GB984402A - Stabilization of sensitivity in intruder detection systems - Google Patents
Stabilization of sensitivity in intruder detection systemsInfo
- Publication number
- GB984402A GB984402A GB2078463A GB2078463A GB984402A GB 984402 A GB984402 A GB 984402A GB 2078463 A GB2078463 A GB 2078463A GB 2078463 A GB2078463 A GB 2078463A GB 984402 A GB984402 A GB 984402A
- Authority
- GB
- United Kingdom
- Prior art keywords
- signals
- output
- pass filter
- produce
- fed
- 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)
- Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)
- Burglar Alarm Systems (AREA)
Abstract
984, 402. Intruder alarm systems. SPECIALITIES DEVELOPMENT CORPORATION. May 24, 1963, No. 20784/63. Heading G4N. [Also in Divisions H3 and H4] In an intruder detection system operating on the Doppler principle, the received signal is mixed with two phase-displaced signals at the transmitted frequency to provide positive or negative resultant signals having a difference frequency component of substantial amplitude throughout variations of the phase relationship of the transmitted and received signals. As described, an output from oscillator 2 is fed to a transmitting transducer 4 and the received signal is fed via reflex amplifiers 10, 12 and high pass filter 16 to produce an output on line 124. The output is added to two anti-phase signals in winding 123 of oscillator 2 and the resulting signals are fed over lines 125, 126 to diodes 129, 132 to produce positive and negative signals containing components at the difference frequency. These signals are then fed via low pass filter 20, amplifiers 10, 12 and low pass filter 14 to produce an output for operating an alarm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB2078463A GB984402A (en) | 1963-05-24 | 1963-05-24 | Stabilization of sensitivity in intruder detection systems |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB2078463A GB984402A (en) | 1963-05-24 | 1963-05-24 | Stabilization of sensitivity in intruder detection systems |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB984402A true GB984402A (en) | 1965-02-24 |
Family
ID=10151630
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB2078463A Expired GB984402A (en) | 1963-05-24 | 1963-05-24 | Stabilization of sensitivity in intruder detection systems |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB984402A (en) |
-
1963
- 1963-05-24 GB GB2078463A patent/GB984402A/en not_active Expired
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