| 摘要 |
SYNC parsing for Cable Modem Clock Synchronization is implemented using software processing with hardware assist in a manner that achieves the cost benefits of software SYNC parsing with the time accuracy of hardware SYNC parsing. Hardware scans for the arrival of new MPEG frames. Whenever any MPEG frame arrives, the MPEG frame is processed to extract MAC packets. If a SYNC packet is discovered during this processing, the software determines the SYNC arrival time, a comparison is made between the time the SYNC arrival time and the SYNC time value, and the software uses the difference to adjust the Cable Modem clock. Implementation variations include different approaches to when timestamps are recorded, the calculation of the SYNC arrival time, the use of software to process the MPEG frame and MAC packets, and the use of software to perform the time comparison.
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