Harmonic coding of speech at 4.8 kb/s
Edward C. Bronson, D. Carlone, Willem Bastiaan Kleijn, Kevin M. O'Dell, Joseph Picone, David L. Thomson · 2005
This paper describes a new speech coding technique which yields improved speech quality over existing 2.4 kb/s LPC vocoders. The method is computationally efficient and operates at a data rate of 4.8 kb/s. Each speech frame is initially classified as voiced or unvoiced. Unvoiced frames are synthesized using a linear predictive coding filter with noise or multipulse excitation. Voiced frames are synthesized using a sum of sinusoids. The frequency of each sinusoid is defined by peaks in the frequency spectrum. A new interpolation technique provides a computationally efficient method of locating the spectral peaks. A real-time, fully quantized version has been implemented in hardware.