Patent ID: 7668711
Filing Date: 2010-02-23
Classification: G10L

Abstract:
1. A coding equipment which generates a coded signal that includes information for generating a signal at a high-frequency range by replicating a signal at a low-frequency range, the ranges being segments in a time direction and in a frequency direction, said coding equipment comprising: a high-frequency tone-to-noise ratio calculation unit operable to (i) calculate, by linear prediction processing, the tone components and the noise components which are included in the signal at the segmented high-frequency range, and (ii) calculate, using the calculated tone components and the noise components, a high-frequency tone-to-noise ratio that is a ratio of an energy sum of the tone components to an energy sum of the noise components at the high-frequency range, the tone having signal components that exist intensely at a specific frequency range and the noise having signal components that exist regardless of frequency range; a low-frequency tone-to-noise ratio calculation unit operable to (i) calculate, by linear prediction processing, the tone components and the noise components which are included in the signal at the low-frequency range corresponding to the high-frequency range, the low-frequency range being to be replicated at the high-frequency, and (ii) calculate, using the calculated tone components and the noise components, a low-frequency tone-to-noise ratio that is a ratio of an energy sum of the tone components to an energy sum of the noise components in the signal at the low-frequency range corresponding to the high-frequency range; an adjustment coefficient calculation unit operable to calculate an adjustment coefficient which is used to adjust tonal characteristics of the signal at the low-frequency range to be replicated at the high-frequency range, based on the high-frequency tone-to-noise ratio and the low-frequency tone-to-noise ratio; and an encoding unit operable to generate the coded signal that includes the calculated adjustment coefficient.