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A 3rd order 3bit Sigma-Delta Modulator with Reduced Delay Time of Data Weighted Averaging

Authors: Hang-Geun Jeong, Soon Jai Yi, Sun-Hong Kim, Seong-Ik Cho


This paper presents a method of reducing the feedback delay time of DWA(Data Weighted Averaging) used in sigma-delta modulators. The delay time reduction results from the elimination of the latch at the quantizer output and also from the falling edge operation. The designed sigma-delta modulator improves the timing margin about 16%. The sub-circuits of sigma-delta modulator such as SC(Switched Capacitor) integrator, 9-level quantizer, comparator, and DWA are designed with the non-ideal characteristics taken into account. The sigma-delta modulator has a maximum SNR (Signal to Noise Ratio) of 84 dB or 13 bit resolution.

Keywords: sigma-delta modulator, DWA, multibit

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