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CMOS Delta-Sigma Frequency Synthesizer with a New Frequency Divider and a Simpli ed MASH Structure
Soo-HwanKim,Min-SunKeel,Ki-WonLee,Suk-KiKim,Shin-IlLim 한국물리학회 2002 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.41 No.6
This paper describes a CMOS implementation of a fractional-N frequency synthesizer adopting a new frequency divider and a new simplified 3-stage MASH (multistage noise shaping) delta-sigma modulator. All functional blocks, except for the low-pass filter (LPF), are integrated on a chip. A simple frequency divider architecture with a digital comparator and a `modulus mapping circuit' in a delta-sigma modulator is suggested for a lower hardware complexity and less power consumption. The proposed fractional-N frequency synthesizer shows a rapid switching time of 2.8 $\mu$s at a 60-MHz frequency step with inherent high reference frequency and a wide loop bandwidth. The tuning range of the voltage-controlled oscillator (VCO) is 1.6$\sim$2.1 GHz in the measured results. The measured VCO phase noise is as low as $-$110.27 dBc/Hz at a 600-kHz offset and $-$122.99 dBc/Hz at a 7.5-MHz offset. The measured fractional spur level is $-$101.6 dBc. The total power consumption is 20.2 mW with a 2.5 V single power supply. The synthesizer is implemented in a 0.25-$\mu$m standard CMOS process (1-poly, 5-metal) and occupies an active area of 760$\times$1280 $\mu$m.
Synthesis of nanosized ZnO powders prepared by precursor process
TakakiMasaki,HironoriWatanabe,KeiMiyamoto,MamoruOhno,Ki-HwanKim,Soo-JongKim 한양대학교 세라믹연구소 2003 Journal of Ceramic Processing Research Vol.4 No.3
Nano-sized ZnO powder was synthesized by a precursor process using zinc sulfate salt and aluminum sulfate salt as starting materials. Pulp and crystalline cellulose were used as precursor materials. The crystallization process, morphologies, and thermal decomposition were studied as a function of calcination temperatures and raw material compositions. The calcined powders were evaluated by SEM, XRD, TG-DTA, and volume resistivity. The volume resistivity of 1.5 × 105 Ω·cm was obtained by using 2.5 mol% Al2O3 doping. The particle size of 40 nm was obtained by selecting appropriate process conditions.
Bin Li,Sang-Bin Lee,Kozo Watanabe,Dong-HwanKim,Muyoung Heo,Young-Seuk Park,Tae-Soo Chon 한국응용곤충학회 2016 한국응용곤충학회 학술대회논문집 Vol.2016 No.04
Investigating loci compositions by conventional methods is limited in fully addressing complex gene information. We applied self-organizing map (SOM) to characterize Amplified Fragment Length Polymorphism (AFLP) of aquatic insects in six streams in Japan in responding to environmental variables. Locus band presence patterns were clustered by the trained SOM. Presence and absence data of loci were altered and cluster change through recognition was Subsequently expressed to indicate sensitivity to environmental variables. The outlier loci were determined based on the 90th percentile. Subsequently environmental responsiveness was obtained for each outlier in different species. Outlier loci were overall sensitive to pollutants and feeding material. Poly-loci like responsiveness was detected in adapting to environmental constraints. SOM training combined with recognition could be an efficient means of characterizing loci information without knowledge on population genetics a prior.