A wideband noise suppressor for the AMR wideband speech codec

A wideband noise suppressor for the AMR (adaptive multi-rate) wideband speech codec is proposed. The wideband noise suppressor features weighted noise estimation for an accurate noise estimate, pseudo noise injection for more suitable spectral gain, and synthesis windowing for smooth transition at frame boundaries. In the subjective evaluation with the AMR wideband speech codec, the proposed noise suppressor satisfies all eighteen provisional requirements, which was originally standardized for AMR narrowband noise suppressor, in absolute category rating, ten out of twelve provisional requirements in comparison category rating (CCR), respectively. Although it does not meet two requirements in CCR, its basic performance suggests that the proposed wideband noise suppressor is most likely to meet all requirements by the evaluation with 24 listeners specified in the test plan for AMR narrowband noise suppressor.