Signal Processing For A Capacitive Sensor System With Robustness To Noise
First Claim
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1. A capacitive sensor, comprising:
- a transmit electrode configured to provide an alternating electric field to a sensor;
one or more receive electrodes for detecting variations in the alternating electric field; and
an adaptive frequency adjustment unit configured to adjust an operating frequency of the alternating electric field responsive to detection of a noise measure.
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Abstract
A capacitive sensor includes a transmit electrode configured to provide an alternating electric field to a sensor; one or more receive electrodes for detecting variations in the alternating electric field; and an adaptive frequency adjustment unit configured to adjust an operating frequency of the alternating electric field responsive to detection of a noise measure, such as noise power.
19 Citations
31 Claims
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1. A capacitive sensor, comprising:
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a transmit electrode configured to provide an alternating electric field to a sensor; one or more receive electrodes for detecting variations in the alternating electric field; and an adaptive frequency adjustment unit configured to adjust an operating frequency of the alternating electric field responsive to detection of a noise measure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for providing noise robustness to a capacitive sensing system, comprising:
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defining a plurality of potential operating transmit frequencies; determining a corresponding noise measure corresponding to each of the potential operating frequencies; operating the capacitive sensing system at one of the plurality of potential operating transmit frequencies; measuring an operating noise measure at the operating frequency; and selecting a new operating frequency responsive to a value of the measured operating noise measure. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A capacitive sensor system, comprising:
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a transmit electrode configured to provide an alternating electric field to a sensor; one or more receive electrodes for detecting variations in the alternating electric field; and an adaptive frequency adjustment unit configured to adjust an operating frequency of the alternating electric field in accordance with modeling the capacitive sensor system as an amplitude modulation system with direct sampling and synchronous demodulation. - View Dependent Claims (25, 26)
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27. The capacitive sensor system of claim 27, wherein the noise measure is a noise power.
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28. Sensor system comprising an alternating electric field sensor arrangement being subject to noise and being coupled with a signal processing unit receiving an analog noisy signal, wherein the signal processing unit converts the analog noisy signal to a digital signal, wherein the signal processing unit is further configured to demodulate the sampled signal by multiplication with (−
- 1)k, where k indicates the discrete time, subsequent low-pass filtering, subsequent decimation by a factor R, and further low-pass filtering.
- View Dependent Claims (29, 30, 31)
Specification