GB1265027A - - Google Patents
Info
- Publication number
- GB1265027A GB1265027A GB1265027DA GB1265027A GB 1265027 A GB1265027 A GB 1265027A GB 1265027D A GB1265027D A GB 1265027DA GB 1265027 A GB1265027 A GB 1265027A
- Authority
- GB
- United Kingdom
- Prior art keywords
- intrusion
- reed
- motion
- doppler
- doppler signals
- 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
Links
Classifications
-
- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B13/00—Burglar, theft or intruder alarms
- G08B13/16—Actuation by interference with mechanical vibrations in air or other fluid
- G08B13/1609—Actuation by interference with mechanical vibrations in air or other fluid using active vibration detection systems
- G08B13/1618—Actuation by interference with mechanical vibrations in air or other fluid using active vibration detection systems using ultrasonic detection means
- G08B13/1627—Actuation by interference with mechanical vibrations in air or other fluid using active vibration detection systems using ultrasonic detection means using Doppler shift detection circuits
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Burglar Alarm Systems (AREA)
Abstract
1,265,027. Ultrasonic Doppler intrusiondetection. FRANCE ARMED FORCES MINISTER OF. 29 May, 1969 [29 May, 1968; 31 Dec., 1968], No. 27243/69. Headings H3T and H4D. [Also in Division G4] In an ultrasonic Doppler device for detecting intrusion of a solid body into a guarded space, false alarms due to air turbulence are prevented by use of a band-pass filter, comprising one or more vibrating blades, to reject low-frequency Doppler signals and pass only Doppler signals with a frequency lying in at least one band (e.g. 10-100 Hz) within the hump of the frequency spectrum characteristic of the intrusion. In the Fig. 3 embodiment amplified Doppler signals drive coil 5 for magnetically vibrating tuned reeds 6, 7, 8. Motion of a reed modulates a light or other radiation beam passing from source 10 to detector 11 (examples of each are specified) to give a driving signal for energizing alarm trigger stage 16. Alternatively, reed motion is detected by an electrostatic, piezoelectric, electromechanical or magneto-electric transducer, or (Figs. 6 and 7, not shown) by means of a bar which the reeds contact intermittently to feed pulses to an integrating circuit to develop a voltage (on capacitor 24) which reaches a value sufficient to trigger uni-junction transistor (25) and hence give an intrusion indication only if the reed motion persists (thus preventing false alarms due to brief electrical noise).
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR153337 | 1968-05-29 | ||
FR182310 | 1968-12-31 |
Publications (1)
Publication Number | Publication Date |
---|---|
GB1265027A true GB1265027A (en) | 1972-03-01 |
Family
ID=26182037
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB1265027D Expired GB1265027A (en) | 1968-05-29 | 1969-05-29 |
Country Status (3)
Country | Link |
---|---|
BE (1) | BE743691A (en) |
DE (1) | DE1927315A1 (en) |
GB (1) | GB1265027A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2131547A (en) * | 1982-12-02 | 1984-06-20 | Lucas Ind Plc | Motion detection systems |
-
1969
- 1969-05-29 GB GB1265027D patent/GB1265027A/en not_active Expired
- 1969-05-29 DE DE19691927315 patent/DE1927315A1/en active Pending
- 1969-12-24 BE BE743691D patent/BE743691A/xx unknown
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2131547A (en) * | 1982-12-02 | 1984-06-20 | Lucas Ind Plc | Motion detection systems |
Also Published As
Publication number | Publication date |
---|---|
DE1927315A1 (en) | 1970-05-27 |
BE743691A (en) | 1970-05-28 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PS | Patent sealed | ||
PCNP | Patent ceased through non-payment of renewal fee |