INTERFERENCE ESTIMATION AND ADAPTIVE RECONFIGURATION OF A CAPACITIVE TOUCH CONTROLLER
First Claim
1. A method for reconfiguring a capacitive touch controller, the method comprising:
- detecting a triggering event for reconfiguring the capacitive touch controller;
measuring a received signal from a capacitive touch panel;
determining an auto-correlation of the received signal;
determining a transmit frequency for stimulating the capacitive touch panel, where the transmit frequency is based on the auto-correlation of the received signal;
determining a filter transfer function for rejecting interference from a subsequently received signal, where the filter transfer function is based on the auto-correlation of the received signal;
stimulating the capacitive touch panel using the transmit frequency; and
filtering a subsequently received signal using the filter transfer function.
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Accused Products
Abstract
Adaptive reconfiguration of a capacitive touch controller is implemented by estimating the interference spectrum of the signal received by the touch controller. The spectrum of the received signal is used to determine a desired frequency, and the touch panel transmitter is configured to use that desired frequency. The spectrum of the received signal is also used to determine an desired filter transfer function. A filter in the touch panel received signal path is configured to use that desired filter transfer function. The adaptive reconfiguration is focused on improving the signal to noise ratio of the received signal without the need for shielding the touch panel, performing additional scans of the touch panel, or using components that operate at higher power levels.
38 Citations
20 Claims
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1. A method for reconfiguring a capacitive touch controller, the method comprising:
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detecting a triggering event for reconfiguring the capacitive touch controller; measuring a received signal from a capacitive touch panel; determining an auto-correlation of the received signal; determining a transmit frequency for stimulating the capacitive touch panel, where the transmit frequency is based on the auto-correlation of the received signal; determining a filter transfer function for rejecting interference from a subsequently received signal, where the filter transfer function is based on the auto-correlation of the received signal; stimulating the capacitive touch panel using the transmit frequency; and filtering a subsequently received signal using the filter transfer function. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A capacitive touch controller comprising:
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a detector configured to detect a triggering event for reconfiguring the capacitive touch controller; a signal processor configured to measure a received signal from a capacitive touch panel of the capacitive touch controller and determine the auto-correlation of the received signal; a frequency processor configured to determine a transmit frequency for stimulating the capacitive touch panel, where the transmit frequency is based on the auto-correlation of the received signal; a filter processor configured to determine a filter transfer function for rejecting interference from a subsequently received signal, where the filter transfer function is based on the auto-correlation of the received signal; a transmitter configured to stimulate the capacitive touch panel using the transmit frequency; and a filter configured to apply the filter transfer function to a subsequently received signal. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A portable data processing device comprising:
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a video display; a capacitive touch panel; a control circuit operative to provide signals to the video display to produce images on the video display and operative to detect touch interactions with the capacitive touch panel, the control circuit including a capacitive touch controller comprising; a detector configured to detect a triggering event for reconfiguring the capacitive touch controller; a signal processor configured to measure a received signal from the capacitive touch panel of the portable data processing device and determine the auto-correlation of the received signal; a frequency processor configured to determine a transmit frequency for stimulating the capacitive touch panel, where the transmit frequency is based on the auto-correlation of the received signal; a filter processor configured to determine a filter transfer function for rejecting interference from a subsequently received signal, where the filter transfer function is based on the auto-correlation of the received signal; a transmitter configured to stimulate the capacitive touch panel using the transmit frequency; and a filter configured to apply the filter transfer function to a subsequently received signal. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification