The Advanced Television Systems Committee has approved a standard designed to facilitate the construction of single frequency network (SFN) transmission systems using distributed transmission.
The new standard defines the mechanisms for synchronization of transmitters emitting 8-VSB signals in accordance with the ATSC DTV Standard (A/53C). It also provides for adjustment of transmitter timing and other characteristics through additional information carried within the specified packet structure.
Distributed transmission involves the use of a separate distribution channel to feed each transmitter in an SFN. This channel can be a conventional studio-to-transmitter link (STL) for distributed transmitters, or it can be a different broadcast channel from that on which the transmitters operate, in the case of distributed translators.
Distributed transmission (DTx) holds the potential to improve the coverage and service areas of DTV transmission, said ATSC president Mark Richer. The ATSC is developing a companion Recommended Practice for the design of synchronized multiple transmitter networks.
ATSC Standard A/110 can be downloaded from www.atsc.org/standards.html. Among other things, it explains the general concept of distributed transmission and offers particulars on synchronization methods.
