ATSC 3.0 Overview – Hitachi Kokusai Electric Comark LLC

ATSC 3.0

Transitioning to the Future with ATSC 3.0

ATSC 3.0 and FCC repacking will cross paths during the next few years and Hitachi-Comark has been working hard to deliver products and technologies that are on point and ready for deployments.

After involvement with live ATSC 3.0 demos at the CES-2015 and NAB-2015 shows, Hitachi-Comark released the EXACT exciter at NAB-2015. EXACT-V2 features “DualCast” technology that is easily upgraded via firmware from ATSC 1.0 to 3.0; protecting investment today for use tomorrow. 

ATSC 3.0 is more than just the RF signal and associated physical layer. It requires the DTV broadcast station to implement several processing functions as indicated in the block diagram below. Note that IP networking has been specified throughout ATSC 3.0 and replaces traditional MPEG-2 transport stream interfaces used in ATSC 1.0 networks. Additional information on the specifics of ATSC 3.0 can be found in the ATSC 3.0 whitepaper.

ATSC 3.0 Starter Package

ATSC 3.0 Starter is an integrated solution available for broadcasters to easily and quickly migrate a DTV station from MPEG-2 ATSC 1.0 workflow to ATSC 3.0. ATSC 3.0 Starter includes HEVC encoding {SD, HD, and UHD programs}, the Broadcast Gateway, and a simple user interface for system configuration. ATSC 3.0 Starter works seamlessly with the EXACT-V2 ATSC 3.0 exciter that is used throughout the Hitachi-Comark DTV transmitter product line. Finally, the QoS-1000 RF testing and monitoring solution is now available with the latest ATSC 3.0 software. Hitachi-Comark’s end-to-end ATSC 3.0 solution is comprehensive and affordable. Download the latest brochure on ATSC 3.0 Starter.

DTV Power Amplifier De-rating with ATSC 3.0

In addition to the IP networked capabilities that ATSC 3.0 will bring to the broadcast industry, impacts to your DTV transmitter plant need to be considered. The table to the right provides a quick overview of the estimated RF output power difference when converting a DTV transmitter from ATSC 1.0 (8VSB) to ATSC 3.0 (OFDM). Why do amplifiers need to be de-rated? The answer lies in the fact that VSB and OFDM have different peak to average power ratios. And since DTV output power is always measured in average watts, the amplifier’s peak power capability limits the average. So when converting a DTV transmitter from 8VSB (6dB peak to average) to ODFM (8 to 10dB peak to average), the peak power must be taken into account.

RF Plant Considerations with ATSC 3.0

Beyond the DTV transmitter that you operate (or plan to replace) other factors should be considered when migrating to ATSC 3.0. These factors are primarily geared towards the transmission line, antenna, and tower structure however it could also impact filters and combiners. To take full advantage of ATSC 3.0, DTV stations should consider transmit antennas that use either Circular Polarization (50% H-Pol with 50% V-Pol) or Elliptical Polarization (70% H-Pol with 30% V-Pol or something similar). Adding a vertical component to your transmit antenna has proven to aid mobile services and deep indoor signal penetration. Remember that ERP is based only on the H-Pol power, therefore a higher power transmitter may be required (2x in the case of Circular Pol) should you decide to add a vertical component for ATSC 3.0.

Most important with ATSC 3.0 is the power handling capability of the mask filter ® transmission line ® transmit antenna. Remember that ATSC 3.0 will have peak power levels 10dB (x10) above the average power of the transmitter output. ATSC 3.0 will also have a wider bandwidth than ATSC 1.0 using 97% of the allocated spectrum compared to 90% for ATSC 1.0. A standard bandpass filter that is tuned for the correct channel should be capable of either format however an ATSC 1.0 sharp tuned filter or channel combiner may have problems with ATSC 3.0. And while reviewing the power handling of the hardware that runs up and is mounted on the top of the tower; remember that the tower should be reviewed for wind loading and compliance with the most recent issues of EIA/TIA engineering standards.

Single Frequency Network with ATSC 3.0

ATSC 3.0 supports both high power – high tower deployments as well as Single Frequency Network (SFN) deployments. We begin by asking the simple question, “What is an SFN?” A Single Frequency Network (SFN) is made up of two or more transmitters simultaneously broadcasting the same time synchronized signal over the same frequency to achieve greater signal coverage and reception. “Why would a Broadcaster want to implement an SFN system?” SFN’s allow broadcasters to more completely “blanket” of RF coverage to their target market. Adding second, third, fourth transmitters in SFN mode in conjunction with a main transmitter can significantly increased signal reception in targeted areas. Consider SFN design parameters including “sparse” SFN transmitter placement and their associated antenna patterns.

 

 

 

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ATSC 3.0 Whitepaper

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