GB1446259A - Electronic theft detection system having uniform field strength - Google Patents

Electronic theft detection system having uniform field strength

Info

Publication number
GB1446259A
GB1446259A GB1568474A GB1568474A GB1446259A GB 1446259 A GB1446259 A GB 1446259A GB 1568474 A GB1568474 A GB 1568474A GB 1568474 A GB1568474 A GB 1568474A GB 1446259 A GB1446259 A GB 1446259A
Authority
GB
United Kingdom
Prior art keywords
windings
theft detection
oscillator
detection system
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
GB1568474A
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.)
Knogo Corp
Original Assignee
Knogo Corp
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 Knogo Corp filed Critical Knogo Corp
Publication of GB1446259A publication Critical patent/GB1446259A/en
Expired 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
    • G08B13/2465—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
    • 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

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Signal Processing (AREA)
  • Automation & Control Theory (AREA)
  • Computer Security & Cryptography (AREA)
  • Burglar Alarm Systems (AREA)
  • Geophysics And Detection Of Objects (AREA)

Abstract

1446259 Theft detection systems KNOGO CORP 9 April 1974 [13 April 1973] 15684/74 Heading G4N [Also in Division H4] A theft detection system comprises at least two windings 24, 36, 38 lying in crossed planes and an arrangement 10-18 for applying signals to the windings at the same frequency but differing in phase. The windings are placed at or around the exit through which protected articles having transponder tags must pass. An oscillator 12 is periodically swept around its centre frequency by a low frequency oscillator 10 and applied to detectors 26, 40 via phase shift networks 16, 18. A rotating magnetic field is produced at the monitored exit. In the presence of a tag or transponder having a resonant frequency at the centre frequency of oscillator 12, energy normally coupled to detectors 26, 40 is partially absorbed via windings 24, 36, 38 and this reduction of energy is detected by 26, 40 to trigger an alarm.
GB1568474A 1973-04-13 1974-04-09 Electronic theft detection system having uniform field strength Expired GB1446259A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US00351018A US3838409A (en) 1973-04-13 1973-04-13 Field strength uniformity control system for article theft detection system

Publications (1)

Publication Number Publication Date
GB1446259A true GB1446259A (en) 1976-08-18

Family

ID=23379238

Family Applications (1)

Application Number Title Priority Date Filing Date
GB1568474A Expired GB1446259A (en) 1973-04-13 1974-04-09 Electronic theft detection system having uniform field strength

Country Status (11)

Country Link
US (2) US3838409A (en)
JP (1) JPS5331720B2 (en)
BE (1) BE813709A (en)
BR (1) BR7402883D0 (en)
CA (1) CA1030239A (en)
FR (1) FR2225794B1 (en)
GB (1) GB1446259A (en)
IT (1) IT1011236B (en)
NL (1) NL171388C (en)
SE (1) SE404443B (en)
ZA (1) ZA742303B (en)

Families Citing this family (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4017858A (en) * 1973-07-30 1977-04-12 Polhemus Navigation Sciences, Inc. Apparatus for generating a nutating electromagnetic field
US3990065A (en) * 1975-02-20 1976-11-02 The Magnavox Company Theft detection system
US4016553A (en) * 1975-06-27 1977-04-05 Knogo Corporation Article detection system with near field electromagnetic wave control
NL7702946A (en) * 1976-04-03 1977-10-05 Bizerba Werke Kraut Kg Wilh METHOD AND ARRANGEMENT FOR DETERMINING THE PRESENCE OF OBJECTS IN A PARTICULAR CONTROL AREA, IN PARTICULAR FOR PREVENTION OF SHOP THEFT.
US4118693A (en) * 1977-05-09 1978-10-03 Knogo Corporation Method and apparatus for producing uniform electromagnetic fields in an article detection system
US4135183A (en) * 1977-05-24 1979-01-16 Minnesota Mining And Manufacturing Company Antipilferage system utilizing "figure-8" shaped field producing and detector coils
JPS55121596A (en) * 1979-03-14 1980-09-18 Yoshida Kogyo Kk Device for protecting shoplifting and theft
US4274090A (en) * 1980-02-19 1981-06-16 Knogo Corporation Detection of articles in adjacent passageways
NL8200138A (en) * 1982-01-14 1983-08-01 Nedap Nv DETECTION SYSTEM.
WO1983003203A1 (en) * 1982-03-15 1983-09-29 Progressive Dynamics Method and apparatus for theft detection systems
US4742356A (en) * 1985-12-09 1988-05-03 Mcdonnell Douglas Corporation Method and apparatus for determining remote object orientation and position
US4737794A (en) * 1985-12-09 1988-04-12 Mcdonnell Douglas Corporation Method and apparatus for determining remote object orientation and position
US4798175A (en) * 1986-10-09 1989-01-17 Alfa-Laval Agri, Inc. Electronic identification system
FR2659173B1 (en) * 1990-03-02 1992-09-18 Neiman Sa EXTRA-FLAT ANTENNA WITH CIRCULAR POLARIZATION, PARTICULARLY FOR AN INTEGRATED AUTOMOTIVE REMOTE CONTROL ASSEMBLY.
GB9125846D0 (en) * 1991-12-04 1992-02-05 Esselte Meto Int Gmbh Improved interrogation and detection means for theft-detection systems
DE4200082A1 (en) * 1992-01-03 1993-07-08 Minnesota Mining & Mfg Magnetisable marking element detecting device - includes signal analyser for analysing receiver output signal, having a band pass filter and comparator
US5646525A (en) * 1992-06-16 1997-07-08 Elbit Ltd. Three dimensional tracking system employing a rotating field
IL102218A (en) * 1992-06-16 2003-06-24 Elbit Systems Ltd Tracker employing a rotating electromagnetic field
CA2183697A1 (en) * 1995-08-23 1997-02-24 David P. Klaehn Electronic article-surveillance apparatus and method of operating same
US5877728A (en) * 1997-05-28 1999-03-02 Checkpoint Systems, Inc. Multiple loop antenna
DE19752506A1 (en) * 1997-11-27 1999-06-02 Meto International Gmbh System for securing articles against theft
US6069564A (en) * 1998-09-08 2000-05-30 Hatano; Richard Multi-directional RFID antenna
US6879300B2 (en) * 2000-02-08 2005-04-12 Cms Partners, Inc. Wireless boundary proximity determining and animal containment system and method
FR2828016B1 (en) * 2001-07-30 2005-03-25 Pygmalyon ANTENNAS OF THE TYPE LOOP
US6836216B2 (en) * 2002-05-09 2004-12-28 Electronic Article Surveillance Technologies, Ltd. Electronic article surveillance system
US20060279406A1 (en) * 2005-06-07 2006-12-14 Robert Stewart Synchronization and adaptive timing method for multiple RFID reader system

Family Cites Families (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE355807A (en) * 1927-11-15
US1915786A (en) * 1929-03-02 1933-06-27 Jr John Hays Hammond System of transmission of radiant energy
FR763681A (en) * 1933-11-10 1934-05-04 Method of locating objects by modifying a magnetic field
US2317071A (en) * 1938-12-30 1943-04-20 Rca Corp Antenna circuit modulation system
US2524760A (en) * 1947-08-28 1950-10-10 Walter J Brown Phase shift bridge
US3500373A (en) * 1966-05-06 1970-03-10 Nat Bank Of North America The Method and apparatus for article theft detection
GB1292380A (en) * 1969-04-02 1972-10-11 Unisearch Ltd Electronic surveillance systems
US3665449A (en) * 1969-07-11 1972-05-23 Minnesota Mining & Mfg Method and apparatus for detecting at a distance the status and identity of objects
US3676772A (en) * 1970-08-18 1972-07-11 Nasa Metallic intrusion detector system
US3740742A (en) * 1971-05-11 1973-06-19 T Thompson Method and apparatus for actuating an electric circuit
BE791039A (en) * 1971-11-08 1973-05-07 Lewis Security Syst Ltd SECURITY SYSTEMS
US3820104A (en) * 1972-12-15 1974-06-25 Stop Loss Inc Method and system for detecting an object within a magnetic field interrogation zone
US3938125A (en) * 1974-02-20 1976-02-10 Minnesota Mining And Manufacturing Company Antipilferage system and marker therefor

Also Published As

Publication number Publication date
FR2225794B1 (en) 1981-10-09
JPS5028799A (en) 1975-03-24
DE2417935B2 (en) 1977-03-17
JPS5331720B2 (en) 1978-09-04
ZA742303B (en) 1975-03-26
FR2225794A1 (en) 1974-11-08
DE2417935A1 (en) 1974-10-24
NL7404896A (en) 1974-10-15
USRE29610E (en) 1978-04-11
NL171388C (en) 1983-03-16
IT1011236B (en) 1977-01-20
CA1030239A (en) 1978-04-25
NL171388B (en) 1982-10-18
US3838409A (en) 1974-09-24
SE404443B (en) 1978-10-02
BR7402883D0 (en) 1974-12-31
AU6785574A (en) 1975-10-16
BE813709A (en) 1974-10-14

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Legal Events

Date Code Title Description
PS Patent sealed [section 19, patents act 1949]
PCNP Patent ceased through non-payment of renewal fee