FR2416514A1 - Electronic surveillance of precisely defined control zone - using HF generator projecting wave to establish first field and FM generator for second field - Google Patents

Electronic surveillance of precisely defined control zone - using HF generator projecting wave to establish first field and FM generator for second field

Info

Publication number
FR2416514A1
FR2416514A1 FR7803078A FR7803078A FR2416514A1 FR 2416514 A1 FR2416514 A1 FR 2416514A1 FR 7803078 A FR7803078 A FR 7803078A FR 7803078 A FR7803078 A FR 7803078A FR 2416514 A1 FR2416514 A1 FR 2416514A1
Authority
FR
France
Prior art keywords
field
generator
control zone
establish
precisely defined
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.)
Granted
Application number
FR7803078A
Other languages
French (fr)
Other versions
FR2416514B1 (en
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 FR7803078A priority Critical patent/FR2416514A1/en
Publication of FR2416514A1 publication Critical patent/FR2416514A1/en
Application granted granted Critical
Publication of FR2416514B1 publication Critical patent/FR2416514B1/fr
Granted legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B13/00—Burglar, theft or intruder alarms
    • G08B13/22—Electrical actuation
    • G08B13/24—Electrical actuation by interference with electromagnetic field distribution
    • G08B13/2402—Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting
    • G08B13/2405—Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting characterised by the tag technology used
    • G08B13/2422—Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting characterised by the tag technology used using acoustic or microwave tags
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B13/00—Burglar, theft or intruder alarms
    • G08B13/22—Electrical actuation
    • G08B13/24—Electrical actuation by interference with electromagnetic field distribution
    • G08B13/2402—Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting
    • G08B13/2465—Aspects related to the EAS system, e.g. system components other than tags
    • G08B13/2468—Antenna in system and the related signal processing
    • G08B13/2471—Antenna signal processing by receiver or emitter

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Automation & Control Theory (AREA)
  • Computer Security & Cryptography (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Burglar Alarm Systems (AREA)
  • Radar Systems Or Details Thereof (AREA)

Abstract

The h. f generator projects an electronic wave into a control zone under surveillance to establish a first field. A frequency modulated (FM) generator is used for establishing a second field throughout the zone. A third field of the same FM carrier frequency, but with a different modulation, is established only at extreme ends of the control zone to define the limits of the control zone. Presence only within the control zone of a transponder causes the re-radiation of a signal comprised of the FM and the h. f signals which, in turn, activates an alarm circuit.
FR7803078A 1978-02-03 1978-02-03 Electronic surveillance of precisely defined control zone - using HF generator projecting wave to establish first field and FM generator for second field Granted FR2416514A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
FR7803078A FR2416514A1 (en) 1978-02-03 1978-02-03 Electronic surveillance of precisely defined control zone - using HF generator projecting wave to establish first field and FM generator for second field

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR7803078A FR2416514A1 (en) 1978-02-03 1978-02-03 Electronic surveillance of precisely defined control zone - using HF generator projecting wave to establish first field and FM generator for second field

Publications (2)

Publication Number Publication Date
FR2416514A1 true FR2416514A1 (en) 1979-08-31
FR2416514B1 FR2416514B1 (en) 1983-04-29

Family

ID=9204195

Family Applications (1)

Application Number Title Priority Date Filing Date
FR7803078A Granted FR2416514A1 (en) 1978-02-03 1978-02-03 Electronic surveillance of precisely defined control zone - using HF generator projecting wave to establish first field and FM generator for second field

Country Status (1)

Country Link
FR (1) FR2416514A1 (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3707711A (en) * 1970-04-02 1972-12-26 Peter Harold Cole Electronic surveillance system
US3895368A (en) * 1972-08-09 1975-07-15 Sensormatic Electronics Corp Surveillance system and method utilizing both electrostatic and electromagnetic fields

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3707711A (en) * 1970-04-02 1972-12-26 Peter Harold Cole Electronic surveillance system
US3895368A (en) * 1972-08-09 1975-07-15 Sensormatic Electronics Corp Surveillance system and method utilizing both electrostatic and electromagnetic fields

Also Published As

Publication number Publication date
FR2416514B1 (en) 1983-04-29

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Legal Events

Date Code Title Description
ST Notification of lapse