DC offset estimation and compensaton for wideband systems

Systems, methods, and other embodiments associated with a DC notch gear filter are described. According to one embodiment, an apparatus includes a digital high pass filter having a cutoff frequency and a gear mechanism configured to successively change the cutoff frequency of the high pass filter based on a sequence of cutoff frequencies. The apparatus also includes a direct current (DC) estimator configured to estimate a DC offset of a digital input signal to the high pass filter based, at least in part, on an output signal of the high pass filter as a cutoff frequency is successively changed. A direct current (DC) compensator is configured to subtract the estimated DC offset from the input signal to the high pass filter.