Signal select in underground line location
First Claim
Patent Images
1. A transmitter, comprising:
- at least one direct digital synthesizer, the direct digital synthesizer producing a composite output signal in response to an input square wave signal, the composite output signal having a first frequency component for a first period followed by a second frequency component for a second period; and
a feedback loop providing a feedback signal coupled with the at least one direct digital synthesizer that adjusts the first and second frequency components of the composite output signal;
wherein the at least one direct digital synthesizer includes a first digital synthesizer that produces an output signal from the input square wave signal and a control phase signal and a second digital synthesizer that provides a sine wave output for generation of the input square wave signal and signals for generating a current phase signal from the feedback signal.
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Abstract
A transmitter and receiver for performing a signal select algorithm are provided. A transmitter for providing a signal on a line to be located includes at least one direct digital synthesizer, the direct digital synthesizer producing two component frequencies in response to an input square wave signal; and a feedback loop providing the input square wave.
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Citations
14 Claims
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1. A transmitter, comprising:
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at least one direct digital synthesizer, the direct digital synthesizer producing a composite output signal in response to an input square wave signal, the composite output signal having a first frequency component for a first period followed by a second frequency component for a second period; and a feedback loop providing a feedback signal coupled with the at least one direct digital synthesizer that adjusts the first and second frequency components of the composite output signal; wherein the at least one direct digital synthesizer includes a first digital synthesizer that produces an output signal from the input square wave signal and a control phase signal and a second digital synthesizer that provides a sine wave output for generation of the input square wave signal and signals for generating a current phase signal from the feedback signal. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A transmitter, comprising:
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a signal generation module that generates a composite output signal, the composite output signal having a first frequency component for a first period followed by a second frequency component for a second period, the signal generation module including; a first direct digital synthesizer that provides the composite output signal, the composite output signal being based on a control phase signal and an FSK control signal; a second direct digital synthesizer that provides a quadrature signal, the quadrature signal being based on the control phase signal and the FSK control signal; and a third direct digital synthesizer that provides an in-phase signal, the in-phase signal being based on the control phase signal and the FSK control signal; an output stage, the output stage coupling the composite output signal to a load conductor; a measurement circuitry that receives a signal from the output stage and phase signals from the signal generation module and providing a feedback signal; and a microprocessor coupled to the signal generation module and the measurement circuitry, the microprocessor controlling the signal generation module in response to the feedback signal. - View Dependent Claims (8, 9)
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10. A method, comprising:
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providing, by a first direct digital synthesizer, a composite output signal based on a control phase signal and an input square wave, the composite output signal including a first frequency component for a first period followed by a second frequency component for a second period; providing, by a second direct digital synthesizer, a sine wave output for generation of the input square wave and for generation of a current phase signal from a feedback signal; and providing, by a feedback loop coupled to the first direct digital synthesizer and the second direct digital synthesizer, a feedback signal that adjusts the first frequency component and second frequency component of the composite output signal. - View Dependent Claims (11, 12, 13, 14)
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Specification