Application of weighing matrices to simultaneous driving technique for capacitive touch sensors

This paper generalizes the capacitive touch sensing problem in a form of weighing matrices which cover Walsh-Hadamard, 4k-order Hadamard, and other types of weighing matrices. The existing regular Hadamard matrix, conference matrix, and other matrices that have a small sum of column weights, increase the signal sensitivity as well as signal-to-noise ratio for the capacitive signals. Experiments show that the proposed design approach and the various types of weighing matrices can meet the different design requirements. The results of this research show that a sophisticated weighing matrix improves sensitivity three times higher than the time-multiplexed method.