Herein, we present a noise shaping successive-approximation-register (SAR) analog-to-digital converter (ADC) with an embedded passive gain multiplication technique. The noise shaping moves the in-band quantization noise from the signal band to out-of-band for improved signal-to-noise ratio (SNR). The proposed approach tackles the drawback of the previous active noise shaping (increased power and extra noise) and passive noise shaping (limited noise suppression and signal loss). Both noise shaping and gain multiplication are realized on-chip in an energy-efficient manner without an opamp. This approach uses only capacitors and switches in the finite impulse response (FIR) and infinite impulse response (IIR) filters. A comparator suppressing kickback noise is presented to handle the tradeoff between noise suppression and the filter capacitor size. The energy-efficient merged-capacitor switching (MCS) technique is effectively combined with rail-to-rail swing comparator and thermometer-coded capacitor array, which reduces the settling error in the digital to analog converter (DAC). The process-induced mismatch effect in the capacitive DAC is investigated using a behavioral model of the ADC. Additionally, we propose dynamic element matching (DEM) for the thermometer-coded capacitor array. The ADC is fabricated using a 0.18 μm CMOS process in an area of 0.26 mm2. Consuming 4.1 μW, the ADC achieves a signal-to-noise and distortion ratio (SNDR) of 66.5 dB and a spurious-free dynamic range (SFDR) of 79.1 dB. The figure-of-merit (FoM) of the ADC is 11.8 fJ/conversion-step.

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In this study, a prototype was constructed and a field experiment was conducted to develop the water supply system that can purify polluted water quickly and efficiently. As a result of water quality analysis on the filtered water treated by a prototype, it could be used for living water, graywater and drinking water. There is the pressurized type filtration system that plays an important role in the water supply and production system. A filtration filter in the pressurized type filtration system absorbs pollutants and produces clean water. Filtration filter that can filter out contaminants is closely related to flow phenomena. Since it is impossible to observe in the vicinity of the filtration filter, the flow phenomenon is analyzed using CFX model. As the inner structure of the filtration was changed, the flow phenomenon in the filtration filter was examined. After changing the angle of the filter plate inside the filtration from 15º to 20º, the velocity distribution was analyzed. The standard deviation was reduced from 0.0575 to 0.0154. A uniform flow velocity distribution was formed around the filter. As a result, filtration efficiency is expected to increase.