An energy extrapolation-based concealment algorithm for an erased excitation signal

We propose an energy extrapolation-based concealment algorithm for an excitation signal of a CELP decoder. In the concealment algorithm, adaptive codebook excitation is generated to maintain continuity of excitation energy on consecutive frames, and high-frequency regions are replaced with random excitation processed through a high-pass filter. The cut-off frequency of the filter is switched according to mode information. The algorithm was implemented on the 3GPP AMR standard decoder, and its performance was compared with that of the standard algorithm. Listening test results suggested that improved subjective quality was produced by the new algorithm.