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US 10,833,901 B2Granted
Signal select in underground line location
AssigneeMetrotech Corporation
InventorsStephen John Petherick, George Mainescu, Ion Dracea, Razvan Gabriel Stefanoiu, John Mark Royle
Life of this patent
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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.
Claims18
A receiver of an underground line locator, comprising:
- an antenna that provides an antenna signal based on a detected signal emitted from an underground line coupled to a transmitter when the antenna is placed over the underground line, the transmitter providing a bifurcated transmission signal having a first frequency and a second frequency to the underground line, the detected signal including a bifurcated first frequency and second frequency;
- an analog filter that filters the antenna signal to generate a filtered signal;
- an amplifier that amplifies the filtered signal to generate an amplified signal;
- a CODEC that receives the amplified signal and provides a decoded signal;
- and
- a digital signal processor that analyzes the decoded signal to generate a signal select signal that includes the bifurcated first frequency and second frequency, the digital signal processor including:
- a demodulator to demodulate and downsample the decoded signal to receive an in-phase component and a quadrature component;
- and
- a calculation that provides an intensity and a phase of a signal formed from the in-phase component and the quadrature component;
- wherein the phase of the signal formed from the in-phase component and the quadrature component corresponds to a phase reference of a transmitted frequency shift keyed (FSK) signal;
- wherein the digital signal processor provides a phase error function based on the in-phase component and the quadrature component.
8 more elements
A method of receiving a frequency modulated signal select signal emitted from an underground line, comprising:
- receiving, by an antenna positioned over the underground line, a signal emitted from the underground line that is coupled to a transmitter, the transmitter providing a bifurcated transmission signal having a first frequency and a second frequency to the underground line, the signal being frequency modulated with a bifurcated first frequency and second frequency;
- demodulating and downsampling, by a demodulator, the received signal to determine an in-phase component and a quadrature component;
- determining, by a digital signal processor, a phase offset of the frequency modulated signal select signal based on the in-phase component and the quadrature component;
- tracking, by the digital signal processor, the frequency modulated signal select signal based on the determined phase offset;
- and
- providing a phase error function based on the in-phase component and the quadrature component.
3 more elements
A method of receiving a signal emitted from an underground line, comprising:
- processing incoming signals from one or more antennas positioned over the underground line, the signals being emitted from the underground line coupled to a transmitter, the transmitter providing a bifurcated transmission signal having a first frequency and a second frequency to the underground line, the signal being frequency modulated with a bifurcated first frequency and second frequency;
- demodulating, by a demodulator, a frequency shift keyed (FSK) signal select waveform from the incoming signals;
- establishing, by a digital signal processor, a phase reference for a transmitter phase;
- accessing, by the digital signal processor, a difference between the phase reference and a measured phase to provide a measure of a phase shift of the FSK signal select waveform;
- tracking, by the digital signal processor, the signal from the underground line based on the measure of the phase shift;
- and
- providing a phase correction to correct for truncation and other accumulated errors during the demodulating.
4 more elements
Dependencies are inferred from the claim text.