Linearization of a transmit amplifier
US8195103B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 15, 2007 |
| Grant date | Jun 5, 2012 |
| Priority date | — |
| Expiry date | Dec 8, 2029 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B2001/0425
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A novel apparatus and method of linearization of a digitally controlled pre-power amplifier (DPA) and RF power amplifier (PA). The mechanism is operative to perform predistortion calibration to compensate for nonlinearities in the DPA and PA circuits. A predistortion look up table (LUT) stores measured distortion compensation data that is applied to the TX data before being input to the digital to frequency converter (DFC), DPA and PA. The mechanism of the invention takes advantage of the on-chip receiver, which is normally inactive during the TX burst in a half-duplex operation, to demodulate the RF PA output and use the digital I/Q RX outputs to perform calibration of the TX pre-distortion tables. Controlled RF coupling is used to provide a sample of the RF output signal that to the receiver chain. The contents of the predistortion LUT are typically updated during the PA power up or down ramp. While the digitally-controlled PA (DPA) code is increasing (or decreasing), the amplitude and phase of the recovered I/Q samples are used to determine the instantaneous value of the AM/AM and AM/PM pre-distortion from which an update to the predistortion tables may be computed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.