Abstract
Traditionally, real-time generation of spectro-temporally modulated noise has been performed on a linear amplitude scale, partially due to computational constraints. Experiments often require modulation that is sinusoidal on a logarithmic amplitude scale as a result of the many perceptual and physiological measures which scale linearly with exponential changes in the signal magnitude. A method is presented for computing exponential spectro-temporal modulation, showing that it can be expressed analytically as a sum over linearly offset sidebands with component amplitudes equal to the values of the modified Bessel function of the first kind. This approach greatly improves the efficiency and precision of stimulus generation over current methods, facilitating real-time generation for a broad range of carrier and envelope signals.
Highlights
Spectro-temporal modulation (STM) is of great interest in psychoacoustics and auditory physiology because of its relevance to speech decoding1–3 as well as the broad applicability of the modulation-based linear-systems approach to parametric investigations
Investigations involving STM have used a variety of modulator shapes and carrier types
Computational constraints and the relative simplicity of its form, many studies use STM with a modulation envelope that is sinusoidal on a linear amplitude scale
Summary
Spectro-temporal modulation (STM) is of great interest in psychoacoustics and auditory physiology because of its relevance to speech decoding as well as the broad applicability of the modulation-based linear-systems approach to parametric investigations. An inherent feature of any finite, practical auditory filter (like that of the human auditory system) is some degree of frequency selectivity Given any such auditory filter and using noise composed of stationary, uncorrelated tones, a tone-density sensitivity threshold exists above which the system is insensitive to further increases in tone density.. The fact that complex stimuli can be represented as a linear sum of simple carrier tones has long been appreciated (and exploited) It allows for the leveraging of powerful mathematical technology, like the discrete Fourier transform (DFT), to generate stimuli much more rapidly than could otherwise be done. Conceptual model helps establish a common framework in which linear and exponential modulations can be developed and compared without unnecessarily constraining how they are applied
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
