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 fieldInfo
- 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
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.
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)
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 |
-
1978
- 1978-02-03 FR FR7803078A patent/FR2416514A1/en active Granted
Patent Citations (2)
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 |