Phase deviations on SDH and SDH/PDH interface

The CCITT Rec. G.708 and G.709 specifying synchronous digital hierarchy (SDH) mapping and pointer action have led to a renewed interest in the problems of phase deviations in digital transmission, commonly known as jitter and wander. The concepts of jitter and wander on a plesiochronous digital hierarchy (PDH) network and their resolution are reviewed. Phase errors on a SDH network are then discussed and some are quantatively examined. The main problems of SDH/PDH interfacing are investigated.<<ETX>>