February 2006 | NTIA Technical Report TR-06-437
Michael G. Cotton; Robert J. Achatz; Jeffery A. Wepman; Roger A. Dalke
Abstract: This report provides results from tests that measured digital television (DTV) susceptibility to ultrawideband (UWB) interference. A test system was developed to inject interference with known characteristics into a victim receiver and quantitatively measure susceptibility. In this experiment, a C-band satellite DTV victim receiver was injected with Dithered-Pulse (DP), Direct-Sequence (DS), and Multi-Band OFDM (MB) UWB interference. Results showed that the UWB signals could be categorized into three signal sets of common DTV susceptibility behavior. Interestingly, the categorized signals, band-limited by the DTV receiver filter, also had common characteristics. Set 1 consists of signals whose DTV susceptibility and band-limited signal characteristics resemble Gaussian noise. Set 2 consists of signals more deleterious than Gaussian noise interference. Notably, these signals had a wide range of band-limited signal characteristics and susceptibilities. Set 3 consists of a signal that is relatively benign. Results also showed that measurable band-limited characteristics, e.g., burst duration (BD), burst interval (BI), fractional on-time (ζDTV), and peak-to-average ratio (P/A), of the interfering signal are useful for predicting susceptibility. Finally, it was determined that continuous and gated noise signals can be used to emulate the interference effects of DS and MB signals for the DTV victim receiver and operational scenarios tested in this study. This might not be true, however, for testing the susceptibility of other victim receivers operating in narrower bandwidths as indicated by amplitude probability distributions as a function of frequency for MB signals band-limited to relatively narrow bandwidths.
Part 1 of this series was published as NTIA Technical Report TR-05-419 Interference potential of ultrawideband signals: Part 1: Procedures to characterize ultrawideband emissions and measure interference susceptibility of C-band satellite digital television receivers and Part 2 as NTIA Technical Report TR-05-429 Interference Potential of Ultrawideband Signals Part 2: Measurement of Gated-Noise Interference to C-Band Satellite Digital Television Receivers.
Keywords: satellite communications; interference; ultrawideband; digital television (DTV)
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Michael G. Cotton
Institute for Telecommunication Sciences
Disclaimer: Certain commercial equipment, components, and software may be identified in this report to specify adequately the technical aspects of the reported results. In no case does such identification imply recommendation or endorsement by the National Telecommunications and Information Administration, nor does it imply that the equipment or software identified is necessarily the best available for the particular application or uses.