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US 7,095,231 B2Granted
Method of and system for locating a single passive underground electronic marker type that distinguishes false indication caused by other marker types
AssigneeTempo Research Corporation
InventorsJames W. Thompson, William C. Wood
Life of this patent
Estimating the term…
Abstract
A method of and system for locating a single passive underground marker type may distinguish false indications caused by other marker types. In accordance with aspects of the present invention, minimization or elimination of false marker indications may be accomplished by processing the response from a marker to determine which frequency has the largest response.
Claims9
A method of locating a selected type of passive electronic marker, said method comprising:
- transmitting a signal at a frequency associated with the selected type of passive electronic marker;
- receiving a signal from the marker;
- determining a frequency distribution of the received signal by performing synchronous detection on the signal received during said receiving;
- indicating presence of the selected type of passive electronic marker if, responsive to said determining, the frequency having the greatest amplitude is the frequency associated with the selected type of passive electronic marker;
- and
- preventing an indication for other passive electronic marker types associated with a frequency having less than the greatest amplitude.
3 more elements
A system for locating a selected type of passive electronic marker;
- said system comprising:
- a transmitter for transmitting a signal at a frequency associated with the selected type of passive electronic marker;
- a receiver for receiving the signal from the marker;
- a processor coupled to the receiver for determining a frequency distribution of the received signal by performing synchronous detection on the received signal;
- and
- a display unit for indicating presence of the selected type of passive electronic marker if a frequency with the greatest amplitude determined by the processor is associated with the selected type of passive electronic marker, wherein said display unit prevents an indication for other passive electronic marker types associated with a frequency having less than the greatest amplitude.
3 more elements
Dependencies are inferred from the claim text.