• Title/Summary/Keyword: Instantaneous frequency

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Convolutive source separation in noisy environments (잡음 환경하에서의 음성 분리)

  • Jang Inseon;Choi Seungjin
    • Proceedings of the KSPS conference
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    • 2003.10a
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    • pp.97-100
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    • 2003
  • This paper addresses a method of convolutive source separation that based on SEONS (Second Order Nonstationary Source Separation) [1] that was originally developed for blind separation of instantaneous mixtures using nonstationarity. In order to tackle this problem, we transform the convolutive BSS problem into multiple short-term instantaneous problems in the frequency domain and separated the instantaneous mixtures in every frequency bin. Moreover, we also employ a H infinity filtering technique in order to reduce the sensor noise effect. Numerical experiments are provided to demonstrate the effectiveness of the proposed approach and compare its performances with existing methods.

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Dynamic Instability and Instantaneous Frequency of a Shallow Arch With Asymmetric Initial Conditions (비대칭 초기 조건을 갖는 얕은 아치의 동적 불안정과 순시 주파수 변화)

  • Shon, Sudeok;Ha, Junhong
    • Journal of Korean Association for Spatial Structures
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    • v.20 no.2
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    • pp.77-85
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    • 2020
  • This paper examined the dynamic instability of a shallow arch according to the response characteristics when nearing critical loads. The frequency changing feathers of the time-domain increasing the loads are analyzed using Fast Fourier Transformation (FFT), while the response signal around the critical loads are analyzed using Hilbert-Huang Transformation (HHT). This study reveals that the models with an arch shape of h = 3 or higher exhibit buckling, which is very sensitive to the asymmetric initial conditions. Also, the critical buckling load increases as the shape increases, with its feather varying depending on the asymmetric initial conditions. Decomposition results show the decrease in predominant frequency before the threshold as the load increases, and the predominant period doubles at the critical level. In the vicinity of the critical level, sections rapidly manifest the displacement increase, with the changes in Instantaneous Frequency (IF) and Instant Energy (IE) becoming apparent.

On-line Faults Signature Monitoring Tool for Induction Motor Diagnosis

  • Medoued, Ammar;Lebaroud, Abdesselem;Boukadoum, Ahcene;Clerc, Guy
    • Journal of Electrical Engineering and Technology
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    • v.5 no.1
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    • pp.140-145
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    • 2010
  • The monitoring and the diagnosis of the faults in induction motors starting from the stator current are very interesting, since it is an accessible and measurable quantity. The spectral analysis of the stator current makes it possible to highlight the characteristic frequencies of the faults but in a wide frequency range depending on half the sampling frequency, making it very difficult to monitor on-line the faults. In order to facilitate the use of the relevant frequencies of machine faults we proposed the extraction of the frequency components using two methods, namely, the amplitude and the instantaneous frequency. The theoretical bases of these methods were presented and the results were validated on a test bench with an induction motor of 5.5 kw.

Broadband Instantaneous Frequency Measurement System Based on the Dual Paths of the Stimulated Brillouin Scattering Effect

  • Jiahong Zhang;Weijie Liao
    • Current Optics and Photonics
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    • v.7 no.4
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    • pp.378-386
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    • 2023
  • A wideband instantaneous frequency measurement (IFM) system is been proposed, designed and analyzed. Phase modulation to intensity modulation conversion is implemented based on the stimulated Brillouin scattering (SBS) effect, and the microwave frequency can be measured by detecting the change in output power. Theoretical analysis shows that the frequency measurement range can be extended to 4fb by adjusting the two sweeping signals of the phase modulators with a difference of 2fb. The IFM system is set up using VPI transmission maker software and the performances are simulated and analyzed. The simulation results show that the measurement range is 0.5-45.96 GHz with a maximum measurement error of less than 9.9 MHz. The proposed IFM system has a wider measurement range than the existing SBS-based IFM system.

An Improved Algorithm for Respiration Signal Extraction from Electrocardiogram Using Instantaneous Frequency Estimation based on Hilbert Transform (힐버트 변환에 기반한 순간주파수 추정을 이용한 개선된 심전도 유도 호흡신호 추출 알고리즘)

  • Park Sung-Bin;Yi Kye-Hyoung;Kim Kyung-Hwan;Yoon Hyoung-Ro
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.53 no.10
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    • pp.733-740
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    • 2004
  • In this paper, an improved algorithm for the extraction of respiration signal from the electrocardiogram (ECG) is proposed. The whole system consists of two-lead electrocardiogram acquisition (lead Ⅰ and Ⅱ), baseline fluctuation elimination, R-wave detection, adjustment of sudden change in R-wave area using moving average, and optimal lead selection. In order to solve the problem of previous algorithms for the ECG-derived respiration (EDR) signal acquisition, we proposed a method for the optimal lead selection. An optimal EDR signal among the three EDR signals derived from each lead (and arctangent of their ratio) is selected by estimating the instantaneous frequency using the Hilbert transform, and then choosing the signal with minimum variation of the instantaneous frequency. The proposed algorithm was tested on 15 subjects, and we could obtain satisfactory respiration signals that shows high correlation (r>0.9) with the signal acquired from the chest-belt respiration sensor.

A new ultrasonic power generator using instantaneous current resultant control-based inverter and its control system

  • Kim, Dong-Hee;Kim, Young-Seok;Yoo, Dong-Wook;Kim, Yo-Hee
    • 제어로봇시스템학회:학술대회논문집
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    • 1987.10b
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    • pp.631-636
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    • 1987
  • The design of ultrasonic transducer energy processing systems requires highly reliable command featuring mechanical frequency tracking and constant velocity control of the ultrasonic transducer with an acoustic load. This paper presents a new conceptional instantaneous current resultant control base high-frequency inverter using self turn-off devices driving an electrostrictive ultrasonic transducer system and its optimum control technique, which is implemented by feed-back of the ultrasonic transducer applied voltage and instantaneous velocity of the transducer vibrating system through a Phase-Locked-Loop control scheme. The feedback voltage corresponding to instantaneous velocity is averaged over a half-period with respect to constant amplitude/constant velocity control strategy. Described are the theory of this signal detection technique and the experimental set-up.

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Design and Fabrication of a C-Band Delay Line Instantaneous Frequency Measurement Receiver with Offset Voltage Compensation (오프셋 전압 보상이 적용된 지연 선로 구조의 C 대역 순시 주파수 측정용 수신기 설계 및 제작)

  • Jeon, Moon-Su;Jeon, Yeo-Ok;Seo, Won-Gu;Bae, Kyung-Tae;Kim, Dong-Wook
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.27 no.1
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    • pp.42-49
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    • 2016
  • In this paper, we design and fabricate an instantaneous frequency measurement receiver with a frequency resolution of 125 MHz which detects and measures continuous signals in 4~6 GHz using path difference of delay lines. The receiver has a 4-bit configuration and consists of power dividers, delay lines, power combiners, power detectors, voltage comparator circuits and so on. The accuracy of the instantaneous frequency measurement is improved by applying offset voltage compensation to the comparator circuits to compensate the frequency-dependent path loss of the delay line and the frequency dependence of power detection.

Open and Short Circuit Switches Fault Detection of Voltage Source Inverter Using Spectrogram

  • Ahmad, N.S.;Abdullah, A.R.;Bahari, N.
    • Journal of international Conference on Electrical Machines and Systems
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    • v.3 no.2
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    • pp.190-199
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    • 2014
  • In the last years, fault problem in power electronics has been more and more investigated both from theoretical and practical point of view. The fault problem can cause equipment failure, data and economical losses. And the analyze system require to ensure fault problem and also rectify failures. The current errors on these faults are applied for identified type of faults. This paper presents technique to detection and identification faults in three-phase voltage source inverter (VSI) by using time-frequency distribution (TFD). TFD capable represent time frequency representation (TFR) in temporal and spectral information. Based on TFR, signal parameters are calculated such as instantaneous average current, instantaneous root mean square current, instantaneous fundamental root mean square current and, instantaneous total current waveform distortion. From on results, the detection of VSI faults could be determined based on characteristic of parameter estimation. And also concluded that the fault detection is capable of identifying the type of inverter fault and can reduce cost maintenance.

Fault Diagnosis Using Wavelet Transform Method for Random Signals (불규칙 신호의 웨이블렛 기법을 이용한 결함 진단)

  • Kim Woo-Taek;Sim Hyoun-Jin;Abu Aminudin bin;Lee Hae-Jin;Lee Jung-Yoon;Oh Jae-Eung
    • Journal of the Korean Society for Precision Engineering
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    • v.22 no.10 s.175
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    • pp.80-89
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    • 2005
  • In this paper, time-frequency analysis using wavelet packet transform and advanced-MDSA (Multiple Dimensional Spectral Analysis) which based on wavelet packet transform is applied fur fault source identification and diagnosis of early detection of fault non-stationary sound/vibration signals. This method is analyzing the signal in the plane of instantaneous time and instantaneous frequency. The results of ordinary coherence function, which obtained by wavelet packet analysis, showed the possibility of early fault detection by analysis at the instantaneous time. So, by checking the coherence function trend, it is possible to detect which signal contains the major fault signal and to know how much the system is damaged. Finally, It is impossible to monitor the system is damaged or undamaged by using conventional method, because crest factor is almost constant under the range of magnitude of fault signal as its approach to normal signal. However instantaneous coherence function showed that a little change of fault signal is possible to monitor the system condition. And it is possible to predict the maintenance time by condition based maintenance for any stationary or non-stationary signals.

Thai Classical Music Matching Using t-Distribution on Instantaneous Robust Algorithm for Pitch Tracking Framework

  • Boonmatham, Pheerasut;Pongpinigpinyo, Sunee;Soonklang, Tasanawan
    • Journal of Information Processing Systems
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    • v.13 no.5
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    • pp.1213-1228
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    • 2017
  • The pitch tracking of music has been researched for several decades. Several possible improvements are available for creating a good t-distribution, using the instantaneous robust algorithm for pitch tracking framework to perfectly detect pitch. This article shows how to detect the pitch of music utilizing an improved detection method which applies a statistical method; this approach uses a pitch track, or a sequence of frequency bin numbers. This sequence is used to create an index that offers useful features for comparing similar songs. The pitch frequency spectrum is extracted using a modified instantaneous robust algorithm for pitch tracking (IRAPT) as a base combined with the statistical method. The pitch detection algorithm was implemented, and the percentage of performance matching in Thai classical music was assessed in order to test the accuracy of the algorithm. We used the longest common subsequence to compare the similarities in pitch sequence alignments in the music. The experimental results of this research show that the accuracy of retrieval of Thai classical music using the t-distribution of instantaneous robust algorithm for pitch tracking (t-IRAPT) is 99.01%, and is in the top five ranking, with the shortest query sample being five seconds long.