Control of lighting devices
First Claim
1. A control system, comprisinga first active sensor comprisinga transmitter arranged to in a first timeslot transmit a first probe signal comprising two non-zero pulses transmitted in respective parts of said first timeslot;
- anda second active sensor comprisinga receiving sensor array arranged to receive said first probe signal; and
a processing unit arranged to, in a second timeslot, determine a difference between signals received in a first part of said second timeslot and signals received in a second part of said second timeslot, the processing unit thereby being arranged to detect cross-interference between the active sensors, cross-interference being detected if the power in the difference signal has an absolute value that is larger than a predefined threshold value.
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Accused Products
Abstract
A network of active sensors in a control system is considered. The active sensors, which may be fixed-infrastructure sensors, provide presence detection information to a distributed lighting system. The active sensors communicate by transmitting probe signals. The communication of probe signals may result in cross-interference which may vary in time. Cross-interference is detected, and can later be avoided, by determining a difference between signals received in a first part of a timeslot and signals received in a second part of the timeslot. In order to do so probe signals comprising two non-zero pulses are transmitted in respective parts of the timeslot. Applications are, for example, active presence sensors in lighting control applications in indoor as well as outdoor environments.
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Citations
15 Claims
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1. A control system, comprising
a first active sensor comprising a transmitter arranged to in a first timeslot transmit a first probe signal comprising two non-zero pulses transmitted in respective parts of said first timeslot; - and
a second active sensor comprising a receiving sensor array arranged to receive said first probe signal; and a processing unit arranged to, in a second timeslot, determine a difference between signals received in a first part of said second timeslot and signals received in a second part of said second timeslot, the processing unit thereby being arranged to detect cross-interference between the active sensors, cross-interference being detected if the power in the difference signal has an absolute value that is larger than a predefined threshold value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of detecting interference in a control system (1), comprising
transmitting, by a first active sensor, in a first timeslot a first probe signal comprising two non-zero pulses transmitted in respective parts of said first timeslot; -
receiving, by a second active sensor, said first probe signal; and determining, by said second active sensor, in a second timeslot a difference between signals received in a first part of said second timeslot and signals received in a second part of said second timeslot, the second active sensor thereby being arranged to detect cross-interference between the active sensors, cross-interference being detected if the power in the difference signal has an absolute value that is larger than a predefined threshold value. - View Dependent Claims (14, 15)
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Specification