Conductor tracing system

摘要: A system for tracing routes of conductors has a transmitter ( 10 ) applying an alternating signal 11 to the conductor be traced 12 ), and field produced by this is detected remotely from conductor. In order distinguish between being fields nearby 14 due capacitive coupling 17 phase-locked first second components with frequencies F 1 2 respectively, related N×F =M×F , where N M are non-adjacent integers greater than 1, one which odd even, having no common factors. The at plurality positions. phase relationship signals investigated determine unambiguously position object concerned.