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Adaptive High-Order Nonlinear Function Approximation Using Time-Domain Volterra Series to Provide Flexible High Performance Digital Pre-Distortion

  • US 20150381216A1
  • Filed: 06/27/2014
  • Published: 12/31/2015
  • Est. Priority Date: 06/27/2014
  • Status: Active Grant
First Claim
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1. A method for predistorting an input signal to compensate for non-linearities of an electronic device that operates on the input signal to produce an output signal, comprising:

  • providing an input circuit for receiving a first input signal as a plurality of signal samples x[n] to be transmitted over a non-linear element;

    providing one or more digital predistortion blocks coupled to the input circuit and generating an output signal y[n] by adaptively modifying the first input signal to compensate for distortion effects in the non-linear element, each digital predistortion block comprising;

    a first delay line for storing a first plurality of signal samples x[n];

    a second delay line for storing a first plurality of amplitude samples A[n] derived from the first plurality of signal samples x[n];

    a plurality of Q predistorter cells, each comprising an input stage multiplier and multiplexer for combining amplitude samples received from the second delay line into a first stage output, a lookup table (LUT) connected to be addressed by the first stage output for generating an LUT output, and one or more output multiplication stages for combining the LUT output with signal samples and amplitude samples received from the first and second delay lines to generate an output signal sample yQ from said predistorter cell; and

    an output adder circuit connected to combine the output signal samples yQ from the plurality of Q predistorter cells into a combined signal; and

    processing the combined signal to generate the output signal y[n] for transmission to the non-linear element.

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