Wideband signal transmission system

摘要

Described is a transmission system ( 10 ) comprising a transmitter ( 12 ) for transmitting a narrowband audio signal to a receiver ( 14 ) via a transmission channel ( 16 ). The receiver ( 14 ) comprises a frequency domain bandwidth extender ( 18 ) for extending a bandwidth of the received narrowband audio signal by complementing the received narrowband audio signal with a highband extension thereof. The bandwidth extender ( 18 ) comprises an amplitude extender ( 24 ) for extending the bandwidth of an amplitude spectrum of the received narrowband audio signal by mapping narrowband amplitudes onto highband amplitudes. The bandwidth extender ( 18 ) further comprises a phase extender ( 26 ) for extending the bandwidth of a phase spectrum of the received narrowband signal and a combiner ( 28 ) for combining the extended amplitude spectrum and the extended phase spectrum into a bandwidth extended audio signal. The transmission system ( 10 ) is characterized in that the amplitude extender ( 24 ) comprises an amplitude mapper ( 42 ) and first and second frequency scale transformers ( 40,44 ). The first frequency scale transformer. ( 40 ) is arranged for transforming a linear frequency scale of the amplitude spectrum into a logarithmic frequency scale, e.g. the Bark scale. The amplitude mapper ( 42 ) is arranged for mapping according to the logarithmic frequency scale the narrowband amplitudes onto the highband amplitudes. The second frequency scale transformer ( 44 ) is arranged for transforming the logarithmic frequency scale of the extended amplitude spectrum into the linear frequency scale.