Vector quantisation of wideband transform coefficient time trajectories in speech coding

A number of methods to perform efficient dynamic bit allocation to perceptually important parameters in the frequency domain results from the combination of vector quantisation techniques and wideband transform coding. Time trajectories of transform coefficients and of magnitude and phase-derivative coefficients are used as vectors for vector quantisation. Speech coders implementable in single DSPs with external memory, having short delay and high robustness to bit stream distortions have been developed