EXCITATION VECTOR GENERATOR, SPEECH CODER AND SPEECH DECODER

摘要

A noise estimating apparatus estimates two types of noise spectra for removing a noise component using the two types of noise spectra. The noise estimating apparatus includes an A/D converter that converts an input speech signal to a digital signal, and a Fourier transformer that performs a discrete Fourier transform on the digital signal having a predetermined time length to obtain an input spectrum and a complex spectrum. The noise estimating apparatus also includes a noise spectrum storage device that stores the two types of noise spectra, including a mean noise spectrum and a compensation noise spectrum, and a noise estimator that estimates a new compensation noise spectrum and a new mean noise spectrum as new two types of noise spectra.