Abstract:
|
Recently, 4G mobile phone systems have been
designed to process wideband speech signals whose
sampling frequency is 16 kHz. However, most part of
mobile and classical phone network, and current 3G
mobile phones, still process narrowband speech signals
whose sampling frequency is 8 kHz. During next future,
all these systems must be living together. Therefore,
sometimes a wideband speech signal (with a bandwidth up
to 7,2 kHz) should be estimated from an available
narrowband one (whose frequency band is 300-3400 Hz).
In this work, different techniques of audio bandwidth
extension have been implemented and evaluated. First, a
simple non-model-based algorithm (interpolation
algorithm) has been implemented. Second, a model-based
algorithm (linear mapping) have been designed and
evaluated in comparison to previous one. Several CMOS
(Comparison Mean Opinion Score) [6] listening tests show
that performance of Linear Mapping algorithm clearly
overcomes the other one. Results of these tests are very
close to those corresponding to original wideband speech
signal. |