IN159180B - - Google Patents

Info

Publication number
IN159180B
IN159180B IN30/DEL/83A IN30DE1983A IN159180B IN 159180 B IN159180 B IN 159180B IN 30DE1983 A IN30DE1983 A IN 30DE1983A IN 159180 B IN159180 B IN 159180B
Authority
IN
India
Prior art keywords
sequence
stations
station
frequency
instant
Prior art date
Application number
IN30/DEL/83A
Inventor
Paul Wilkinson Dent
Original Assignee
Marconi Co Ltd
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 Marconi Co Ltd filed Critical Marconi Co Ltd
Publication of IN159180B publication Critical patent/IN159180B/en

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04K—SECRET COMMUNICATION; JAMMING OF COMMUNICATION
    • H04K1/00—Secret communication
    • H04K1/003—Secret communication by varying carrier frequency at or within predetermined or random intervals

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Reduction Or Emphasis Of Bandwidth Of Signals (AREA)
  • Input Circuits Of Receivers And Coupling Of Receivers And Audio Equipment (AREA)
  • Radio Relay Systems (AREA)

Abstract

A frequency-hopping radio communication system in which a network of stations operate on the same sequence of frequencies, in synchronism, controlled by pseudo-random generators which are initially synchronised. Each station has means for modifying its p.r. sequence dependent only upon the instant in the main line sequence at which the modification is switched. In order to communicate, one station transmits, on the current main-line frequency sequence, the address of the desired other station and then signals the sequence switch. At this instant both transmitting and receiving stations switch to a modified frequency sequence and are thus isolated from the remaining stations. At the end of the message a signal from the transmitting to the receiving station causes both stations to revert to the main line sequence.
IN30/DEL/83A 1982-01-27 1983-01-18 IN159180B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB8202357 1982-01-27

Publications (1)

Publication Number Publication Date
IN159180B true IN159180B (en) 1987-04-04

Family

ID=10527920

Family Applications (1)

Application Number Title Priority Date Filing Date
IN30/DEL/83A IN159180B (en) 1982-01-27 1983-01-18

Country Status (7)

Country Link
EP (1) EP0084967B1 (en)
JP (1) JPS58161438A (en)
AT (1) ATE13789T1 (en)
AU (1) AU553652B2 (en)
DE (1) DE3360246D1 (en)
GB (1) GB2114402B (en)
IN (1) IN159180B (en)

Families Citing this family (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2129655B (en) * 1982-09-08 1986-02-05 Racal Res Ltd Improvements in and relating to radio communications
IL82561A (en) * 1986-05-27 1991-12-15 Fairchild Weston Systems Inc Secure communication system for multiple remote units
US5056108A (en) * 1990-04-04 1991-10-08 Van Metre Lund Communication system
CA2116219C (en) * 1991-08-23 1998-10-13 Hiroshi Kobayashi Radio information and communication system using multicarrier spread-spectrum transmission system
CN1088035A (en) * 1992-04-15 1994-06-15 客运电迅传送有限公司 Signal distribution system
US5533046A (en) * 1992-10-08 1996-07-02 Lund; Vanmetre Spread spectrum communication system
US5809417A (en) * 1994-07-05 1998-09-15 Lucent Technologies Inc. Cordless telephone arranged for operating with multiple portable units in a frequency hopping system
US5463659A (en) * 1994-07-05 1995-10-31 At&T Ipm Corp. Apparatus and method of configuring a cordless telephone for operating in a frequency hopping system
GB9508885D0 (en) * 1995-05-02 1995-06-21 Plessey Semiconductors Ltd Wireless local area networks
GB2300547B (en) * 1995-05-02 1999-08-25 Plessey Semiconductors Ltd Wireless local area neworks
GB9513398D0 (en) * 1995-06-30 1995-09-27 Boateng Jacob K Automatic exchangeless universal radio phone
EP1002375A1 (en) * 1997-08-14 2000-05-24 Siemens Aktiengesellschaft Method and device for producing a random number sequence for carrier frequencies in a mobile radiotelephone system
EP1088404A1 (en) * 1998-06-18 2001-04-04 Siemens Aktiengesellschaft Method and device for converting a random number sequence into carrier frequencies for mobile radio transmission
US8069468B1 (en) * 2000-04-18 2011-11-29 Oracle America, Inc. Controlling access to information over a multiband network
JP7197011B2 (en) * 2019-06-26 2022-12-27 日本電気株式会社 Height estimation device, height estimation method and program
CN114641794A (en) * 2019-10-31 2022-06-17 日本电气株式会社 Image processing apparatus, image processing method, and non-transitory computer-readable medium storing image processing program
JP7355674B2 (en) 2020-02-18 2023-10-03 株式会社日立製作所 Video monitoring system and video monitoring method

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH499931A (en) * 1968-02-12 1970-11-30 Patelhold Patentverwertung Synchronization method for program-controlled carrier shift keying
DE1939975A1 (en) * 1969-08-06 1971-02-18 Licentia Gmbh System for the transmission of binary coded messages
DE2457027B2 (en) * 1974-12-03 1977-02-03 Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt PROCEDURE FOR PROGRAMMING ARRANGEMENTS FOR GENERATING RANDOM BINARY STRINGS

Also Published As

Publication number Publication date
JPH0234499B2 (en) 1990-08-03
AU1062383A (en) 1983-08-04
DE3360246D1 (en) 1985-07-18
JPS58161438A (en) 1983-09-26
AU553652B2 (en) 1986-07-24
EP0084967A3 (en) 1983-08-10
GB2114402A (en) 1983-08-17
GB2114402B (en) 1985-06-05
EP0084967A2 (en) 1983-08-03
EP0084967B1 (en) 1985-06-12
ATE13789T1 (en) 1985-06-15

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