Various systems and methods for implementing frequency domain adaptive motion cancellation filters. An example method includes receiving an optical signal representative of a physiological function. The example method further includes receiving a motion signal from an accelerometer. From the motion signal, a known motion spectrum is expressed as a sum of a product of coefficients for each component of the motion spectrum, wherein the coefficients are representative of the strength of the coupling between the motion signal and the optical signal. The example method may further include determining the coefficients of the motion spectrum using gradient descent and generating a decontaminated optical signal based on the optical signal and the motion model spectrum. Other systems, apparatuses, and methods are described.
