US2276132A - Carrier frequency system - Google Patents

Carrier frequency system Download PDF

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Publication number
US2276132A
US2276132A US285238A US28523839A US2276132A US 2276132 A US2276132 A US 2276132A US 285238 A US285238 A US 285238A US 28523839 A US28523839 A US 28523839A US 2276132 A US2276132 A US 2276132A
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US
United States
Prior art keywords
frequency
carrier frequency
band
carrier
station
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
US285238A
Other languages
English (en)
Inventor
Wiessner Alfred
Nitz Herbert
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.)
Alcatel Lucent Deutschland AG
C Lorenz AG
Original Assignee
Standard Elektrik Lorenz AG
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 Standard Elektrik Lorenz AG filed Critical Standard Elektrik Lorenz AG
Application granted granted Critical
Publication of US2276132A publication Critical patent/US2276132A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J1/00—Frequency-division multiplex systems
    • H04J1/02—Details
    • H04J1/04—Frequency-transposition arrangements
    • H04J1/045—Filters applied to frequency transposition
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J1/00—Frequency-division multiplex systems
    • H04J1/02—Details
    • H04J1/08—Arrangements for combining channels
    • H04J1/085—Terminal station; Combined modulator and demodulator circuits
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M1/00—Substation equipment, e.g. for use by subscribers
    • H04M1/78—Circuit arrangements in which low-frequency speech signals proceed in one direction on the line, while speech signals proceeding in the other direction on the line are modulated on a high-frequency carrier signal

Definitions

  • the invention deals with carrier frequency systems of this kind, that is, systems of the multi-channel type which involve the use of a multi-stage modulating method, and has for its object to interconnect the terminal toll exchange thereof and of the respective subscribers telephone station in a manner to abolish the split connection customarily provided in this terminal toll exchange and subscribers station and thereby to avoid a reflux caused by an imperfection of the balancing or simulation device.
  • the drawing is a diagrammatic representation showing one embodiment of the invention.
  • Ts denotes a subscribers station which is connectcd to a terminal station belonging to a toll exchange E.
  • the low-frequency speech currents liowing from the microphone Mi of station Ts are transferred through a low-pass iilter T1 and a two-wire line L to the exchange E and are there conveyed over a low-pass filter Ta to a modulator M1 where they serve to modulate an intermediate frequency of say 9 kilo cycles which is produced by a generator G.
  • One of the side bands originating by such modulation is conveyed through a filter Fi of a second modulating stage M2 where it serves to modulate in company with an additional number of Wave bands a high carrier frequency of say 60 kilo cycles. This carrier frequency is used for long-distance transmission.
  • the carrier frequency being of the same order of frequency as that output from M2
  • the carrier frequency is amplified by device A and is then demodulated by a demodulating means D.
  • the resultant side bands of the appertaining intermediate carriers are not demodulated with the aid of a second modulating stage.
  • VThey are merely supplied with the carrier from source G which is added to them by a device M3 to which output waves from D are conveyed over a filter F2.
  • the carrier and appertaining side band are conveyed over a highpass lter H1 to the two-wire line L of station Ts.
  • they are separated with the aid of a second high-pass filter H2 from the low-frequency currents, whereupon they are demodulated by a device D2.
  • the product of demodulation that is, the low-frequency currents originating in Dz, is reproduced by telephone receiver T.
  • a toll exchange with a 'multi-channel carrier wave system terminating in this exchange, the incoming carrier waves each being modulated with a side-band of a signalmodulated intermediate frequency
  • means at said toll exchange to demodulate the incoming carrier waves on each channel and thereby derive the signal-modulated intermediate frequency side-band for each channel
  • a subscribers telephone station a two-wire line for conveying said intermediate frequency side-band of one of said channels to said subscribers station
  • means at the toll exchange for adding to said transmitted side-band a carrier wave of said intermediate frequency
  • means in the subscribers station for demodulating said added carrier wave and said transmitted nals.

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  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
  • Mobile Radio Communication Systems (AREA)
US285238A 1938-07-26 1939-07-19 Carrier frequency system Expired - Lifetime US2276132A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DEL95240D DE733974C (de) 1938-07-26 1938-07-26 Traegerfrequenz-UEbertragungsanlage mit Mehrstufenmodulation

Publications (1)

Publication Number Publication Date
US2276132A true US2276132A (en) 1942-03-10

Family

ID=5827296

Family Applications (1)

Application Number Title Priority Date Filing Date
US285238A Expired - Lifetime US2276132A (en) 1938-07-26 1939-07-19 Carrier frequency system

Country Status (5)

Country Link
US (1) US2276132A (enrdf_load_stackoverflow)
BE (1) BE435593A (enrdf_load_stackoverflow)
CH (1) CH216072A (enrdf_load_stackoverflow)
DE (1) DE733974C (enrdf_load_stackoverflow)
FR (1) FR858181A (enrdf_load_stackoverflow)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2883464A (en) * 1953-02-18 1959-04-21 Ericsson Telefon Ab L M Device for signal receivers
US4996709A (en) * 1988-05-12 1991-02-26 Tandy Corporation Intercom telephone

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2883464A (en) * 1953-02-18 1959-04-21 Ericsson Telefon Ab L M Device for signal receivers
US4996709A (en) * 1988-05-12 1991-02-26 Tandy Corporation Intercom telephone

Also Published As

Publication number Publication date
DE733974C (de) 1943-04-06
BE435593A (enrdf_load_stackoverflow) 1939-08-31
FR858181A (fr) 1940-11-19
CH216072A (de) 1941-07-31

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