US2323033A - Carrier frequency telephone system - Google Patents

Carrier frequency telephone system Download PDF

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Publication number
US2323033A
US2323033A US389714A US38971441A US2323033A US 2323033 A US2323033 A US 2323033A US 389714 A US389714 A US 389714A US 38971441 A US38971441 A US 38971441A US 2323033 A US2323033 A US 2323033A
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US
United States
Prior art keywords
frequency
band
cycles
line
voice
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Expired - Lifetime
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US389714A
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English (en)
Inventor
Hagen Wolfgang
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Individual
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Individual
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Publication of US2323033A publication Critical patent/US2323033A/en
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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B3/00—Line transmission systems
    • H04B3/02—Details
    • H04B3/36—Repeater circuits
    • H04B3/38—Repeater circuits for signals in two different frequency ranges transmitted in opposite directions over the same transmission path
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62H—CYCLE STANDS; SUPPORTS OR HOLDERS FOR PARKING OR STORING CYCLES; APPLIANCES PREVENTING OR INDICATING UNAUTHORIZED USE OR THEFT OF CYCLES; LOCKS INTEGRAL WITH CYCLES; DEVICES FOR LEARNING TO RIDE CYCLES
    • B62H1/00—Supports or stands forming part of or attached to cycles
    • 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
    • H04B1/38—Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
    • H04B1/40—Circuits
    • H04B1/54—Circuits using the same frequency for two directions of communication
    • H04B1/58—Hybrid arrangements, i.e. arrangements for transition from single-path two-direction transmission to single-direction transmission on each of two paths or vice versa
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62H—CYCLE STANDS; SUPPORTS OR HOLDERS FOR PARKING OR STORING CYCLES; APPLIANCES PREVENTING OR INDICATING UNAUTHORIZED USE OR THEFT OF CYCLES; LOCKS INTEGRAL WITH CYCLES; DEVICES FOR LEARNING TO RIDE CYCLES
    • B62H2700/00—Supports or stands for two-wheel vehicles
    • B62H2700/005—Stands or support attached to bicycle pedals, stands or supports in combination with locking devices, stands to be used as luggage carrier

Definitions

  • the present invention relates to carrier ,fre-' quency telephone systems, and more particularly to systems of the lgind in which a pair of conductors forms the transmission channels necessary in establishing two-way intercommunication.
  • the heretofore known two-way-carrier frequency communication systems in which a single pair of conductors forms the transmission line, generally employ. different frequency ranges for each direction of transmission.
  • This facility introduces the disadvantages that in the first instance the one transmission channel offers an attenuation which is different from thatof the other. channel and, on the other hand, that the frequency band subject to transmission over the line is at least twice as wide as that of the normal voice frequency band.
  • separate filter means must be provided in order to segregate these different frequencies.
  • the normal voice frequencies emitted in both directions of communication are so transposed within the same band that the corresponding transmission band frequencies are reversed, that is, the transposition frequency employed inone direction is located at the lower end and the transposition frequency in the opposite direction is located ,at
  • the terminal or intermediate stations may suitably be provided with line branches which either include the requisite number of filter means or form a suitable combination therewith.
  • line branches which either include the requisite number of filter means or form a suitable combination therewith.
  • FIG. 2 shows its application to a two-wire line amplifier.
  • Voice frequency oscillations say between 300 and 2700 cycles
  • incoming over the line NFI are selected by the line branch G1 andapplied to amodulator M1 through a filter F1 which excludes the mean frequency of 1500 cycles.
  • the remaining frequencies of the voice frequency band are then transposed in the modulator M1 into an intermediate frequency band of the same width including the frequency range between 3300 and 5700 cycles in such manner, that the intermediate frequency of 3300 v cycles is obtained from the 300 cycles voice freconvenience can be eliminated by so designing the filters that the mean frequency is excluded,
  • incoming intermediate frequency of 4500 cycles is converted into 1500 cycles, which frequency actuates a ringing current responsive device R: in the output circuit of the demodulator D2 which device in turn applies ringing current to the outgoing line NFz.
  • a balancing network Ni When a line branch, such as G1, is used, a balancing network Ni must be combined therewith in order to balance the line L with respect to the intermediate frequency band between 3300 and 5700 cycles. Such balancing will be readily obtained since this transmission band is rather narrow.
  • the same voice frequency band between 300 and 2700 cycles is used.
  • the modulator M2v effects transposition thereof into an intermediate frequency band ranging between 3300 and 5700 cycles which band nected to this line.
  • the Fig. 2 shows the invention as applied to a two-wire line amplifier.
  • Communication from line NF! to line NF: is effected through line branch G1, voice frequency amplifier A1, line branch G1, over the line L, and through the line branch G1, voice frequency amplifier A2, and line branch G1 to the line NFa.
  • the voice frequencies are subjected to a reversal in the modulator M2, that is, the frequency of 300 cycles is converted into a frequency of 2700 cycles and the voice frequency of 2700 cycles is converted into a frequency of 300 cycles, which is readily possible by subjecting the voice frequency band between 300 and 2700 cycles to a first modulation with 8000 cycles.
  • the resulting lower side-band including the frequencies of 5300 to 7700 cycles is then again modulated with a modulation frequency of 5000 cycles resulting in a voice frequency band of 300 to 2700 cycles.
  • the frequency characteristic of this band is opposite to that of the voice frequencies.
  • the 1500 cycles mean frequency of this band must be particularly considered with respect to the balancing of the line since the singing tendency becomes more severe at this frequency.
  • a two-wire carrier frequency telephone system according to claim 2, wherein the said voice frequency band is subjected to at least two different frequency transpositions.
  • a two-wire carrier frequency telephone system according to claim 2, wherein line branches are provided for interconnecting said terminal stations with said transmission line.
  • a two-wire carrier frequency telephone system wherein balancing networks are provided in the terminal stations for balancing said line with special reference to.
  • i mean frequency of the said transmission band and the said voice frequency band, respectively.
  • a two-wire carrier frequency telephone system according to claim 2, wherein the distance from the singing point for one terminal station is twice as large as the attenuation of the loop circuit at said station.
  • a two-wire carrier frequency telephone system according to claim 2, wherein means are provided for suppressing the mean frequency of the said voice frequency band and the said transmission band, respectively.
  • a two-way electric wave signalling system comprising a first terminal station, a second terminal station, a two-wire transmission line extending between said first and said second stations, means in said stations for producing voice frequency signal waves, means in one of said stations for impressing upon said transmission line waves containing voice frequency signal components and extending over a predetermined frequency band in which the frequency amplitude characteristic of the voice frequency signal waves is inverted and means in the other station for impressing upon said transmission line waves containing voice frequency signal components and extending over the same predetermined frequency band but in which the frequency amplitude characteristic of the voice frequency signal waves is unchanged.
  • a two-way electric wave signalling system comprising a first repeater station, a second repeater station, a two-wire on line ex-- tending between said tirstand second stations, means in said stations for producing voice frequency signal waves extending over a predetermined band in the frequency spectrum, means 1 in. one'ot said stations for impressing upon said transmission line waves extending over said pre- WOLFGANG HAGEN.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mechanical Engineering (AREA)
  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
US389714A 1940-03-13 1941-04-22 Carrier frequency telephone system Expired - Lifetime US2323033A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE216838X 1940-03-13

Publications (1)

Publication Number Publication Date
US2323033A true US2323033A (en) 1943-06-29

Family

ID=5830413

Family Applications (1)

Application Number Title Priority Date Filing Date
US389714A Expired - Lifetime US2323033A (en) 1940-03-13 1941-04-22 Carrier frequency telephone system

Country Status (4)

Country Link
US (1) US2323033A (enrdf_load_stackoverflow)
BE (2) BE440664A (enrdf_load_stackoverflow)
CH (1) CH216838A (enrdf_load_stackoverflow)
FR (1) FR873651A (enrdf_load_stackoverflow)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5125026A (en) * 1989-12-21 1992-06-23 H & K Devices, Inc. Internal telephone intercom system

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5125026A (en) * 1989-12-21 1992-06-23 H & K Devices, Inc. Internal telephone intercom system

Also Published As

Publication number Publication date
FR873651A (fr) 1942-07-16
BE440664A (enrdf_load_stackoverflow)
CH216838A (de) 1941-09-15
BE440661A (enrdf_load_stackoverflow)

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