filters.py

from scipy import signal


def filtfilt_lowpass(sig,cutoff,Fs=1,order=5):
    """ Low pass butterworth filt filter
    """
    nyq = np.float(Fs)/2
    cutoffnorm = cutoff/nyq;
    b, a = signal.butter(order,cutoffnorm,btype='low');
    sig = signal.filtfilt(b,a,sig)
    return sig

def filtfilt_highpass(sig,cutoff,Fs=1,order=5):
    """ high pass butterworth filt filter
    """
    nyq = np.float(Fs)/2
    cutoffnorm = cutoff/nyq;
    b, a = signal.butter(order,cutoffnorm,btype='high');
    sig = signal.filtfilt(b,a,sig)
    return sig


def filtfilt_bandpass(sig,lowcut,highcut,Fs=1,order=5):
    """ Band pass butterworth filt filter
    """
    nyq = np.float(Fs)/2
    lowcut = lowcut/nyq
    highcut = highcut/nyq
    
    b, a = signal.butter(order,[lowcut,highcut],btype='band')

    sig = signal.filtfilt(b,a,sig)

    return sig