• Title/Summary/Keyword: difference-signal

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A Study on Polarization Diversity for the Next Generation Mobile Radio Communications

  • Jung, Hee-Chang;Park, Seung-Keun;Ha, Deock-Ho
    • Journal of Electrical Engineering and information Science
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    • v.3 no.1
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    • pp.117-125
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    • 1998
  • In this paper, in order to investigate the fading reduction effect of narrowband and broadband signals in an indoor multipath propagation environment, both the received narrowband signal while a vehicle unit in motion and the frequency sweeped broadband signal received by vertical polarized antenna, horizontal polarized antenna and circularly polarized antenna are analyzed. Specifically, in order to evaluate polarization diversity effect, we examined the difference of fading reduction effect between the polarization diversity reception and the space diversity reception. Using the correlation coefficient and correlation graph for the polarization diversity branches, the diversity effect is evaluated. And also, using the cumulative distribution for the received signal strength simulated by diversity reception, the diversity effect is also estimated. From the evaluation results it was found that the polarization diversity which use a circularly polarized antenna at the transmitting end and the vertical and horizontal polarized antenna branches at the receiving end is markedly excellent.

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Simulation for the analysis of distortion and electrical characteristics of a two-dimensional BJT (2차원 BJT의 전기적 특성 및 왜곡 해석 시뮬레이션)

  • 이종화;신윤권
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.35D no.4
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    • pp.84-92
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    • 1998
  • A program was developed to analyze the electrical characteristics and harmonic distrotion in a two-dimensional silicon BJT. The finite difference equations of the small signal and its second and thired harmonics for basic semiconductor equations are formulated treating the nonlinearity and time dependence with Volterra series and Taylor series. The soluations for three sets of simultaneous equations were obtained sequantially by a decoupled iteration method and each set was solved by a modified Stone's algorithm. Distortion magins and ac parameters such as input impedance and current gains are calculated with frequency and load resistance as parameters. The distortion margin vs. load resistancecurves show cancellation minima when the pahse of output voltage shifts. It is shown that the distortionof small signal characteristics can be reduced by reducing the base width, increasing the emitter stripe length and reducing the collector epitaxial layer doping concentration in the silicon BJT structure. The simulation program called TRADAP can be used for the design and optimization of transistors and circuits as well as for the calculation of small signal and distortion solutions.

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Ranging Performance for Spoofer Localization using Receiver Clock Offset

  • Lee, Byung-Hyun;Seo, Seong-Hun;Jee, Gyu-In;Yeom, Dong-Jin
    • Journal of Positioning, Navigation, and Timing
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    • v.5 no.3
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    • pp.137-144
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    • 2016
  • In this paper, the performance of ranging measurement, which is generated using two receiver clock offsets in one receiver, was analyzed. A spoofer transmits a counterfeited spoofing signal which is similar to the GPS signal with hostile purposes, so the same tracking technique can be applied to the spoofing signal. The multi-correlator can generate two receiver clock offsets in one receiver. The difference between these two clock offsets consists of the path length from the spoofer to the receiver and the delay of spoofer system. Thus, in this paper, the ranging measurement was evaluated by the spoofer localization performance based on the time-of-arrival (TOA) technique. The results of simulation and real-world experiments show that the position and the system clock offset of the spoofer could be estimated successfully.

Merits of all-electric subsea production control system

  • Oh, Jin-Seok;Kang, Se-Ra
    • Journal of Advanced Marine Engineering and Technology
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    • v.38 no.2
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    • pp.162-168
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    • 2014
  • Recently, researches on all-electric subsea system have been in progress. This paper describes a subsea tree using a lot of electrical signal and subsea control system. The way of subsea control is classified as all-electric systems or electro hydraulic systems. One of that has more merits in terms of cost, weight, power consumption, etc. because it uses electric signal instead of hydraulic signal. This paper describes the difference of each system's power consumption and simulation. As the result, if each system applies the same number of sensors, actuators, etc. The power consumption of all-electric system's load is less than at least 400kWh/day compared to the electro hydraulic system load.

A Study on the Parameter Adaptive Current Controlled PWM Inverter for AC Drives. (교류전동기를 위한 Parameter Adaptive Control 방식의 PWM 인버터에 관한 연구)

  • 황영문;안진우
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.36 no.4
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    • pp.259-266
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    • 1987
  • In order to drive motor control system precisely, the motor is to be controlled by mmfs and current with sinusoidal waveforms. In this paper the Delta Modulation (DM) Technique is used for generating PWM pulse with sinusoidal waveform. However the motor currents yet contain odd harmonics due to leakage inductances, speed and exitation. To reduce harmonics, the parameter adaptive control method is introduced. That is, Req.C parameter of Delta Modulator is controlled adaptively by parameter adaptor. The adaptive signal is achieved by the difference between motor current and reference waveform, and this signal is converted to the voltage commend signal by adaptive mechanism. The test reslts show that this system is operated smoothly over a wide range of motor speed and motor current is controlled to be sinusoidal waveform adaptively.

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Diagnostics on Gear Faults Using Transmission Error : Simulation vs Experiment (전달오차를 이용한 기어고장진단: 해석 vs 실험적 방법론)

  • Park, Jungho;Ha, Jongmoon;Choi, Jooho;Park, Sungho;Youn, Byeng D.
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2014.10a
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    • pp.499-502
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    • 2014
  • This paper presents a comparison study between simulation and experiment for fault diagnostics of a spur gear. In simulation, fault diagnostics using transmission error (TE) was performed and concluded to be valid. In a real experiment, however, it is not as easy to detect faults of gears using TE as in simulation. In this paper, after seeding the various faults like tooth crack of different length, tooth breakage and spalling in test rig, TE was calculated. Then, several signal processing techniques were performed to overcome the limitations of an experiment in detecting the fault signals of TE. After signal processing, we could detect the various faults of spur gears and different amplitude of TE sparks from cracks of different length. Then we discussed the difference between simulation and experment.

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Development of automatic flow control system based on LabView (LabView를 이용한 자동유량제어 시스템의 개발)

  • Kang, Tae-Won;Kim, Du-Seob;Ann, Sung-Gyu
    • Journal of Engineering Education Research
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    • v.19 no.2
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    • pp.3-7
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    • 2016
  • A flow control system was designed and fabricated to control the flow rate of liquid through the pipe. This control system was composed of hardwares and software, hardwares as controller, gate valve, orifice meter and data aquisition board and software as National instruments Labview program. Control of flow rate was executed by adjusting the pneumatic valve located at the center of pipe line based on the control signal generated by LabView PID control algorithm, which converts analog signal measured by pressure difference of orifice to digital signal to adjust pneumatic valve. For the controller setup Ziegler-Nichols tuning technique was applied and control performances were investigated for not only the disturbance but also the set point changes. Developed system showed good control performances in flow control enough to use as teaching tool of feedback control theory and practice in university, and also as industrial application.

Multimodal Curvature Discrimination of 3D Objects

  • Kim, Kwang-Taek;Lee, Hyuk-Soo
    • Journal of the Institute of Convergence Signal Processing
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    • v.14 no.4
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    • pp.212-216
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    • 2013
  • As virtual reality technologies are advanced rapidly, how to render 3D objects across modalities is becoming an important issue. This study is therefore aimed to investigate human discriminability on the curvature of 3D polygonal surfaces with focusing on the vision and touch senses because they are most dominant when explore 3D shapes. For the study, we designed a psychophysical experiment using signal detection theory to determine curvature discrimination for three conditions: haptic only, visual only, and both haptic and visual. The results show that there is no statistically significant difference among the conditions although the threshold in the haptic condition is the lowest. The results also indicate that rendering using both visual and haptic channels could degrade the performance of discrimination on a 3D global shape. These results must be considered when a multimodal rendering system is designed in near future.

Characteristics of Plasma Emission Signals in Fiber Laser Welding of API Steel (IV) - Correlation of Keyhole's Periodic Motion and FFT Analysis Results - (API강재의 파이버레이저 용접시 유기하는 플라즈마의 방사특성 (IV) - 키홀의 주기운동과 FFT분석의 상관성 -)

  • Kim, Jong-Do;Lee, Chang-Je;Suh, Jeong
    • Journal of Welding and Joining
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    • v.31 no.4
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    • pp.28-33
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    • 2013
  • The effects of laser welding beam quality is very large. However, not an analysing case was found for the difference on the plasma emission signal during laser welding according to the beam quality. Therefore, in this study, we compared and evaluated penetration and signal change according to the beam quality at the a similar wavelength band by using a fiber laser and Nd:YAG laser. In addition, we took high speed videography in order to make sure that FFT analysis reflects the actual motion period of keyhole and found the period of video analysis and FFT mostly matched. As a result, it is expected to secure higher reliability than evaluating signal intensity when appling FFT to monitoring.

Dispersion tolerant transmission of the return-to-zero signal with alternate-phase generated from a rational harmonic mode-locked ring laser (유리수차 조화 모드잠김 광섬유 링레이저로부터 발생된 교차 위상 RZ(return-to-zero) 신호의 분산 제어 전송)

  • Jo, Hyun-Jeong;Hwang, Jong-Gyu;Kim, Baek-Hyun;Baek, Jong-Hyun
    • Proceedings of the IEEK Conference
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    • 2006.06a
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    • pp.203-204
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    • 2006
  • We present and demonstrate a novel method of alternate-phase return-to-zero (RZ) signal generation and pulse-amplitude equalization simultaneously in a rational harmonic mode-locked fiber ring laser, using a dual-drive Mach-Zehnder (MZ) modulator. By adjusting the voltages applied to both arms of the modulator, the rational harmonic mode-locked pulse trains are equalized in their amplitudes. In addition to that, the amplitude-equalized pulse trains multiplying the repetition rate at ${\sim}10\;GHz$ have alternate $\pi$ phase difference between adjacent pulses. The alternate-phase RZ signal generated by the proposed method enhances transmission performance through the single-mode fiber (SMF) links without dispersion compensation.

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