Distinguishing false signals in cable locating based on a modulated reference signal
First Claim
1. 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, said system comprising:
- a transmitter for generating said locating signal frequency for coupling onto the first cable and for transmitting a reference signal, which includes said locating signal frequency modulated thereon; and
a receiver configured to distinguish the locating signal from the false locating signal based on a modulation envelope of the reference signal as compared to the locating signal and the false locating signal.
1 Assignment
0 Petitions
Accused Products
Abstract
A cable locating system includes a transmitter for generating a locating signal frequency for coupling onto a first cable and for transmitting a reference signal, which includes the locating signal frequency modulated on the reference signal. A second cable emits a false locating signal. A receiver distinguishes the locating signal from a false locating signal based on a modulation envelope of the reference signal as compared to the locating signal and the false locating signal.
35 Citations
20 Claims
-
1. 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, said system comprising:
-
a transmitter for generating said locating signal frequency for coupling onto the first cable and for transmitting a reference signal, which includes said locating signal frequency modulated thereon; and a receiver configured to distinguish the locating signal from the false locating signal based on a modulation envelope of the reference signal as compared to the locating signal and the false locating signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
-
Specification