Method and system for DC offset correction of a quadrature modulated RF signal
US6434204B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 4, 1999 |
| Grant date | Aug 13, 2002 |
| Priority date | — |
| Expiry date | Mar 4, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2027/0018
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
The DC offset error of a quadrature modulated RF signal is corrected by introducing a specific trial offset correction value, D, into the DC offset correction circuits 3, 4 or 5 times, by measuring the carrier power resulting from each trial introduction, and by using the information to determine the DC offset correction components, Icor and Qcor. According to an ideal case first embodiment, specific offset D is employed in three different measurement combinations to determine the correction factors Icor and Qcor. According to an alternative embodiment, a fourth offset correction measurement, needed to estimate a single offset control scale factor, is used to account for an unknown power scale factor A. According to a second alternative embodiment, five offset correction measurements are used to account for separate offset control scale factors for the I and Q channels.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.