US Patent 10126870 Techniques for mitigating noise in capacitive sensing devices

Disclosed herein are techniques for reducing certain types of noise in capacitive sensing devices. The techniques generally comprise utilizing a low-pass filter in conjunction with a comb filter to “zero out” frequency components associated with certain types of noise. More specifically, the comb filter is configured to zero out noise associated with the fundamental frequency and harmonics of noise that approximates a square wave or an impulse train. The frequency of the sensing signal for capacitive sensing is chosen such that the comb filter does not zero out such frequency.