Switched split vector quantizer applied for encoding the LPC parameters of the 2.4 Kbits/s MELP speech coder

In this paper, we present an optimized switched split vector quantization (SSVQ) scheme developed for low bit-rate encoding of the LPC parameters represented by the line spectral frequencies (LSF). It will be shown that the SSVQ provides better performance in terms of bit-rate, spectral distortion and computational complexity than the traditional split vector quantizer. We further applied our SSVQ encoding system, called LSF-SSVQ encoder, to quantize the LSF parameters of the 2.4 Kbits/s normalised speech coder MELP operating over an ideal noiseless channel.