To improve compression rate when a voice signal is predicted and coded by calculating the difference and a plurality of predicted values from a summation signal and a difference signal of two systems, respectively, and calculating respective prediction residual of the plurality of predicted values and the difference, and selecting a minimum value of these prediction residuals.
An addition circuit and a subtraction circuit calculate sum and difference signals, (L+R), (L-R) of stereo 2 ch signals L, R. Difference arithmetic circuits 11D1, 11D2 calculate present and previous differences Δ(L+R), Δ(L-R) respectively for sample values (L+R), (L-R). For example, for the difference Δ(L+R), prediction apparatuses 12a-1 to 12a-n calculate each predicted value of the difference Δ(L+R) based on each prediction coefficient, and subtracters 13a-1 to 13a-n calculate each prediction residue of this predicted value and the difference Δ(L+R). A buffer/selector 16D1 temporarily stores the prediction residues and selects minimum prediction residue according to designation by a selected signal creator 17.
UENO SHOJI
TANAKA YOSHIAKI
