GB580843A - Improvements in or relating to secrecy communication systems - Google Patents

Improvements in or relating to secrecy communication systems

Info

Publication number
GB580843A
GB580843A GB1637841A GB1637841A GB580843A GB 580843 A GB580843 A GB 580843A GB 1637841 A GB1637841 A GB 1637841A GB 1637841 A GB1637841 A GB 1637841A GB 580843 A GB580843 A GB 580843A
Authority
GB
United Kingdom
Prior art keywords
wave
pulses
circuit
modulated
masking
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
GB1637841A
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 BE471102D priority Critical patent/BE471102A/xx
Priority to BE473048D priority patent/BE473048A/xx
Application filed by Standard Telephone and Cables PLC filed Critical Standard Telephone and Cables PLC
Priority to GB1637841A priority patent/GB580843A/en
Priority to GB1493842A priority patent/GB582709A/en
Priority to US500416A priority patent/US2412964A/en
Priority to FR939295D priority patent/FR939295A/en
Publication of GB580843A publication Critical patent/GB580843A/en
Priority to FR939428D priority patent/FR939428A/en
Priority to ES0177437A priority patent/ES177437A1/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K7/00—Modulating pulses with a continuously-variable modulating signal
    • H03K7/02—Amplitude modulation, i.e. PAM
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04K—SECRET COMMUNICATION; JAMMING OF COMMUNICATION
    • H04K1/00—Secret communication
    • H04K1/02—Secret communication by adding a second signal to make the desired signal unintelligible

Landscapes

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

Abstract

580,843. Secret transmission. STANDARD TELEPHONES & CABLES, Ltd., CHATTERJEA, P. K., and HOUGHTON, L. W.. Dec. 18, 1941, No. 16378. [Class 40 (iv)] [Also in Group XL] A masking wave is periodically reduced for a brief period to zero or some other definite amplitude as shown in Fig. 3 by means of a circuit 6 supplied with pulses from a source 2, Fig. 7, pulses from the same source are amplitude-modulated by the signal that it is desired to send and the masking wave and the modulated impulses are combined in a circuit 7 in such a way that the modulated impulses occupy the interruptions in the masking wave. The combined wave is then used to modulate a carrier which is received by the circuit shown in Fig. 8. Pulses synchronous with the signal pulses and derived from the combined wave or from some other transmission are used to render a circuit 15 conducting periodically so that appropriate portions of the received carrier are passed on to a demodulator 17 where they are converted to modulated pulses which are converted to speech &c. currents in circuit 18. The masking wave may be noise or speech or scrambled speech or the complex wave from a distributer or carrier multiplex system.
GB1637841A 1941-12-18 1941-12-18 Improvements in or relating to secrecy communication systems Expired GB580843A (en)

Priority Applications (8)

Application Number Priority Date Filing Date Title
BE471102D BE471102A (en) 1941-12-18
BE473048D BE473048A (en) 1941-12-18
GB1637841A GB580843A (en) 1941-12-18 1941-12-18 Improvements in or relating to secrecy communication systems
GB1493842A GB582709A (en) 1941-12-18 1942-10-23 Improvements in or relating to secrecy communication systems
US500416A US2412964A (en) 1941-12-18 1943-08-28 Secrecy communication system
FR939295D FR939295A (en) 1941-12-18 1946-08-29 Improvements to electrical systems for transmitting a secret message
FR939428D FR939428A (en) 1941-12-18 1946-11-27 Secret communications transmission systems
ES0177437A ES177437A1 (en) 1941-12-18 1947-03-31 SECRET COMMUNICATION SYSTEM

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1637841A GB580843A (en) 1941-12-18 1941-12-18 Improvements in or relating to secrecy communication systems

Publications (1)

Publication Number Publication Date
GB580843A true GB580843A (en) 1946-09-23

Family

ID=10076234

Family Applications (2)

Application Number Title Priority Date Filing Date
GB1637841A Expired GB580843A (en) 1941-12-18 1941-12-18 Improvements in or relating to secrecy communication systems
GB1493842A Expired GB582709A (en) 1941-12-18 1942-10-23 Improvements in or relating to secrecy communication systems

Family Applications After (1)

Application Number Title Priority Date Filing Date
GB1493842A Expired GB582709A (en) 1941-12-18 1942-10-23 Improvements in or relating to secrecy communication systems

Country Status (2)

Country Link
ES (1) ES177437A1 (en)
GB (2) GB580843A (en)

Also Published As

Publication number Publication date
ES177437A1 (en) 1947-05-01
GB582709A (en) 1946-11-26

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