Patent ID: 7379479

Claim:
A communication apparatus comprising: a receiving unit that receives a processed data packet including a first time stamp; a first computation unit that computes a second time stamp for the processed data packet received on a network, the second time stamp computed by determining an arrival time of the processed data packet based on a first count value of clock pulses synchronized to an asynchronous clock signal of the network, and comparing the first count value with synchronization information associated with the processed data packet; a second computation unit that computes a third time stamp, the third time stamp computed by removing a time shift between an internal reference clock and the second time stamp, wherein the internal reference clock is not synchronized to the asynchronous clock of the network; and a renewal unit that replaces the first time stamp in the processed data with the third time stamp; wherein the synchronization information is computed based on a phase difference between an asynchronous clock of a different network and the first time stamp associated with the processed data packet.