Note
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Linear Gammachirp filters¶
Example of the use of the class LinearGammachirp
available
in the library. It implements a filterbank of FIR gammatone filters with linear
frequency sweeps as described in Wagner et al. 2009, “Auditory responses in the
barn owl’s nucleus laminaris to clicks: impulse response and signal analysis of
neurophonic potential”, J. Neurophysiol. In this example, a white noise is
filtered by a gammachirp filterbank and the resulting cochleogram is plotted.
The different impulse responses are also plotted.
from brian2 import *
from brian2hears import *
sound = whitenoise(100*ms).ramp()
sound.level = 50*dB
nbr_center_frequencies = 10 #number of frequency channels in the filterbank
#center frequencies with a spacing following an ERB scale
center_frequencies = erbspace(100*Hz, 1000*Hz, nbr_center_frequencies)
c = 0.0 #glide slope
time_constant = linspace(3, 0.3, nbr_center_frequencies)*ms
gamma_chirp = LinearGammachirp(sound, center_frequencies, time_constant, c)
gamma_chirp_mon = gamma_chirp.process()
figure()
imshow(gamma_chirp_mon.T, aspect='auto')
figure()
plot(gamma_chirp.impulse_response.T)
show()
Total running time of the script: ( 0 minutes 0.268 seconds)