AUDIO SIGNAL BANDWIDTH EXTENSION

摘要

Described is a transmission system comprising a transmitter for transmitting a narrowband audio signal to a receiver via a transmission channel. The receiver comprises a bandwidth extender 18 for generating a wideband audio signal from the narrowband audio signal. The bandwidth extender 18 comprises spectral folding means 30 for generating a spectrally folded audio signal 33 by spectrally folding at least part of the narrowband audio signal. The transmission system according to the invention is characterized in that the bandwidth extender 18 comprises a noise shaper 32 for generating a shaped noise signal 35 by shaping a noise signal 31 in accordance with at least part of the spectrally folded audio signal 33, and in that the bandwidth extender 18 further comprises a combiner 34 for combining the shaped noise signal 35 and the spectrally folded audio signal 33 into the wideband audio signal. In this way metallic sounds which were introduced by the spectral folding are masked by combining the shaped noise signal 35 with the spectrally folded signal 33.