Axcera | DTxA2B - Distributed Transmission Adaptor for Distributed Transmitter Networks, Distributed Translator Networks

Distributed Transmission Adaptor

Axcera’s distributed transmission network solution consists of the DTxA2B Distributed Transmission Adaptor, two or more slave transmitters with GPS receivers for precise reference, as well as system design, coverage analysis and integration services. This approach allows multiple signals to be broadcast in overlapping coverage areas on the same channel using the ATSC candidate standard for distributed transmission.

To achieve the necessary synchronization, the DTxA2B accepts a SMPTE 310M data stream with embedded placeholder packets and outputs a modified SMPTE 310M stream. The modified stream includes cadence sync for system timing and distributed transmission packets that contain all of the information necessary to operate the network.

The signal is then transported to the slave transmitters through a standard digital studio-to-transmitter link. The slaves accept the modified SMPTE 310M stream and respond to the cadence sync and distributed transmission packets, synchronizing their symbols, timing and pilot frequencies. Frequency synchronization and timing reference is achieved through GPS receivers at each location.

In cases where two or more channel frequencies are available, the main transmitter can serve as the transport mechanism for the modified SMPTE 310M signal, eliminating the need for separate STLs for each site. The main transmitter, on a unique channel, serves two purposes: 1 to broadcast the main signal to the city-of-license or primary coverage area and 2 to transport the SMPTE 310M signal to the slave transmitters. All translators can then broadcast synchronously, using distributed transmission to share a second channel.

With proper system design, standard consumer DTV receivers will successfully decode the synchronized signals, treating the time-displaced signals from multiple transmitters as simple multipath. When compared to the historical single-site broadcast model, Axcera’s distributed transmission solutions provide an innovative approach to improving coverage and can even reduce power bills.