Distinguishing false signals in cable locating using a reference signal

摘要

A method is described for use with first and second in-ground cables 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 can be coupled to the second cable to cause the second cable to generate a false locating signal. The method includes generating the locating signal frequency. A reference signal is produced. The locating signal frequency is impressed on the reference signal in a way which provides for distinguishing between the locating signal and the false locating signal. The locating signal frequency and the reference signal are summed to produce a summer output. The summer output is coupled onto the first cable such that the first cable emanates the locating signal and the reference signal, and the reference signal can be received for distinguishing between the locating signal and the false locating signal.