Compact tone-behavior model for Delta-Sigma modulators

This paper proposes a compact mathematical model for predicting and analyzing Delta-Sigma modulator´s spurious tones. The model is based on frequency modulation and it outputs an accurate quantization noise estimate array for an arbitrary modulator stimulus: dc, ramp, sinusoid, two-tone, etc. For predicting the pattern noise or limit cycles, the proposed estimation model was found very precise. The model is applicable to a wide range of Delta-Sigma modulator types: low- and high-order, single- and multibit as well as to low- and band-pass types. The proposed model also takes different quantizer types (mid-rise and mid-tread) into account. The in-band quantization noise estimate can be used to predict the modulator´s performance.