Electronics Letters, v. 37, issue. 11, page. 724-726
Abstract
The authors propose a predictive pyramid VQ (PPVQ) that uses the safety-net concept
to quantise the LSF parameters of wideband speech. A first-order auto-regressive (AR)
predictor is used to predict the LSF parameters. To quantise the prediction error
signal effectively, a pyramid VQ (PVQ) is used while a memoryless PVQ is used to
encode low-correlation frames. By combining the PPVQ and the memoryless PVQ, denoted
'safety-net pyramid VQ', the advantages of quantisation methods can be utilised.
The average SD value of a safety-net pyramid VQ is 035 dB less than that of a
predictive split VQ (PSVQ). The safety-net pyramid VQ also requires low complexity
and does not require any memory for the codebook storage.