GB556001A - Improvements relating to electrical communication systems - Google Patents

Improvements relating to electrical communication systems

Info

Publication number
GB556001A
GB556001A GB3374/42A GB337442A GB556001A GB 556001 A GB556001 A GB 556001A GB 3374/42 A GB3374/42 A GB 3374/42A GB 337442 A GB337442 A GB 337442A GB 556001 A GB556001 A GB 556001A
Authority
GB
United Kingdom
Prior art keywords
carrier
sub
wave
signal
modulated
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
GB3374/42A
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
Priority to BE476184D priority Critical patent/BE476184A/xx
Priority to NL67408D priority patent/NL67408C/xx
Priority to NL136059D priority patent/NL136059B/xx
Application filed by Standard Telephone and Cables PLC filed Critical Standard Telephone and Cables PLC
Priority to GB3374/42A priority patent/GB556001A/en
Priority to US476072A priority patent/US2489268A/en
Publication of GB556001A publication Critical patent/GB556001A/en
Priority to FR939087D priority patent/FR939087A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B14/00—Transmission systems not characterised by the medium used for transmission
    • H04B14/02—Transmission systems not characterised by the medium used for transmission characterised by the use of pulse modulation

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
  • Near-Field Transmission Systems (AREA)

Abstract

556,001. Wireless and like signalling. STANDARD TELEPHONES & CABLES, Ltd., CHATTERJEA, P. K., and AMBROSE, D. M. March 13, 1942, No. 3374. [Class 40 (v)] Modulation is effected by varying the waveform of a sub-carrier or carrier wave, in accordance with a signal voltage. A sine wave of a sub-carrier frequency higher than is contained in the signal is applied at 3, 4 to the grid of a valve V2, and the signal voltage is applied at 1, 2 to the grid of a valve V1. The two valves have a common anode load resistance 17, across which is developed a sub-carrier wave modulated in amplitude. The peaks and troughs of this wave are cut off by oppositely-connected biased diodes V3, V4 giving at the output terminals. a wave which varies in form between a pure sine wave and a sloping-sided pulse as shown in Fig. 3. This wave is modulated on to a carrier at the terminals 5, 6 of a radio transmitter. At the receiving station the sub-carrier, after detection, is passed through limiters to a filter which rejects the fundamental sub-carrier but passes its harmonics to an ordinary rectifying detector, from which the signal passes through a lowpass filter to the phones or other receiving instrument. Alternatively the received modulated sub-carrier may pass to a damped circuit tuned to the sub-carrier frequency. The oscillations thus produced in this circuit vary in amplitude with the voltage variations of the original signal. The Provisional Specification states that the carrier may be transmitted over a wave guide, and that the sub-carrier may be transmitted directly over a line.
GB3374/42A 1942-03-13 1942-03-13 Improvements relating to electrical communication systems Expired GB556001A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
BE476184D BE476184A (en) 1942-03-13
NL67408D NL67408C (en) 1942-03-13
NL136059D NL136059B (en) 1942-03-13
GB3374/42A GB556001A (en) 1942-03-13 1942-03-13 Improvements relating to electrical communication systems
US476072A US2489268A (en) 1942-03-13 1943-02-16 Electrical communication system
FR939087D FR939087A (en) 1942-03-13 1946-04-01 Electrical communications systems

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB3374/42A GB556001A (en) 1942-03-13 1942-03-13 Improvements relating to electrical communication systems

Publications (1)

Publication Number Publication Date
GB556001A true GB556001A (en) 1943-09-15

Family

ID=9757111

Family Applications (1)

Application Number Title Priority Date Filing Date
GB3374/42A Expired GB556001A (en) 1942-03-13 1942-03-13 Improvements relating to electrical communication systems

Country Status (5)

Country Link
US (1) US2489268A (en)
BE (1) BE476184A (en)
FR (1) FR939087A (en)
GB (1) GB556001A (en)
NL (2) NL67408C (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2564769A (en) * 1949-10-25 1951-08-21 Rca Corp Translating circuit
US2929924A (en) * 1955-02-21 1960-03-22 Westinghouse Electric Corp Radiation suppression circuit
US2956153A (en) * 1957-11-08 1960-10-11 Sylvania Electric Prod Electrical noise reduction techniques

Family Cites Families (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1584327A (en) * 1926-05-11 Electric-wave transmission system
US1564627A (en) * 1920-03-31 1925-12-08 Rca Corp Wireless telegraph and telephone transmission
US1678163A (en) * 1923-12-29 1928-07-24 Western Electric Co Modulation
US1655543A (en) * 1924-04-18 1928-01-10 Western Electric Co Transmission system
US1911253A (en) * 1926-09-13 1933-05-30 Clinton Dorothy Radio receiving apparatus
US1699570A (en) * 1927-09-23 1929-01-22 American Telephone & Telegraph Carrier suppression modulation
US1876793A (en) * 1929-10-22 1932-09-13 Frank C Talmadge Radio circuit
US1971383A (en) * 1932-03-11 1934-08-28 Telefunken Gmbh Transmitter
GB398853A (en) * 1932-03-22 1933-09-22 Marconi Wireless Telegraph Co Improvements in or relating to radio and other high frequency modulated carrier wave systems
US2061734A (en) * 1934-09-29 1936-11-24 Rca Corp Signaling system
US2279659A (en) * 1937-04-13 1942-04-14 Rca Corp Frequency modulator
NL88393C (en) * 1937-06-18
US2205359A (en) * 1938-06-24 1940-06-18 Hygrade Sylvania Corp Superheterodyne receiver
US2230243A (en) * 1938-06-28 1941-02-04 Philip M Haffcke Signal selection by amplitude discrimination
US2257282A (en) * 1939-04-27 1941-09-30 Rca Corp Frequency modulation of signals
US2303493A (en) * 1940-05-17 1942-12-01 Rca Corp Diversity signaling system
US2404306A (en) * 1941-04-01 1946-07-16 Rca Corp Communication system
NL137118C (en) * 1942-08-24

Also Published As

Publication number Publication date
BE476184A (en)
US2489268A (en) 1949-11-29
NL136059B (en)
FR939087A (en) 1948-11-03
NL67408C (en)

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