TELEPHONE SYSTEM AND CONFERENCE SPEECH PROCESSING CIRCUIT THEREOF

摘要

PROBLEM TO BE SOLVED: To suppress the prolonging of delay time caused by the arithmetic processing of conference speech processing and to suppress the effects due to the fluctuation of cells concerning a conference speech processing circuit for telephone system to use an asynchronous transfer mode(ATM) exchange system. SOLUTION: A conference speech processing circuit 14 receives audio data made into ACT cell at an ATM cell receiving part 141, sends them to a received ATM layer processing part 142, processes the ATM header of the ATM cell, selects the required cell, and obtains the data of the selected cell information field. A received ATM adaptation layer(ALL) processing part 143 extracts the audio data of cell units from the data of the cell information field. In addition, the ALL processing part 143 is provided with a fluctuation absorption buffer and sends the audio data of cell units of plural speakers to perform conference speed processing to an arithmetic processing part 144, while synchronizing them. The arithmetic processing part 144 mixes and calculates the audio data of cell units from the plural transmission sources at high speed. The data of the cell information field, including the audio data of the mixed and calculated results, are generated and outputted as the ATM cell, while adding the ATM header.