Sensing phase sequence to suppress single tone noise
First Claim
1. A single tone noise suppression method for a capacitance-to-voltage converter in a capacitance measurement system, comprising:
- performing three or more successive capacitive measurements on a capacitance under test to produce respective single tone noise responses, each successive measurement using a different sequence of sensing signals;
disregarding the capacitance measurement with the highest single tone noise response; and
averaging the remaining measurements to obtain a capacitance measurement with reduced single tone noise levels.
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Abstract
A noise suppression method for a capacitance-to-voltage converter varies a sequence of sensing signal edges during a plurality capacitance measurements to produce a number of noise responses. The sensing signal edges are varied in a repetitive rising and falling edge pattern for each sequence. Three or more such sequences can be used, and the sequence with the highest noise is eliminated and the others are averaged. The noise suppression method can be implemented during calibration and then used for a number of normal acquisitions. The noise suppression method can be applied to capacitance-to-voltage converters having monitoring and integration phases.
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Citations
18 Claims
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1. A single tone noise suppression method for a capacitance-to-voltage converter in a capacitance measurement system, comprising:
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performing three or more successive capacitive measurements on a capacitance under test to produce respective single tone noise responses, each successive measurement using a different sequence of sensing signals; disregarding the capacitance measurement with the highest single tone noise response; and averaging the remaining measurements to obtain a capacitance measurement with reduced single tone noise levels. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A single tone noise suppression method for a capacitance-to-voltage converter in a capacitance measurement system, comprising:
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performing three or more successive capacitive measurements on a capacitance under test; varying a sequence of monitoring and integrating phases during each of the capacitance measurements, wherein the monitoring and integrating phases are varied for each sequence, to produce a plurality of noise responses; eliminating the capacitance measurement with the highest single tone noise response; and averaging the remaining measurements to obtain a capacitance measurement with reduced single tone noise levels. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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Specification