TRANSMISSION BAND CONTROL CIRCUIT

摘要

PROBLEM TO BE SOLVED: To provide a simplified transmission band control circuit for ATM (asynchronous transfer mode) communication where transmission of multiple channel cell is controlled. SOLUTION: A cell transmission-enable times ST of a group of a control object channel stored in a control memory 14 is sequentially read for a time TM outputted from a time counter according to a cell synchronizing signal SY and a difference DF from the time TM is calculated. A transmission discrimination section 17 outputs a transmission-enable channel number AC. A pre- discrimination section 18 stores a channel number that reaches a transmission time within a prescribed time. The stored channel numbers are sequentially shifted by the cell synchronizing signal SY and the result is outputted as a transmission-enable channel number AC from the pre-discrimination section 18 when the transmission time comes. The transmission-enable channel number AC is processed sequentially by a contention discrimination section 19 and the result is given to a memory control section 12 as a transmission channel number SC and a corresponding cell is read from a cell storage memory 13 and transmitted.