Effective-fourth-order resonator based MASH bandpass sigma-delta modulators
نویسندگان
چکیده
Two novel effective-fourth-order (eighth-order) resonator based MASH bandpass Σ−∆ modulators are introduced at the behavioural level and subsequently examined by simulations utilising the ALTA SPW environment. The considered bandpass configurations have in their loop filter a cascade of standard second-order resonator structures in order to achieve appropriate noise shaping. The quantisation noise in each stage is suppressed by feeding the error of each section into the input of the following stage. It is demonstrated in this paper that the quadruple effective-first-order cascade configuration has significantly better performance as well as conforming more closely with theory in comparison with the effectivesecond-order effective-second-order cascade. The superior performance of the former can be attributed to the cumulative effect of the multi-bit outputs as well as the presence of more notch filters.
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