Model-based adaptive feedforward amplifier linearizer
US5959500A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 26, 1998 |
| Grant date | Sep 28, 1999 |
| Priority date | — |
| Expiry date | Jan 26, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F1/3223
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A linear RF transmitter uses an adaptive forward model of the power amplifier in a feedforward linearization system. The forward model outputs a modeled power amplifier output signal, which is then used to calculate the error signal. The error signal represents the distortion caused by the power amplifier, which is then subtracted from the power amplifier output signal. The forward model can optionally model memory effects of the power amplifier transfer characteristic to more accurately generate the error signal. In addition, the forward model may be generated from the power amplifier output signals using orthogonal predictor variables to further improve performance. These orthogonal predictor values are then used to calculate parameter values used by a feedforward filter to model the power amplifier. A coordinate mapper then maps these calculated parameter values into a set of parameter values having the same coordinate system of the feedforward filter. Still further, in-band distortion may be filtered out of the power amplifier output signal before calculating the parameter values to more accurately model the distortion of the power amplifier.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.