An analog-to-digital converter for a multi-channel signal acquisition system, a signal acquisition system, a method of generating a digital output code from an analog input signal, and a method of converting a plurality of analog signals to a digital signal are provided. The system and method modifies already existing display technology, including using the underlying structure of many types of existing displays as the touch detecting structure. An algorithm sets forth the method comprising misalignment correction, chromatic aberration correction, and power shift correction due to differences between aberration measurement wavelength and peak vision wavelength, and differences between aberration measurement location and aberration correction location.