Atsushi Motozawa

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This paper proposes novel feedforward architecture of the second-order multibit ΔΣAD modulator with single DAC-feedback topology. The ΔΣAD modulator realizes high resolution by oversampling and noise shaping techniques. However, its SNDR (Signal to Noise and Distortion Ratio) is limited by the dynamic range of the input signal and nonidealities of circuit(More)
This paper describes Data-Weighted-Averaging (DWA) algorithms for multibit complex bandpass ∆ΣAD modulators with arbitrary signal bands. In most of bandpass ∆ΣAD modulators, their sampling frequency is chosen as four times of the center frequency of their signal band in order to simplify the following digital filter design. But with this relationship, their(More)
A case of aggressive fibromatosis (extra-abdominal desmoid) found in a 9-month-old male mixed breed cat is described. The right forearm was almost completely effaced by fibrous tissue and there were some tumours in the area from the shoulders to the mandible. These tumour-like tissues were composed of abundant collagen fibres and sparse numbers of(More)
This paper proposes novel feedforward architecture of a second-order ΔΣAD modulator with single DACfeedback topology. ΔΣAD modulator realizes high resolution by oversampling and noise shaping technique. However, its SNDR (Signal to Noise and Distortion Ratio) is limited by the dynamic range of the input signal and non-idealities of building blocks,(More)
This paper describes applications of continuous-time feed-forward Sigma-Delta (ΣΔ) modulators to control DC-DC converters as follows. We propose to use continuous-time feedforward ΣΔ controllers in DC-DC converters, and show that their transient response is faster than discrete-time and/or feedbacktype ΣΔ controllers. We also show that second-order ΣΔ(More)
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