Measuring Gain Imbalance and Quadrature Error in WiMAX Transmitters

The paper presents a new method for measuring the most common I/Q impairments affecting WiMAX transmitters, that are gain imbalance and quadrature error. The method operates on the signal at the output of the transmitter, acquired through a general purpose I/Q receiver. It is designed to correctly take into account the peculiarities of systems compliant to the standard IEEE 802.16-2004, such as the potentially noxious effects of impairments on signal normalization. The results of experiments carried out on standard-compliant signals are also given.