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 # [scipy.signal](https://docs.scipy.org/doc/scipy/reference/signal.html) -- Butterworth low, high and band-pass
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 ## Goal
 
 Sometimes we need to remove of frequency range from a time series. For this we can use a Butterworth filter [scipy.signal.butter](https://docs.scipy.org/doc/scipy/reference/generated/scipy.signal.butter.html) and the [scipy.signal.filtfilt](https://docs.scipy.org/doc/scipy/reference/generated/scipy.signal.filtfilt.html) command.