DELTA-SIGMA MODULATOR BASED A D CONVERSION WITHOUT OVERSAMPLING/

Although Delta Sigma modulators are widely used for low to moderate ra te analog-to-digital conversion, the time oversampling requirement has discouraged their application to higher rate converters, This paper p resents an architecture wherein multiple Delta Sigma modulators are co mbined so that neither time oversampling nor time interlacing are nece ssary, Instead, the system achieves the effect of oversampling from th e multiplicity of Delta Sigma modulators, For a system containing M P- th-order Delta Sigma modulators, approximately P bits of accuracy are gained for every doubling of M. A major benefit of the architecture is that it retains much of the robustness of the individual Delta Sigma modulators to nonideal circuit behavior, As a result, the architecture offers the potential of integrating high-precision, high-speed A/D co nverters together with digital signal processing functions using VLSI processes optimized for digital circuitry, The paper presents the gene ral architecture and provides a performance analysis closely supported by computer simulations.