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Use of wideband DTV overlay signals for brevity signaling and public safety

  • US 6,498,627 B1
  • Filed: 10/21/1999
  • Issued: 12/24/2002
  • Est. Priority Date: 10/21/1999
  • Status: Expired due to Term
First Claim
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1. A brevity signaling module for a digital television (DTV) receiver which is equipped to receive and process a wideband overlay signal used for multipath processing, the brevity signaling module being adapted to enable reception of emergency broadcast messages and comprising:

  • a receiver front end for receiving and detecting the wideband overlay signal;

    a squaring loop for squaring the detected wideband overlay signal detected by the receiver front end to generate a spectral line at 2ω

    , where ω

    =2π

    f and f is the overlay signal center frequency, said squaring loop including a narrow band filter having a bandwidth sufficient to pass a spectrum containing a plurality of tones 2ω

    , 2ω

    1, 2ω

    2, . . . , 2ω

    n, where 2ω

    1, 2ω

    2, . . . , 2ω

    n are different frequency tones assigned to different auxiliary functions;

    tone identification logic to detect, in the spectrum produced by said filter, a transmitted tone corresponding to one of the tones 2ω

    , 2ω

    1, 2ω

    2, . . . , 2ω

    n; and

    a control module responsive to the tone identification logic to determine whether normal multipath processing should be performed or whether multipath processing should be suppressed and auxiliary functions performed.

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