The ATSC has published its candidate standard for automatic power control of ENG transmitters over data return link bands created as part of the re-farmed TV broadcast auxiliary service between 2025MHz and 2110MHz and is seeking comment on the specification from members and non-members of the organization.
As part of the relocation of TV BAS operations to 2GHz, the FCC allocated two 500kHz swaths of spectrum for digital return link (DRL) use. Each is divided into 20 25kHz wide channels. The DRL channels allow communications between ENG receive-only sites and ENG trucks for automatic transmitter power control. Additionally, the channels can be used for two-way data communications, camera intercom and control functions.
The ATSC candidate standard for Automatic Transmitter Power Control (ATPC) includes:
· basic system parameters, including modulation type, occupied bandwidth, radiated power, emission mask, and frequency stability;
· protocols and signaling;
· operational issues, including data transmitted, priority of messages and station identification.
According to the ATSC, a major benefit of implementing a digital return link ATPC system is that only the necessary ENG output power to achieve a reliable link is used, which ensures greater efficiency and minimizes the likelihood of interference.
The candidate standard specifies:
· what’s needed to build a DRL system for automatic transmitter control use;
· the mechanisms needed for identification and power control of TV BAS transmitters in automatic or manual modes;
· the transmitter transmission parameters for a DRL system; and
· receiver implementation information.
The ATSC is seeking comment on the candidate standard and expects it to progress to the status of Proposed Standard by Dec. 15.
For more information, visit www.atsc.org.
