Samsung Electronics Co., Ltd.

Hong-kook Kim

Moo-young Kim

Yong-duk Cho

Sang-ryong Kim

Kee-eun Oh

An apparatus for quantizing a spectral envelope with noise robustness showing high performance even under a background noise environment and a channel noise environment, and a method therefor, are provided. The spectral envelope quantizing apparatus includes a spectral envelope quantizing apparatus with noise robustness for representing a spectral envelope of speech by a minimum number of bits for the optimal coding of a speech signal. The apparatus includes a line spectrum frequencies (LSFs) input portion for converting linear predictive coding coefficients extracted from the speech into Nth order line spectrum frequencies coefficients and inputting the coefficients as the LSFs of a current frame. It also includes a linked split-vector quantizing portion for dividing the LSFs into a predetermined number of linked sub-vectors and quantizing the sub-vectors, and a predictive linked split-vector quantizing portion for obtaining the difference between the LSFs and the LSFs of a previous frame and vector-quantizing the difference. The apparatus further includes an error selector for comparing the error values of the LSFs quantized in the linked split-vector quantizing portion and the predictive linked split-vector quantizing portion, selecting the codebook index of the quantized LSFs having the smaller error value, and outputting the selected codebook index together with a mode bit.

Apparatus for quantizing spectral envelope including error selector for selecting a codebook index of a quantized LSF having a smaller error value and method therefor

In a voice coding and decoding method and apparatus using an RCELP technique, a CELP-series decoder can be obtained at a low transmission rate. A voice spectrum is extracted by performing a short-term linear prediction on voice signal. An error range in a formant region is widened during adaptive and renewal codebook search by passing said preprocessed voice through a formant weighting filter and widening an error range in a pitch on-set region by passing the same through a voice synthesis filter and a harmonic noise shaping filter. An adaptive codebook is searched using an open-loop pitch extracted on the basis of the residual minus of a speech. A renewal excited codebook produced from an adaptive codebook excited signal is searched. Finally, a predetermined bit is allocated to various parameters to form a bit stream.

Voice coding and decoding method and device therefor

A method for generating a random code book having a characteristic similar to a periodic component of voice in code-excited linear predictive (CELP) coding. The method includes generating an adaptive code book that removes the periodic component of a current subframe of a speech signal. An adaptive code book array is generated with respect to the current subframe on the basis of an optimal delay and gain obtained in generating the adaptive code book. A number of code word arrays are generated from the adaptive code book array and the excited signal of the immediately previous subframe. A code word that has the maximum value is selected from each code word array generated in the code word array generating step. Each code word array is normalized using the selected code word. The normalized maximum value in each code word array is selected and scaled by the power of the most previous frame. A random code book including a set of the scaled selected maximum values is generated. The method for generating a random code book generates a random code book using adaptive code book information, and, as a result, has the effect of providing improved synthesized sound compared with a conventional CELP coder.

Growing community of inventors

Suwon, South Korea

Hong-kook Kim