Usage

[outsig, fc] = dau1996_preproc(insig,fs);
[outsig, fc] = dau1996_preproc(insig,fs,...);

Input parameters

Warning: This code is incorrect, the Dau 1996 models uses a transmission-line model from Strube 1985, while this code erroneously uses the gammatone filters. If/when the Strube model is included in AMToolbox, this function will be fixed.

dau1996_preproc(insig,fs) computes the internal representation of the signal insig sampled with a frequency of fs Hz as described in Dau, Puschel and Kohlrausch (1996a).

[outsig,fc]=dau1996_preproc(...) additionally returns the center frequencies of the filter bank.

The Dau 1996 model consists of the following stages:

1. a gammatone filter bank with 1-erb spaced filtes.
2. an envelope extraction stage done by half-wave rectification followed by low-pass filtering to 1000 Hz.
3. an adaptation stage modelling nerve adaptation by a cascade of 5 loops.
4. a modulation low pass filter liming modulations to below 50 Hz.

Any of the optinal parameters for auditoryfilterbank, ihcenvelope and adaptloop may be specified for this function. They will be passed to the corresponding functions.

The model implemented in this file is not identical to the model published in Dau et. al. (1996a). An overshoot limit has been added to the adaptation stage to fix a problem where abrupt changes in the input signal would cause unnaturally big responses. This is described in Dau et. al. (1997a).