GB1501127A – False alarm inhibitor
– Google Patents
GB1501127A – False alarm inhibitor
– Google Patents
False alarm inhibitor
Info
Publication number
GB1501127A
GB1501127A
GB16654/75A
GB1665475A
GB1501127A
GB 1501127 A
GB1501127 A
GB 1501127A
GB 16654/75 A
GB16654/75 A
GB 16654/75A
GB 1665475 A
GB1665475 A
GB 1665475A
GB 1501127 A
GB1501127 A
GB 1501127A
Authority
GB
United Kingdom
Prior art keywords
detector
output
switch
integrator
inhibitor
Prior art date
1974-04-23
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
GB16654/75A
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.)
Cadin Electronics Pty Ltd
Original Assignee
Cadin Electronics Pty 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.)
1974-04-23
Filing date
1975-04-22
Publication date
1978-02-15
1975-04-22
Application filed by Cadin Electronics Pty Ltd
filed
Critical
Cadin Electronics Pty Ltd
1978-02-15
Publication of GB1501127A
publication
Critical
patent/GB1501127A/en
Status
Expired
legal-status
Critical
Current
Links
Espacenet
Global Dossier
Discuss
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
1501127 Intruder alarms CADIN ELECTRONICS PTY Ltd 22 April 1975 [23 April 1974] 16654/75 Heading G4N An intruder detector comprises a Doppler detection device including a transmitter 10, a receiver 11, quadrature mixers 12, 13 for multiplying a reference signal and the output signal of the receiver to discern between positive and negative Doppler shifts, an integrator 22 for integrating the output of the detection device, an alarm 24 adapted to be activated when the output of the integrator reaches a predetermined threshold level, and a false alarm inhibitor 25 which includes means activated when the output from the integrator reaches a predetermined level lower than said predetermined threshold level for phase-shifting by 90 degrees the difference in phase of the receiver output signal with respect to the reference signal. As shown in Fig. 1, the inhibitor 25 comprises a level detector 26 connected directly to a switch 27 and via an inverter 29 to a switch 28, the switch 27 being connected between a +45 degree phase shift network 30 and a buffer amplifier 32, and the switch 28 being connected between a – 45 degree phase shift network 31 and the amplifier 32, the networks 30, 31 being supplied from the oscillator of the transmitter 10 and the buffer amplifier 32 supplying the reference signal to the Œ45 degree phase shift networks of the mixers 12, 13. Thus, in operation, one of the switches 27, 28 is normally closed and the other normally open, but when the level of detector 26 is exceeded, e.g. Œ0À5 volts, the switches change over thereby phase shifting by 90 degrees the reference signal with respect to the received signal. Thus the directional sense of the integrator output due to the interfering source is reversed and will fluctuate about the level of detector 26 until removed. However, upon deflecting a genuine movement, the frequency of the received signal changes and the output of integrator 22 is not affected by the phase switch. A circuit arrangement of inhibitor 25 is described with reference to Fig. 2 (not shown). The inhibitor 25
GB16654/75A
1974-04-23
1975-04-22
False alarm inhibitor
Expired
GB1501127A
(en)
Applications Claiming Priority (1)
Application Number
Priority Date
Filing Date
Title
AU734174
1974-04-23
Publications (1)
Publication Number
Publication Date
GB1501127A
true
GB1501127A
(en)
1978-02-15
Family
ID=3698010
Family Applications (1)
Application Number
Title
Priority Date
Filing Date
GB16654/75A
Expired
GB1501127A
(en)
1974-04-23
1975-04-22
False alarm inhibitor
Country Status (3)
Country
Link
US
(1)
US3987427A
(en)
AU
(1)
AU8033275A
(en)
GB
(1)
GB1501127A
(en)
Cited By (1)
* Cited by examiner, † Cited by third party
Publication number
Priority date
Publication date
Assignee
Title
GB2118342A
(en)
*
1982-04-08
1983-10-26
Elsec Electronic Security Syst
Intrusion detector
Families Citing this family (8)
* Cited by examiner, † Cited by third party
Publication number
Priority date
Publication date
Assignee
Title
FR2315733A1
(en)
*
1975-06-23
1977-01-21
Tacussel Maurice
RADAR, ESPECIALLY FOR THE SURVEILLANCE OF A PREMISES
CA1084618A
(en)
*
1976-11-10
1980-08-26
Martin T. Cole
Phase difference sensitive movement detectors
DE2722982C2
(en)
*
1977-05-20
1979-04-26
Siemens Ag, 1000 Berlin Und 8000 Muenchen
Circuit arrangement for an ultrasonic burglar alarm system that works according to the Doppler principle
JPS5563774A
(en)
*
1978-11-08
1980-05-14
Matsushita Electric Works Ltd
Detector for moving body
EP0058205B1
(en)
*
1980-08-20
1987-01-14
Secom Co, Ltd.
Ultrasonic warning system
US4382291A
(en)
*
1980-10-17
1983-05-03
Secom Co., Ltd.
Surveillance system in which a reflected signal pattern is compared to a reference pattern
US6248068B1
(en)
*
2000-02-03
2001-06-19
Zeyn Seabron
Ultrasonic monitor
CA2453816C
(en)
*
2003-12-22
2010-05-18
Shih-Ming Hwang
Intelligent microwave detecting system
Family Cites Families (4)
* Cited by examiner, † Cited by third party
Publication number
Priority date
Publication date
Assignee
Title
US3727216A
(en)
*
1971-01-28
1973-04-10
Mosler Safe Co
Electromagnetic and ultrasonic doppler correlation intrusion alarm system
US3733581A
(en)
*
1971-08-17
1973-05-15
H Kalmus
Acoustic doppler wave recognition
US3760400A
(en)
*
1972-02-10
1973-09-18
Aerospace Res
Intrusion detection system employing quadrature sampling
US3863240A
(en)
*
1972-12-08
1975-01-28
Aerospace Res
Electromagnetic intrusion detection system
1974
1974-04-23
AU
AU80332/75A
patent/AU8033275A/en
not_active
Expired
1975
1975-04-22
GB
GB16654/75A
patent/GB1501127A/en
not_active
Expired
1975-04-23
US
US05/570,878
patent/US3987427A/en
not_active
Expired – Lifetime
Cited By (1)
* Cited by examiner, † Cited by third party
Publication number
Priority date
Publication date
Assignee
Title
GB2118342A
(en)
*
1982-04-08
1983-10-26
Elsec Electronic Security Syst
Intrusion detector
Also Published As
Publication number
Publication date
AU8033275A
(en)
1976-10-21
US3987427A
(en)
1976-10-19
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Legal Events
Date
Code
Title
Description
1978-06-28
PS
Patent sealed [section 19, patents act 1949]
1982-11-24
PCNP
Patent ceased through non-payment of renewal fee
