Transmitter for emitting reference signal to distinguish false signals in cable locating

Abstract

A transmitter is part of a cable locating system for use in a region which contains at least first and second in-ground cables, each of which cables includes an electrically conductive component such that, when the first cable is driven at a locating signal frequency to emit a locating signal in an electromagnetic form, the locating signal is coupled to the second cable in a way which causes the second cable to generate a false locating signal in electromagnetic form. The transmitter generates the locating signal frequency for coupling onto the first cable and for transmitting a reference signal, which includes the locating signal frequency such that the reference signal includes a modulation envelope for comparison of the modulation envelope to the locating signal and to the false locating signal at a receiving location to distinguish the locating signal from the false locating signal.

Dependencies are inferred from the claim text.