Patent ID: 7127389

Claim:
A speech decoder comprising: a spectrum reconstructor operative to reconstruct the spectrum of a speech segment from the amplitude envelope of the spectrum of said speech segment and pitch information; a phase combiner operative to reconstruct the complex spectrum of said speech segment from said reconstructed spectrum, phase information describing said speech segment, and pitch information describing said speech segment; a delay operative to store a complex spectrum of a previous speech segment; and a segment aligner operative to: determine the relative offset between said complex spectrum of said speech segment and the complex spectrum of said previous speech segment; align the position of the first pitch excitation of said current speech segment to the last pitch excitation of said previous speech segment; and apply a time shift and a complex Hilbert filter to said complex spectra, wherein said segment aligner is operative to cross-correlate said complex spectra as C ⁡ ( τ ) = ∑ n = 0 N ⁢ F n ⁢ G _ m ⁢ ⅇ - 2 ⁢ ⁢ π ⁢ ⁢ ⅈ ⁢ ⁢ n ⁢ ⁢ τ , m = ⌊ n ⁢ p G p F + 0.5 ⌋ . where F h , and G m are the computed complex magnitude of the pitch harmonics n and m of the current and previous spectra respectively, and p F and p G are their corresponding pitch periods.