Abstract: The high performance multiplexed transmission system of this invention is configured by a sound coding unit for coding voice input information by separating it into a core information part for assuring the minimum acceptable sound quality and a supplementary information part discardable in stages per the transmission priorities. There is a silent section detecting unit for detecting silent sections of voice input information. In addition, there is a multiplexing unit for multiplexing only the information synchronizing with the correspondent's coder for the voice channels from which no sound is detected, or first the core information part and second the supplementary information part from the ones with the highest priorities in stages in fixed length frames, for discarding the supplementary information parts, which cannot be multiplexed because of a band deficiency.

Abstract: Coding transmission equipment wherein an plurality of adaptive coding units having different processing characteristics are provided, and the adaptive coding unit having the optimum processing characteristic for a current input signal is selected from among the plurality of adaptive coding units, and an output signal from the optimum adaptive coding unit and the unit number thereof are transmitted to the receiver side. At the receiver side, the processing characteristic of a decoder is changed to become the optimum processing characteristic indicated by the received unit number, whereby a high quality recovered signal is realized.