Algorithm for improving SNR using high voltage and differential Manchester code for capacitive touch screen panel

An algorithm for a capacitive touch screen panel that can make the sum of the signal into `0´ for the use of high voltage is presented. The differential Manchester code is combined with the Walsh-Hadamard code to generate an input coded signal. Owing to the property of the differential Manchester code, the Moore-Penrose pseudoinverse matrix is employed to decode-mutual capacitance from the received signal. As only the variation between the un-touch and touch condition is detected at the receiver, a high-voltage input coded signal is used. Unlike a normal touch system, the decoded sensing capacitance in the proposed algorithm does not have an absolute value. Positive decoded capacitance is the un-touch condition and negative decoded capacitance is the touch condition. The simulated signal-to-noise ratio (SNR) of the proposed algorithm is 27.9 dB, which is 8.26 dB higher than SNR in not return to zero (NRZ).