METALLIC CONDUCTOR DISTURBANCE DETECTION DEVICE AND METHOD

摘要

A method of detecting disturbance in a metallic conductor (34), comprises the steps of providing an inductance sensing circuit (12) in mechanically and electrically connected to a metallic conductor (34) having a monitorable inductance, tuning the inductance sensing circuit (12) based on an electromagnetic field impressed upon the metallic conductor (34) and an internally generated circuit oscillation, and outputting an alert signal when a tuned output signal from the tuned inductance sensing circuit (12) becomes detuned due to a change in inductance of the metallic conductor (34) by addition to or removal of at least a portion of the metallic conductor (34). A metallic conductor disturbance detection device (10) for such a method is also provided, the device (10) comprising an amplitude and/or frequency tuneable inductance sensing circuit (12), and an alarm circuit (16) for outputting an alarm signal based on an output of the inductance sensing circuit (12).