• Title, Summary, Keyword: Reference Signal

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Comparison of On-Line Diagnotic Methods on Multi-Channel Signals in Nuclear Plant (원자력발전소 다채널 신호의 온라인 진단방법 비교)

  • Lee, Kwang-Dae;Yang, Seung-Ok
    • Proceedings of the KIEE Conference
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    • pp.705-708
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    • 2003
  • In this paper, we have evaluated the methods to generate the reference signal for the diagnosis of multi-channel signals. The channel signal integrity can be known by the difference between the reference signal and each channel value. The generation method of reference signal is important in the diagnosis of multi-channel measurement system. The continuous weighting average method rejects the abnormal signal using weighting method and makes the reference signal using sumation of all channel values. This gives the simple and reasonable reference signal. The principle component analysis, one of the multivariate analysis methods, and the neural network method give the reliable reference signal by using signal models, and learning algorithm. Two methods can make the reliable reference if all signals are normal, but any signal having the drift have an effect on the reference.

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Phase Retrieval Using an Additive Reference Signal: I. Theory (더해지는 기준신호를 이용한 위성복원: I. 이론)

  • Woo Shik Kim
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.31B no.5
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    • pp.26-33
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    • 1994
  • Phase retrieval is concerned with the reconstruction of a signal from its Fourier transform magnitude (or intensity), which arises in many areas such as X-ray crystallography, optics, astronomy, or digital signal processing. In such areas, the Fourier transform phase of the desired signal is lost while measuring Fourier transform magnitude (F.T.M.). However, if a reference 'signal is added to the desired signal, then, in the Fourier trans form magnitude of the added signal, the Fourier transform phase of the desired signal is encoded. This paper addresses uniqueness and retrieval of the encoded Fourier phase of a multidimensional signal from the Fourier transform magnitude of the added signal along with the Fourier transform magnitude of the desired signal and the information of the additive reference signal. In Part I, several conditions under which the desired signal can be uniquely specified from the two Fourier transform magnitudes and the additive reference signal are presented. In Part II, the development of non-iterative algorithms and an iterative algorithm that may be used to reconstruct the desired signal(s) is considered.

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Phase Retrieval Using an Additive Reference Signal: II. Reconstruction (더해지는 기준신호를 이용한 위성복원: II. 복원)

  • Woo Shik Kim
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.31B no.5
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    • pp.34-41
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    • 1994
  • Phase retrieval is concerned with the reconstruction of a signal from its Fourier transform magnitude (or intensity), which arises in many areas such as X-ray crystallography, optics, astronomy, or digital signal processing In such areas, the Fourier transform phase of the desired signal is lost while measuring Fourier transform magnitude (F.T.M.). However, if a reference 'signal is added to the desired signal, then, in the Fourier trans form magnitude of the added signal, the Fourier transform phase of the desired signal is encoded This paper addresses uniqueness and retrieval of the encoded Fourier phase of a multidimensional signal from the Fourier transform magnitude of the added signal along with Fourier transform magnitude of the desired signal and the information of the additive reference signal In Part I, several conditions under which the desired signal can be uniquely specified from the two Fourier transform magnitudes and the additive reference signal are presented In Part II, the development of non-iterative algorithms and an iterative algorithm that may be used to reconstruct the desired signal (s) is considered

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A Design and Measurement of a Reference Signal Generator for a Radar System

  • Kim, Dong-Sik;Kim, Min-Chul;Lee, Su-Ho;Baik, Seung-Hun;Kwon, Ho-Sang;Jeong, Myung-Deuk
    • Journal of electromagnetic engineering and science
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    • v.9 no.3
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    • pp.118-123
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    • 2009
  • This paper discusses the design and fabrication of a reference signal generator for a naval radar system, including the vibration environment test. The transmit signals of the S-band radar system are synthesized by the reference signal and the phase noise must lower than - 130 dBc/Hz at a 10 kHz offset frequency. To achieve this specification, the phase noise of the reference signal needs to be less than -165 dBc/Hz at a 10 kHz offset. For achieving very low phase noise performance by the reference signal generator, the phase locked loop technique is applied with a 10 Hz loop bandwidth. Also, this reference signal generator has ${\pm}0.35\;ppb$ short-term stability to minimize instant phase errors and high vibration sensitivity against a ship's shaking, unbalanced rotating of antennas and so on.

Accurate Current Reference Generator for Active Power Filters (능동전력필터의 정밀 기준신호 발생기)

  • Bae Byung-Yeol;Jon Young-Soo;Han Byung-Moon;Soh Yong-Choel
    • Proceedings of the KIPE Conference
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    • pp.575-578
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    • 2004
  • The performance of an active power filter(APF) depends on the inverter characteristic, the control method, and the accuracy of reference signal generator. The accuracy of reference generator is the most critical item to determine the performance of active power filter. This paper introduces a novel reference signal generator composed of improved adaptive predictive filter. The performance of proposed reference signal generator was first verified through a simulation with MATLAB. Furthermore, the application of feasibility was evaluated through experimenting with a single-phase APF prototype based on the proposed reference generator, which was implemented using the TMS320C31 floating-point signal processor. Both simulations and experimental results confirm that our reference signal generator can be used successfully in practical active power filters.

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Active Control of Noise from Fan Blowers in Tower-type Air Conditioners (타워형 에어컨 송풍기 소음의 능동제어)

  • Ryu, Kyungwan;Hong, Chinsuk;Jeong, Wei Bong
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.27 no.1
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    • pp.87-93
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    • 2017
  • This paper investigates active noise control of tower-type air conditioners using the filtered-x least mean square (FXLMS) algorithm to reduce fan blower noise transmission. Firstly, the main components required for the active control system including the error sensor, the control speaker and the reference sensors are selected. Since the noise could significantly reduce if the reference signal includes every frequency response information, a various reference signals from accelerometers and a microphone are used. Secondly, the controller based on the FXLMS algorithm with a single-channel reference signal is implemented. Then, the control performance is examined experimentally for the different reference signals. It is found that the accelerometer signal well possesses the motor vibration related noise and a microphone signal could includes global noise. When using the reference signal with a microphone located near the motor and the fan blower, the active control system reduces the noise globally, except for several peaks.

Novel Reference Signal Generator for Active Power Filter Using Improved Adaptive Predictive Filter (개선된 적응 예측 필터를 이용한 새로운 능동전력필터용 기준신호발생기)

  • Bae, Byung-Yeul;Kim, Hee-Joong;Han, Byung-Moon
    • Proceedings of the KIEE Conference
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    • pp.212-216
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    • 2003
  • The performance of active power filter depends on the inverter characteristic, the control method, and the accuracy of reference signal generator. The accuracy of reference generator is the most critical item to determine the performance of active power filter. This paper introduces a novel reference signal generator composed of improved adaptive predictive filter. The performance of proposed reference signal generator was verified by means of simulation with MATLAB. The simulation result confirm that the proposed reference signal generator can be utilized for the active power filter.

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Active noise control algorithm based on noise frequency estimation (소음 주파수 추정 기법을 이용한 능동소음제어 알고리즘)

  • 김선민;박영진
    • 제어로봇시스템학회:학술대회논문집
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    • pp.321-324
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    • 1997
  • In this paper, Active Noise Control(ANC) algorithm is proposed based on the estimated frequency estimator of the reference signal. The conventional feedforward ANC algorithms should measure the reference and use it to calculate the gradient of the squared error and filter coefficients. For ANC systems applied to aircrafts and passenger ships, engines from which reference signal is usually measured is so far from seats where main part of controller is placed that the scheme might be difficult to implement or very costly. Feedback ANC algorithm which doesn't need to measure the reference uses the error signal to update the filter and is sensitive to unexpected transient noise like a sneeze, clapping of hands and so on The proposed algorithm estimates frequencies of the desired signal in real time using adaptive notch filter. New frequency estimation algorithm is proposed with the improved convergence rate, threshold SNR and computational simplicity. Reference is not measured but created with the estimated frequencies. It has strong similarity to the conventional feedback control because reference is made from error signal. Enhanced error signal is used to update the controller for better performance under the measurement noise and impact noise. The proposed ANC algorithm is compared with the conventional feedback control.

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Performance Analysis of Improved Adaptive Predictive Filter to Generate Reference Signal in Active Power Filter (능동전력필터의 기준신호발생을 위한 개선된 적응예측필터의 성능 분석)

  • Bae Byung-Yeol;Baek Seung-Taek;Han Byung-Moon
    • The Transactions of the Korean Institute of Power Electronics
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    • v.9 no.6
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    • pp.592-601
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    • 2004
  • The performance of active power filter depends on the inverter characteristic, the control method, and the accuracy of reference signal generator. The accuracy of reference signal generator is the most critical item to determine the performance of active power filter. This paper introduces a novel reference signal generator composed of improved adaptive predictive filter. The performance of proposed reference signal generator was verified by means of simulation with MATLAB. The application feasibility was evaluated by building and experimenting a single-phase active power filter based on the proposed reference generator, which was implemented in the DSP(digital signal processor) TMS320C31. Both simulation and experimental results confirm that the proposed reference signal generator can be utilized for the active power filter.

Study of Cross Correlation Using DRS(Delayed Reference Sample) for Precision Time Measurement of Input Signal on Multilateration (다변측정감시시스템 신호 입력 시각 정밀 측정을 위한 DRS(Delayed Reference Sample)를 이용한 Cross Correlation 방안 연구)

  • Chang, Jae-Won;Lee, Sang Jeong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.46 no.3
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    • pp.244-250
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    • 2018
  • Multilateration acquires the transponder signal of target from receivers installed on the ground and calculates the position of the target using the difference of the signal acquisition time of each receiver. One of the factors that influence the positioning accuracy of Multilateration using the TDOA calculation method is the error due to the precision measurement of signal input time. When measuring the signal input time at the receiver, the input signal is sampled using the reference clock of the receiver and a reference sample having the same sampling rate is applied to the cross correlation technique. Therefore, the accuracy of the signal input time is proportional to the reference clock. In this paper, the algorithm for precisely measuring the signal input time by performing cross correlation between the input signal of the receiver and DRS(Delayed Reference Sample) is proposed. In order to verify this, we implemented the pulse signal of the transponder that is transmitted from the target using Matlab. Through the simulation, cross correlation between the proposed DRS and the input signal was performed. From this result, the performance of the precise measurement of signal input time was analyzed.