• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.3
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• pp.417-422
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• 2021

In this paper, a ZQ calibration using a time domain comparator is proposed. The proposed comparator is designed based on VCO, and an additional clock generator is used to reduce power consumption. By using the proposed comparator, the reference voltage and the PAD voltage were compared with a low 1 LSB voltage, so that the additional offset cancelation process could be omitted. The proposed time domain comparator-based ZQ calibration circuit was designed with a 65nm CMOS process with 1.05V and 0.5V supply voltages. The proposed clock generator reduces power consumption by 37% compared to a single time domain comparator, and the proposed ZQ calibration increases the mask margin by up to 67.4%.

• Journal of Convergence for Information Technology
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• v.11 no.9
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• pp.124-129
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• 2021

A time-interpolation technique has been applied to the conventional FLASH analog-to-digital converter (ADC) to increase a number of quantization level, thus it reduces not only a power dissipation, but also minimize an active chip area. In this work, we demonstrated 5-bit ADC which has 31 quantization levels consisting of 16 conventional voltage-mode comparators and 15 time-mode comparators. As a result, we have achieved about 48.4% voltage-mode comparator reductions. The ADC is fabricated in a 14nm fin Field-effect transistor (FinFET) process with an active die area of 0.0024 mm2 while consuming 0.82 mW through a 0.8 V supply. At 400-MS/s conversion rate, the ADC performs 28.03 dB SNDR (4.36 ENOB) at 21MHz input frequency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.1A
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• pp.167-177
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• 2000

In this paper, a new algorithm to design a time-domain equalizer (TEQ) for an xDSL system employing the discrete multitone (DMT) modulation is proposed. The proposed algorithm, derived by neglecting the terms whichdo not affect the performance of a DMT system in ARMA modeling, is shown to have similar performance tothe previous TEQ algorithms such as matrix inverse algorithm, fast algorithm, iterative algorithm, and inversepower method, even with the significantly lower computational complexity. In addition, since the proposedalgorithm requires only the received signal, the information on the channel impulse response or training sequenceis not needed. It is also shown that for the case where bridged tap is not included, the number of TEQ tapsrequired can be reduced to half(from 16 to 8) without affecting the overall performance. The performances of theproposed and previous TEQ algorithms are compared by applying them to ADSL environment.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.75-76
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• 2008

이산시간 모델로부터 시간응답 설계 명세를 만족시키도록 직접 디지털 제어기를 설계하는 새로운 방법을 제시한다 R-S-T형의 고정된 제어기 구조에서 폐루프 전달함수가 원하는 기준전달함수와 일치하도록 제어기 이득을 구한다. 시간 응답을 만족시키는 목표전달함수는 w-영역에서 CRA를 이용하여 선택되며 이 함수를 z-영역으로 변환시켜 얻는다. 예제를 통해 제시한 방법의 유용성을 보이고 극배치 방식과 비교한다.

• Proceedings of the Korea Multimedia Society Conference
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• 2004.05a
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• pp.379-382
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• 2004

적응신호처리 분야에서 LMS알고리듬은 수식이 간단하고, 적은 계산량으로 인해 널리 사용되고 있지만, 시간영역의 적응알고리즘은 입력신호의 고유치 분포폭이 넓게 분포한 때는 수렴속도가 느려지는 단점이 있다. 이런 문제점을 개선하기 위하여 본 논문에서는 시간영역의 적응 알고리즘을 변환영역에서 수행하고, 변환영역에서 수렴성능 향상과 계산량을 줄이기 위하여 웨이블렛기반의 고속 적응 알고리즘을 제안하였다. 제안한 알고리즘을 OFDM 적응등화기에 적용하여, 기존의 OFDM 등화기 알고리즘과 비교하여 제안한 적응알고리즘의 성능이 우수함을 보인다.

• Journal of Digital Contents Society
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• v.7 no.2
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• pp.109-115
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• 2006

In this paper, we design and performance evaluate the equalizer for S-DMT table modem, which supports more channels and better quality symmetric mutimedia services over HFC network. We verified that both of the designed equalizers show good convergence characteristics and that the performance of the time domain equalizer is 1 dB better than that of the frequency domain equalizer overall range of Eb/No.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.5
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• pp.117-124
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• 2004

Various multimedia systems have been developed and their application areas widely proliferate. Thus, the interoperability is getting important among various networks and devices. The video transcoding is a technology to solve this interoperability problem among various coding standards. Transcoding can be defined as the conversion of one compressed coded data to another. In this paper, MPEG-2 to MPEG-4 transcoder in the spatial domain is compared with that in the DCT domain. The transcoder is very useful when a video sequence that is originally encoded for digital TV, DVD or satellite broadcasting is served in mobile environment. In order to compare two transcoders, all modules except motion compensation and down sampling are implemented identically. In addition, both transcoders do not search for motion vector. Instead, the decoded information is reused to the encoder. The experimental results show that the transcoder in the spatial domain is usually better than that in the DCT domain with respect to PSNR (Peak Signal-to-Noise Ratio), bitrate and execution time.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.6 no.1
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• pp.17-27
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• 1995

In this paper, Finite Difference Time Domain (FDTD) method is used to analyze characteristics of the electromagnetically coupled broadband microstrip antenna, and to optimize the antenna parameters. By using short tuning stub in feedline, electromagnetically coupled microstrip antenna shows broadband (approximatcly equal 13%) characteristics, and the characteristics are varied as a function of length, width, and position of the tuning stub. Operating frequency, return loss, VSWR and input impedance are calculated by Fourier transforming the time domain results. Measurement data from fabricated electromagnetically coupled microstrip antenna are compared with FDTD results and are shown to be in good agreement. After optimization of the parameters, maximum bandwidth of about 15% is achieved.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.2 no.1 s.2
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• pp.25-40
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• 2003

The purpose of this thesis is development of detection algorithm for stop-line detector. Detail detection area is set in basing detection area($1.8{\times}4.0m$) and traffic information(volume, occupancy, nonoccupancy) is collected by passive infrared detector at designing detection area. The basis detection area($1.8{\times}4.0m$) is named existing PIR and detection area applied on development algorithm is named proposal PIR. The proposal PIR is collected data such volume, occupancy, nonoccupancy, speed and lane change, but this thesis is limited to evaluate for volume, occupancy and nonoccupancy The procedure and each step of being developed algorithm is described in the next (1) The detection area of proposal PIR is made up of 2 of $1.8{\times}0.6m$ size(the detection area is named 1 and 3) and 1 of $1.8{\times}1.78m$ size(the detection area is named 2) (2) The image detection area is set on monitor to analyze outdoor photographing data then video frame analysis has been done by analyzer. (3) The occupancy, nonoccupancy and speed data of vehicle have been collected with the detection area 1 and 3 and lane change has been collected with combination of detection area 1, 2 and 3 The MAD and MAPE have been utilized to being compared with volume, occupancy and nonoccupancy for the field application and evaluation of a algorithm As the result, the proposal PIR data have been identified superior to the existing PIR data and the effect has been improved its information(volume, occupancy and nonoccupancy)

• The Journal of the Acoustical Society of Korea
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• v.12 no.2
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• pp.14-27
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• 1993

본 논문은 매 40ms 정도의 음성파형으로부터 추출된 6내지 9ms 정도의 1피치주기 파형을 합성단위로 사용하여 합성시킨 시간영역에서의합성방식을 한국어 문어 변환 시스템내에서의 음성합성기에 적용시킨 연구결과이다. 시험 결과, 4가지 유형의 한국어 음절 합성이 가능하고, 장단강약과 같은 운율요소의 제어가 용이하고, 또한 합성 알고리즘이 간단하여 실시간 처리가 가능하였으나, 문장 단위의 음성을 합성하기 위하여는 문장내에서의 다양한 피치 패턴에 대한 연구와 이의 효율적인 제어에 관한 연구가 이루어져야 할 것이다. 합성음에 대한 평가방법으로는 원음과 합성음에 대한 시간영역에서의 파형비교, 주파수 영역에서의 스펙트럼 포락선 유사성 비교 및 합성음에 대한 청취도 실험을 행하였다.