A new line spectrum pair representation for spectral envelope quantization

This paper introduces a new parametric formulation for the line spectrum pairs representation. Due to its robustness against to quantization, LSPs are widely utilized as an alternative of the LPC parameters. In the conventional method, the explicit formula having a fixed order has been employed for computing the LSP parameters where the vocal track information is embedded on. Subsequently, the LSP parameters are quantized into a priori assigned number of bits. To provide the flexibility on bit allocation for the LSP parameters, this paper proposes a new explicit LSP representation such that the spectral envelope component is represented in terms of the reduced number of LSPs without causing any major spectral distortions. This invokes the reduction on the bit allocation for the LSP parameters, and provides the ability of quantizing the spectral envelope at a variable bit rate depending on the characteristics of the framed speech. Simulation results are presented to show the validity of the proposed formulation.