| 摘要 |
The present invention relates to an improved magnetic marker and method for manufacturing same. The marker includes a ribbon of magnetic signal material of relatively low coercivity having coupled thereto at least two control elements of a ferro-magnetic material which may be permanently magnetized by a control signal in order to saturate the strip of first ferromagnetic material, thereby preventing the first ferromagnetic material from generating higher order harmonics when interrogated by a periodic magnetic signal of fundamental frequency.
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