TAKANEN2013_LSO - Model of the lateral superior olive

Usage:

output = takanen2013_lso(ipsilateral, contralateral, fs, fc);

Input parameters:

`ipsilateral`	The ipsilateral "where" stream output from the model of the periphery
`contralateral`	The contralateral "where" stream output from the model of the periphery
`fs`	sampling rate
`fc`	characteristic frequencies

Output parameters:

output

Spatial cues for separate narrow bandwidths

Description:

This function models the lateral superior olive (LSO) by processing the output of the periphery model with the following steps:

First-order lowpass filter is applied to both the ipsilateral and contralateral sides, and the contralateral side is delayed
The output is saturated at a certain dB level and limited signals.
Weighted moving average filters with a short and longer time constant are applied, the latter only below 1 kHz in order to slow the response

References:

V. Pulkki and T. Hirvonen. Functional count-comparison model for binaural decoding. Acta Acustica united with Acustica, 95(5):883 -- 900, Sept./Oct. 2009.