# -*- coding: utf-8 -*-
"""
Created on Wed Feb 14 03:37:26 2018

@author: fakher
"""
from scipy.signal import butter, lfilter
#filter
def butter_lowpass(cutoff, fs, order=5):
    nyq = 0.5 * fs
    normal_cutoff = cutoff / nyq
    b, a = butter(order, normal_cutoff, btype='low', analog=False)
    return b, a

def butter_lowpass_filter(data, cutoff, fs, order=5):
    b, a = butter_lowpass(cutoff, fs, order=order)
    y = lfilter(b, a, data)
    return y

def bandpass_filter(self, data, lowcut, highcut, signal_freq, filter_order):
        nyquist_freq = 0.5 * signal_freq
        low = lowcut / nyquist_freq
        high = highcut / nyquist_freq
        b, a = butter(filter_order, [low, high], btype="band")
        y = lfilter(b, a, data)
        return y




