Abstract
Low bitrate audio coding is an enabling technology for a number of applications such as digital radio, Internet streaming and mobile multimedia applications. Using perceptual codecs at low bitrates however has disadvantages. Below 128 kbps, the perceived audio quality deteriorates significantly because of the limited bandwidth and often creates annoying artifacts. Spectral Band Replication (SBR) is a technique that significantly improves the compression efficiency of perceptual audio codecs and the quality of audio, by reconstructing the high frequency components of an audio signal on the decoder side. The missing fundamental is a phenomenon exhibited by a sound when the overtones suggest a fundamental frequency but the sound lacks a component at the fundamental frequency itself. This concept could be used to create a low frequency pitch perception in small speakers, which do not actually have the capabilities to reproduce such low frequencies. This thesis is an attempt to combine these two techniques (SBR and missing fundamental) to improve the quality of audio in portable audio devices.