| Summary: | 碩士 === 國立交通大學 === 電信研究所 === 85 === Packet communication increases the utilization efficiency of
channel capacity by exploiting the bursty nature of voice
traffic. Depending upon the contents of speech packets,
numerous recovery techniques have been proposed to combat the
packet loss due to channel impairments or excessive delay.
Most previous research has emphasized the pissing packet
recovery techniques for PCM and DPCM coded speech. When using a
DM encoder, however, the missing samples in the discarded
packets cannot be reconstructed by zero-amplitude stuffing or
waveform substitution techniques. In this thesis, we show that
the packet loss effects of DM system or using a tree search
interpolation. In this work, we first provide experimental
results for EDM coding of speech sources under packet loss
conditions. For the tree search interpolation, we explore
the benefits of delayed decoding by using an interpolative DM
code generator to form a tree of sample possibilities given the
remaining adjacent samples.
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