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Predistortion circuit for a power amplifier

  • US 4,465,980 A
  • Filed: 09/23/1982
  • Issued: 08/14/1984
  • Est. Priority Date: 09/23/1982
  • Status: Expired due to Fees
First Claim
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1. An RF predistortion circuit for an RF power amplifier which, as a function of the power level of an RF input signal, has non-linear gain and phase shift characteristics for a signal passing therethrough, comprising in combination:

  • a circuit input terminal to which may be applied an RF input signal of time-varying power;

    a dual gate FET including a first gate, a second gate, a drain and source, one of the latter two of which is coupled to said RF amplifier;

    an inductive matching network coupled between the circuit input terminal and first gate; and

    means coupled between the circuit input terminal and second gate for applying to said second gate a signal which is a function of the power level of said input signal for varying the gain through said FET of the RF signal in response to the input signal to compensate for the non-linear gain characteristics of said RF amplifier and wherein the combination of said inductive matching network and signal from the signal applying means varies the phase of the signal passing through said FET to compensate for said phase non-linearity in the RF amplifier.

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