Nonlinear Stability Prediction of Multibit Delta-Sigma Modulators for Sinusoidal Inputs

作者：Lota Jaswinder^*; Al Janabi Mohammed; Kale Izzet

来源：IEEE Transactions on Instrumentation and Measurement, 2014, 63(1): 18-26.

DOI：10.1109/TIM.2013.2273597

• Delta-sigma
• multibit quantizer
• nonlinear gains
• stability

This paper proposes a novel algorithm that can be integrated with various design and evaluation tools, to more accurately and rapidly predict stability in multibit delta-sigma (Delta-Sigma) modulators. Analytical expressions using the nonlinear gains from the concept of modified nonlinearity in control theory are incorporated into the mathematical model of multibit Delta-Sigma modulators to predict the stable amplitude limits for sinusoidal input signals. The nonlinear gains lead to a set of equations, which can numerically estimate the quantizer gain as a function of the input sinusoidal signal amplitude. This method is shown to accurately predict the stable amplitude limits of sinusoids for second-sixth-order three-and five-level midtread quantizer-based Delta-Sigma modulators. The algorithm is simple to apply and can be extended to midrise quantizers or to any number of quantizer levels. The only required input parameters for this algorithm are the number of quantizer levels and the coefficients of the noise transfer function.

• 出版日期2014-1