Method and apparatus for digital detection of electronic markers using frequency adaptation
First Claim
1. A marker locator, comprising:
- at least one transmitter channel coupled to provide a transmitter signal to an electromagnetic field generator, wherein the transmitter signal is phase shifted to substantially zero and is capable of exciting multiple types of markers;
at least one receiver channel coupled to receive time decay signals from an electromagnetic field detector; and
a digital processor coupled to provide digitized transmitter output signals to the at least one transmitter channel and to receive digitized time decay signals from the at least one receiver channel, wherein the digital processor receives the digitized time decay signals from the at least one receiver channel in the time interval between pulses of application of digitized transmitter output signals to the at least one transmitter channel, the averages the digitized time decay signals received from the at least one receiver channel, adapts the frequency of the averaged time decay signals, wherein the adapted frequency and the averaged time decay signals can assist in distinguishing between the multiple types of markers.
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Accused Products
Abstract
An electronic marker locator with a digital architecture for providing accurate and consistent estimation of the signal strength is presented. The marker locator includes a Digital Phase-Locked Loop (DPLL) structure. The electronic marker locator transmits known and adjustable frequency bursts corresponding to the markers to be located while synchronously capturing the signals returned from the markers. Because of the convergence properties of the DPLL, very consistent measurements of the reflected marker signal field strength are possible, resulting in both an improvement of maximum detection depth and depth accuracy. Further, the analog front-end hardware can be reduced, offering wider resistance to component tolerances, lower calibration and test times, and flexible frequency selectivity.
102 Citations
27 Claims
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1. A marker locator, comprising:
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at least one transmitter channel coupled to provide a transmitter signal to an electromagnetic field generator, wherein the transmitter signal is phase shifted to substantially zero and is capable of exciting multiple types of markers;
at least one receiver channel coupled to receive time decay signals from an electromagnetic field detector; and
a digital processor coupled to provide digitized transmitter output signals to the at least one transmitter channel and to receive digitized time decay signals from the at least one receiver channel, wherein the digital processor receives the digitized time decay signals from the at least one receiver channel in the time interval between pulses of application of digitized transmitter output signals to the at least one transmitter channel, the averages the digitized time decay signals received from the at least one receiver channel, adapts the frequency of the averaged time decay signals, wherein the adapted frequency and the averaged time decay signals can assist in distinguishing between the multiple types of markers. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18-24. -24. (canceled)
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25. A marker locator, comprising:
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means for generating pulses of a transmit signal from a frequency, field strength, and phase from one or more markers, wherein these pulses can excite multiple types of markers and each type of marker represents a different type of utility line;
means for receiving signals from one or more markers between applications of the transmit signal;
means for averaging the received signals to form an average decay signal;
means for determining the frequency, field strength, and phase of one or more markers from the average decay signal, wherein the determined frequency the determined field strength, and the determined phase can assist in distinguishing between multiple types of markers. - View Dependent Claims (26, 27)
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Specification