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Method for the transmission of digital data

  • US 4,774,716 A
  • Filed: 12/08/1986
  • Issued: 09/27/1988
  • Est. Priority Date: 01/22/1986
  • Status: Expired due to Fees
First Claim
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1. Method for demodulating received data modulated in a received data signal, said signal being composed of several transmission sections of fixed length, each transmission section having a fixed carrier frequency, which is changing in steps from one transmission section to the next and is modulated by means of m discrete permitted phase values by phase modulation of a carrier frequency, each transmission section containing the data in the form of a plurality of symbols and said signal containing the data to be transmitted plural times, including using different transmission sections for the same data, said method comprising the steps of:

  • determining for each transmission section a mean phase value (φ

    i);

    determining the phase difference (Δ

    φ

    ik) between the symbol phase (φ

    ik) and the mean phase value (φ

    i) of the associated transmission section for each symbol within a transmission section;

    allocating a weighting factor (Wik, Wi'"'"'k'"'"') which functionally depends on the phase difference (Δ

    φ

    ik) multiplied by m/2 and which characterizes the reliability of the transmission, to each symbol;

    selecting the functional dependence of each weighting factor such that ##EQU3## demodulating the received data by first multiplying the symbol values of the symbols by the associated weighting factor (Wik, Wi'"'"'k'"'"') and then forming a linear combination of corresponding weighted symbol values to determine the received data.

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