Theft detection magnetic marker mfr. method - uses transverse bands cut from ribbon of low coercivity magnetic material having attached control strips of ferro-magnetic material

摘要

The magnetic marker includes a ribbon of magnetic signal material of relatively low coercivity having coupled to it at least two control elements of a ferro-magnetic material. This may be permanently magnetized by a control signal in order to saturate the strip of the ferromagnetic material. This prevents the first ferromagnetic material from generaring higher order harmonics when interrogated by a periodic magnetic signal. The marker used with a system which detects the marker is used with a system which detects the market when it is in an interrogation zone in which a magnetic field varies periodically at a predetermined fundamental frequency. This system includes a sensor for actuating a security readout following the detection of a high harmonic frequency generated by the magnetic marker.