Granted Patent B2

US 10,305,521 · App. 15/682,431 · Granted May 28, 2019

Inventors: Dali Yang (Mountain View, CA); Jia Yang (Mountain View, CA)

Assignee: Dali Wireless, Inc.

H04B1/0475H03F1/3247H03F3/19H03F3/21H03F3/24H03F2200/451H03F2200/57H03F2201/3215H03F2201/3233H04B2001/0425Y02D70/00

Abstract

Claims (33)

1. A predistortion system for linearizing an output of a power amplifier, the predistortion system comprising:

a first input operable to receive a first input signal representative of an analog RF modulated signal;

a second input operable to receive a digitized reference signal representative of an idealized reference signal;

a third input operable to receive a digitized feedback signal representative of nonlinear characteristics of the power amplifier;

a predistortion controller operable to generate, using a lookup table, a predistortion correction signal based on a first error signal between the digitized reference signal and the digitized feedback signal;

combining logic operable to combine the first input signal and the predistortion correction signal to produce a predistortion signal that is supplied to the power amplifier to linearize the output of the power amplifier; and

error logic operable to determine the first error signal as a difference between a square of the digitized reference signal and a square of the digitized feedback signal.

2. The predistortion system of claim 1 , further comprising:

a multiplier operable to multiply the first error signal by an adaptive factor.

3. The predistortion system of claim 1 , wherein the digitized reference signal and the digitized feedback signal each include an in-phase component and a quadrature component, and wherein the predistortion controller is operable to form a first component of the predistortion correction signal using the in-phase components and a second component of the predistortion correction signal using the quadrature components.

4. The predistortion system of claim 3 , wherein the predistortion controller is operable to perform a first lookup in the lookup table for the in-phase component of the digitized reference signal and a second lookup in the lookup table for the quadrature component of the digitized reference signal.

5. The predistortion system of claim 1 , wherein the lookup table receives, as a first lookup table input, an address derived from the digitized reference signal.

6. The predistortion system of claim 5 , wherein the predistortion controller further comprises an address former operable to generate the address based on the digitized reference signal.

7. The predistortion system of claim 5 , wherein the lookup table receives, as a second lookup table input, a second error signal derived from the first error signal and from a previous value output by the lookup table.

8. A method for linearizing an output of a power amplifier, the method comprising:

receiving a first input signal representative of an analog RF modulated signal of a predistortion system;

receiving a digitized reference signal representative of an idealized reference signal;

receiving a digitized feedback signal representative of nonlinear characteristics of the power amplifier;

generating, using a lookup table, a predistortion correction signal based on a first error signal between the digitized reference signal and the digitized feedback signal;

combining the first input signal and the predistortion correction signal to produce a predistortion signal that is supplied to the power amplifier to linearize the output of the power amplifier; and

determining the first error signal as a difference between a square of the digitized reference signal and a square of the digitized feedback signal.

9. The method of claim 8 , further comprising:

multiplying the first error signal by an adaptive factor.

10. The method of claim 8 , further comprising:

receiving, as a first input to the lookup table, an address derived from the digitized reference signal.

11. The method of claim 10 , further comprising:

receiving, as a second input to the lookup table, a second error signal derived from the first error signal and from a previous value output by the lookup table.

12. The method of claim 8 , wherein the digitized reference signal and the digitized feedback signal each include an in-phase component and a quadrature component, the method further comprising:

forming a first component of the predistortion correction signal using the in-phase components; and

forming a second component of the predistortion correction signal using the quadrature components.

13. The method of claim 12 , further comprising:

performing a first lookup in the lookup table for the in-phase component of the digitized reference signal; and

performing a second lookup in the lookup table for the quadrature component of the digitized reference signal.

Assignments (3)

Continuity (11)