GB1443702A - Alarm systems - Google Patents

Alarm systems

Info

Publication number
GB1443702A
GB1443702A GB4023772A GB4023772A GB1443702A GB 1443702 A GB1443702 A GB 1443702A GB 4023772 A GB4023772 A GB 4023772A GB 4023772 A GB4023772 A GB 4023772A GB 1443702 A GB1443702 A GB 1443702A
Authority
GB
United Kingdom
Prior art keywords
timer
reset
doppler
threshold
integrator
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
GB4023772A
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.)
GRANLEY PRODUCTS LONDON Ltd
Original Assignee
GRANLEY PRODUCTS LONDON 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 GRANLEY PRODUCTS LONDON Ltd filed Critical GRANLEY PRODUCTS LONDON Ltd
Priority to GB4023772A priority Critical patent/GB1443702A/en
Publication of GB1443702A publication Critical patent/GB1443702A/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
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
    • G01S15/02—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems using reflection of acoustic waves
    • G01S15/50—Systems of measurement, based on relative movement of the target
    • G01S15/52—Discriminating between fixed and moving objects or between objects moving at different speeds
    • G01S15/523—Discriminating between fixed and moving objects or between objects moving at different speeds for presence detection

Abstract

1443702 Intruder alarms GRANLEY PRODUCTS (LONDON) Ltd 23 Aug 1973 [30 Aug 1972 (2)] 40236/72 and 40237/72 Heading G4N [Also in Division H4] False operations of an ultrasonic Doppler intruder alarm system are minimized by arranging for the alarm to be actuated only if signals corresponding to Doppler cycles persist above a threshold amplitude for a given time. In the Fig. 1 embodiment a unit 11 integrates the Doppler signal and removes any integration component arising from turbulence or high frequency noise. If the integrator output exceeds a threshold value, level detector 16 turns on and the integrator is then reset, via delay 18, unless the Doppler signals are persistently above the threshold. When detector 16 turns on, a timer 23 is started. Oscillator M is operative while detector 16 is on, and its cycles are counted at 19. After a given time period (e.g. 2 minutes) set by timer 23 counter 19 is reset. If, within that period, the count reaches a preset value the alarm, 22, is actuated and the timer 23 is reset. In the Fig. 2 embodiment, timer 45 is started when the Doppler signal amplitude exceeds a threshold set at 36. The number of Doppler cycles exceeding this threshold and occurring within the timed period (2 minutes) is then effectively "counted" by a monostable/integrator combination 37, 38. The integrator is reset at the end of the period. The alarm is actuated if the integrator output reaches a level set at 39, and the timer 43 is then reset.
GB4023772A 1972-08-30 1972-08-30 Alarm systems Expired GB1443702A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB4023772A GB1443702A (en) 1972-08-30 1972-08-30 Alarm systems

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB4023672 1972-08-30
GB4023772A GB1443702A (en) 1972-08-30 1972-08-30 Alarm systems

Publications (1)

Publication Number Publication Date
GB1443702A true GB1443702A (en) 1976-07-21

Family

ID=26264350

Family Applications (1)

Application Number Title Priority Date Filing Date
GB4023772A Expired GB1443702A (en) 1972-08-30 1972-08-30 Alarm systems

Country Status (1)

Country Link
GB (1) GB1443702A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0202634A2 (en) * 1985-05-24 1986-11-26 Cerberus Ag Proximity monitoring device with sound wave source
GB2271873A (en) * 1992-09-03 1994-04-27 Josef Petr Prokopius Electronic burglar alarm system

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0202634A2 (en) * 1985-05-24 1986-11-26 Cerberus Ag Proximity monitoring device with sound wave source
EP0202634A3 (en) * 1985-05-24 1987-10-21 Cerberus Ag Proximity monitoring device with sound wave source
US4755973A (en) * 1985-05-24 1988-07-05 Cerberus Ag Space surveillance apparatus with sound source and method of short-range space surveillance
GB2271873A (en) * 1992-09-03 1994-04-27 Josef Petr Prokopius Electronic burglar alarm system
GB2271873B (en) * 1992-09-03 1997-02-26 Josef Petr Prokopius Electronic burglar alarm system

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Legal Events

Date Code Title Description
PS Patent sealed
732 Registration of transactions, instruments or events in the register (sect. 32/1977)
732 Registration of transactions, instruments or events in the register (sect. 32/1977)
732 Registration of transactions, instruments or events in the register (sect. 32/1977)
PCNP Patent ceased through non-payment of renewal fee