Broadcast quality video over SDH networks; eradicating sub carrier corruption due to pointers

The Synchronous Digital Hierarchy (SDH) has been developed to meet the demands of future networks in providing a transport infrastructure as a common platform for the building of diverse networks. The largest of these is telephony, but the SDH system was intended to be the backbone for broadband networks such as ATM (asynchronous transfer mode) and broadcast television. This paper examines how the SDH transport system may introduce unacceptably high phase disturbances to video signals carried across it, and looks at the effects these may have on studio equipment. The paper defines a new desynchroniser at the SDH/decoder boundary which controls this phase to within PAL video standards and proposes some basic aspects of building broadcast video networks on SDH transport systems