Title:
SYSTEM AND METHOD FOR DIFFERENTIAL IQ DELAY COMPENSATION IN A COMMUNICATIONS SYSTEM UTILIZING ADAPTIVE AQM COMPENSATION
Document Type and Number:
WIPO Patent Application WO2006017115
Kind Code:
A3
Abstract:
A system and method for compensating for the time delay between the in-phase I and the quadrature Q paths of a digitally modulated transmitter incorporating an analog quadrature modulator (114) is disclosed. The time delay between the inphase 1 and the quadrature Q paths is computed and used to calibrate a set of interpolation filters (11,21) in the forward path that compensate for this delay, reducing the frequency dependent degradation in performance of the analog quadrature modulator. The disclosed system and method provides improved compensation of gain, phase and DC offsets in the analog quadrature modulator over a broader bandwidth. Fractional delay interpolation filters may be used to estimate the delay between the in-phase and quadrature paths. This eliminates the need for a factory calibration procedure, speeding up manufacture and reducing costs.
Inventors:
LUKE CHRISTIAN G (GB)
JOHNSON IAN (GB)
WOOD STEVEN A (GB)
JOHNSON IAN (GB)
WOOD STEVEN A (GB)
Application Number:
PCT/US2005/024082
Publication Date:
March 30, 2006
Filing Date:
July 07, 2005
Export Citation:
Assignee:
POWERWAVE TECHNOLOGIES INC (US)
LUKE CHRISTIAN G (GB)
JOHNSON IAN (GB)
WOOD STEVEN A (GB)
LUKE CHRISTIAN G (GB)
JOHNSON IAN (GB)
WOOD STEVEN A (GB)
International Classes:
(IPC1-7): H04K1/02; H04L25/49
Foreign References:
| US20020058486A1 | 2002-05-16 | |||
| US6313703B1 | 2001-11-06 | |||
| US20020181611A1 | 2002-12-05 | |||
| US20030058960A1 | 2003-03-27 |
Other References:
See also references of EP 1766825A4
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