CIRCUIT FOR RECOVERING TIME STAMP OF CABLE MODEM

摘要

PURPOSE: A circuit for recovering a time stamp of a cable modem is provided to quickly and accurately synchronize a time stamp of a cable modem using a time stamp received from a CMTS(Cable Modem Termination System). CONSTITUTION: A time stamp error detector(602) obtains a time stamp error from a difference between a time stamp received from a CMTS through a synchronous message and a local time stamp. A loop filter(604) filters an output of the time stamp error detector(602) using a certain filter value and obtains an error average value. A numeral control oscillator(606) receives an output of the loop filter(604) and calculates a certain correction value. A time stamp counter(608) adds the correction value of the numeral control oscillator(606) to the received time stamp or the local time stamp and outputs a time stamp synchronized to the CMTS.