Nils Westerlund , pp. 47. Inst för telekommunikation och signalbehandling/Dept. of Telecommunications and Signal Processing, 2000.
Many occupations of today requires the usage of personal
preservative equipment such as a mask to protect the employee from dangerous substances or the usage of a pair of ear-muffs to damp high sound pressure levels. The goal of this Master thesis is to investigate the possibility of placing a microphone for communication purposes inside such a preservative mask as well as the possibility of placing the microphone inside a persons auditory meatus and perform a digital channel equalization on the speech path in question in order to enhance the speech intelligibility.
Subjective listening tests indicates that the speech quality and intelligibility can be considerably improved using some of the methods described in this thesis.