IP電話和3G手機的寬帶語音編碼的機遇和挑戰(英文PDF 6)

Introduction
The proliferation of IP telephones and the approaching roll out of 3G wireless handsets
have created a tremendous opportunity to provide better than toll-quality audio
performance in the “new” packet-based telephone network. This better than toll-quality
sound is achieved by using the capabilities of the data network that is not limited to
8-KHZ sampling rate (~4-KHZ pass-band) present in the existing telephone network.
The availability of inexpensive DSPs that can compress wide bandwidth signals for
transmission over the packet network is also a reason why this capability is becoming
feasible today.
The wideband vocoders and the challenges to their implementation is the topic of this
paper. We will survey the standardized wideband vocoders and discuss the current
state of the art and where they are heading. Also, we will discuss the system
implications and some of the roadblocks to widespread use.
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