Distortion detection apparatus for controlling predistortion, carrier cancellation and feed-forward cancellation in linear RF power amplifiers
US6359508B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Aug 17, 2000 |
| Grant date | Mar 19, 2002 |
| Priority date | — |
| Expiry date | Aug 17, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2201/3212
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
RF power amplifier distortion can be accurately measured in the presence of multi-carrier input signals, by using a common swept local oscillator to tune RF input and output receivers, whose outputs are monitored for distortion correction purposes. In carrier cancellation and feedforward cancellation mode, when the power detected by the input receiver exceeds a power threshold, the processor accumulates a digital representation of uncancelled carrier energy detected by the output receiver when sampling the signal at the output of the carrier cancellation combiner. It otherwise accumulates uncancelled IMD sampled at the output of the amplifier downstream of the feedforward cancellation coupler. In predistortion mode, the output receiver monitors only the output of the carrier cancellation combiner. When the power detected by the input receiver does not exceed the carrier power threshold, any energy measured by the output receiver corresponds to residual distortion energy from the predistorted main amplifier. This allows predistortion to be adaptively controlled by minimizing accumulated energy detected by the output receiver when it monitors the output of the carrier cancellation co…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.