INTRODUCTION

The in-phase and quadrature modulator (IQ modulator) is a key component in modern wireless transmitters. It provides a convenient method for modulating data bits or symbols onto an RF carrier. IQ upconversion has become the architecture of choice for implementing transmitter signal chains for end applications such as cellular, WiMAX, and wireless point-topoint. IQ modulators, however, can degrade signal fidelity in ways that are somewhat unique. These effects can degrade the quality of the transmitted signal during the modulation process, resulting in degraded error vector magnitude (EVM) at the receiver, which in turn degrades bit error rate (BER). Fortunately, algorithms exist that can correct these imperfections.