.. currentmodule:: brian

.. index::
   pair: example usage; tone
   pair: example usage; FunctionFilterbank
   pair: example usage; Gammatone
   pair: example usage; erbspace
   pair: example usage; LowPass
   pair: example usage; whitenoise

.. _example-hears_cochleagram:

Example: cochleagram (hears)
============================

Example of basic filtering of a sound with Brian hears.
This example implements a cochleagram based on a gammatone filterbank
followed by halfwave rectification, cube root compression and 10 Hz
low pass filtering.

::

    from brian import *
    from brian.hears import *
    
    sound1 = tone(1*kHz, .1*second)
    sound2 = whitenoise(.1*second)
    
    sound = sound1+sound2
    sound = sound.ramp()
    
    cf = erbspace(20*Hz, 20*kHz, 3000)
    gammatone = Gammatone(sound, cf)
    cochlea = FunctionFilterbank(gammatone, lambda x: clip(x, 0, Inf)**(1.0/3.0))
    lowpass = LowPass(cochlea, 10*Hz)
    output = lowpass.process()
    
    imshow(output.T, origin='lower left', aspect='auto', vmin=0)
    show()