Signal pre-distortion facility for amplifier non-linearity compensation
View Patent ↗A digital pre-distortion system which can provide the flexibility to model the highly non-linear distortion associated with High Efficiency RF Power Amplifiers while through a novel implementation of a least squares estimation process allows an implementation well suited for an FPGA application where limited resources and in particular memory resources are available.
1. A system comprising:
a pre-distorter for introducing distortion into an input signal of an amplifier based on distortion coefficients that are linearly interpolated from coefficients that are retrieved from a lookup table in response to the input signal, and that are generated based on a least squares optimized model of time varying non-linearity characteristics derived from samples of the amplifier output.
2. A system comprising:
a capture facility for digitally capturing signal samples associated with an amplifier;
an estimator facility for estimating the amplifier non-linearity by separating a portion of the digitally captured signal samples into magnitude differentiated groups to form a complex matrix equation that produces a subset of coefficients that define a distortion compensation model; and
a pre-distorter facility for introducing non-linearity into an input signal of the amplifier based on the distortion compensation model.
3. The system of claim 1 , wherein the distortion coefficients are linearly interpolated to provide magnitude-specific refinements of the coefficients retrieved from the lookup table.
4. The system of claim 1 , wherein the linearly interpolated distortion coefficients are stored in the lookup table.
5. The system of claim 1 , wherein the linearly interpolated distortion coefficients are transient.