Distortion compensation quadrature modulator and radio transmitter
US7529313B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 9, 2005 |
| Grant date | May 5, 2009 |
| Priority date | — |
| Expiry date | Jul 5, 2027 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/364
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
An apparatus includes: an affine transformer that subjects input complex IF signals I(t) and Q(t) to affine transformation according to affine transformation coefficients, and outputs compensated signals a(t) and b(t); a quadrature modulator that applies quadrature modulation on a local oscillation signal according to the compensated signals, and outputs a modulated signal (RF transmission signal); a quadrature wave detector that removes a carrier component from the modulated signal and outputs complex feedback signals I′(t) and Q′(t); and a control portion that extracts linear distortions remaining in the complex feedback signals I′(t) and Q′(t) as plural distortion coefficients (DC offsets of the I-phase and the Q-phase, an IQ gain ratio, and a deviation in orthogonality), and updates the current affine transformation coefficients in accordance with updating equations including the distortion coefficients to set updated affine transformation coefficients again in the affine transformation portion.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.