• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.2
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• pp.330-336
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• 2007

A single pixel photon counting type image sensor which is applicable for medical diagnosis with digitally obtained image and industrial purpose has tern designed with $0.18{\mu}m$ triple-well CMOS process. The designed single pixel for readout chip is able to be operated by single supply voltage to simplify digital X-ray image sensor module and a preamplifier which is consist of folded cascode CMOS operational amplifier has been designed to enlarge signal voltage(${\Delta}Vs$), the output voltage of preamplifier. And an externally tunable threshold voltage generator circuit which generates threshold voltage in the readout chip has been newly proposed against the conventional external threshold voltage supply. In addition, A dark current compensation circuit for reducing dark current noise from photo diode is proposed and 15bit LFSR(Linear Feedback Shift Resister) Counter which is able to have high counting frequency and small layout area is designed.

• The Journal of the Acoustical Society of Korea
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• v.42 no.3
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• pp.227-232
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• 2023

Underwater noise pollution has a significant impact on the marine environment. This study proposed a simple approach to estimate the acoustic radiation efficiency of structures with air bubble layers. The method considered the insertion loss caused by the air bubble layer through post-processing of numerical results, assuming that insertion loss is equivalent to attenuation as demonstrated by previous studies. The proposed approach was validated by comparing it with a fully coupled analysis for plate structure models. The commercial finite element program COMSOL Multiphysics was used for the acoustic-structure interaction analysis, and the acoustic characteristics of air bubble layer for the fully coupled analysis was simulated by on the Commander and Prosperetti theory. The trends indicated good agreement between the simple approach and the fully coupled analysis in terms of radiation efficiency. It is confirmed that the proposed method is providing insight into the principal mechanism of underwater noise reduction for the bubble layer on the wedge-shaped structure.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.3A
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• pp.362-374
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• 2000

In this paper, trellis coded 16 QAM Multi-Carrior CDMA system is proposed, Using the equivalent signal-to-noise plus interference Power ratio (SNIR) of Multi-Carrier CDMA system in the reverse link, capacity and BER performance of trellis coded 16 QAM Multi-Carrier CDMA system are analyzed taking into account the number of multi-carrier, the number of multiple access user, the number of SC/MRC diversity branch, and Rician fading parameter in multiuser interference and Rician fading channel. And the capacity and the BER performance of trellis coded 16 QAM Multi-Carrier CDMA system using selection combining (SC) and maximal ratio cabining (MRC) diversity are numerically compared. Obtained results show that the capacity of proposed system depends on the number of multi-carrier. ti is found that the trellis coded 16 QAM Multi-Carrier CDMA system with SC/MRC antenna diversity scheme is efficient to combat multipath fading and to increase the maximum number of users in high speed data communication. With the results of analysis. MRC diversity technique provides the performance fro high speed data communications. Finally, we present a numerical approach to derive the capacity and the BER performance and to find the maximum number of multiple access user for Multi-Carrier system in multiuser interference and Rician fading channel.

• Journal of electromagnetic engineering and science
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• v.3 no.2
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• pp.118-125
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• 2003

This paper presents a 5.8-㎓ oscillator that uses a novel defected ground structure(DGS), which is etched on the metallic ground plane. As the suggested defected ground structure is the structure for mounting an active device, it is the roles of a feedback loop inducing a negative resistance as well as a frequency-selective circuit. Applying the feedback loop between the drain and the gate of a FET device produces precise phase conversion in the feedback loop. The equivalent circuit parameters of the DGS are extracted by using a three-dimensional EM simulation ,md simple circuit analysis method. In order to demonstrate a new DGS oscillator, we designed the oscillator at 5.8-㎓. The experimental results show 4.17 ㏈m output power with over 22 % dc-to-RF power efficiency and - 85.8 ㏈c/Hz phase noise at 100 KHz offset from the fundamental carrier at 5.81 ㎓.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.11
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• pp.1027-1033
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• 2013

In this work, a D-band imaging detector has been developed in a 65-nm CMOS technology for high frequency imaging application. The circuit was designed based on the resistive self-mixing of MOSFET devices. The fabricated detector exhibits a maximum responsivity of 400 V/W and minimum NEP of 100 $pW/Hz^{1/2}$ at 145 GHz. The chip size is $400{\mu}m{\times}450{\mu}m$ including the probing pads and a balun, while the core of the circuit occupies only $150{\mu}m{\times}100{\mu}m$.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.2041-2044
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• 2004

A pyroelectric sensor using $PbTiO_3$/P(VDF/TrFE) nanocomposites thin film for sensing materials has been fabricated and evaluated with other commercial pyroelectric sensors that use ceramic materials for sensing. The device was mounted in a TO-5 housing to detect infrared light of 5.5 ~ 14 ${\mu}m$ wavelength. The NEP (noise equivalent power) and specific detectivity D of the device were 1.30 ${\times}$ $10^{-8}$W and 1.53 ${\times}$ $10^7$cm /W respectively under emission energy of 13 ${\mu}$W/c$m^2$ respectively. This result shows a better characteristic than the other commercial pyroelectric infrared sensors.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.10
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• pp.35-42
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• 2002

Modulation frequency dependences of the pyroelectric properties of PLT (P $b_{1-x}$ L $a_{x}$ $Ti_{1-x}$ 4/ $O_3$) thin films with La concentrations of 5, 10 and 15㏖% have been investigated by using the dynamic method. The PLT thin film with 10㏖% of the La concentration (PLT(10) thin film) shows the most excellent pyroelectric properties among the films. For PLT(10) thin film, the pyroelectric coefficient shows the maximum value of 6.6$\times$10$^{-9}$ C/$\textrm{cm}^2$ㆍK without frequency dependence. The figure of merits for the voltage responsivity and specific detectivity are 1.03$\times$10$^{-11}$ Cㆍcm/J and 1.46$\times$10$^{-9}$ Cㆍcm/J, respectively. Voltage responsivity corresponding to the pyroelectric voltage is almost constant at low modulation frequency and decreases in proportional to frequency at high modulation frequency. Voltage responsivity is 5.15 V/W at 8Hz. Noise equivalent power (NEP) and specific detectivity ( $D^{*}$) of the PLT(10) thin film are 9.93$\times$10$^{-8}$ W/H $z^{1}$2/ and 1.81$\times$10$^{6}$ cmH $z^{1}$2/W at the frequency of 100Hz, respectively. The results indicate that PLT(10) thin film is very suitable for pyroelectric IR sensors.s.s.

• The Journal of the Acoustical Society of Korea
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• v.9 no.2
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• pp.61-69
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• 1990

We have investigated the digital bit synchronization problem in baseband communication receiver systems using the Gauss-Markov estimation technique which is equivalent to the weighted least square method. The realized bit synchronizer, including the data detector, processes the input signal two dimensionally into the transition phase and data level under the white Gaussian noise environment. We have confirmed the relization of the bit synchronizer via computer simulation. In addition, we have compared and evaluated the estimation error performance of the proposed method with that of the conventional DTTL method and of the minimum likelihood method.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.55 no.1
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• pp.13-20
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• 2006

In this paper, a control method of ozone generator for a tiny deodorizer is proposed, and also a cooling technique is described which is cooling down the flowing air gap into a silent discharger to $2[^{\circ}C]$ to generate ozone of high density and diffusing power. As the digital control system for this method, a double feedback loop is designed which detects the voltage and current of equivalent capacitor of the discharger and compensates for the poor power waveform caused by the noise at high discharging frequency. During the plant modeling of this system, computing time factor is considered as a unique parameter of the power system to improve the respond characteristics with regard to fluctuating load and to replenish the computing time delay of the controller. Through the experiment, sinusoidal input current for discharger can be acquired and all the effectiveness of this accurate control system over unstable ozone discharger are proved.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.609-612
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• 1998

Pyroelectric properties of rhombohedral $Pb(ZrxTi_1-x)O_3ceramics$ with various Zr/Ti ratios of 84/16, 87/13, 90/10, and 93/7 are investigated using dynamic method. The response characteristics of PZT samples are examined by considering frequency dispersion. Since the reorientation of the grain does not the influence on the increase of frequency at low frequency (2~200Hz), the maximum pyroelectric response can be obtained with the change of spontaneous polarization. However, the pyroelectric response of PZT samples could be reduced as the spontaneous polarization decreases due to the restrain of the reorientation of the grain with the increasing of requency at high frequency (200~2000Hz). We have obtained the good pyroelectric response in the PZT sample having 84/16 Zr/Ti ratio, then the pyroelectric coefficient (${\gamma}$) and the figure of merit (FV) were $17.3nC/\textrm{cm}^2K$ and 2.28$\times$10-11Ccm/J, respectively. The noise equivalent power (NEP), the detectivity (D*) were 1.21$\times$10-7W/Hz$\frac{1}{2}$ and 8.26$\times$106cmHz$\frac{1}{2}$/W, respectively.