• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2570-2572
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• 2001

본 논문에서는 저주파 신호 증폭기에서 DC 이득에 의해 앰프가 포화되는 것을 막기 위해 필요한 큰 커플링 커패시터와 바이어스 저항의 면적을 줄이기 위한 회로를 제안한다. 또한, 이 경우 연산증폭기의 양 입력 단에 연결되는 바이어스 저항과 앰프의 이득을 설정하기 위해 사용되는 저항사이의 큰 값의 차이로 인해 발생하는 오프셋을 줄이기 위해 적절한 기준 전압을 정의하는 방법을 소개한다. 제안된 회로를 사용했을 때, 기존의 저항으로 앰프의 입력단을 바이어스할 때의 한계인 오프셋의 문제를 해결함으로써 보다 최적화된 면적으로 설계가 가능했다. 이 기법을 적외선 리모콘 수신 IC의 앰프에 적용했을 때, 커플링 커패시터와 바이어스 저항으로 설정되는 -3dB 주파수를 3kHz에 설정한 경우, 저항과 커패시터가 차지하던 면적의 12%를 차지했다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.180-182
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• 2005

비냉각형 적외선 검출 회로 설계 시 공정상 변화에 의해 발생하는 센서의 저항값 변동이 크다. 본 논문에서는 이것을 해결하기 위해 차동적 입력 수신 구조를 이용한 방법을 제시하였다. 볼로미터 타입 비냉각형 적외선 영상 센서 회로는 입사된 적외선 에너지 양에 따라 센서의 저항값이 변하는 특성을 이용하며 그에 따른 전압 또는 전류의 변화를 측정하여 적외선의 파장을 알아내는 방식으로 검출회로 설계 시 가장 큰 문제점인 공정상의 변화 등으로 인한 신호검출 회로의 오동작을 개선하기 위하여 검출회로의 입력단을 차동적으로 받아들이도록 설계하였다.

• The Journal of the Acoustical Society of Korea
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• v.35 no.3
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• pp.175-182
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• 2016

For application to several MHz photoacoustic imaging systems, a needle hydrophone was designed and fabricated by using PMN-PZT piezoelectric single crystal, and its characteristics were evaluated through comparison with a commercial PVDF(Polybinylidene Fluoride) hydrophone of which receiving sensitivity is known. The simulation using the KLM model results show that the peak receiving impulse response for $50{\Omega}$ terminating impedance of the fabricated hydrophone is -261.6 dB re $1V/{\mu}Pa$ and the frequency response is relatively flat over 2 ~ 12 MHz with fluctuation less than 5 dB. The measurement results using tone burst signals also show that it has higher (ave. 10.9 dB) sensitivity than the commercial hydrophone in 2 ~ 8 MHz, and the receiving sensitivity of $-255.8{\pm}2.8$ dB re $1V/{\mu}Pa$ was measured for the fabricated hydrophone. In addition, it is known that the photoacoustic signals and the image of a hair obtained by a mechanical scanned photoacoustic imaging system with the fabricated hydrophone were bigger and better than those obtained with the commercial hydrophone.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.9
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• pp.1087-1093
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• 2012

In this paper, we implemented a HF-band magnetic-field communication system consisting of an amplitude shift keying(ASK) transmitter, a pair of loop antennas, and an ASK receiver. Especially, we suggested a new ASK transmitter architecture, where a drain bias of class E amplifier is switched alternatively between two voltage levels with respect to input data. A maximum 5 W class E amplifier was designed using a low cost IRF510 power MOSFET at the frequency of 6.78 MHz. A measured sensitivity of the designed ASK receiver is -78 dBm, which consists of a log amplifier, a filter, and a comparator. Maximum communication range of magnetic-wave communication system with loop antennas was calculated using magnetic field equations in both near-field and far-field ranges. Also, in order to verify the calculated values, an indoor propagation loss was measured using a pair of loop antennas whose dimensions are $30{\times}30cm$. Maximum operating range is estimated about 35 m in case of transmitter's output power of 1 W and receiver sensitivity of -70 dBm, respectively. Finally, the communication field test using the designed ASK transmitter and receiver was successfully done at the distance of 5 m.

• Journal of Navigation and Port Research
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• v.27 no.4
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• pp.443-447
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• 2003

In this work. using 0.2 GaAs modulation doped FET(MODFET), a high performance DBS downconverter MMIC was developed for direct broadcasting satellite (DBS) application. Without LNA, the downconverter MMIC showed a very low noise of 4.8 dB, which is lower by 3 dB than conventional ones. A low LO power of -10 dBm was required for the normal DBS operation of the downconverter MMIC. which reduced the power consumption via a removal of LO amplifier on MMIC. It required only a low power consumption of 175 mW, which is lower than 70 percent of conventional ones. The LO leakage power at IF output was suppressed to a lower level than 30 dBm, which removes a bulky LO rejection filter on a board. The fabricated chip, which include a mixer, If amplifiers. LO rejection filter, and active balun, exhibited a small size of $0.84{\times}0.9\textrm{mm}^2$.

• Journal of the Institute of Convergence Signal Processing
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• v.20 no.1
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• pp.16-23
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• 2019

Fine particulate matter known as PM 2.5 refers to the atmospheric particulate matter that has a diameter less than 2.5 micrometer identified as dangerous element for human health and its concentration can provide us a clear picture about air dust concentration. Humans stay indoor almost 90% of their life time and also there is no official indoor dust concentration data, so our study is focused on measuring the indoor air quality. Indoor dust data monitoring is very important in hospital environments beside that other places can also be considered for monitoring like classrooms, cements factories, computer server rooms, petrochemical storage etc. In this paper, visible light communication system is proposed by Manchester encoding technique for electromagnetic interference (EMI)-free indoor dust monitoring. Important indoor environment information like dust concentration is transferred by visible light channel in wide range. An average voltage-tracking technique is utilized for robust light detection to eliminate ambient light and low-frequency noise. The incoming light is recognized by a photo diode and are simultaneously processed by a receiver micro-controller. We can monitor indoor air quality in real-time and can take necessary action according to the result.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.12
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• pp.77-84
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• 2007

In this parer, a wideband low-noise amplifier (LNA) has been realized in a 0.18mm CMOS technology for the applications of subsampling direct-conversion RF receivers. By exploiting the inverter-type transimpedance input stage with a 3rd-order Chebyshev matching network, the wideband LNA demonstrates the measured results of the -3dB bandwidth of 5.35GHz, the power gain (S21) of $12\sim18dB$, the noise figure (NF) of $6.9\sim10.8dB$, and the broadband input/output impedance matching of less than -10dB/-24dB within the bandwidth, respectively. The chip dissipates 32.4mW from a single 1.8V supply, and occupies the area of $0.56\times1.0mm^2$.

• Journal of IKEEE
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• v.13 no.2
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• pp.118-125
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• 2009

With recent advancement of high-speed, multi-gigabit data transmission capabilities, transmitters usually send data without clock signals for reduction of hardware complexity, power consumption, and cost. Therefore clock and data recovery circuits(CDR) become important to recover the clock and data signals and have been widely studied. This paper presents the design of 10Gbps CDR in 0.18$\mu$m CMOS process. A quarter-rate bang-bang phase detector is designed to reduce the power and circuit complexity, and a 4-stage LC-type VCO is used to improve the jitter characteristics. Simulation results show that the designed CDR consumes 80mW from a 1.8V supply, and exhibits a peak-to-peak jitter of 2.2ps in the recovered clock. The chip layout area excluding pads is 1.26mm$\times$1.05mm.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.2
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• pp.54-61
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• 1999

This paper describes the design of a 4-Mbps wireless infrared data transceiver chip. The receiver consits of the analog front-end, clock recovery and frame generator, and demodulator. The transmitter consists of the demodulator and LED driver. The versatile analog front- end consisting of multiple amplifiers makes it possible for the chip to be applied to various infrared environments by compensating DC and offset signal components. A 4PPM (pulse position modulation) scheme is used for data transfer in order to meet the IrDA standards. The chip was fabricated in a $0.8-{\mu}m$ 2-poly, 2-metal CMOS technology and dissipates 122mW for ${\pm}2.5V$ supply.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.6
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• pp.665-670
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• 2015

In this paper, We proposed a broadband RF amplifier for Microwave band receiver. We also proposed a broadband RF amplifier, designed by using EM simulation for reliable amplification of the received signal. Connected to a source terminal to via, it minimizes those which are the active elements of source-side oscillation as the operating element in an ideal GND, and a constant gain characteristic in a broadband. The goal of this was to obtain stable amplification characteristics. For implementing this architecture, we designed the broadband(500 MHz ~ 7 GHz) RF amplifier by using commercial GaAs FET, which operate on 720 MHz, 4,595 MHz, and 6,035 MHz by impedance matching. The voltage gain is 10.635 dB ~ 14.407 dB(737.5 MHz ~ 6.0575 GHz), P1dB is 20 dBc of band(1st harmonic/2nd harmonic).