A Comprehensive BIST Solution for Polar Transceivers Using On-Chip Resources

Abstract

This article presents a Built-in self-test (BIST) solution for polar transceivers with low cost and high accuracy. Radio frequency (RF) Polar transceivers are desirable for portable devices due to higher power efficiency compared to traditional RF Cartesian transceivers. Unfortunately, their design is quite challenging due to substantially different signal paths that need to work coherently to ensure signal quality. In the receiver, phase and gain mismatches degrade sensitivity and error vector magnitude. In the transmitter, delay skew between the envelope and phase signals and the finite envelope bandwidth can create intermodulation distortion, which leads to violation of spectral mask requirements. Typically, these parameters are not directly measured but calibrated through spectral analysis using expensive RF equipment, leading to lengthy and costly measurement/calibration cycles. However, characterization and calibration of these parameters with analytical model would reduce the test time and cost considerably. In this article, we propose a technique to measure with the intent to calibrate impairments of the polar transceiver in the loop-back mode. Simulation and hardware measurement results show that the proposed technique can characterize the targeted impairments accurately.