Abstract: According to an embodiment, the transmission processor of the master terminal includes a sending/receiving processor which sends a synchronization request demanding packet to a particular slave terminal and sends a synchronization reply packet when receiving a synchronization request packet from the slave terminal that has received the synchronization request demanding packet, and a synchronization controller which calculates a synchronization band from the time of the receipt of the data packet and from time information added to the received data packet to determine a synchronization state and which adjusts a correction amount in accordance with the synchronization state and sends an internal timing correction command to the timing generator.

Abstract: According to an embodiment, the transmission processor of the master terminal includes a sending/receiving processor which sends a synchronization request demanding packet to a particular slave terminal and sends a synchronization reply packet when receiving a synchronization request packet from the slave terminal that has received the synchronization request demanding packet, and a synchronization controller which calculates a synchronization band from the time of the receipt of the data packet and from time information added to the received data packet to determine a synchronization state and which adjusts a correction amount in accordance with the synchronization state and sends an internal timing correction command to the timing generator.

Abstract: The present invention provides a digital voice communication apparatus and method capable of suppressing noise even when error data has occurred in digital voice communications. A data receiving unit divides received data into ADPCM frame data and outputs the same together with frame error information about an error of each ADPCM frame data. A G. 726 decoder performs decoding defined in G. 726 of the ITU-T recommendation to convert the ADPCM frame data to PCM system-based data and outputs the same data to a Claw error correction processing unit. When no error is contained in the frame data, the ?-law error correction processing unit outputs the inputted frame data to a G. 711 decoder as it is. When the error is contained in the frame data, the ?-law error correction processing unit sets a substitution range, based on maximum and minimum values of normal frame data located immediately before the frame data and substitutes the error-contained frame data with data lying within the substitution range.