Coherent Envelope Detection for Modulation Filtering of Speech
Steven M. Schimmel, Les Atlas · 2006
Modulation filtering, which has been previously described as several related approaches to achieve modification of speech temporal dynamics, is shown to be less effective than intended. In particular, past Hilbert envelope approaches generate distortion which spreads across frequency sub-bands and modulation rejection is far from the amount intended. The source of this distortion is analyzed and a solution, based upon coherent envelope detection in each sub-band is proposed. This coherent approach is shown to be substantially more effective than conventional incoherent approaches on speech samples.