Zero-overhead self test and calibration of RF transceivers

Abstract

In this paper we present a self-test method for RF transceivers to determine IQ imbalance, time skews, IIP3, IIP5, AM/AM, and AM/PM distortion with no hardware overhead. The analysis is done through the loop-back set-up over two frames, each of which is 200us in duration. The overall measurement time is less than 10ms including the computation time. The determined parameters can be used for digital calibration, which greatly enhances reliability and yield by widening the tolerance of the parameters. We show through hardware measurements that the target performance parameters can be determined accurately and the EVM can be reduced more than 5 folds, making even highly impaired systems usable. The only additional component to enable our approach is an attenuator in the loop-back path, which can be placed outside the chip. Hence, we call this self test and calibration approach a zero overhead approach.