| 摘要 |
An underground marker and methodology for locating the same is discussed. The marker has a tuned circuit and an energy storage device. The marker also has a transponder that is coupled to the tuned circuit. When the tuned circuit receives electromagnetic energy at its tuned frequency, the tuned circuit resonates and provides power to the energy storage device, which in turn powers a transponder. The transponder has a memory containing a coded signal. The transponder transmits this coded signal using the tuned circuit. The transponder alters the impedance of the tuned circuit in accordance with the coded pattern. In this manner, an addressable underground marker can be used to locate particular types of buried structures. Nonaddressable markers can be used to locate addressable markers by providing a reference point for searches.
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