GB807391A - Improvements in single channel carrier frequency telephone communication system - Google Patents

Improvements in single channel carrier frequency telephone communication system

Info

Publication number
GB807391A
GB807391A GB9513/57A GB951357A GB807391A GB 807391 A GB807391 A GB 807391A GB 9513/57 A GB9513/57 A GB 9513/57A GB 951357 A GB951357 A GB 951357A GB 807391 A GB807391 A GB 807391A
Authority
GB
United Kingdom
Prior art keywords
carrier
modulator
transistor
pass filter
passive
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
Application number
GB9513/57A
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.)
STC PLC
Original Assignee
Standard Telephone and Cables PLC
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 Telephone and Cables PLC filed Critical Standard Telephone and Cables PLC
Publication of GB807391A publication Critical patent/GB807391A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B3/00—Line transmission systems
    • H04B3/02—Details
    • H04B3/44—Arrangements for feeding power to a repeater along the transmission line

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)

Abstract

807,391. Carrier transmission. STANDARD TELEPHONES & CABLES Ltd. March 22, 1957 [March 28, 1956], No. 9513/57. Class 40 (4). In a single-channel carrier telephone system of the kind having one main station which feeds carrier to the line and one, or more, passive secondary stations, the (or each) passive station employs a dynamic microphone and includes a transistor microphone amplifier the power for which is provided by rectified carrier from the modulator-demodulator. As shown, carrier current incoming from the main station (not shown) is applied via a phase corrector FC to the modulator/demodulator MD, the direct current output of which produces a unidirectional voltage which is applied across the capacitor C to provide the supply voltage for the transistor TR. When the operator at the passive station speaks into his electrodynamic microphone the output therefrom is amplified by the transistor amplifier having a gain of about 20-25 db., and is applied via the low-pass filter FL1 to the modulator. The modulation products pass to line via the usual band-pass filter (not shown). Incoming currents from the main station, which consist of sidebands and carrier, are demodulated in MD, and the voice-frequency demodulation products pass via the low-pass filter FL1 to the receiver T.
GB9513/57A 1956-03-28 1957-03-22 Improvements in single channel carrier frequency telephone communication system Expired GB807391A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
IT807391X 1956-03-28

Publications (1)

Publication Number Publication Date
GB807391A true GB807391A (en) 1959-01-14

Family

ID=11317038

Family Applications (1)

Application Number Title Priority Date Filing Date
GB9513/57A Expired GB807391A (en) 1956-03-28 1957-03-22 Improvements in single channel carrier frequency telephone communication system

Country Status (1)

Country Link
GB (1) GB807391A (en)

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