a capacitive sensing system are configured to sense a capacitance value and convert the sensed capacitance value to a digital format . the capacitive sensing system provides good selectivity and immunity to noise and interference , which can be further enhanced by enabling spread spectrum excitation . in some embodiments , the capacitive sensing system utilizes a sinusoidal excitation signal that results in low electromagnetic emissions , limited to narrow frequency band . in some embodiments , the capacitive sensing system is configured to operate in a spread spectrum mode , in which the majority of the excitation signal power is carried in the assigned bandwidth . the excitation frequency and the bandwidth of the spread spectrum excitation signal are programmable in a wide range , which allows for avoiding frequency conflicts in the operating environment .