Design Methodology for f Σ Δ Modulators

An analytical approach for modulator design is presented, leading to a new generalized class of continuous-time (CT) bandpass (BP) sigma-delta modulators with fractional delays (fSigmaDelta). First, original closed form fSigmaDelta equations are obtained. A behavioral modeling technique is then developed, in order to apply the model in a standard analog integrated circuit (IC) design environment. The design was implemented in both software (SPICE and Verilog $Atrade) and an IC (using SiGe technology), in order to verify the methodology via both simulations and experimental results. The experimental results confirmed validity of both the newly developed analytical models and the design methodology. Possible applications for fSigmaDelta modulators resulting from this work are also discussed