Patent Document ID: 4519085
Application ID: 06423726
Patent Flag: 1

Claim One:
1. A differential digital data coding-decoding process reducing propagation of transmission errors, comprising the steps of: (A) coding a signal to be transmitted, said coding including the steps of : (a) quantizing a forecasting error between a digital quantity to be coded, and a forecast value of said digital quantity, calculated on the basis of reconstructed previous values of said digital quantity, (b) quantizing the forecast value and (c) assigning a code word, selected from 2.sup.k (where k is an integer) code words, to the quantized forecasting error, the code word being based at least in part on the quantized forecast value, (B) transmitting the assigned code word, and (C) receiving the transmitted code word and, decoding it, the decoding including the steps of (a) deducing from the code word received the corresponding forecast error and forecast value, then (b) deducing the corresponding reconstructed value for a forecast calculated in substantially the same way as for coding, from reconstructed previous values, the forecasting error being calculated during decoding, on the basis of the quantized forecast, a transmission error which during decoding causes an error in a corresponding quantized forecast value for a following value being compensated for calculation of the forecasting error, which takes this quantized forecast into account.