November 2, 2009
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FCC Publishes Test Results for Coupon-Eligible Converter Boxes

The Federal Communications Commission (FCC) Laboratory conducted a test program on behalf of the National Telecommunications and Information Administration (NTIA) to determine if a converter box met the criteria to be included in the program. They tested 136 models, and found that 116 of these met the minimum performance criteria (some after resubmission). The FCC Laboratory performed about 300 tests related to NTIA requirements on each of the models. In addition to the pass/fail tests; the FCC Laboratory performed measurements of paired-interferer rejection performance on each converter box model to contribute to knowledge of interference vulnerabilities caused by third-order intermodulation (IM3) in the DTV tuners.

The FCC determined that there were 13 different brands of demodulator chips used.

The report asserts that:
"The tested RF reception performance characteristics were:

  • Sensitivity (i.e., minimum RF input signal at the threshold at which the TV picture begins to degrade);
  • Ability to tolerate phase noise and burst noise;
  • Ability to reject interference from;
    • a single NTSC signal on co-and adjacent-channels
    • a single DTV signal on adjacent and taboo channels, and
    • a pair of DTV signals at channel offsets that place third-order intermodulation (IM2) products in the channel to which the converter box is tuned
  • Multipath rejection performance (single static echo and field ensembles);
  • RF pass-through performance on converter boxes that were equipped with RF pass-through capability.

    The other functionalities that were tested included the following:
  • Image decoding (ability to decode 36 combinations of digital picture resolutions, interlacing, and frame rates);
  • Ability to process and display certain Program and System Information Protocol (PSIP) data;
  • Parental control (V-chip) functions, including ability to adapt to changes in the rating system through downloadable ratings tables;
  • Caption pass-through to the connected analog television (on line 21)."


    • The report is organized into chapters. Chapter 1 has the introduction. Chapters 2 through 6 present performance data for the 116 converter box models that were approved. The chapter titles in the report are:
  • "Chapter 2 - RF performance test results including dynamic range, susceptibility to phase noise and burst noise, interference susceptibility (including paired DTV interferers), and RF pass-through performance;
  • Chapter 3 - Multipath performance test results including receiver performance against laboratory-generated single static echoes and performance with the 50 ATSC-recommended field ensembles;
  • Chapter 4 - variations in RF performance as a function of tuner implementation (single or double conversion);

  • Chapter 5 - variations in RF performance as a function of RF pass-through implementation (no pass through, switched/unamplified pass through, and amplified pass through); and
  • Chapter 6 - power-consumption.


    • The report also provided other chapters as follows:
  • Chapter 7 describes the failures of 92 converter box models that initially failed one or more tests; in cases where requirements or standards were unclear, the test criteria that were applied in the converter box program are identified.
  • Chapter 8 lists characteristics that were judged to be functional deficiencies in some converter boxes, but for which available rules and standards documents provided no specific basis for pass/fail thresholds; these are provided for possible consideration by standards committees when relevant standards are being revised.
  • Chapter 9 discusses lessons learned regarding DTV receiver testing.

  • Chapter 10 summarizes the findings of the report."

    • This 202-page report contains a significant quantity of data, showing performance is generally improved over earlier models. Many plots are provided with the assessment of the state of the art that the results indicate. The ability to handle the RF captures is perhaps the most meaningful finding; however, one of the more interesting findings was the much increased echo range as compared to the initial range of some early receivers. The results show the limits of range were not found for all devices as the testing was only from -50 µs to +50 µs; so some chips have even more range/level capability. Another finding was that dynamic range has generally increased by raising the maximum power level while reducing minimum power needed for detection. The multipath figure below is one of many graphical presentations in the report.



    The full report is at: http://www.fcc.gov/oet/info/documents/reports/9TR1003-ConverterBoxTestReport.pdf.


    NAB's Graham Jones Receives SMPTE Award
    Graham Jones, Director of Communications Engineering in the NAB Science and Technology Department, received the "2009 Citation of Outstanding Service to the Society" from the Society of Motion Picture and Television Engineers (SMPTE) at their Conference in Los Angeles last week. He was recognized for his exceptional service to the Society most particularly for his support of the activities and membership of the Washington, D.C. section of SMPTE. Graham also serves on the SMPTE Board of Governors as Governor of the Eastern region.Graham is shown in the photo to the left receiving his award from Kenneth Fuller, President of SMPTE














    2009 ATSC Seminar on Audio Loudness
    Wednesday, November 4, 2009
    Wiley Rein Conference Center
    1776 K St, NW
    Washington, DC 20006
    http://www.atsc.org/seminars/loudness09.php
    Cost for ATSC members is $50.00 for pre-registrants, $75.00 on-site.

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