Single and double frame quantization of LSF parameters using noise feedback coding
A.R. Fazel, Amir Keyvan Khandani · 2002
We present a scheme for single frame (20 msec) and double frame (40 msec) quantization of line spectral frequency (LSF) parameters in a code-excited linear prediction (CELP) speech coder using noise feedback coding. To improve the performance, an appropriate lattice structure is used as the quantizer in the noise feedback loop. We also consider a switched structure based on using either a double frame quantizer or two single frame quantizers for two subsequent frames where an extra bit is used to specify the choice offering a lower distortion. Numerical results are presented showing an excellent performance with very low complexity.