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
Application number
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 filed Critical
Publication of GB1265027A publication Critical patent/GB1265027A/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
    • G08B13/16—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

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).
GB1265027D 1968-05-29 1969-05-29 Expired GB1265027A (en)

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)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2131547A (en) * 1982-12-02 1984-06-20 Lucas Ind Plc Motion detection systems

Cited By (1)

* Cited by examiner, † Cited by third party
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