Active IR intrusion detector
First Claim
1. Active infrared detector for detecting movements in a monitored room, having an emitter for emitting modulated infrared radiation into the monitored room, having a receiver for the infrared radiation reflected from the monitored room, and having an analysis circuit connected to the receiver and containing means for obtaining a working signal, characterised in that the analysis circuit (2, 2'"'"') has a controller for outputting a compensating signal (Ik) which is superimposed over the incoming signal (Ie), which on the one hand receives the working signal (Un) and on the other hand is connected to the output of the receiver (5), and that the compensating signal is selected so that the working signal is corrected to the value zero.
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Accused Products
Abstract
The infrared detector contains an emitter (4), a receiver (5) and an analysis circuit (2'"'"') for obtaining a working signal (Un). The analysis circuit (2'"'"') contains a controller (29) for outputting a compensating signal (Ik) superimposed over the incoming signal (Ie), which on the one hand receives the working signal (Un) and on the other hand is connected to the output of the receiver (5). The compensating signal (Ik) is selected so that the working signal (Un) is corrected to the value zero so that the maximum sensitivity is retained at all times.
15 Citations
38 Claims
- 1. Active infrared detector for detecting movements in a monitored room, having an emitter for emitting modulated infrared radiation into the monitored room, having a receiver for the infrared radiation reflected from the monitored room, and having an analysis circuit connected to the receiver and containing means for obtaining a working signal, characterised in that the analysis circuit (2, 2'"'"') has a controller for outputting a compensating signal (Ik) which is superimposed over the incoming signal (Ie), which on the one hand receives the working signal (Un) and on the other hand is connected to the output of the receiver (5), and that the compensating signal is selected so that the working signal is corrected to the value zero.
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22. Apparatus for detecting movements in a monitored space, comprising an infrared radiation emitter for emitting modulated infrared radiation into the monitored space, a receiver for receiving infrared radiation reflected from the monitored space and producing a corresponding incoming signal;
- a circuit for receiving said incoming signal and producing a working signal; and
a compensation signal generator connected to said circuit for receiving said working signal and producing a compensating signal for adjusting said incoming signal so that said working signal is corrected substantially to zero to maximize the sensitivity of the apparatus. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
- a circuit for receiving said incoming signal and producing a working signal; and
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37. Apparatus for monitoring a space, comprising an infrared emitter for emitting modulated radiation into the monitored space, means for receiving infrared radiation from the monitored space and producing corresponding incoming signals;
- and means for producing signals for balancing said incoming signals substantially to zero to maximize the sensitivity of the apparatus.
- View Dependent Claims (38)
Specification