• Title/Summary/Keyword: waveform design

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Design of a New PN Sequence Waveform for Spread Spectrum Communication (대역 확산 통신에 쓰이는 새로운 PN 시퀀스 파형의 설계)

  • 김발기;은종관
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.20 no.4
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    • pp.61-66
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    • 1983
  • This paper is concerned with the design of a pseudonoise (PN) sequence used in direct-sequence spread spectrum multiple-access (DS/SSMA) communication systems. Here we propose a new waveform, a generalized version of rectangular waveform, which can reduce the multiple access interference to zero as the pulse width becomes narrower. It gives far better performance than either rectangular or sine waveform.

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Design of PDP driving waveform for the addressing problem with wide screen driving (대화면 구동에 따른 데이터 기입 문제 해결을 위한 PDP 구동파형 설계)

  • O, Sun-Taek;Kim, Jun-Hyeong;Lee, Dong-Ho
    • Proceedings of the KIEE Conference
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    • 2003.11c
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    • pp.848-851
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    • 2003
  • Display devices are becoming increasingly important as an interface between humans and machines in the growing information society In display device, PDP(Plasma Display Panel) has many advantages in that wide screen, light weight, thin, wide viewing angle and unaffected by magnetic field. In this paper, modified ramp waveform is suggested by Vt Close Curve, and PDP driving circuit is designed by modified ramp waveform, this modified ramp waveform have more addressing wall voltage better then the old ramp waveform.

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The design of high-voltage rectangular waveform generator (저주파 변압기를 이용한 구형파 증폭시스템)

  • Lee, B.H.;Choi, W.G.;Lim, J.K.;Lee, B.W.
    • Proceedings of the KIEE Conference
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    • 1999.07e
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    • pp.2152-2154
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    • 1999
  • In this paper, we suggested the design rule of high-voltage rectangular waveform generator working in low frequency domain (5Hz $\sim$ 60Hz). Most of the commonly used power electronic switching devices have voltage ratings up to several kV. So it is difficult to design and fabricate high-voltage switching systems with the power electronic devices alone. We have combined IGBTC(1200V, 50A) with the specially designed transformer to get the high-voltage rectangular waveforms up to 40kV. In this work. next two things are the main factors. The first one is design of transformer working low-frequency domain close to 5Hz. And the second one is additional voltage source to floating the transformer voltage output. As a result, we can get frequency-variable and high-voltage rectangular voltage waveform and this can be a more efficient power source of sandpaper manufacturing process.

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OFDM MIMO radar waveform design for targets identification

  • Bai, Ting;Zheng, Nae;Chen, Song
    • ETRI Journal
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    • v.40 no.5
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    • pp.592-603
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    • 2018
  • In order to obtain better target identification performance, an efficient waveform design method with high range resolution and low sidelobe level for orthogonal frequency division multiplexing (OFDM) multiple-input multiple-output (MIMO) radar is proposed in this paper. First, the wideband CP-based OFDM signal is transmitted on each antenna to guarantee large bandwidth and high range resolution. Next, a complex orthogonal design (COD) is utilized to achieve code domain orthogonality among antennas, so that the spatial diversity can be obtained in MIMO radar, and only the range sidelobe on the first antenna needs suppressing. Furthermore, sidelobe suppression is expressed as an optimization problem. The integrated sidelobe level (ISL) is adopted to construct the objective function, which is solved using the Broyden-Fletcher-Goldfarb-Shanno (BFGS) algorithm. The numerical results demonstrate the superiority in performance (high resolution, strict orthogonality, and low sidelobe level) of the proposed method compared to existing algorithms.

Effect of Shifting the Pole-shoe and Damper-bar Centerlines on the No-load Voltage Waveform of a Tubular Hydro-generator

  • Fan, Zhen-nan;Han, Li;Liao, Yong;Xie, Li-dan;Wen, Kun;Wang, Jun;Dong, Xiu-cheng;Yao, Bing
    • Journal of Electrical Engineering and Technology
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    • v.13 no.3
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    • pp.1294-1303
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    • 2018
  • This study optimises the no-load voltage waveform of tubular hydro-generators by a simple design scheme. For different centerlines of the pole shoe and damper bar, the optimisation effects on the no-load voltage waveform are investigated in two tubular hydro-generators with different weighted powers (34 MW and 18 MW). The results are compared with those of the traditional stator-slots skewed design. The quality of the no-load voltage waveform was related to the shifting degree, and the different optimisation effects between the integer slot generator (q = 2) and the fractional slot generator (q = 11/2) were analysed. This research can improve the quality of the power output and no-load voltage waveform, and provide an effective reference for improving the industrial design and manufacture level of tubular hydro-generators.

Design of FMCW radar waveform for flow measurement (유량 측정을 위한 FMCW 레이다 파형 설계)

  • Lee, Changki
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.24 no.1
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    • pp.83-90
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    • 2020
  • A commercial flow measurement radar sensor estimates a quantity of flowed water using surface flow rate. In this way, the amount of water flowing per unit time cannot be measured accurately because of using an estimation result and it can't response environmental changes. For more accurate flow measurements we need width of waterway, water level and distance that water moved per unit time. Commonly two sensors are used to measure water level and flow rate. In this paper, we propose a method to simultaneously measure the water level and surface flow velocity using a single FMCW radar sensor and design the transmission waveform. In order to verify the waveform design, received signal is modelled based on transmission waveform. In addition, we consider phenomenons and problems that may occur in signal processing.

Transmission waveform design for compressive sensing active sonar using the matrix projection from Gram matrix to identity matrix and a constraint for bandwidth (대역폭 제한 조건과 Gram 행렬의 단위행렬로의 사영을 이용한 압축센싱 능동소나 송신파형 설계)

  • Lee, Sehyun;Lee, Keunhwa;Lim, Jun-Seok;Cheong, Myoung-Jun
    • The Journal of the Acoustical Society of Korea
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    • v.38 no.5
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    • pp.522-533
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    • 2019
  • The compressive sensing model for range-Doppler estimation can be expressed as an under-determined linear system y = Ax. To find the solution of the linear system with the compressive sensing method, matrix A should be sufficiently incoherent and x to be sparse. In this paper, we propose a transmission waveform design method that maintains the bandwidth required by the sonar system while lowering the mutual coherence of the matrix A so that the matrix A is incoherent. The proposed method combines two methods of optimizing the sensing matrix with the alternating projection and suppressing unwanted frequency bands using the DFT (Discrete Fourier Transform) matrix. We compare range-Doppler estimation performance of existing waveform LFM(Linear Frequency Modulated) and designed waveform using the matched filter and the compressive sensing method. Simulation shows that the designed transmission waveform has better detection performance than the existing waveform LFM.

Design and Implementation of a Multi Level Three-Phase Inverter with Less Switches and Low Output Voltage Distortion

  • Ahmed, Mahrous E.;Mekhilef, Saad
    • Journal of Power Electronics
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    • v.9 no.4
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    • pp.593-603
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    • 2009
  • This paper proposes and describes the design and operational principles of a three-phase three-level nine switch voltage source inverter. The proposed topology consists of three bi-directional switches inserted between the source and the full-bridge power switches of the classical three-phase inverter. As a result, a three-level output voltage waveform and a significant suppression of load harmonics contents are obtained at the inverter output. The harmonics content of the proposed multilevel inverter can be reduced by half compared with two-level inverters. A Fourier analysis of the output waveform is performed and the design is optimized to obtain the minimum total harmonic distortion. The full-bridge power switches of the classical three-phase inverter operate at the line frequency of 50Hz, while the auxiliary circuit switches operate at twice the line frequency. To validate the proposed topology, both simulation and analysis have been performed. In addition, a prototype has been designed, implemented and tested. Selected simulation and experimental results have been provided.

A Study on Welding Process Algorithm through Real-time Current Waveform Analysis (실시간 공정신호를 통한 용접공정 알고리즘에 관한 연구)

  • Yoon, Jin Young;Lee, Young Min;Shin, Soon Cheol;Choi, Hae Woon
    • Journal of Welding and Joining
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    • v.33 no.4
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    • pp.24-29
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    • 2015
  • The current waveform was analysed to monitor the weld quality in real time process. The acquired current waveform was discretely analysed for the top and bottom limits of peaks as well as the pulse frequency measurement. Fast Fourier Transform was implemented in the program to monitor the pulse frequency in real time. The developed algorithm or program was tested for the validation purpose. The cross-section of weld profile was compared to the current waveform profile to correlate the monitored signal and the actual parts. Pulse frequency was also used as auxiliary tool for the quality monitoring. Based on the results, it was possible to evaluate the quality of welding by measure the current waveform profile and frequency measurement.

Design of Digital Systems for Web -based Pulse Diagnosis Database

  • Lee, Junyoung;Lee, Sungjae;Lee, Myoungho;Kim, Jeonghoon
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.181.4-181
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    • 2001
  • In this study, we have developed the digital hardware system which performs signal processing necessary for the filtering to eliminate noises by inputting pulse wave signals from the sensor group. With a view to obtain clinically effective information, we analyzed structural elements of pulse waveform and, thus, conducted a systematic classification. What is more, this study has conducted researches in the web-based diagnosis data management system of pulse waveform as well as the method of transmitting the data of pulse waveform. In order to set the standard for the documents of the pulse ...

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