees
  • a circuit arrangement as claimed in claim 1 for causing the last mentioned phase displacement, and a common circuit associated with the said symmetric circuits' 4.
  • a Wheatstone bridge arrangement having a variable condenser in each of two adjacent arms thereof, two impedances in the other arms of said bridge, said impedances having values differing greatly from those of said condensers, another Wheatstone bridge similarly constructed to said first bridge, both said bridges being connected together at one of their apices, means for applying at two other opposite apices of each of said bridges two waves of equal aniplitune, but in phase quadrature with respect to each other, and terminal connections to the fourth and last apex of each of said bridges for obtaining currents therefrom.
  • the method of communication which includes shifting the phase of a portion of the current of the first wave spectrum twice successively, each time so degrees with respect to said first wave spectrmn in order to obtain one of said desired wave spectrums and shifting the phase of the current a third successive time again by 90 degrees to obtain the other desired wave spectrum.
  • the method of communication which includes shifting the phase of a portion of the current of the first wave spectrum twice successively, each time 90 degrees with respect to said first wave spectrum and adding to said twice shifted wave spectrum another portion of said first wave spectrum obtained without any phase shift in order to obtain one of said desired wave spectrums, and shifting the phase or" a portion of the current of the first wave spectrum a third successive time again by 90 degrees and adding thereto still another portion of said first wave'spectrum obtained merely by a 90 degrees phase shift in order to obtain the other desired wave spectrum.

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  • Transmitters (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Near-Field Transmission Systems (AREA)
  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
US520309A 1930-03-05 1931-03-05 Method of signaling Expired - Lifetime US1946274A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR642238X 1930-03-05

Publications (1)

Publication Number Publication Date
US1946274A true US1946274A (en) 1934-02-06

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US520309A Expired - Lifetime US1946274A (en) 1930-03-05 1931-03-05 Method of signaling

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US (1) US1946274A (de)
DE (1) DE642238C (de)
FR (1) FR708058A (de)
GB (1) GB363904A (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2450616A (en) * 1944-08-05 1948-10-05 Rca Corp Electrical networks for phase shifters
US2452586A (en) * 1944-03-23 1948-11-02 Sperry Corp Phase shift circuits
US2701862A (en) * 1949-11-16 1955-02-08 Rca Corp Electric wave filter
US2956242A (en) * 1957-10-22 1960-10-11 Philamon Lab Inc Tuning fork oscillator

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL184927B (nl) * 1953-11-18 Stork Brabant Bv Werkwijze voor het vormen van voor reproduktie geschikte gerasterde beelden.
DE1029468B (de) * 1955-08-22 1958-05-08 Siemens Ag Schaltungsanordnung zur Erzeugung einer gegenueber einer gegebenen Spannung (Eingangsspannung) phasengedrehten, insbesondere um 90íÒ phasengedrehten, frequenzunabhaengigen Spannung

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2452586A (en) * 1944-03-23 1948-11-02 Sperry Corp Phase shift circuits
US2450616A (en) * 1944-08-05 1948-10-05 Rca Corp Electrical networks for phase shifters
US2701862A (en) * 1949-11-16 1955-02-08 Rca Corp Electric wave filter
US2956242A (en) * 1957-10-22 1960-10-11 Philamon Lab Inc Tuning fork oscillator

Also Published As

Publication number Publication date
GB363904A (en) 1931-12-31
DE642238C (de) 1937-03-09
FR708058A (fr) 1931-07-20

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