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System and method for communicating data using constant amplitude equalized waveform

  • US 7,508,884 B2
  • Filed: 03/24/2005
  • Issued: 03/24/2009
  • Est. Priority Date: 03/24/2005
  • Status: Active Grant
First Claim
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1. A system for communicating data, which comprises:

  • a transmitter for transmitting a communications signal that carries communications data, and including an encoder for encoding the communications data with a forward error correction code, a single interleaver for interleaving the encoded communications data in a serial data stream, a data randomizer that extracts bits from the interleaver corresponding to the communications data and processes the extracted bits with a random bit sequence, a combining circuit for combining the communications data processed with the random bit sequence with known symbols into frames, and a modulator for mapping the framed communications data from the combining circuit into minimum shift keying or Gaussian minimum shift keying (MSK or GMSK) symbols based on a specific mapping algorithm without spread spectrum modulation to form a communications signal having a constant amplitude MSK or GMSK waveform over which the communications data can be transmitted; and

    a receiver for receiving the communications signal from the transmitter, and including a filter that is matched to a main pulse of the MSK or GMSK waveform and a block or symbol equalizer for equalizing the communications signal, and further comprising a block or symbol equalizer and a clamping circuit operative for clamping received communications data symbols of the communications signal to a real symbol (+/−

    1 ) or an imaginary symbol (+/−

    j) such that odd communications data symbols are clamped to a one of the real symbols or the imaginary symbols and even communications data symbols are clamped to the other one of the real symbols or the imaginary symbols depending on the starting phase of MSK or GMSK.

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