Patent ID: 7813931
Filing Date: 2010-10-12
Classification: G10L

Abstract:
1. A method of improving intelligibility of a speech signal comprising: identifying a frequency passband having a passband lower frequency limit and a passband upper frequency limit; defining a threshold frequency within the frequency passband that generally preserves a tone quality and pitch of a received speech signal; receiving the speech signal, the speech signal having a frequency spectrum, a highest frequency component of which is greater than the passband upper frequency limit; compressing a portion of the speech signal frequency spectrum in a first frequency range between the threshold frequency and the highest frequency component of the speech signal into a frequency range between the threshold frequency and the passband upper frequency limit; and normalizing a peak power of the compressed portion of the speech signal by an amount that is based on an amount of compression in the frequency range between the threshold frequency and the passband upper frequency limit, where the act of normalizing comprises reducing the peak power by an amount proportional to an amount of compression in the frequency range between the threshold frequency and the passband upper frequency limit.