I-Q signal generation techniques for communication IC testing and ATE systems

This paper describes application of a complex band-pass (BP) ΔΣ DA modulator to I-Q signal generation for I-Q balance testing of communication IC as well as ATE system usage. First we explain that the complex BP ΔΣ DA modulator is superior to two real-BP ΔΣ DA modulators regarding to noise-shaping characteristics. Then we examine the characteristics of the complex BP ΔΣ DA modulator and its extension - a complex multi-BP modulator - as well as its newly derived Data Weighted Averaging (DWA) algorithm for its linearity enhancement. We also propose a digital self-calibration technique, and show their simulation results. Their combination is also investigated. We discuss application of our proposed techniques to IC testing.