LINE NOISE ANALYSIS AND DETECTION AND MEASUREMENT ERROR REDUCTION
First Claim
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1. A method comprising:
- sensing a process parameter to generate a sensor signal that includes a process signal and line noise components;
digitizing the sensor signal at a sample rate;
detecting line noise zero crossings in the sensor signal;
determining a line noise frequency as a function of the detected line noise zero crossings; and
adjusting the sample rate as a function of the line noise frequency to reduce an impact of line noise on the digitized sensor signal.
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Abstract
A method includes sensing a process parameter to generate a sensor signal that includes a process signal and line noise components, digitizing the sensor signal at a sample rate, detecting line noise zero crossings in the sensor signal, determining a line noise frequency as a function of the detected line noise zero crossings, and adjusting the sample rate as a function of the line noise frequency to reduce an impact of line noise on the digitized sensor signal.
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Citations
22 Claims
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1. A method comprising:
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sensing a process parameter to generate a sensor signal that includes a process signal and line noise components; digitizing the sensor signal at a sample rate; detecting line noise zero crossings in the sensor signal; determining a line noise frequency as a function of the detected line noise zero crossings; and adjusting the sample rate as a function of the line noise frequency to reduce an impact of line noise on the digitized sensor signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of line noise management comprising:
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establishing a noise amplitude threshold; sensing a process parameter to generate a sensor signal that includes a process signal and line noise components; digitizing the sensor signal at a sample rate; comparing the sensor signal to the noise amplitude threshold; generating an interrupt signal indicative of when the sensor signal crosses the noise amplitude threshold; and lowering the sample rate as a function of the interrupt signal when an amplitude of the sensor signal is greater than or equal to the noise amplitude threshold. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. An industrial process transmitter assembly comprising:
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a sensor for sensing a process parameter and generating a sensor signal as a function of the process parameter; an analog-to-digital converter having filter circuitry, wherein the analog-to-digital converter is configured to receive the sensor signal and to generate a digitized sensor signal at a sample rate; noise detector circuitry comprising; a voltage follower configured to receive the sensor signal; a bandpass filter operably connected to the voltage follower; a tunable voltage threshold input; and a comparator operably connected to both the bandpass filer and the tunable voltage threshold input, and configured to generate an interrupt signal as a function of the sensor signal; and a microprocessor operably connected to the analog-to-digital converter and to the noise detector circuitry, wherein the microprocessor is configured to control the analog-to-digital converter as a function of the interrupt signal and to produce an output signal based upon the digitized sensor signal. - View Dependent Claims (20, 21, 22)
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Specification