Testing Wander on Practical Transmission Systems

In this paper, we address practical wander measurements, which are usually regarded as less important than the jitter ones, though sometimes unjustifiably, as wander, if accumulated steadily, can seriously harm the bit-error-rate performance. With this respect, we firstly present the mechanisms of jitter and wander generation in digital transmission systems, and then provide an overview of standard functions that quantify these impairments according to relevant ITU-T recommendations, primarily focusing wander, which is usually regarded as less important than jitter and so sometimes neglected though its excessive values, too, can harm the transmission performance. Measurements were accomplished on live 155 Mbit/s SDH microwave radio-relay transmission system, encompassing 4 hops. The analysis of the obtained wander test results well reflects the health of the synchronization system.