Patent ID: 9552823
Date: 2017-01-24
CPC Classifications: G10L

Claim:
1. Apparatus for generating a frequency enhancement signal, comprising: a signal generator for generating an enhancement signal from a core signal, the enhancement signal comprising an enhancement frequency range not comprised in the core signal, wherein a time portion of the enhancement signal comprises one or more subband signals for single subband or a plurality of subbands; a synthesis filterbank for generating the frequency enhanced signal using the enhancement signal, wherein the signal generator is configured for performing an energy limitation in order to make sure that the frequency enhanced signal acquired by the synthesis filterbank is so that an energy of a higher band is, at the most, equal to an energy in a lower band or is greater than the energy of the lower band, at the most, by a predefined threshold, wherein the signal generator is configured to generate the plurality of subband signals of the enhancement signal by mirroring a plurality of subbands of the core signal, and wherein the signal generator is configured to perform the mirroring based on the following equations: wherein Qr(t,f) is a real value of a subband signal at a time-index t and subband-index f, wherein Qi(t,f) is an imaginary value of a subband signal at a time index t and the subband index f, wherein xover is a subband referring to a crossover frequency, and wherein nBands is an integer number of bands to be reconstructed, wherein at least one of the signal generator and the synthesis filterbank comprises a hardware implementation.