Statistical Block Protection Coding for DPCM-Encoded Speech
Robert JC Steele, Nuggehally S. Jayant, C. E. Schmidt · Bell System Technical Journal · 1979
Blocks of speech-carrying dpcm bits are protected from transmission errors by means of explicit communication of two block statistics–the maximum and the root-mean-square (rms) values of the adjacent-sample differences in the dpcm-quantized speech. At the receiver, the maximum value is used as a cue for error-detection, white the rms value is used for a partial waveform correction procedure that provides intelligible speech at bit error rates as high as 10 percent.