Title :
A gain/phase imbalance minimization technique for LINC transmitter
Author :
Xuejun Zhang ; Nanawa, P. ; Larson, L.E. ; Asbeck, P.M.
Author_Institution :
Center for Wireless Commun., California Univ., San Diego, La Jolla, CA, USA
Abstract :
A simple calibration scheme for correction of the path imbalance in a LINC transmitter has been demonstrated. In this algorithm a baseband DSP evaluates the gain and phase imbalance with a set of calibration signals through a feedback loop. Compensation of path imbalance is accomplished within the DSP by introducing a pre-distortion term. The quadrature errors of the I/Q modulators set a limit on the overall performance of this algorithm. A prototype LINC system has been tested for CDMA IS95 baseband input and -38 dBc ACI was achieved.
Keywords :
amplification; calibration; circuit feedback; compensation; minimisation; mobile radio; radio transmitters; ACI; CDMA IS95 baseband input; I/Q modulators; LINC transmitter; baseband DSP; calibration scheme; calibration signals; compensation; feedback loop; gain imbalance minimization technique; phase imbalance minimization technique; pre-distortion term; quadrature errors; Baseband; Broadband antennas; Calibration; Digital signal processing; Error correction; Feedback loop; High power amplifiers; Phase modulation; Transmitters; Wireless communication;
Conference_Titel :
Microwave Symposium Digest, 2001 IEEE MTT-S International
Conference_Location :
Phoenix, AZ, USA
Print_ISBN :
0-7803-6538-0
DOI :
10.1109/MWSYM.2001.967013
