Patent ID: 8015001

Claim:
A signal encoding apparatus comprising: a spectral transformation unit that transforms an input time domain audio signal per preset unit time to a frequency domain spectral signal; a normalization unit that receives the frequency domain spectral signal from the spectral transformation unit and (a) generates a plurality of normalized spectral signals by selecting a like plurality of normalization factors having a preset step width with respect to each of a plurality of spectral signal bands and normalizing the spectral signal through use of a selected normalization factor, and (b) generates a normalization factor index by converting the normalization factor per normalized spectrum; a range conversion unit that receives the normalized spectral signals from the normalization unit and converts the amplitude range of the normalized spectral signals to generate range-converted spectral signals; a quantization accuracy determining unit that receives the range-converted spectral signals from the range conversion unit and adds a weighting factor per range-converted spectral signal to a normalization factor index used for the normalization and determining quantization accuracy of each normalized spectral signal based on the result of addition; a quantization unit that quantizes each normalized spectral signal according to the quantization accuracy determined by the quantization accuracy determining means to generate a quantized spectral signal; and an encoder that generates code strings by encoding each quantized spectral signal, the normalization factor index, and weight information on the weighting factor, wherein, the spectral transformation unit is in direct communication with the encoding to supply information regarding the number of spectral signals generated to the encoding means, the normalization unit is in direct communication with the encoding means and the quantization accuracy determining means to supply information regarding the normalization factor index to the encoding means and the quantization accuracy, and the quantization accuracy determining unit is in direct communication with the encoding means to supply said weight information on the weighting factor to the encoding means.