Abstract
A multi-channel model, describing the effects of spectral and temporal
integration in amplitude-modulation detection for a stochastic noise
carrier, is proposed and validated. The model is based on the modulation
filterbank concept which was established in the accompanying paper
Dau et al., J. Acoust. Soc. Am. 102, 2892–2905 (1997) for modulation
perception in narrow-band conditions (single-channel model). To integrate
information across frequency, the detection process of the model
linearly combines the channel outputs. To integrate information across
time, a kind of ‘‘multiple-look’’ strategy, is realized within the
detection stage of the model. Both data from the literature and new
data are used to validate the model. The model predictions agree
with the results of Eddins J. Acoust. Soc. Am. 93, 470–479 (1993)
that the ‘‘time constants’’ associated with the temporal modulation
transfer functions ~TMTF! derived for narrow-band stimuli do not
vary with carrier frequency region and that they decrease monotonically
with increasing stimulus bandwidth. The model is able to predict
masking patterns in the modulation-frequency domain, as observed
experimentally by Houtgast J. Acoust. Soc. Am. 85, 1676–1680 (1989).
The model also accounts for the finding by Sheft and Yost J. Acoust.
Soc. Am. 88, 796–805 (1990) that the long ‘‘effective’’ integration
time constants derived from the data are two orders of magnitude
larger than the time constants derived from the cutoff frequency
of the TMTF. Finally, the temporal-summation properties of the model
allow the prediction of data in a specific temporal paradigm used
earlier by Viemeister and Wakefield J. Acoust. Soc. Am. 90, 858–865
(1991). The combination of the modulation filterbank concept and
the optimal decision algorithm proposed here appears to present a
powerful strategy for describing modulation-detection phenomena in
narrow-band and broadband conditions.
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