Investigating the Use of Asymmetric Windows in CELP Vocoders

Dinei A. Florencio

Abstract

The behavior of several windows in relation to time delay

and spectral estimation is analyzed in its application

to CELP coders, with emphasis on time delay considerations.

From the data, the importance of Asymmetric

Windows in such context becomes evident. In

order to get objective conclusions, we have used a perceptually

weighted residual energy as the comparison

criteria. It is shown that a reduction in delay of up to 8

ms can be obtained with no penalty in quality, simply

with the correct choice of the window. Application to

the military CELP standard, and considerations about

the choice of asymmetric windows for other CELP implementations

are also included.

Details

Publication typeInproceedings
Published inICASSP
PublisherIEEE SPS
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