Noise filtering devices, systems and methods for capacitance sensing devices
First Claim
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1. A capacitance sensing system, comprising:
- a sense network including a sense surface having a plurality of electrodes and configured to generate a plurality of position detection signals in response to a touch event on the sense surface;
a noise listening circuit coupled to the sense network, wherein the noise listening circuit is configured to detect noise in the plurality of position detection signals associated with the plurality of electrodes and compare the detected noise in the plurality of position detection signals to a first noise threshold value; and
a filtering circuit coupled to the noise listening circuit, wherein the filtering circuit is configured to, for each of the plurality of position detection signals;
in accordance with a determination that the detected noise in the respective position detection signal is greater than the first noise threshold value, determine that the touch event occurs on or proximate to a subset of electrodes corresponding to the respective position detection signal, and provide an extended scan and local noise filtering to process the respective position detection signal, wherein local noise filtering removes local noise caused on the respective subset of electrodes by the touch event; and
in accordance with a determination that the detected noise in the respective positon detection signal is not greater than the first noise threshold value, provide a standard scan and non-local noise filtering to process the respective position detection signal;
wherein the extended scan includes a larger number of sample operations or lasts a longer duration than those of the standard scan.
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Abstract
A capacitance sensing system can filter noise that presents in a subset of electrodes in the proximity of a sense object (i.e., finger). A capacitance sensing system can include a sense network comprising a plurality of electrodes for generating sense values; a noise listening circuit configured to detect noise on a plurality of the electrodes; and a filtering circuit that enables a filtering for localized noise events when detected noise values are above one level, and disables the filtering for localized noise events when detected noise values are below the one level.
67 Citations
20 Claims
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1. A capacitance sensing system, comprising:
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a sense network including a sense surface having a plurality of electrodes and configured to generate a plurality of position detection signals in response to a touch event on the sense surface; a noise listening circuit coupled to the sense network, wherein the noise listening circuit is configured to detect noise in the plurality of position detection signals associated with the plurality of electrodes and compare the detected noise in the plurality of position detection signals to a first noise threshold value; and a filtering circuit coupled to the noise listening circuit, wherein the filtering circuit is configured to, for each of the plurality of position detection signals; in accordance with a determination that the detected noise in the respective position detection signal is greater than the first noise threshold value, determine that the touch event occurs on or proximate to a subset of electrodes corresponding to the respective position detection signal, and provide an extended scan and local noise filtering to process the respective position detection signal, wherein local noise filtering removes local noise caused on the respective subset of electrodes by the touch event; and in accordance with a determination that the detected noise in the respective positon detection signal is not greater than the first noise threshold value, provide a standard scan and non-local noise filtering to process the respective position detection signal; wherein the extended scan includes a larger number of sample operations or lasts a longer duration than those of the standard scan. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for controlling noise, comprising:
at a capacitive sensing system including a sense network with a sense surface having a plurality of electrodes, the sense network being configured to generate a plurality of position detection signals in response to a touch event on the sense surface, the capacitive sensing system further including one or more processors and memory storing instructions for execution by the one or more processors; detecting noise in the plurality of position detection signals associated with the plurality of electrodes; comparing the detected noise in the plurality of position detection signals to a first noise threshold value; and for each of the plurality of position detection signals; in accordance with a determination that the detected noise in the respective position detection signal is greater than the first noise threshold value, determining that the touch event occurs on or proximate to a subset of electrodes corresponding to the respective position detection signal, and providing an extended scan and local noise filtering to process the respective position detection signal, wherein local noise filtering removes local noise caused on the respective subset of electrodes by the touch event; and in accordance with a determination that the detected noise in the respective positon detection signal is not greater than the first noise threshold value, providing a standard scan and non-local noise filtering to process the respective position detection signal; wherein the extended scan includes a larger number of sample operations or lasts a longer duration than those of the standard scan. - View Dependent Claims (13, 14, 15, 16)
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17. A non-transitory computer readable storage medium storing one or more programs configured for execution by one or more processors, the one or more programs comprising instructions for:
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at a capacitive sensing system including a sense network with a sense surface having a plurality of electrodes, the sense network being configured to generate a plurality of position detection signals in response to a touch event on the sense surface, the capacitive sensing system further including one or more processors and memory storing instructions for execution by the one or more processors; detecting noise in the plurality of position detection signals associated with the plurality of electrodes; comparing the detected noise in the plurality of position detection signals to a first noise threshold value; and for each of the plurality of position detection signals; in accordance with a determination that the detected noise in the respective position detection signal is greater than the first noise threshold value, determining that the touch event occurs on or proximate to a subset of electrodes corresponding to the respective position detection signal, and providing an extended scan and local noise filtering to process the respective position detection signal, wherein local noise filtering removes local noise caused on the respective subset of electrodes by the touch event; and in accordance with a determination that the detected noise in the respective positon detection signal is not greater than the first noise threshold value, providing a standard scan and non-local noise filtering to process the respective position detection signal; wherein the extended scan includes a larger number of sample operations or lasts a longer duration than those of the standard scan. - View Dependent Claims (18, 19, 20)
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Specification