US1663880A - Signaling apparatus - Google Patents

Signaling apparatus Download PDF

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Publication number
US1663880A
US1663880A US47655A US4765525A US1663880A US 1663880 A US1663880 A US 1663880A US 47655 A US47655 A US 47655A US 4765525 A US4765525 A US 4765525A US 1663880 A US1663880 A US 1663880A
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US
United States
Prior art keywords
wave
intermediate frequency
circuit
detector
filter
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
US47655A
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English (en)
Inventor
John C Gabriel
George M Thurston
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.)
AT&T Corp
Original Assignee
Western Electric Co Inc
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Western Electric Co Inc filed Critical Western Electric Co Inc
Priority to US47655A priority Critical patent/US1663880A/en
Application granted granted Critical
Publication of US1663880A publication Critical patent/US1663880A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G3/00—Gain control in amplifiers or frequency changers
    • H03G3/20—Automatic control
    • H03G3/22—Automatic control in amplifiers having discharge tubes
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/06—Receivers
    • H04B1/16—Circuits
    • H04B1/30—Circuits for homodyne or synchrodyne receivers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/06—Receivers
    • H04B1/16—Circuits
    • H04B1/30—Circuits for homodyne or synchrodyne receivers
    • H04B1/302—Circuits for homodyne or synchrodyne receivers for single sideband receivers

Definitions

  • the beat current produced by the interaction of the two waves will be transmitted through the intermediate frequency selective and amplifying circuits and will interact with the signal modulated intermediate frequencywave resulting from the incoming wave to be received, to produce an interfering tone in the indicator or receiving instrument.
  • the incoming wave comprises a S] gnal modulated carrier wave consistlng of a carrier component and both side-band components
  • the received signal is frequently distorted due to the two side bands beating together or combining to produce a current of audible frequency that may combine with the modulating current to produce an lnterfering tone in the indicator or telephone receiver.
  • difiiculty is frequently experienced in radio reception, especially at short wave lengths due to the periodic increase and decrease in the volume of the received signal, commonly called fading.
  • One reason for this may be a phase shift between the two side bands of the signal modulated wave in the transmission medium, which causes irregular operation of the receiver.
  • One object of this invention is to prevent interference, in a system of the above mentioned type, due to undesired beats produced by combining two incoming waves.
  • Another object is to prevent distortion of the signals caused by the side bands of a modulated wave being combined.
  • detector of this type is disc osed in U. S. Patent 1,343,308, June 15, 1920 to Carson, to which reference may be made for a description of its method of operation.
  • any other suitable source of oscillations may be employed to produce oscillations having a frequency differing from the frequency of the ncoming signal Wave by an amount adapted to combme with the received wave to produce a wave of desired intermediate frequency.
  • the intermediate frequency wave is impressed upon the amplifier 6, herein shown as comprising four stages of amplification.
  • the amplifier 6 since the purpose of the amplifier 6 is merely to increase the amplitude of the intermediate frequency wave so that a signal of the desired intensity is produced in the indicator, it may consist of any number of stages.
  • Amplifier 6 consists of space discharge devices 7 coupled by transformers 8 which are designed to cooperate with the devices 7 to selectively amplify a wave of predetermined intermediate frequency.
  • Polarizing potential is applied to the grids or control electrodes of the amplifier tubes'7 by the sources 9.
  • Condensers 10 serve to by-pass high frequency current around the various direct current sources.
  • the intermediate frequency wave after being amplified by the amplifier 6 is supplied to a filter 11 or 12', either of which. may be included in the circuit by actuating the switch 13.
  • Filter '11 is designed to pass without appreciable attenuation both side bands and the unmodulated component of the intermediate frequency wave, while filter 12 is designed to freely pass only one side band and to suppress the second side band and the unmodulated carrier component of intermediate frequency.
  • Waves passed through filter 11 or 12 are impressed upon the second detector 14 through transformer 15 and detected.
  • the current resulting from this stage of detection may he amplified by an audio frequency amplifier 16,- if desired, and used to actuate phone receiver 17.
  • the local oscillations produced 'anv suitable indicating means such as a teleby an oscillator 19 are-amplified by a device 20, and impressed upon-the resistance 18 included in the grid filament circuit of detector 14.
  • the device 20 serves to amplify the oscillation produced by source 19 to the desired intensity and toprevent variations in load impedance from affecting the frequency of the oscillations generated.
  • the source 19 supplies oscillations of desired intensity the amplifier 20 would not be used.
  • Source 21 supplies space current to the various space discharge devices. Filament heating current supplied from source 22.
  • filter 12 is designed to pass only a single side band and to suppress the second side band and the unmodulated carrier component, there may pass through this filter some small portion of the unmodulated component which would combine with the transmitted side band to produce an interfering tone in the receiver 17
  • a push-pull detector 14 which operates in a manner similar to push-pull detector 1, the unsuppressed unmodulated component and the transmitted side band will be symmetritransmitted through the intermediate frequency circuits.
  • switch 13 When it is desired to employ both side bands of the intermediate frequency wave, switch 13 is thrown to the left to connect filter 11 into the circuit and to interrupt the filament heating circuit of one of the two ill] detectors 14, oscillator 19 and amplifier 20,
  • a signaling system means for receivin an incoming wave carrying signals, a local oscillator, means for combining said received wave with oscillations supplied by said local oscillator to produce an intermediate frequency wave carrying signals, means for suppressing a portion of said 1ntermediate frequency wave, means for 10- cally supplying energy of the frequencv of at least a part of said suppressed portion of the intermediatefrequency wave, and means for combining said local energy with the unsuppressed portion of said intermediate frequency wave to produce signal currents.
  • a system of the character described com rising means for receiving a wave 1ncludlng modulated and unmodulated components, a source of local oscillations, means for combining said local oscillations with said received wave to produce an intermediate frequency signal modulated wave, means for suppressing the unmodulated component thereof, a local oscillator for supplying locally oscillations of the frequency o the unmodulated component, means for combining said locally supplied oscillations with the modulated components of said intermediate frequency wave to produce a low frequency signal, and means for indicating said low frequency signal.
  • means for receiving a wave comprising two side bands and an unmodulated carrier component a local oscillator, means for combining said received .wave with currents from. said local source to produce a wave of an intermedlate freunmodulated component, means for combining said local carrier oscillations with said unsuppressed side band to produce a signal of a third frequency, and means for indicating said last mentioned signal.
  • a radio receiving circuit comprising means for receiving a wave comprising modulated and unmodulated components, a local oscillator, means for'comfbining said received wave with currents from said local oscillator whereby a wave of intermediate frequency is produced, said combining means being adapted to suppress other signals of said intermediate frequency produced by the interaction of two received waves, means for amplifying said intermediate frequency wave; a filter adapted to pass said modulated and unmodulated components thereof, a second filter adapted to pass one of said modulated components only and to suppress the other of said modulated components and the unmodulated component, switching means for connecting either one or the other of said filters in circuit, means for rectifying said intermediate frequency signal comprising two space discharge detectors in push-pull relationship, a source of local oscillations for supplying a local carrier to said push-pull detector when said second mentioned filter is connected in the circuit, means for rendering inoperative one of said space discharge detectors when said first mentioned filter is connected in circuit, and means for determining said received signal.
  • a radio receiving system comprising a loop antenna adapted to. receive a transmitted wave composed of unmodulated and modulated components, a source of local os-.
  • a detector comprisin space discharge devices connected in pusdi-pull relationship for combining said local oscillations with said received wave to produce a Wave of an intermediate frequency, said detector being adapted to suppress signals of said intermediate frequency produced by the combinatlon of two received waves, a space discharge amplifier for amplifying said intermediate frequency wave, a filter adapted to pass the unmodulat ed and modulated components of said intermediate frequency wave, a second filter adapted to pass one of said modulated components only and to sup-,
  • push-pull vacuum tube detector having its input circuit connected thereto, a local source of oscillations connected to the input circuit of said detector, said connection lying in the common path of the push-pull detector input circuit and said antenna being oppositely connected'tothe grid circuits of the individual vacuum tubes, whereby radiation of the locally produced oscillations from said antenna is revented.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Noise Elimination (AREA)
US47655A 1925-08-03 1925-08-03 Signaling apparatus Expired - Lifetime US1663880A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US47655A US1663880A (en) 1925-08-03 1925-08-03 Signaling apparatus

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US47655A US1663880A (en) 1925-08-03 1925-08-03 Signaling apparatus
GB30731/25A GB258131A (en) 1925-12-05 1925-12-05 Improvements in receiving systems for the detection of signals from high frequency waves

Publications (1)

Publication Number Publication Date
US1663880A true US1663880A (en) 1928-03-27

Family

ID=10312259

Family Applications (1)

Application Number Title Priority Date Filing Date
US47655A Expired - Lifetime US1663880A (en) 1925-08-03 1925-08-03 Signaling apparatus

Country Status (5)

Country Link
US (1) US1663880A (enrdf_load_stackoverflow)
DE (1) DE575427C (enrdf_load_stackoverflow)
FR (1) FR609393A (enrdf_load_stackoverflow)
GB (1) GB258131A (enrdf_load_stackoverflow)
NL (1) NL18794C (enrdf_load_stackoverflow)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE925180C (de) * 1952-10-14 1955-03-14 Rohde & Schwarz Verfahren zum Betrieb eines Empfaengers fuer amplitudenmodulierte Zweiseitenbandsendungen

Also Published As

Publication number Publication date
NL18794C (enrdf_load_stackoverflow)
DE575427C (de) 1933-04-27
FR609393A (fr) 1926-08-13
GB258131A (en) 1926-09-16

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