Non-Orthogonal Touch Demodulation With Decoding Matrices
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Solution Overview
Problem
Existing touch systems face challenges in reducing the signal band when transmitting multiple signals to multiple electrodes, as they require large bandwidth and complex design to maintain orthogonality, which complicates the system's design and increases interference risks.
Innovation Solution
The use of decoding matrices in a non-orthogonal demodulation method to compute energies corresponding to transmitted signals, allowing for the determination of touch event coordinates without the need for orthogonal signals, thereby reducing the signal band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If orthogonal signals are transmitted to multiple electrodes, then signal differentiation is achieved, but signal band increases and design complexity increases
Solution Approach 1:
The patent changes the fundamental parameter of signal orthogonality from frequency separation to spatial coding. Instead of using orthogonal frequencies (which require large bandwidth), the system uses non-orthogonal frequencies combined with decoding matrices that exploit the spatial arrangement of electrodes to differentiate signals. This parameter change allows signal differentiation without requiring large frequency gaps, thus reducing the signal band.
Solution Approach 2:
The patent introduces decoding matrices as an intermediary computational element between signal transmission and signal differentiation. These matrices act as a mediator that processes the mixed non-orthogonal signals from multiple electrodes and separates them into individual signal components. This intermediary approach enables signal differentiation without requiring the signals to be orthogonal in the frequency domain, thereby reducing bandwidth requirements.
2Measurement precision
If orthogonal signals are transmitted to multiple electrodes, then signal differentiation is achieved, but system design complexity increases
Solution Approach 1:
The patent simplifies system design by changing from orthogonal frequency modulation to non-orthogonal frequency modulation with spatial decoding. This parameter change eliminates the need to carefully select and maintain orthogonal frequency pairs, reducing the complexity of frequency planning and signal allocation while still achieving accurate signal differentiation through the decoding matrix approach.
Solution Approach 2:
The decoding matrices serve as a computational intermediary that centralizes the signal differentiation function. Instead of requiring complex orthogonal frequency management across multiple electrodes, the system uses these matrices to handle the separation task in a unified manner, simplifying the overall system architecture and reducing design complexity.
3Area of stationary object
If orthogonal signals are transmitted, then signal band increases, but interference risk increases
Solution Approach 1:
The patent changes the approach to signal separation from frequency-based orthogonality to spatial-based decoding. By using non-orthogonal frequencies with the decoding matrix method, the system reduces the signal band occupation while simultaneously lowering interference risk. The spatial decoding approach inherently handles interference better by considering the geometric relationships between electrodes and signal sources.
Data Source
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AI summary
The present application provides a non-orthogonal demodulation module, receiving a received signal and the received signal is related to a summation of a plurality of transmitted signals. The plurality of transmitted signals are corresponding to a plurality of frequencies, and the plurality of transmitted signals are not orthogonal to each other. The non-orthogonal demodulation module comprises a mixing-and-integrating unit, configured to perform mixing operations and integrating operations on the received signal respectively at the plurality of frequencies, to generate a plurality of in-phase components and a plurality of quadrature components corresponding to the plurality of frequencies; and a decoding unit, configured to generate at least a decoding matrix, and compute a plurality of energies corresponding to the plurality of transmitted signals according to the at least a decoding matrix, the plurality of in-phase components and the plurality of quadrature components.