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GB776129A - Improvements in or relating to secret signalling systems - Google Patents

Improvements in or relating to secret signalling systems

Info

Publication number
GB776129A
GB776129A GB3129255A GB3129255A GB776129A GB 776129 A GB776129 A GB 776129A GB 3129255 A GB3129255 A GB 3129255A GB 3129255 A GB3129255 A GB 3129255A GB 776129 A GB776129 A GB 776129A
Authority
GB
United Kingdom
Prior art keywords
modulated
intensity
source
amplitude
frequency
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
GB3129255A
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.)
Individual
Original Assignee
Individual
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 Individual filed Critical Individual
Priority to GB3129255A priority Critical patent/GB776129A/en
Publication of GB776129A publication Critical patent/GB776129A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/11—Arrangements specific to free-space transmission, i.e. transmission through air or vacuum

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Optical Communication System (AREA)

Abstract

776,129. Optional signalling systems. TOUVET, G. Nov. 2, 1955, No. 31292/55. Class 40(3). In a secret signalling system using optical radiation the intensity of the optical radiation is modulated in accordance with the intelligence to be transmitted, the overall amplitude of the intensity being kept constant. As shown (Fig. 4), radiation from a source 8 of constant intensity such as a filament lamp or an arc is focused by a lens 9 on an electro-optical modulating device 10 such as a Kerr cell in which the intensity of the light source is modulated. The modulating device is controlled by the output of an oscillator 14 modulated at 13 with the intelligence to be transmitted. The modulation may comprise (a) two components of different frequencies whose amplitudes are complementarily modulated so that the amplitude of one increases as the other decreases; (b) a single frequency modulated component the amplitude of the frequency modulated carrier being maintained constant; (c) a single-phase modulated component; or (d) a frequency shift telegraph system in which an oscillator is keyed between two alternative frequencies one of which represents marks and the other spaces. The effective strength of the source is kept constant while the frequency changes. In the arrangement of Fig. 5 (not shown), two different light sources are used the modulation being of the kind referred to at (a) and (c) above. In the arrangement of Figs. 1 and 2 (not shown), the intensity of the source itself is modulated. Specification 774,471 is referred to.
GB3129255A 1955-11-02 1955-11-02 Improvements in or relating to secret signalling systems Expired GB776129A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB3129255A GB776129A (en) 1955-11-02 1955-11-02 Improvements in or relating to secret signalling systems

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB3129255A GB776129A (en) 1955-11-02 1955-11-02 Improvements in or relating to secret signalling systems

Publications (1)

Publication Number Publication Date
GB776129A true GB776129A (en) 1957-06-05

Family

ID=10320968

Family Applications (1)

Application Number Title Priority Date Filing Date
GB3129255A Expired GB776129A (en) 1955-11-02 1955-11-02 Improvements in or relating to secret signalling systems

Country Status (1)

Country Link
GB (1) GB776129A (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3175088A (en) * 1961-06-22 1965-03-23 Bell Telephone Labor Inc Optical frequency modulation and heterodyne recovery system
US3204104A (en) * 1962-07-02 1965-08-31 Gen Telephone & Elect Single-sideband light modulator
US3284633A (en) * 1963-12-24 1966-11-08 Rca Corp Signal transmission and reception system comprising frequency modulated light beam
US3297876A (en) * 1963-04-16 1967-01-10 United Aircraft Corp Amplitude modulation for lasers
GB2458872A (en) * 1995-07-31 2009-10-07 Secr Defence Communications system

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3175088A (en) * 1961-06-22 1965-03-23 Bell Telephone Labor Inc Optical frequency modulation and heterodyne recovery system
US3204104A (en) * 1962-07-02 1965-08-31 Gen Telephone & Elect Single-sideband light modulator
US3297876A (en) * 1963-04-16 1967-01-10 United Aircraft Corp Amplitude modulation for lasers
US3284633A (en) * 1963-12-24 1966-11-08 Rca Corp Signal transmission and reception system comprising frequency modulated light beam
GB2458872A (en) * 1995-07-31 2009-10-07 Secr Defence Communications system
DE19629467A1 (en) 1995-07-31 2009-12-17 The Secretary Of State For Defence In Her Britannic Majesty's Government Of The United Kingdom Of Great Britain And Northern Ireland Communication system and communication method
US7639950B1 (en) 1995-07-31 2009-12-29 Qinetiq Limited Communications system
GB2458872B (en) * 1995-07-31 2010-03-03 Secr Defence Communication System

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