Non-Linear Modeling of a Physical System Using Look-Up Table with Polynomial Interpolation
First Claim
1. A method for evaluating a non-linear function for a complex input value, comprising:
- obtaining at least one look-up table with polynomial interpolation that represents said non-linear function, wherein entries in said look-up table comprise polynomial coefficients of at least degree two for different segments of said non-linear function;
obtaining a point from said look-up table that is near a magnitude of said complex input value; and
generating a complex output value by evaluating said polynomial coefficients at said point to perform a Taylor Series expansion from said point.
6 Assignments
0 Petitions
Accused Products
Abstract
Methods and apparatus are provided for non-linear modeling of a physical system using look-up tables with polynomial interpolation. A non-linear function is evaluated for a complex input value by obtaining at least one look-up table with polynomial interpolation that represents the non-linear function, wherein entries in the look-up table comprise polynomial coefficients of at least degree two for different segments of the non-linear function; obtaining a point from the look-up table that is near a magnitude of the complex input value; and generating a complex output value by evaluating the polynomial coefficients at the point to perform a Taylor Series expansion from said point. The non-linear function characterizes, for example, a power amplifier or an inverse of a power amplifier and the look-up tables can be used, for example, to implement digital pre-distortion. The look-up table can be stored in a memory of a digital processor, and the polynomial interpolation can be performed as part of a user-defined non-linear instruction that takes a complex number as an input, x, and computes ƒ(x).
26 Citations
20 Claims
-
1. A method for evaluating a non-linear function for a complex input value, comprising:
-
obtaining at least one look-up table with polynomial interpolation that represents said non-linear function, wherein entries in said look-up table comprise polynomial coefficients of at least degree two for different segments of said non-linear function; obtaining a point from said look-up table that is near a magnitude of said complex input value; and generating a complex output value by evaluating said polynomial coefficients at said point to perform a Taylor Series expansion from said point. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
-
11. A digital signal processor that evaluates a non-linear function for a complex input value, comprising:
-
a memory storing at least one look-up table with polynomial interpolation that represents said non-linear function, wherein entries in said look-up table comprise polynomial coefficients of at least degree two for different segments of said non-linear function; and at least one processor, coupled to the memory, operative to; obtain a point from said look-up table that is near a magnitude of said complex input value; and generate a complex output value by evaluating said polynomial coefficients at said point to perform a Taylor Series expansion from said point. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
-
Specification