CA2301994C - High quality speech coder at low bit rates - Google Patents

Abstract

In a speech coder, a spectral parameter computer obtains a plurality of spectral parameters from an input speech signal and quantizes the obtained spectral parameters. Even at low bit rates, the speech coder requires relatively less computational effort and experiences less sound quality deterioration.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A speech coder comprising a spectral parameter computer for obtaining spectral parameters from an input speech signal and quantizing the spectral parameters thus obtained, an impulse response computer for computing impulse responses corresponding to the spectral parameters, a first correlation computer for computing correlations of the input signal and the impulse response, a second correlation computer for computing correlations among the impulse responses, a first pulse data computer for computing positions of first M1 pulses, wherein M1 >= 2 from the outputs of the first and second correlation computers, a third correlation computer for correcting the output of the first correlation computer by using the output of the first M1 pulse data computer, and a second pulse data computer for jointly computing positions of second M2 pulses, wherein M2 >= 2, from the output of the third and second correlation computers, the pulse data computation being made by executing the correlation correction and the pulse data computation iteratedly a predetermined number of times.