GammatoneBank

The GammatoneBank implements a bank of gammatone filters. The number of filters in the bank is given by the parameter NUM_CHANS. These filters are arranged on either an ERB, a Mel, or a linear scale between a lower and upper centre frequency given by the parameters LOWER and UPPER respectively.

For every sample arriving at the input a vector of dimensionality NUM_CHANS is produced at each of the four output sockets. The vector output at out1 samples the instantaneous envelope for each channel; out2 is a simulation of basilar membrane displacement; out3 if the instantaneous frequency and out4 is the amplitude modulation frequency.

Inputs	Meaning	Sample	1-D frame	2-D frame
in1	input sample data	Yes	No	No

Outputs	Meaning
out1	instantaneous envelope
out2	basilar membrane displacement
out3	instantaneous frequency
out4	AM frequency

Parameters	Type	Default	Meaning
NUM_CHANS	Integer	64	Number of gammatone filter channels
LOWER	Float	50.0	Centre frequency of lowest frequency channel
UPPER	Float	5000.0	Centre frequency of highest frequency channel
SCALE	{ERB, MEL, LINEAR}	ERB	The frequency scale on which to space the filters