Multimode speech coding apparatus and decoding apparatus

摘要

Square sum calculator 603 calculates a square sum of evolution in smoothed quantized LSP parameter for each order. A first dynamic parameter is thereby obtained. Square sum calculator 605 calculates a square sum using a square value of each order. The square sum is a second dynamic parameter. Maximum value calculator 606 selects a maximum value from among square values for each order. The maximum value is a third dynamic parameter. The first to third dynamic parameters are output to mode determiner 607, which determines a speech mode by judging the parameters with respective thresholds to output mode information.