Spurious noise filter
First Claim
1. A method for filtering a process sensor signal comprising:
- determining a spurious noise threshold;
receiving a process sensor signal;
determining a representative value of the process sensor signal; and
replacing the process sensor signal with the representative value when a calculated value of the process sensor signal exceeds the spurious noise threshold, thereby providing a processed signal, wherein the spurious noise threshold includes a dynamic threshold and a minimum threshold, the dynamic threshold varying over time in response to variations of the process sensor signal, and the minimum threshold establishing a floor beneath which the dynamic threshold may not fall.
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Accused Products
Abstract
According to the principles of the invention, there is provided a system that identifies spurious noise values in an input signal and replaces them with substitute values representative of the spurious-noise-free signal. The system is activated when the signal deviation exceeds a predetermined threshold, otherwise passing the signal unchanged. The substituted representative values are determined based on historical signal data, preferably a moving average with a fixed window. There is further provided a maximum glitch width which prevents inadvertent suppression of a true step in the input signal, and a relaxation time which prevents consecutive filter activations from unduly masking the input signal.
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Citations
17 Claims
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1. A method for filtering a process sensor signal comprising:
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determining a spurious noise threshold;
receiving a process sensor signal;
determining a representative value of the process sensor signal; and
replacing the process sensor signal with the representative value when a calculated value of the process sensor signal exceeds the spurious noise threshold, thereby providing a processed signal, wherein the spurious noise threshold includes a dynamic threshold and a minimum threshold, the dynamic threshold varying over time in response to variations of the process sensor signal, and the minimum threshold establishing a floor beneath which the dynamic threshold may not fall. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A system for filtering a signal comprising:
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means for determining a spurious noise threshold;
means for receiving a process sensor signal;
means for determining a representative value of the process sensor signal; and
means for replacing the process sensor signal with the representative value when a calculated value of the process sensor signal exceeds the spurious noise threshold, thereby providing a processed signal, wherein the process sensor signal is a magnetic flowmeter signal and wherein the spurious noise threshold includes a dynamic threshold and a minimum threshold. - View Dependent Claims (8, 9, 10, 11)
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12. A computer program product for filtering a signal comprising:
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machine executable code to determine a spurious noise threshold;
machine executable code to receive a process sensor signal;
machine executable code to determine a representative value of the process sensor signal; and
machine executable code to replace the process sensor signal with the representative value when a calculated value of the process sensor signal exceeds the spurious noise threshold, thereby providing a processed signal, wherein the spurious noise threshold includes a dynamic threshold and a minimum threshold. - View Dependent Claims (13, 14, 15, 16, 17)
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Specification