Abstract
Traditional methods for system-level design of Delta–Sigma (∆Σ) modulators typically assume linear modeling of the modulator, in which quantization noise is modeled as additive independent white noise. But it is well known that the ∆Σ modulator is a non-linear system and linear modeling is only an approximation. Also, circuit-level non-idealities, which may greatly change the modulator behavior, are typically neglected at system-level design. As a result, system-level modulator designs obtained from traditional methods may not be realistically optimal. This paper presents a system-level post-optimization method for ∆Σ modulators so that modulator designs initially obtained from traditional methods are post-optimized considering non-linear and non-ideal characteristics of ∆Σ modulators including both quantization noise and circuit-level non-idealities. The post-optimization algorithm is based on Finite Difference Stochastic Approximation due to the stochastic nature of modeling of some circuit-level non-idealities in system-level design. During the post-optimization run, each candidate design is simulated for performance measures and stability has always been a must constraint. Results on two ∆Σ modulators have shown that post-optimized modulator designs outperform the original designs from traditional methods.
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Tang, H. System-level post-optimization of Delta–Sigma modulators using finite difference stochastic approximation. Analog Integr Circ Sig Process 88, 31–42 (2016). https://doi.org/10.1007/s10470-016-0729-x
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DOI: https://doi.org/10.1007/s10470-016-0729-x