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Digital predistortion for amplifiers

  • US 6,304,140 B1
  • Filed: 06/12/2000
  • Issued: 10/16/2001
  • Est. Priority Date: 06/12/2000
  • Status: Expired due to Fees
First Claim
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1. A method for predistorting a digital signal prior to amplification comprising:

  • computing a look-up table using power values of digital input signal samples as look-up values wherein the look-up table is a function of pre-measured calibration data;

    wherein the step of computing comprises;

    determining a set of input power values;

    obtaining the pre-measured calibration data including an output power data value and phase data value of the amplifier corresponding to each of the input power values;

    deriving a set of calibration power values using the output power data values;

    deriving amplitude predistortion calibration values using the calibration power values and the input power values;

    determining phase predistortion calibration values from the phase data values;

    interpolating the calibration power values and corresponding amplitude predistortion calibration values to provide amplitude predistortion values;

    interpolating the calibration power values and corresponding phase predistortion calibration values to provide phase predistortion values; and

    wherein the look-up table is computed from the amplitude predistortion values and the phase predistortion values; and

    applying the look-up table to digital input signals for producing the predistorted signal;

    wherein, the amplitude predistortion values and the phase predistortion values are polar values, the method further comprising;

    translating the amplitude predistortion values and the phase predistortion values from polar values to Cartesian values.

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