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US 2003/0142230 A1Published application
Camera system including a safety circuit
AssigneeThomson Licensing
InventorsPeter C. Schmale, Marinus C.W. Van Buul
Life of this patent
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Abstract
Camera systems are often built up from a base station, a detachable cable, and a camera. A dangerous situation may arise the moment the cable is detached from the camera because there is (still) a voltage present on the cable. The invention provides a camera system in which this problem is solved by means of a safety circuit capable of detecting from the base station whether a camera is connected to the cable or not.
Claims6
A camera system comprising a base station and a camera coupled to the base station by means of a detachable cable, the cable comprising at least two conductors, characterized in that:
- the base station comprises power supply means for providing power supply to the two conductors, a controlled switch (S) for coupling or not power supply means with the conductors, a current injector (AC-INJ) connected in parallel to the two conductors, the current injector providing an AC current at a predetermined frequency, and a current detector (AC-DET) connected in parallel to the two conductors, the current detector measuring the AC current at the predetermined frequency,
- the camera comprises means (C) for shortening the AC current at the predetermined frequency.
Dependencies are inferred from the claim text.