AUDIO SIGNAL ENCODER

摘要

An audio signal encoder comprises a mapping transformation section (11) for subjecting an input audio signal to mapping transformation to generate a frequency range signal the domain of which is frequency, a quantity-of-codes designating section (12) for outputting a preset encoding bit rate as the quantity of codes, a frequency range signal compression-encoding section (13) for compression-encoding the frequency range signal according to the quantity of codes and thereby generating a bit stream, and band limiting section (10) for limiting the band by multiplying the value of the frequency range signal in an attenuation frequency domain which is a part of the frequency domain of the frequency range signal by an attenuation coefficient of 1 or less so as to attenuate the frequency range signal in the attenuation frequency domain and outputting the frequency range signal the band of which is limited to the frequency range signal compression-encoding section. Thus the frequency range signal in a predetermined frequency band is attenuated, and the signal of the frequency band which is not the object of encoding is eliminated with a low degree of computational complexity.