Patent ID: 7483758

Claim:
Method for obtaining an envelope adjusted and frequency-translated signal by high-frequency spectral reconstruction, of complex subband signals in channels within a reconstruction range using complex subband signals in source area channels derived from a lowband signal, using a digital filter bank having an analysis part and a synthesis part, the reconstruction range including channel frequencies which are higher than frequencies in the source area channels, the method: filtering the lowband signal by means of the analysis part to obtain of the complex subband signals in the source area channels; calculating a number of consecutive complex subband signals in channels within the reconstruction range using a number of frequency-translated consecutive complex subband signals in the source area channels and an envelope correction for obtaining a predetermined spectral envelope, using the following equation: v M+k ( n )= e M+k ( n ) v M−S−P+k ( n ), wherein M indicates a number of a channel of the synthesis part, the channel being a start channel of the reconstruction range, wherein S indicates the number of source area channels, S being a integer greater than or equal to 1 and lower than or equal to M, wherein P is an integer offset greater than or equal to 0 and lower than or equal to M−S; wherein v i indicates a band pass signal v for a channel i of the synthesis part, wherein e i indicates an envelope correction for a channel i of the synthesis part to obtain the desired spectral envelope, wherein n is a time index, and wherein k is an integer index between zero and S−1, wherein a complex subband signal in a source area channel having an index i is frequency-translated to a complex subband signal in a reconstruction range channel having an index j, and wherein a complex subband signal in a source area channel having an index i+1 is frequency-translated to a complex subband signal in a reconstruction range channel having an index j+1; and filtering the consecutive complex subband signals in channels within the reconstruction rage by means of the synthesis part to obtain an envelope adjusted and frequency translated signal.