GB1364436A - Theft detection system - Google Patents

Theft detection system

Info

Publication number
GB1364436A
GB1364436A GB3862170A GB3862170A GB1364436A GB 1364436 A GB1364436 A GB 1364436A GB 3862170 A GB3862170 A GB 3862170A GB 3862170 A GB3862170 A GB 3862170A GB 1364436 A GB1364436 A GB 1364436A
Authority
GB
United Kingdom
Prior art keywords
alarm
duty ratio
receiver
oscillator
gate
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
GB3862170A
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.)
EURONICS Ltd
Original Assignee
EURONICS 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 EURONICS Ltd filed Critical EURONICS Ltd
Priority to GB3862170A priority Critical patent/GB1364436A/en
Priority to ZA715293A priority patent/ZA715293B/en
Priority to AU32173/71A priority patent/AU3217371A/en
Priority to FR7129196A priority patent/FR2102180B3/fr
Publication of GB1364436A publication Critical patent/GB1364436A/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
    • G08B13/242—Tag deactivation
    • 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
    • G08B13/2428—Tag details
    • G08B13/2431—Tag circuit details
    • 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
    • G08B13/2428—Tag details
    • G08B13/2434—Tag housing and attachment details
    • 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
    • G08B13/2428—Tag details
    • G08B13/2437—Tag layered structure, processes for making layered tags
    • G08B13/2445—Tag integrated into item to be protected, e.g. source tagging
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
    • H03B5/00—Generation of oscillations using amplifier with regenerative feedback from output to input
    • H03B5/08—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance
    • H03B5/12—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance active element in amplifier being semiconductor device
    • H03B5/1203—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance active element in amplifier being semiconductor device the amplifier being a single transistor
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
    • H03B5/00—Generation of oscillations using amplifier with regenerative feedback from output to input
    • H03B5/08—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance
    • H03B5/12—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance active element in amplifier being semiconductor device
    • H03B5/1231—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance active element in amplifier being semiconductor device the amplifier comprising one or more bipolar transistors

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Automation & Control Theory (AREA)
  • Computer Security & Cryptography (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Burglar Alarm Systems (AREA)

Abstract

1364436 Theft alarms EURONICS Ltd 10 Nov 1971 [11 Aug 1970] 38621/70 Heading G4N [Also in Divisions H4 and H3] Unauthorized removal of articles through an exit is detected by a receiver at the exit which responds to the field produced by a batterypowered oscillator concealed in each article, and which operates an alarm. The oscillator shown produces bursts of r.f. at a pulse rate in the audio range, so that the receiver can operate an audio alarm at that frequency, and so that battery life is prolonged. The timed circuit LC1 determines the r.f. and C3R2 determines the duty ratio of the pulses of r.f. oscillation; or if R2 is shorted out and C3 omitted the feedback circuit C2R1 will control the duty ratio. The radio frequency is between 10KHz and 10MHz and is preferably 500KHz; the duty ratio is between 10 and 1000 to 1, and preferably the bursts last for 35 Ás and the gaps for 1À3 mS. By selecting different gaps, different audio tones are produced by the alarm for different articles. A portable receiver and alarm also may be provided. An alternative oscillator circuit replaces T by a dual gate FET, one gate being connected through a diode to the source, and the other gate to the upper end of LC1, the two gates being also connected across C2.
GB3862170A 1970-08-11 1970-08-11 Theft detection system Expired GB1364436A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
GB3862170A GB1364436A (en) 1970-08-11 1970-08-11 Theft detection system
ZA715293A ZA715293B (en) 1970-08-11 1971-08-09 Theft detection system
AU32173/71A AU3217371A (en) 1970-08-11 1971-08-10 Theft detection system
FR7129196A FR2102180B3 (en) 1970-08-11 1971-08-10

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB3862170A GB1364436A (en) 1970-08-11 1970-08-11 Theft detection system

Publications (1)

Publication Number Publication Date
GB1364436A true GB1364436A (en) 1974-08-21

Family

ID=10404630

Family Applications (1)

Application Number Title Priority Date Filing Date
GB3862170A Expired GB1364436A (en) 1970-08-11 1970-08-11 Theft detection system

Country Status (4)

Country Link
AU (1) AU3217371A (en)
FR (1) FR2102180B3 (en)
GB (1) GB1364436A (en)
ZA (1) ZA715293B (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2318939A (en) * 1996-11-01 1998-05-06 Richard James Harvey Infra-red identification device
EP0911756A2 (en) * 1997-10-24 1999-04-28 BSH Bosch und Siemens Hausgeräte GmbH Device for machine readable characterization of textiles

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB9823657D0 (en) * 1998-10-30 1998-12-23 Secr Defence Brit Combined oscillator and voltage step-up circuit

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2318939A (en) * 1996-11-01 1998-05-06 Richard James Harvey Infra-red identification device
EP0911756A2 (en) * 1997-10-24 1999-04-28 BSH Bosch und Siemens Hausgeräte GmbH Device for machine readable characterization of textiles
EP0911756A3 (en) * 1997-10-24 2001-04-11 BSH Bosch und Siemens Hausgeräte GmbH Device for machine readable characterization of textiles

Also Published As

Publication number Publication date
ZA715293B (en) 1972-04-26
FR2102180B3 (en) 1974-04-26
FR2102180A3 (en) 1972-04-07
AU3217371A (en) 1973-02-15

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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