N-of-M coding strategies enhance spectral contrast by retaining only largest-amplitude bands

Evidence

The working principle of the coding strategy can affect speech intelligibility. For example “NofM” strategies such as ACE were developed in the 1990s to separate speech signals into M sub-bands and derive envelope information from each band signal. N bands with the largest amplitude are then selected for stimulation (N out of M). One of the consequences here is that the spectral contrast of the spectrum is enhanced, as only the N maxima are retained for stimulation. — Dijk, Pim van, Physiology, Psychoacoustics and…, 1823

Categorization

• DEFINE: Explains the N-of-M/ACE strategy mechanism that any reading of this chapter depends on.