Apparatus for distinguishing false signals in cable locating
First Claim
1. 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 can be coupled to the second cable in a way which causes the second cable to generate a false locating signal in electromagnetic form, as part of an overall apparatus for discriminating between the locating signal and the false locating signal, a transmitter, comprising:
- a frequency generator for generating said locating signal frequency;
a phase shifter that is configured for receiving the locating signal frequency and subjecting the locating signal frequency to a given phase shift to produce a phase shifted locating signal frequency;
an arrangement producing a reference signal and for impressing the phase shifted locating signal frequency thereon, to provide for distinguishing between the locating signal and the false locating signal and for transferring the reference signal; and
a coupling configuration for coupling the locating signal frequency onto the first cable to generate the locating signal in a way which subjects the locating signal frequency to a coupling configuration phase shift such that the phase shifted locating frequency, as part of the reference signal subsequent to transfer thereof, can compensate for the coupling configuration phase shift of the locating signal frequency in the locating signal as emitted by the first cable.
1 Assignment
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Accused Products
Abstract
Discriminating between a cable locating signal and a false cable locating signal is described. A reference signal, which contains a locating signal frequency impressed on it, is transmitted in a way which provides for detection of a phase shift between the locating signal and the false locating signal. Based on the phase shift, a receiver is used to distinguish the locating signal from the false locating signal.
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Citations
31 Claims
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1. 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 can be coupled to the second cable in a way which causes the second cable to generate a false locating signal in electromagnetic form, as part of an overall apparatus for discriminating between the locating signal and the false locating signal, a transmitter, comprising:
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a frequency generator for generating said locating signal frequency; a phase shifter that is configured for receiving the locating signal frequency and subjecting the locating signal frequency to a given phase shift to produce a phase shifted locating signal frequency; an arrangement producing a reference signal and for impressing the phase shifted locating signal frequency thereon, to provide for distinguishing between the locating signal and the false locating signal and for transferring the reference signal; and a coupling configuration for coupling the locating signal frequency onto the first cable to generate the locating signal in a way which subjects the locating signal frequency to a coupling configuration phase shift such that the phase shifted locating frequency, as part of the reference signal subsequent to transfer thereof, can compensate for the coupling configuration phase shift of the locating signal frequency in the locating signal as emitted by the first cable. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. 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 can be coupled to the second cable in a way which causes the second cable to generate a false locating signal in electromagnetic form, as part of an overall apparatus for discriminating between the locating signal and the false locating signal, a receiver, comprising:
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a receiver section that receives the locating signal and the false locating signal as well as receiving a reference signal which contains said locating signal frequency impressed thereon, wherein a transmitter transmits said reference signal in a way which provides for distinguishing between the locating signal and the false locating signal; and a detector for distinguishing the locating signal from the false locating signal based on said locating signal frequency as contained by the reference signal. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. 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 can be coupled to the second cable in a way which causes the second cable to generate a false locating signal in electromagnetic form, as part of an overall apparatus for discriminating between the locating signal and the false locating signal, a transmitter, comprising:
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a frequency generator for generating said locating signal frequency; an arrangement for producing a reference signal and for impressing the locating signal frequency thereon, in a way which provides for distinguishing between the locating signal and the false locating signal; and a coupling arrangement for summing the locating signal frequency and the reference signal to produce a summer output and for coupling the summer output onto the first cable such that the first cable emanates the locating signal and the reference signal. - View Dependent Claims (31)
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Specification