Joint Signal Processing for Spherical Logarithmic Quantization and DPCM

Abstract:
Spherical logarithmic quantization (SLQ) is a vector quantization method for efficient digitizing analog signals at a high dynamic range as well as a high Signal-to-Noise Ratio (SNR) while preserving the original waveform as close as possible. Short vectors of samples are represented in sphere coordinates while correlations within the source signal are exploited by means of differential pulsecode modulation (DPCM). This paper introduces a solution for combining this vector quantization scheme with DPCM in the sense of a stepwise spherical quantization which results in an extreme reduction of computational effort with respect to the state of the art. Moreover an optimum indexing of the quantization cells covering the surface of a multidimensional unit sphere is presented for both the encoder and the decoder side.