Patent ID: 6272138
Filing Date: 2001-08-07
Classification: H04J

Abstract:
An apparatus for reducing jitter and wander on internetworking between an asynchronous transfer mode (ATM) network and a plesiochronous digital hierarchy (PDH) network, comprising:a timing recovery unit which receives a system clock of the ATM network and divides the system clock to produce a reference clock and a first transmission clock related to the PDH network in order to recover a synchronized clock in the PDH network by using synchronized clock information of a PDH user in an ATM cell stream transmitted from the ATM network;a clock smoother which reduces jitter or wander contained in said first transmission clock and generates a second transmission clock;a segmentation and reassembly device which segments the ATM cell stream transmitted from the ATM network into a PDH data stream and transmits the PDH data stream to the PDH network, or reassembles the PDH data stream transmitted from the PDH network to an ATM cell stream, and receives the reference clock from said timing recovery unit and provides synchronous residual timing stamp codes related to synchronized clock information of the PDH user to said timing recovery block and outputs the PDH data stream containing jitter according to said first transmission clock;a jitter absorber which receives the PDH data stream containing jitter, and reduces the jitter generated in said segmentation and reassembly device and outputs the PDH data stream according to said second transmission clock;a framer which receives said second transmission clock and the PDH data stream in which jitter or wander is reduced, and segments the PDH data stream transmitted from the PDH network into each time slot or reassembles the time slots into the PDH data stream.