• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.48 no.3
• /
• pp.34-41
• /
• 2011

This paper presents a wide tuning range, fine-resolution DCO (Digitally Controlled Oscillator) with an active inductor. In order to control the frequency of the DCO, the transconductance of the active inductor is tuned digitally. In addition, the DCO gain needs to be calibrated digitally to compensate for gain variations. To cover the wide tuning range, an automatic three-step coarse tuning scheme is proposed. The DCO total frequency tuning range is 1.4 GHz (2.1 GHz to 3.5 GHz), it is 58 % at 2.4 GHz. An effective frequency resolution is 0.14 kHz/LSB. The proposed DCO is implemented in 0.13 ${\mu}m$ CMOS process. The total power consumption is 6.6 mW from a 1.2 V supply voltage. The phase noise of the DCO output at 2.4 GHz is -120.67 dBc/Hz at 1 MHz offset.

• Journal of Life Science
• /
• v.27 no.12
• /
• pp.1410-1414
• /
• 2017

Escherichia coli tryptophan synthase (TS) contains ${\alpha}_2{\beta}_2$, which catalyzes the final two steps in Trp biosynthesis. A molecular tunnel exists between the two active sites of ${\alpha}$ and ${\beta}$ subunits in TS. Via intersubunit communication, TS increases catalytic efficiency, including substrate channeling. The ${\beta}$ subunit of TS is composed of two domains, one of which, the COMM (communication) domain, plays an important role in intersubunit communication. The ${\alpha}$ subunit has a TIM barrel structure. This protein has functional regions at the C terminal of ${\beta}$ pleated sheets and in its loop regions. Three regions of the ${\alpha}$ subunit (${\alpha}L6$ [${\alpha}-loop$ L6], ${\alpha}L2$, and ${\alpha}L3$) are implicated in intersubunit communication. In the present study, conformational changes in ${\alpha}L6$ were monitored by measuring the sensitivity of mutant proteins in these regions to trypsin. The addition of a ${\alpha}$ subunit-specific ligand, D,L-${\alpha}$-glycerophosphate (GP), partially restored the sensitivity of mutant proteins to trypsin. In contrast, the addition of the ${\beta}$ subunit-specific ligand L-serine (Ser) resulted in varied sensitivity to trypsin, with an increase in PT53 (substitution of Pro with Thr at residue 53) and DG56, decrease in NS104 and wild type, and no change in GD51 and PH53. This finding may be related to several reaction intermediates formed under this condition. The addition of both GP and Ser led to a highly stable state of the complex. The present results are consistent with the current model. The method used herein may be useful for screening residues involved in intersubunit communication.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.48 no.2
• /
• pp.7-13
• /
• 2011

This paper presents a Time-to-Digital Converter which is a key block of an All-Digital Phase Locked Loop. In this work, a Vernier Delay Line is added in a conventional Gated Ring Oscillator, so it could get multi-phases and a high resolution. The Gated Ring Oscillator uses 7 unit delay cell, the Vernier Delay Line is used each delay cell. So proposed Time-to-Digital Converter uses total 21 phases. This Time-to-Digital Converter circuit is designed and laid out in $0.13{\mu}m$ 1P-6M CMOS technology. The proposed Time-to-Digital Converter achieves 26ps resolution, maximum input signal frequency is 100MHz and the digital output of proposed Time-to-Digital Converter are 8-bits. The proposed TDC detect 5ns phase difference between Start and Stop signal. A power consumption is 8.4~12.7mW depending on Enable signal width.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.47 no.2
• /
• pp.94-99
• /
• 2010

This paper presents a charge pump architecture for correcting the current mismatch due to the PVT variation. In general, the current mismatch of the charge pump should be minimized to improve the phase noise and spur performance of the PLL. In order to correct the current mismatch of the charge pump, the current difference is detected by the replica charge pump and fed back into the main charge pump. This scheme is very simple and guarantees the high accuracy compared with the prior works. Also, it shows a good dynamic performance because the mismatch is corrected continuously. It is implemented in 0.13um CMOS process and the die area is $100{\mu}m\;{\times}\;160{\mu}m$. The voltage swing is from 0.2V to 1V at supply voltage of 1.2V. The charging and discharging currents are $100{\mu}A$, respectively and the current mismatch due to the PVT variation is less than 1%.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.43 no.12 s.354
• /
• pp.47-54
• /
• 2006

This work proposes a dual-channel 6b 1GS/s ADC for ultra wide-band communication system applications. The proposed ADC based on a 6b interpolated flash architecture employs wide-band open-loop track-and-hold amplifiers, comparators with a wide-range differential difference pre-amplifier, latches with reduced kickback noise, on-chip CMOS references, and digital bubble-code correction circuits to optimize power, chip area, and accuracy at 1GS/s. The ADC implemented in a 0.18um 1P6M CMOS technology shows a signal-to-noise-and-distortion ratio of 30dB and a spurious-free dynamic range of 39dB at 1GS/s. The measured differential and integral non-linearities of the prototype ADC are within 1.0LSB and 1.3LSB, respectively. The dual-channel ADC has an active area of $4.0mm^2$ and consumes 594mW at 1GS/s and 1.8V.

• Journal of IKEEE
• /
• v.2 no.1 s.2
• /
• pp.1-14
• /
• 1998

In this paper, Antenna, LNA, Mixer, VCO, and Modulation/Demodulation in Baseband processor which are the RF main components in Wireless LAN system for ultra high-speed communications network are studied. Antenna bandwidth and selective fading due to multipath can be major obstacles in high speed digital communications. To solve this problem, wide band MSA which has loop-structure magnetic antenna characteristics is designed. Distributed mixer using dual-gate GaAs MESFET can achieve over 10dB LO/RF isolation without hybrid, and minimize circuit size. As linear mixing signal is produced, distortions can be decreased at baseband signals. Conversion gain is achieved by mixing and amplification simultaneously. Mixer is designed to have wide band characteristics using distributed amplifier. In VCO design, Oscillator design method by large signal analysis is used to produce stable signal. Modulation/Demodulation system in baseband processor, DS/SS technique which is robust against noise and interference is used to eliminate the effect of multipath propagation. DQPSK modulation technique with M-sequences for wideband PN spreading signals is adopted because of BER characteristic and high speed digital signal transmission.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.15 no.2
• /
• pp.269-272
• /
• 2015

this is the study of the human body antenna device which can detect the powder in a 360-degree on(under) the ground whether it is metal or nonmetal using superhigh frequency RF beam equipped with the body. and it is able to transmit the data of the detection of the powder, battle combats can share that among them. with its flexible roof radial antenna structure, it emits the superhigh frequency RF beam to the front and flank multiply, preprocesses through the powder preprocessing part. and with the non-linear regression model algorism engine part, reflecting the attenuation characteristics depend on the delayed time of degree of the signal power which is received to the superhigh frequency RF beam. so it is able to detect the signal of the most likely mine or powder based on the degree of the answer signal power according to the delayed time of the superhigh frequency RF beam. also, it can detect the powder whether it is metal or nonmetal, mine, dud, VBIED. it can increase the chance of detection about 90% more than existing mine detector.

• Journal of the Korean Magnetics Society
• /
• v.13 no.3
• /
• pp.97-102
• /
• 2003

Synthetic ferrimagnetic layer (SyFL) with structure NiFe/Ru/NiFe which can be applied high density TMR device in free layer were prepared by an inductively coupled plasma (ICP) helicon-sputter. We proposed a model of predicting coercivity (H$\_$c/), spin-flopping field (H$\_$sf/), and saturation field (H$\_$s/) as a function of Ru thicknesses, from the equilibrium state of energies of Zeeman, exchange, and uniaxial anisotropy. We fabricated the samples of Ta(50 ${\AA}$)/NiFe(50${\AA}$)nu(4∼20${\AA}$)NiFe(30 ${\AA}$)/Ta(50${\AA}$), and measured the M-H loops with a superconduction quantum interference device (SQUID) applying the external field up to ${\pm}$ 15 kOe. The result was well agreed with the proposed model, and reveal K$\_$u = 1000 erg/㎤, J$\_$ex/ =0.7 erg/$\textrm{cm}^2$. We report that H$\_$c/ below 10 Oe is available, and R$\_$u/ thickness range should be in 4-10 ${\AA}$ for MRAM application. Our result implies that permalloy layers may lead to considerable magnetostriction effect in SyFL and intermixing in NiFe/Ru interfaces.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.25 no.11
• /
• pp.1128-1134
• /
• 2014

In this paper, the effects of a metamaterial slab with negative permeability in a magnetically coupled wireless power transfer system (WPT) in the overall performance are analyzed quantitatively in terms of the effective quality factors of the loop resonators and coupling coefficient considering the slab losses, based on an equivalent circuit. Using the ideal metamaterial slab(lossless slab), the WPT efficiency is improved considerably by the magnetic flux focusing. However, the practical lossy slab made of RRs or SRRs limits the significant enhancement of WPT efficiency due to the relatively high losses in the slab consisting of RRs or SRRs near the resonant frequency. For the practical loop resonator, other than a point magnetic charge, using the practical lossy metamaterial slab in order to improve the transfer efficiency, the width of the slab needs to be optimized somewhat less than the half of the distance between two loop resonators. For the low-loss slab with its loss tangent of 0.001, the WPT efficiency is maximized at 93 % when the ratio of the slab width and the distance between the two resonators is approximately 0.35, compared with 53 % for the case without the slab. The efficiency in case of employing the high-low slab(loss tangent: 0.2) is maximized at 61 % when the slab ratio is 0.25.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.12B
• /
• pp.1452-1458
• /
• 2009

In this paper, Our proposed Multipurpose Complex Card UHF band RFID small-size Tag antenna. Multi purpose Complex Card UHF band RFID small-size Tag antenna that is to minimize the low efficiency of RFID Tag Read Range that generates space limitation and a conductor surrounded by inducing fingerpring system with dual(HF, UHF) Card is presented. Our proposed UHF band RFID small-size Tag antenna is for the Multipurpose Complex Card that is mounted on the fingerpring system as well as the HF Tag. It also enables to minimize and facilitates Tag chip matching by adjusting Tapered, Meander line and Loop structure. Given the card substance properties and periphery circuit, the proposed small-size Tag antenna, in this report, is designed with PET film with size of $50{\times}15mm^2$. The RFID small-size Tag method for measurements is used by EPCglobal Static Test instrument in Anechoic Chamber, which is tested with dual Card, within the car and in wallet. It is found that Read Range is 3.8m from the EPCglobal Static Test, Maximum Read Range within the car from the field test results in 7.6m. Proposed Tag antenna is will be used in the parking control security system.