Patent ID: 7262607

Claim:
A system comprising: at least one first conductive element and at least one second conductive element; a transmitter conductively coupled to at least one said first conductive element without also being conductively coupled to any said second conductive element, the transmitter being operable to drive a first electromagnetic signal along the at least one first conductive element; a receiver for receiving signals from the at least one second conductive element; and a coupler, mounted for so sliding through a range of positions with respect to the first and second conductive elements as to respond to the first electromagnetic signal by launching on the second conductive element a second electromagnetic signal received by the receiver with a timing with respect to the first electromagnetic signal that depends on the coupler's position; and a processing element responsive to the second electromagnetic signal to generate, at least in part from the second magnetic signal's time delay with respect to the first electromagnetic signal, an output indicative of the value of a quantity on which the coupler's location depends.