Sensor Panel Frequency-Domain Interference Mitigation for Touch Accuracy
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Solution Overview
Problem
Existing sensor panels face difficulties in accurately detecting touch inputs due to impulse noise and tone interference, which can lead to incorrect position calculations and reduced detection accuracy, especially when using a stylus or pen.
Innovation Solution
The implementation of a sensor panel control module that converts received signals from the time domain to the frequency domain and processes them using clipping or blanking techniques to mitigate the effects of impulse noise and tone interference, employing Hadamard orthogonal frequency division multiplexing (OFDM) to improve signal processing and reduce peak-to-average power ratio (PAPR).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional time domain signal processing is used in sensor panels, then the device complexity is low, but the measurement precision deteriorates due to impulse noise and tone interference
Solution Approach 1:
The patent replaces traditional time-domain signal processing methods with frequency-domain processing using Fast Fourier Transform (FFT). This substitution enables effective mitigation of impulse noise and tone interference by identifying and removing interfering frequency components, thereby improving touch input detection accuracy while maintaining manageable system complexity through well-established FFT algorithms.
2Measurement precision
If signal distortion techniques are applied to mitigate noise, then the measurement precision improves, but the loss of information increases due to signal distortion
Solution Approach 1:
The patent extracts and removes only the specific interfering components (impulse noise and tone interference) from the frequency spectrum while preserving the rest of the signal. By identifying interfering frequency components and selectively eliminating them through spectral subtraction or nulling, the method improves measurement precision without applying broad signal distortion that would cause information loss.
3Reliability
If higher signal processing power is used to mitigate interference, then the reliability improves, but the use of energy increases
Solution Approach 1:
The patent transforms the signal processing approach by changing from time-domain to frequency-domain analysis using FFT. This parameter change enables more efficient interference mitigation because frequency-domain processing allows for targeted removal of interfering components without requiring excessive computational power, thus improving reliability while controlling energy consumption through algorithmic efficiency.
Data Source
AI summary
An electronic device is described which has a sensor panel comprising a plurality of receive electrodes configured to measure signals received from one or more transmit electrodes. The device has a sensor panel control module configured to: receive signals from the plurality of receive electrodes in the presence of at least one tone interferer. The module is configured to convert the received signals from a time domain into a frequency domain; and to process the received signals in the frequency domain in order to mitigate the effect of the tone interferer.