RF BIST for ADPLL-based polar transmitters with wide-band DCO gain calibration

Abstract

We propose a BIST scheme to provide online testing for all-digital PLL based polar transmitters. Multiple digital signatures are collected by adding a branch digital filter optimized to increase the sensitivities to nonidealities. The test signatures are processed using simple digital processing to provide an estimate for error vector magnitude (EVM), a key RF performance measure for the transmitter. Additionally, a digital self-calibration scheme is proposed to eliminate the EVM degradation due to large wide-band DCO gain mismatch. We show that a proper exploration of digital implementation style is instrumental for facilitating novel low-cost built-in test and calibration solutions for mixed-signal and RF applications.