Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Bandwidth Extension of Narrowband Speech for Low Bit-Rate Wideband
  Coding   Wireless telephone speech is usually limited to the 300-3400 Hz band, which
reduces its quality. There is thus a growing demand for wideband speech systems
that transmit from 50 Hz to 8000 Hz. This paper presents an algorithm to
generate wideband speech from narrowband speech using as low as 500 bits/s of
side information. The 50-300 Hz band is predicted from the narrowband signal. A
source-excitation model is used for the 3400-8000 Hz band, where the excitation
is extrapolated at the receiver, and the spectral envelope is transmitted.
Though some artifacts are present, the resulting wideband speech has enhanced
quality compared to narrowband speech.

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The categories of this paper are: dg-ga
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The categories of this paper are: astro-ph
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The categories of this paper are: eess
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The categories of this paper are: hep-lat
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The categories of this paper are: nucl-ex
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The categories of this paper are: nucl-th
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The categories of this paper are: chao-dyn
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The categories of this paper are: nlin
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The categories of this paper are: atom-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: gr-qc
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The categories of this paper are: math-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: supr-con
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The categories of this paper are: hep-ex
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The categories of this paper are: chem-ph