GB1484353A - Electronic security systems incorporating noise rejection circuitry - Google Patents

Electronic security systems incorporating noise rejection circuitry

Info

Publication number
GB1484353A
GB1484353A GB36028/74A GB3602874A GB1484353A GB 1484353 A GB1484353 A GB 1484353A GB 36028/74 A GB36028/74 A GB 36028/74A GB 3602874 A GB3602874 A GB 3602874A GB 1484353 A GB1484353 A GB 1484353A
Authority
GB
United Kingdom
Prior art keywords
circuit
flop
electronic security
flip
output
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
GB36028/74A
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
Publication of GB1484353A publication Critical patent/GB1484353A/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
    • G08B13/2405—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
    • G08B13/2414—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 inductive 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

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Signal Processing (AREA)
  • Automation & Control Theory (AREA)
  • Computer Security & Cryptography (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Burglar Alarm Systems (AREA)
  • Radar Systems Or Details Thereof (AREA)
  • Credit Cards Or The Like (AREA)
  • Geophysics And Detection Of Objects (AREA)

Abstract

1484353 Pulse circuits; transponder systems G J LICHTBLAU 15 Aug 1974 [20 Aug 1973] 26028/74 Headings H3T and H4L [Also in Division G4] A missing pulse detector for use in an electronic security system (see also Division G4) comprises an R3 integrator R2, C2 associated with a shunt transistor switch S2, a threshold circuit 54, a set-reset flip-flop 50 and an OR circuit 52. In operation, the leading edge of input pulses momentarily close switch S2 via OR 52 to discharge C2 and also set flip-flop 50 as to produce a high level output. This output opens switch S2 to permit C2 to charge. The time constant of R2, C2 is adjusted to be larger than the input pulse period so that C2 is periodically discharged before the threshold of 54 is exceeded. In the event of a missing pulse, the flip-flop 50 is reset by the threshold circuit output to produce a low level output. The electronic security system operates by detecting the presence of a resonant tag circuit 15 in an electromagnetic field repetitively swept through a predetermined frequency range and established between antennas 12, 14. The system includes a band pass filter 16 and band limiting circuits in 22 for limiting the frequency range of operation. The system also includes noise rejection circuitry 24 for discriminating between pulses produced by detection of the tag circuit and spurious signals of different periodicity.
GB36028/74A 1973-08-20 1974-08-15 Electronic security systems incorporating noise rejection circuitry Expired GB1484353A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US00389728A US3828337A (en) 1973-08-20 1973-08-20 Noise rejection circuitry

Publications (1)

Publication Number Publication Date
GB1484353A true GB1484353A (en) 1977-09-01

Family

ID=23539479

Family Applications (1)

Application Number Title Priority Date Filing Date
GB36028/74A Expired GB1484353A (en) 1973-08-20 1974-08-15 Electronic security systems incorporating noise rejection circuitry

Country Status (9)

Country Link
US (1) US3828337A (en)
JP (1) JPS533913B2 (en)
BR (1) BR7406375D0 (en)
CA (1) CA1033027A (en)
DE (1) DE2438218C2 (en)
FR (1) FR2241837B1 (en)
GB (1) GB1484353A (en)
IT (1) IT1011583B (en)
ZA (1) ZA744889B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2282720A (en) * 1993-09-10 1995-04-12 Thomson Consumer Electronics Circuit for synchronizing a microprocessor in a TV receiver

Families Citing this family (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4223830A (en) * 1978-08-18 1980-09-23 Walton Charles A Identification system
US4236068A (en) * 1979-03-29 1980-11-25 Walton Charles A Personal identification and signaling system
JPS57124548A (en) * 1981-01-26 1982-08-03 Nippon Koki Kk Casting method
US4429302A (en) * 1981-10-08 1984-01-31 I. D. Engineering, Inc. Electronic security system with noise rejection
US4476459A (en) * 1981-10-23 1984-10-09 Knogo Corporation Theft detection method and apparatus in which the decay of a resonant circuit is detected
US4728938A (en) * 1986-01-10 1988-03-01 Checkpoint Systems, Inc. Security tag deactivation system
US4779077A (en) * 1987-04-13 1988-10-18 Lichtblau G J Continuously armed high reliability pulse train processor
EP0390779A4 (en) * 1988-06-20 1991-04-24 George J. Lichtblau Continuously armed high reliability pulse train processor
DK0774740T3 (en) 1989-10-31 2003-06-10 Checkpoint Systems Inc Label for use with an electronic product monitoring system
US5081445A (en) * 1991-03-22 1992-01-14 Checkpoint Systems, Inc. Method for tagging articles used in conjunction with an electronic article surveillance system, and tags or labels useful in connection therewith
US5508684A (en) * 1995-03-02 1996-04-16 Becker; Richard S. Article tag
US5798693A (en) * 1995-06-07 1998-08-25 Engellenner; Thomas J. Electronic locating systems
US5812065A (en) * 1995-08-14 1998-09-22 International Business Machines Corporation Modulation of the resonant frequency of a circuit using an energy field
US7002475B2 (en) * 1997-12-31 2006-02-21 Intermec Ip Corp. Combination radio frequency identification transponder (RFID tag) and magnetic electronic article surveillance (EAS) tag
US7123129B1 (en) 1995-08-14 2006-10-17 Intermec Ip Corp. Modulation of the resonant frequency of a circuit using an energy field
AU2546597A (en) * 1996-04-10 1997-10-29 Sentry Technology Corporation Electronic article surveillance system
US5909178A (en) * 1997-11-28 1999-06-01 Sensormatic Electronics Corporation Signal detection in high noise environments

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3115622A (en) * 1958-10-15 1963-12-24 Polard Electronics Corp Panoramic scanning counter
US3500373A (en) * 1966-05-06 1970-03-10 Nat Bank Of North America The Method and apparatus for article theft detection
US3521280A (en) * 1969-01-16 1970-07-21 Gen Res Corp Coded labels
US3624631A (en) * 1970-04-27 1971-11-30 Sanders Associates Inc Pilferage control system
US3696379A (en) * 1970-12-02 1972-10-03 Knogo Corp Apparatus for article theft detection
US3752960A (en) * 1971-12-27 1973-08-14 C Walton Electronic identification & recognition system

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2282720A (en) * 1993-09-10 1995-04-12 Thomson Consumer Electronics Circuit for synchronizing a microprocessor in a TV receiver

Also Published As

Publication number Publication date
DE2438218A1 (en) 1975-02-27
IT1011583B (en) 1977-02-10
FR2241837A1 (en) 1975-03-21
BR7406375D0 (en) 1975-06-03
US3828337A (en) 1974-08-06
FR2241837B1 (en) 1978-11-24
JPS5051300A (en) 1975-05-08
JPS533913B2 (en) 1978-02-10
DE2438218C2 (en) 1985-08-14
CA1033027A (en) 1978-06-13
ZA744889B (en) 1975-08-27

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Legal Events

Date Code Title Description
PS Patent sealed [section 19, patents act 1949]
PE20 Patent expired after termination of 20 years

Effective date: 19940814