• Title/Summary/Keyword: frequency characteristics

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A Study on Functional Characteristics of Electrolarynx "Evada" Using Force Sensing Resistor(FSR) Sensor (Force Sensing Resistor(FSR) Sensor를 이용한 전기인공후두 "Evada"의 기능적 특성에 대한 연구)

  • 박용재;최홍식;이주형;이성민;김광문
    • Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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    • v.9 no.1
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    • pp.11-16
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    • 1998
  • Background and Objectives : Electrolarynx has been used as one of the methods of rehabilitation for the laryngectomees. Previous electrolarynx could not alter frequency and intensity simultaneously. This institute developed an electrolarynx named "Evada" using FSR(force sensing resistor) sensor, which can control the frequency(and/or intensity) simultaneously. This study was performed for the normal control and laryngectomees with three types of electrolarynx (Evada, Servox-inton, Nu-vois) to reveal functional characteristics of Evada Materials and Methods : five laryngectomees and five normal adults were made to express there sentences(discriptive sentence, "You stay here" ; question sentence, "You stay here?" ; exclamation sentence, "You!! stay here!"), using three types of electrolarynx. Frequency change and intensity change from first and last vowel was calculated in three sentences and analyzed statistically by paired T-test. Results : The frequency change in the question sentence and exclamation sentence was more prominent in Evada than in Servox-inton and Nu-vois. The intensity change in the question sentence and exclamation sentence was also more prominent in Evada than in Servox-inton and Nu-vois. Conclusions : Evada could control frequency and intensity simultaneously and control degree of frequency(and/or intensity) according to the pressing force into the button. Evada could adjust continuously frequency and intensity during conversation. So, Evada is better in producing intonation and contrastive stress than Nu-vois and Servox-inton.

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Design and Reliability Analysis of Frequency Locked Loop Circuit with Symmetric Structure (대칭적 구조를 가진 주파수 고정 루프 회로의 설계 및 신뢰성 분석)

  • Choi, Jin-Ho
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.18 no.12
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    • pp.2933-2938
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    • 2014
  • In this paper, the FLL(Frequency Locked Loop) circuit using current conveyor circuit is designed by $0.35{\mu}m$ CMOS process. The FLL circuit is built in a frequency divider, a frequency-to-voltage converter, a voltage subtractor and a oscillator and the circuit blocks have a symmetric structure to improve a reliability characteristics with a process variation. From the simulation results, the variation rate of output frequency is about less than ${\pm}1%$ when the channel length, channel width, resistance and capacitance are varied ${\pm}5%$.

A Fast Parameter Estimation of Time Series Data Using Discrete Fourier Transform (이산푸리에변환과 시계열데이터의 고속 파라미터 추정)

  • Shim, Kwan-Shik;Nam, Hae-Kon
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.55 no.7
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    • pp.265-272
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    • 2006
  • This paper describes a method of parameter estimation of time series data using discrete Fourier transform(DFT). DFT have been mainly used to precisely and rapidly obtain the frequency of a signal. In a dynamic system, a real part of a mode used to learn damping characteristics is a more important factor than the frequency of the mode. The parameter estimation method of this paper can directly estimate modes and parameters, indicating the characteristics of a dynamic system, on the basis of the Fourier transform of the time series data. Real part of a mode estimates by subtracting a frequency of the Fourier spectrum corresponding to 0.707 of a magnitude of the peak spectrum from a peak frequency, or subtracting a frequency of the power spectrum corresponding to 0.5 of the peak power spectrum from a peak frequency, or comparing the Fourier(power) spectrum ratio. Also, the residue and phase of time signal calculate by simple equation with the real part of the mode and the power spectrum that have been calculated. Accordingly, the proposed algorithm is advantageous in that it can estimate parameters of the system through a single DFT without repeatedly calculating a DFT, thus shortening the time required to estimate the parameters.

Quasi-Resonant PWM Converter Controlled by Constant Frequency (일정한 주파수로 제어되는 쿼지 공진형 PWM 컨버터)

  • Joung, Gyubum
    • Journal of Satellite, Information and Communications
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    • v.12 no.2
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    • pp.28-32
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    • 2017
  • In this paper, a quasi-resonant PWM converter, which is controlled by constant frequency, has been suggested. As quasi-resonant converter, the switches of the suggested converter has soft switching characteristics, which can operate to high frequency with high efficiency. Comparing with varied controlled frequency of quasi-resonant converter for controlling output voltage, the suggested converter has advantages which optimize filter and EMI filter design at constant switching frequency. The converter has been analyzed by switch mode analysis which verified soft switching operation. Also, the PWM operation and characteristics of the converter are verified by simulation and experiment of 100 kHz DC-DC converter.

Characteristics of Grounding Impedances of Carbon Compound Grounding Electrodes (탄소혼합물 접지전극의 접지임피던스의 특성)

  • Lee, Kang-Soo;Lee, Bok-Hee
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.25 no.5
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    • pp.54-60
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    • 2011
  • This paper presents characteristics of frequency-dependent grounding impedance and transient grounding impedance for the carbon compound grounding electrode used in the installation of computerized electronic equipment and lightning protection system. The frequency-dependent grounding impedances were measured by applying sinusoidal currents in the frequency range from 100 [Hz] to 10[MHz], and the transient grounding impedances were examined by subjecting the impulse current with the front-time between 1~80[${\mu}s$]. As a result, the ground resistance of the carbon compound grounding electrode is less than that of another type grounding electrodes. The transient grounding impedance is relatively low and the conventional grounding impedance is rather lower than the ground resistance. The frequency-dependent grounding impedance of the carbon compound grounding electrode is capacitive and the grounding impedance is decreased with increasing the frequency of injected currents. Therefore in the case that the carbon compound grounding electrode is jointly used with large-scaled grounding electrodes, it is possible to reduce the high frequency grounding impedance of the integrated grounding electrode system.

Analysis of Frequency Characteristics for the Finite Frequency Selective Surface with the Consideration of Curvature Effect (유한크기 FSS의 곡률효과에 따른 주파수 특성 해석)

  • Hong, Ic-Pyo;Chun, Heung-Jae;Lee, Myung-Gun;Jung, Yong-Sik
    • Journal of the Korea Institute of Military Science and Technology
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    • v.15 no.6
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    • pp.779-785
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    • 2012
  • In this paper, we have analyzed the curvature effects of the finite FSS(frequency selective surface) using the 3-D method of moment using the BiCGSTab algorithm as an iterative method. To validate the analysis method in this paper, we compared the RCS(radar cross section) of PEC(perfect electric conductor) sphere with theoretical results and it shows well agreements. The tripole slot FSSs which have many application in military were selected for the investigation of curvature effect and RCS as a frequency characteristics were observed with the variation of the curvature rate. Simulation results shows that curvature effect can significant effect the passband frequency and bandwidth of FSS. We suggest that the curvature effect must be considered at the stage of design FSS application like FSS radome.

The Influence of Pulse Frequency and Duty Factor on Surface Characteristics during Low Temperature Plasma Nitrocarburizing Treatment of Duplex Stainless Steel (Duplex Stainless Steel의 저온 플라즈마 침질탄화시 Pulse Frequency 및 Duty Factor에 따른 표면 특성평가)

  • Cheon, Chang-Seok;Lee, Insup
    • Journal of the Korean institute of surface engineering
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    • v.47 no.5
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    • pp.221-226
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    • 2014
  • A low temperature plasma nitrocarburizng was implemented on the duplex stainless steel to achieve the enhancement of surface hardness without degradation of its corrosion resistance. Attempts were made to investigate the influence of Pulse frequency and Duty factor of pulsed power in a high Pulse frequency regime on the surface characteristics of the hardened layer. The hardened layer (S-phase) was formed on all of the treated surfaces. Surface hardness reached up to 1300 $HV_{0.1}$ which is about 4.6 times higher than that of the untreated material (280 $HV_{0.1}$). The thickness of the hardened layer tends to increase lightly with the higher Pulse frequency and the higher Duty factor. The corrosion resistance of nitrocarburized duplex stainless steel was almost similar to that of the untreated material. Both the Pulse frequency and the Duty factor do not have a significant influence on the corrosion property of plasma treated duplex stainless steel.

Analysis of Frequency Lock-in Breakings with Random Dithering in a Ring Laser Gyroscope (랜덤 디더링을 이용한 링레이저 자이로 주파수 잠김 깨짐 특성 분석)

  • Woo-Seok Choi;Byung-Yoon Park
    • Korean Journal of Optics and Photonics
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    • v.34 no.2
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    • pp.76-83
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    • 2023
  • In this paper, the results of analyzing the frequency lock-in breaking characteristics of a ring laser gyroscope with random dithering through numerical experiments are presented. By observing the variant features in the frequency lock-in characteristics according to the dithering amplitude noise, it was possible to analyze the minimum noise condition that causes the frequency lock-in to be broken. It was confirmed that the result is closely related to the relative difference between the dynamic frequency lock-in corresponding to the average dithering amplitude and the frequency determined by the Sagnac effect corresponding to an input rotational angular velocity.

Design of Dual-band Frequency Selective Surface Applicable to Wi-Fi 6E System (Wi-Fi 6E 시스템에 적용 가능한 이중대역 주파수 선택표면 구조 설계)

  • Yun-Seok Mun;Sung-Sil Cho;Ic-Pyo Hong
    • Journal of IKEEE
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    • v.27 no.1
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    • pp.71-77
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    • 2023
  • In this paper, a dual-band stopband frequency selective surface that can be applied to Wi-Fi 6E systems is designed to block external interfering signals with adjacent operating frequency spectrum in indoor wireless LAN environments. The proposed frequency selective surface structure has frequency blocking characteristics in the 2.4GHz and 6GHz bands, and is realized through a modified crossed dipole structure and an interlocking puzzle form between unit structures. The proposed structure is designed to have stable frequency response characteristics with respect to incident angle and polarization, and the experimental results show good agreement with the simulation results for incident waves from 0° to 45°.

Biochemical Characteristics and Dietary Intake according to the Frequency of Milk Consumption in Korean Adolescents: Data from the 2010~2011 Korea National Health and Nutrition Examination Survey (한국 청소년의 우유섭취 빈도에 따른 혈액 생화학적 특성 및 영양 섭취: 2010~2011 국민건강영양조사 자료를 이용하여)

  • Kim, Ji Hyun;Kim, Sook-Bae
    • Korean Journal of Community Nutrition
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    • v.25 no.6
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    • pp.485-501
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    • 2020
  • Objectives: The purpose of this study was to examine the biochemical characteristics and dietary intake of adolescents aged 12 to 18 years according to the frequency of milk consumption. Methods: Data from the 2010~2011 Korea National Health and Nutrition Examination Survey was used for the study. The study examined adolescents' (12~18 years) demographic characteristics (house income level, residence region, skipping or not-skipping of breakfast/lunch/dinner, eating-out frequency), anthropometric characteristics (height, weight, weight status), biochemical characteristics (fasting plasma glucose, blood urea nitrogen, creatine, triglycerides, cholesterol, HDL-cholesterol, hemoglobin, hematocrit) and nutrient intakes through quantitative and qualitative evaluation using the Korean Dietary Reference Intakes (KDRI), index of nutrition quality (INQ), nutrition adequacy ratio (NAR) of 3 groups (< 1/week, 1~6/week, ≥ 1/day) according to the frequency of milk consumption. Results: There were significant differences in gender and income levels among the 3 groups. There were no differences in height, weight, and weight status among groups. There were differences in biochemical characteristics and nutrient intake. In boys, there were differences in the mean of BUN and HDL-cholesterol, in quantitative intakes of riboflavin, calcium, phosphorus, potassium by KDRI levels, in qualitative intakes of riboflavin, calcium, phosphorus by INQ and riboflavin, calcium, phosphorus by NAR among 3 groups. In girls, there were differences in the mean of blood urea nitrogen, creatine, HDL-cholesterol, in quantitative intakes of protein, riboflavin, calcium, phosphorus by KDRI levels, in qualitative intakes of riboflavin, calcium, phosphorus by INQ and riboflavin, calcium, phosphorus by NAR among the 3 groups. Conclusions: In Korean adolescents, boys had a higher frequency of milk consumption than girls, and higher the income level, higher the frequency of milk consumption. Consumption of milk appeared to have a positive association with triglycerides, HDL-cholesterol, and indices related to muscle mass. Regular consumption of milk is an important factor in enhancing the intake of riboflavin, calcium, and phosphorus, which adolescents lack. The results of the study indicate a need to prepare an environment and education program to increase milk consumption in adolescents at home and school.