Many sensors have a small analog signal that rides on top of a larger dc pedestal. For these circuits (Fig. 1), the signal must be ac coupled and amplified before it’s digitized. The feedback of an ...

A filter that blocks low frequencies and allows higher frequencies to pass through. Such filters are used in devices such as POTS splitters that direct phone and DSL signals to different lines.

Try looking up Fast Fourier Transforms. That will convert your signal to an array of frequency magnitudes, you can attenuate the lower frequencies, and then reverse-FFT back to the filter signal.