def notch_filter(data, lowcut, highcut, fs, order=5, rs=10):
# Chebyshev notch filter centered on 50Hz
nyquist = fs / 2.0
b, a = filter_design.iirfilter(order,
(lowcut/nyquist, highcut/nyquist),
rs=rs,
ftype='cheby2')
# filter the signal
arrFiltered = filtfilt(b, a, data)
return arrFiltered
Wp = cutoff_hz/nyq_rate # Cutoff frequency
Ws = (cutoff_hz+1.5)/nyq_rate # Stop frequency
Rp = 1 # Ripple in the passband maximum loss (gpass)
As = 42 # Min Attenuation in the stoppand (gstop)
Filters = {'ellip' : (), 'cheby2' : (), 'butter' : (), 'cheby1' : (), 'bessel' : ()}
# The ellip and cheby2 filter design
Filters['ellip'] = fd.iirdesign(Wp, Ws, Rp, As, ftype='ellip')
Filters['cheby2'] = fd.iirdesign(Wp, Ws, Rp, As, ftype='cheby2')
Filters['butter'] = fd.iirdesign(Wp, Ws, Rp, As, ftype='butter')
Filters['cheby1'] = fd.iirdesign(Wp, Ws, Rp, As, ftype='cheby1')
# The bessel max order of 8 for this cutoff, can't use
# iirdesign have to use iirfilter.
Filters['bessel'] = fd.iirfilter(8, Wp, btype='lowpass', ftype='bessel')
## Pass the signal though the filter
velocity = reference_velocity.getAxis(0)
velocityfilter = {'ellip' : (), 'cheby2' : (), 'butter' : (), 'cheby1' : (), 'bessel' : ()}
velocityfilter['ellip'] = sig.lfilter(Filters['ellip'][0], Filters['ellip'][1], velocity)
velocityfilter['cheby2'] = sig.lfilter(Filters['cheby2'][0], Filters['cheby2'][1], velocity)
velocityfilter['butter'] = sig.lfilter(Filters['butter'][0], Filters['butter'][1], velocity)
velocityfilter['cheby1'] = sig.lfilter(Filters['cheby1'][0], Filters['cheby1'][1], velocity)
velocityfilter['bessel'] = sig.lfilter(Filters['bessel'][0], Filters['bessel'][1], velocity)
#################
### GRAPHICS ###
#################
plt.figure(4)
def filter_50Hz(sample):
# Chebyshev notch filter centered on 50Hz
nyquist = FREQ / 2.
b, a = filter_design.iirfilter(3, (49. / nyquist, 51. / nyquist), rs=10, ftype='cheby2')
sample_50Hz = filtfilt(b, a, sample)
return(sample - sample_50Hz)
print(name)
dset = f['signal_1/sig']
print(dset)
print(dset.shape)
# print dset.type
# frequence d'echantillonage en Hz
freq = 250
length_acquisition = dset.shape[0] / (freq*60) # in minutes
print("the acquisition is ", length_acquisition, " minutes long")
plt.plot(dset)
plt.ylabel('Louis Gauche Raw signal')
plt.show()
# Chebyshev notch filter centered on 50Hz
nyquist = freq / 2.
b, a = filter_design.iirfilter(3, (49. / nyquist, 51. / nyquist), rs=10,
ftype='cheby2')
# filter the signal
print("filtering ...")
x50 = filtfilt(b, a, dset)
xfilt = dset - x50
plt.plot(xfilt, label='50Hz bandpass-filtered')
plt.show()
#print (str(audio_data[m])+" "+str(audio_output[m])+" "+str(absolute[m])+"\n")
if order==3:
for m in range(0, length_audio_data):
audio_output[m]=audio_data[m-3]-3*a_cong*audio_data[m-2]+3*(a_cong**2)*audio_data[m-1]-(a_cong**3)*audio_data[m]+(a**3)*audio_output[m-3]-3*(a**2)*audio_output[m-2]+3*a*audio_output[m-1]
absolute[m]=np.absolute(audio_output[m])
absolute[m]=absolute[m].astype(int)
audio_input[m]=audio_data[m]
------------------------------------------------------------------------
if order==4:
for m in range(0, length_audio_data):
audio_output[m]=audio_data[m-4]-4*(a_cong)*audio_data[m-3]+6*(a_cong**2)*audio_data[m-2]-4*(a_cong**3)*audio_data[m-1]+(a_cong**4)*audio_data[m]-(a**4)*audio_output[m-4]+4*(a**3)*audio_output[m-3]-6*(a**2)*audio_output[m-2]+4*a*audio_output[m-1]
absolute[m]=np.absolute(audio_output[m])
audio_input[m]=audio_data[m]
if order==5:
for m in range(0, length_audio_data):
audio_output[m]=audio_data[m-5]-5*(a_cong)*audio_data[m-4]+10*(a_cong**2)*audio_data[m-3]-10*(a_cong**3)*audio_data[m-2]+5*(a_cong**4)*audio_data[m-1]-(a_cong**5)*audio_data[m]+(a**5)*audio_output[m-5]-5*(a**4)*audio_output[m-4]+10*(a**3)*audio_output[m-3]-10*(a**2)*audio_output[m-2]+5*a*audio_output[m-1]
absolute[m]=np.absolute(audio_output[m])
audio_input[m]=audio_data[m]
"""
n=17
wp=0.27
ws=0.7
a,b=fd.iirfilter(n,[0.27,0.67],btype='lowpass', ftype='butter')
print(str(a))