• Title, Summary, Keyword: Frequency variation

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Voltage and Frequency Tuning Methodology for Near-Threshold Manycore Computing using Critical Path Delay Variation

  • Li, Chang-Lin;Kim, Hyun Joong;Heo, Seo Weon;Han, Tae Hee
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.15 no.6
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    • pp.678-684
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    • 2015
  • Near-threshold computing (NTC) is now regarded as a promising candidate for innovative power reduction, which cannot be achieved with conventional super-threshold computing (STC). However, performance degradation and vulnerability to process variation in the NTC regime are the primary concerns. In this paper, we propose a voltage- and frequency-tuning methodology for mitigating the process-variation-induced problems in NTC-based manycore architectures. To implement the proposed methodology, we build up multiple-voltage multiple-frequency (MVMF) islands and apply a voltage-frequency tuning algorithm based on the critical-path monitoring technique to reduce the effects of process variation and maximize energy efficiency in the post-silicon stage. Experimental results show that the proposed methodology reduces overall power consumption by 8.2-20.0%, compared to existing methods in variation-sensitive NTC environments.

The Design of Robust DSC-PLL under Distorted Grid Voltage Contained Unbalance on Frequency Variation (주파수 변동시 불평형 전압에 강인한 DSC-PLL 설계 연구)

  • Lee, Jae Do;Cha, Han Ju
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.67 no.11
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    • pp.1447-1454
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    • 2018
  • In this paper, the design of robust DSC-PLL(Delayed Signal Cancellation Phase Locked Loop) is proposed for coping with frequency variation. This method shows significant performance for detection of fundamental positive sequence component voltage when the grid voltage is polluted by grid unbalance and frequency variation. The feedback frequency estimation of DSC-PLL is tracking the drift in the phase by unbalance and frequency variation. The robust DSC PLL is to present the analysis on method and performance under frequency variations. These compensation algorithms can correct for discrepancies of changing the frequency within maximum 193[ms] and improve traditional DSC-PLL. Linear interpolation method is adopted to reduce the discretized errors in the digital implementation of the PLL. For verification of robust characteristic, PLL methods are implemented on FPGA with a discrete fixed point based. The proposed method is validated by both Matlab/Simulink and experimental results based on FPGA(XC7Z030).

A Study on the Variation of the Mechanical Properties and Mode of the Hot-Rolled Mild Stell plate under Fatigue Loading (피로 하중을 받는 열간 압연 연강판재의 기계적 성질과 모우드 변화에 관한 연구)

  • Kim, Hak-Yoon;Lee, Seong-Ho
    • Journal of the Korean Society for Heat Treatment
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    • v.8 no.4
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    • pp.326-332
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    • 1995
  • Using natural frequency measurement method, which is one of NDT method, natural frequency of the hot-rolled mild steel plate(specimen) under fatigue loading was measured. Between the degradation of the specimen under fatigue loading and the variation of the natural frequency of the specimen was investigated. As a result, the degradation of the specimen was described and monitored as variation of natural frequency of specimen. The natural frequency of specimen decreased gradually under fatigue loading. This means the variation of material properties of specimen. Especially. It means the variation of Young's modulus of specimen.

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An Applicability of Teager Energy Operator and Energy Separation Algorithm for Waveform Distortion Analysis : Harmonics, Inter-harmonics and Frequency Variation

  • Cho, Soo-Hwan;Hur, Jin;Chung, Il-Yop
    • Journal of Electrical Engineering and Technology
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    • v.9 no.4
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    • pp.1210-1216
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    • 2014
  • This paper deals with an application of Teager Energy Operator (TEO) and Energy Separation Algorithm(ESA) to detect and determine various voltage waveform distortions like harmonics, inter-harmonics and frequency variation. Because the TEO and DESA algorithm was initially proposed for speech or communication analysis, its applications are limited to some types of waveform in the power quality analysis area. For example, an undistorted voltage signal is similar with a pure sinusoid. A voltage fluctuation is very similar with an amplitude-modulated signal, from the viewpoint of signal theory. And a continuous frequency variation is similar with a frequency-modulated signal, which is also known as a chirp signal. This paper is written to show that the TEO and DESA algorithm can be used for detecting occurrences of the representative waveform distortions and determining their instantaneous information of amplitude and frequency.

The Performance Comparison of Frequency Translators Using RHTL and LHTL Phase Shifters (RHTL과 LHTL 형태의 위상변위기를 이용한 주파수 변환기 성능비교)

  • Han, Heejae;Park, Hongwoo;Kim, Hongjoon
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.63 no.3
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    • pp.371-375
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    • 2014
  • In this paper, we compared the performances of the Right Handed Transmission Line (RHTL) and the Left Handed Transmission Line (LHTL) phase shifters as a frequency translator. Unlike other phase shifters, both phase shifters show a $0^{\circ}-360^{\circ}$ phase variation for a broadband frequency and compact in size which are ideal to use as a frequency translator. For the performance comparison, we fabricated both a RHTL and a LHTL phase shifter to cover 1.5 GHz - 2.4 GHz range with the whole $360^{\circ}$ phase variation. For the frequency range, a LHTL based frequency translator showed a much better performance whose Spurious Free Dynamic Range (SFDR) is 4dB - 17dB higher than the RHTL based frequency translator when the sawtooth modulation freqncy is 11 kHz. This is due to the linear phase-voltage variation of LHTL phase shifter. Furthermore, the LHTL phase shifter shows a less insertion loss and a insertion loss variation than the RHTL phase shifter. Overall, the LHTL based frequency translator outperformed RHTL based freqency translator.

A Study on the Compensating System for the Acoustic Characteristics Caused by the Variation of Distance from Sound Source to Microphone (음원과 마이크로폰 사이의 거리변화에 의한 음향 특성 보정에 관한 연구)

  • Jeoung, Byung-Chul;Choe, Yoon-Sik
    • The Journal of the Acoustical Society of Korea
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    • v.31 no.3
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    • pp.197-204
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    • 2012
  • In this thesis, studied the method to minimize the changes in frequency response and level due to the variation of the distance from the source to the microphone. selecting three microphones (omni directional, cardioid, super cardioid) which are being used generally, frequency responses were measured in accordance with the distance changes. Gotten the difference from the reference as the result of measurement, changed responses for each frequency range were compensated in comparison of the original human vocal source. In low frequency range, the low frequency boost caused by the proximity effect and decrease in accordance with the distance were compensated. The variation in mid-frequency range is comparatively small, however since the mid-range is the most important part of the human vocal signal, were compensated the mid-frequency range in comparison of the reference. The human vocal signal variation in high frequency range is extremely small and the high frequency is compensated close to the original source without difficulty. Understanding the microphone characteristics and compensations, this study showed that the response can be maintain among the change of the distance from the source to the microphone.

The Design of Frequency Variation Compensator for Digital Protection Relay (디지털 보호 계전기를 위한 주파수 변동 보상기의 설계)

  • Kim, Beung-Jin;Lee, Bo-In;Kim, Jung-Han
    • Proceedings of the KIEE Conference
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    • pp.563-565
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    • 2002
  • The designed frequency compensator is proposed to make the estimation of amplitude of fundamental frequency immune to frequency variation. The designed method which has a simple structure and low calculation burden is proper to apply digital protective relay. The results of experimental demonstrate that the frequency compensator has good performance to the estimation of amplitude of fundamental frequency against frequency variation.

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Development of Eddy Current Sensor Considering Frequency and Velocity (주파수 및 속도 변화에 따른 와전류 센서의 개발)

  • Choi, Duck-Su;Lee, Hyang-Beom
    • Proceedings of the KIEE Conference
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    • pp.770-772
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    • 2002
  • In this paper, the eddy current sensor is develped for observing the ability of detecting defect with variation of frequency and velocity. The circuit designed for processing detected voltage and changing frequency is used for eddy current sensor to detect defect with variation of frequency. The ability of eddy current sensor to detect defects is studied with variation of velocity adjusted by rotating the circular plate. This study shows that the ability of eddy current sensor for detecting defect is increased and decreased by frequency. This fact means that the sensor has its best ability at a certain frequency. And the ability of eddy current sensor by velocity is decreased by increased velocity. Therefore, the eddy current sensor has to be developed with consideration of its operation velocity and frequency.

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Current Control of a Single-phase PWM Converter under the Distorted Source Voltage and Frequency Condition (전원 전압 왜곡과 주파수 변동 시 단상 PWM 컨버터의 전류 제어)

  • Ahn, Chang-Heon;Kim, Sang-Hoon
    • The Transactions of the Korean Institute of Power Electronics
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    • v.20 no.4
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    • pp.356-362
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    • 2015
  • This paper presents a current control strategy in the synchronous reference frame for a single-phase PWM converter, which ensures sinusoidal input current control under the distorted source voltage and frequency condition. Given that the distorted source voltage distorts the phase angle for PWM converter control, the input current contains the same harmonics as the source voltage. Aside from the distorted voltage, the variation in source frequency reduces the performance of input current control. To achieve sinusoidal input current control under the distorted source voltage and frequency condition, this paper proposes a compensation strategy of current reference with the distortion component extracted from the phase angle and a detection strategy of frequency variation from the output of a synchronous reference frame phase-lock loop. The experimental results confirm the validity of the proposed method under the distorted source voltage and frequency condition.

Frequency properties of Microstrip Antenna using LiNbO$_3$ (마이크로스트립 안테나의 주파수 이동 특성에 관한 연구)

  • 오승재;우형관;하용만;김영훈;송준태
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.375-378
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    • 2000
  • This paper investigated that resonant frequencies of microstrip patch antenna were tunable when piezoelectric materials were used as the antenna substrates. The resonant frequencies of the microstrip antenna using the piezoelectric substrate, like PZT, LiNbO$_3$ were able to be controlled by applied DC voltage. The frequency variation of the air gap antenna was 29MHz when the voltage variation was 14[kV/cm], and the frequency variation of microstrip patch antenna made of LiNbO$_3$substrate was 29MHz when voltage variation was 6[kV/cm].

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