It was clear transmitter manufacturers wanted to be considered part of the ATSC Mobile DTV roll-out. Even manufacturers that didn't have a working Mobile DTV transmitter or exciter were promising one soon. Broadcasters will have many choices when it comes to ATSC Mobile DTV products. While Harris and Rohde and Schwarz were the only ones with their exciters used in over-the-air demonstrations at the NAB show, expect to see products from other manufacturers before the big Mobile DTV roll out late this year. This wide support from multiple vendors is one reason ATSC Mobile DTV is not the video version of AM stereo. There is one format and manufacturers are rallying around it.
In addition to a choice of manufacturers, stations will also have a choice in the way they get the signal to the exciters and distributed transmission system (DTS) transmitters. Harris and Axcera use the ATSC A/110 protocol for DTS. Rohde and Schwarz uses its system which takes advantage of the A/153 candidate standard to synchronize transmitters. Grass Valley (formerly Thomson, Thales, etc.) combines the conventional ATSC signal with a separate ATSC Mobile DTV signal delivered over an IP connection at the transmitter site. They have not selected a method for implementing DTS.
The availability of exciters from many manufacturers with a wide range of features bodes well for the future of Mobile DTV.
