Multi-pulse type encoder having a low transmission rate
AssigneeNEC Corporation
InventorTetsu Taguchi
Life of this patent
Estimating the term…
Abstract
In an encoder for encoding a speech signal having a spectrum envelope into a plurality of excitation pulses, a spectrum emphasis unit emphasizes peak components of the spectrum envelope to produce an emphasized speech signal. As a result of a spectrum emphasis operation, the emphasized speech signal has an emphasized spectrum envelope which substantially comprises a plurality of line spectra. Responsive to the emphasized speech signal, a pulse producing unit produces a plurality of excitation pulses by the use of a pulse search method.
Claims5
An encoder for use in encoding a speech signal into a plurality of pulse signals, each having an amplitude and a location determined by said speech signal, said speech signal having spectrum envelope which has a plurality of peak components, wherein the improvement comprises:
- parameter calculating means responsive to said speech signal for calculating parameters specific to said spectrum envelope to produce a parameter signal representative of said parameters:
- a spectrum emphasis filter responsive to said speech signal and said parameter signal for emphasizing said peak components of said spectrum envelope to produce an emphasized speech signal in accordance with said parameter signal, said emphasized speech signal having spectrum envelope which substantially comprises a plurality of line spectra;
- and
- pulse producing means coupled to said spectrum emphasis filter for reproducing said plurality of pulse signals in response to said emphasized speech signal.
Dependencies are inferred from the claim text.