Quantifying and Exploiting Speech Memory for the Improvement of Narrowband Speech Bandwidth Extension

to Dina, Hana, and the hometown of Euclid ii iii Since its standardization in the 1960s, the bandwidth of traditional telephony speech has been limited to the 0.3–3.4 kHz range. Such narrowband speech exhibits not only a quality that is noticeably inferior to its wideband counterpart, but also reduced intelligibility espe-cially for consonant sounds. Wideband speech reconstruction through artificial bandwidth extension (BWE) attempts to regenerate the highband frequency content above 3.4 kHz in the receiving end, thereby providing backward compatibility with existing networks. Al-though BWE has been the subject of considerable research, BWE schemes have primarily relied on memoryless mapping to capture the correlation between narrowband and high-band spectra. In this thesis, we investigate exploiting speech memory—in reference to the long-term information in segments longer than the conventional 10–30ms frames—for the purpose of improving the cross-band correlation central to BWE