GB526483A - Improvements in or relating to telephone systems - Google Patents

Improvements in or relating to telephone systems

Info

Publication number
GB526483A
GB526483A GB856239A GB856239A GB526483A GB 526483 A GB526483 A GB 526483A GB 856239 A GB856239 A GB 856239A GB 856239 A GB856239 A GB 856239A GB 526483 A GB526483 A GB 526483A
Authority
GB
United Kingdom
Prior art keywords
speech
transmission
line
carrier
modulate
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
GB856239A
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.)
GURNEY OLIVER PROBERT
RICHARD ADNEY MEERS
STC PLC
Original Assignee
GURNEY OLIVER PROBERT
RICHARD ADNEY MEERS
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 GURNEY OLIVER PROBERT, RICHARD ADNEY MEERS, Standard Telephone and Cables PLC filed Critical GURNEY OLIVER PROBERT
Priority to GB856239A priority Critical patent/GB526483A/en
Publication of GB526483A publication Critical patent/GB526483A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/02—Channels characterised by the type of signal
    • H04L5/06—Channels characterised by the type of signal the signals being represented by different frequencies

Abstract

526,483. Diplex transmission. STANDARD TELEPHONES & CABLES, Ltd., MEERS, R. A., and PROBERT, G. O. March 17,1939, No. 8562. [Class 40 (iv)] Speech or music from two sources modulates respectively two carrier waves of the same comparatively low frequency, the upper side band being selected for transmission in one case and the lower in the other so that both channels are in the audible range and can be transmitted and received over circuits originally designed to handle only one channel. As shown, speech currents from line L1 after passing a volume range compressor and a low pass filter LP1 passing frequencies up to 12750 modulate a carrier of 3,000 cycles and the lower of the resulting side-bands is selected for transmission. Speech from line L3 is similarly treated but the upper side-band is selected. Both selected sidebands then pass to a telephone line or modulate a common carrier in a wireless transmitter T. Conversely, signals detected by a wireless receiver R2 are divided by filters into separate audio frequency channels which are converted by demodulation into intelligible speech signals which are fed to the respective lines via volume range expanders.
GB856239A 1939-03-17 1939-03-17 Improvements in or relating to telephone systems Expired GB526483A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB856239A GB526483A (en) 1939-03-17 1939-03-17 Improvements in or relating to telephone systems

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB856239A GB526483A (en) 1939-03-17 1939-03-17 Improvements in or relating to telephone systems

Publications (1)

Publication Number Publication Date
GB526483A true GB526483A (en) 1940-09-19

Family

ID=9854858

Family Applications (1)

Application Number Title Priority Date Filing Date
GB856239A Expired GB526483A (en) 1939-03-17 1939-03-17 Improvements in or relating to telephone systems

Country Status (1)

Country Link
GB (1) GB526483A (en)

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