Complexity reduction methods for vector excitation coding

Vector Excitation Coding (VXC) is based on a new and general source-filter modeling technique in which the excitation signal for a speech production model is encoded at very low bit-rates using vector quantization. Various speech coder structures which fall into this class have recently been shown to reproduce speech with very high perceptual quality. The primary drawback of VXC is the large amount of computation required in the process of selecting an optimal excitation signal. We present several schemes in this paper which substantially reduce search computation in VXC coders while retaining their remarkably high reconstructed speech quality.