Adaptive clock method and system

An ATM cell reassembly device having an AAL1 terminator for receiving an ATM cell from each connection through an ATM network for termination, and a shared reassembly buffer memory for accumulating an AAL1 payload of said ATM cell received from said AAL1 terminator for absorbing a delay, said ATM cell reassembly device comprising:

• an accumulated amount aggregating unit for aggregating the amount of said AAL1 payload data accumulated in said reassembly buffer memory for each said connection;
• a target value managing unit for holding a target value for said accumulated amount for each said connection;
• a clock calculating unit for calculating a read clock frequency, said unit is operative for a first connection to receive said accumulated amount from said accumulated amount aggregating unit and said target value from said target value managing unit, respectively, and to start a correction of a read clock in a comparison of said target value with a count value for said accumulated amount when the count value for said accumulated amount reaches said target value, said clock calculating unit operative for second and subsequent connections to compare a total sum of count values for so far corrected connections and a current count value with a total sum of previous target values and a target value for a current connection to correct the read clock frequency;
• a clock restoring unit for restoring said read clock based on the frequency calculated by said clock calculating unit;
• and
• a data reading unit driven by said read clock restored by said clock restoring unit to read said AAL1 payload data from said reassembly buffer memory.