• Title, Summary, Keyword: Insertion Loss

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Performance Test and Evaluation of Ship Exhaust Huffier (선박용 소음기 성능 시험 및 평가)

  • Kim, Bong-Ki;Kim, Sang-Ryul;Kim, Hyun-Sil;Shin, Min-Chol
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.158-163
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    • 2008
  • Muffler design in the exhaust system is critical to provide for low noise in shipboard spaces. In an attempt to effectively design the low noise muffler, it is important to evaluate the performance of the muffler considering not only the noise, but also pressure drop as well. For this purpose, a test system of large exhaust muffler for ship propulsion systems was designed based on ISO 7235. The substitution test for determining both the insertion loss and pressure drop of mufflers was carried out. A ship exhaust muffler is considered as a test example and the insertion loss and pressure drop are obtained.

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Exhaust Noise Control of Marine Diesel Engine by using Resonator Type Silencer (공명형 소음기를 이용한 박용 디젤엔진 배기 소음 제어)

  • Lee, Tae-Kyung;Joo, Won-Ho;Bae, Jong-Gug
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.350-354
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    • 2008
  • Low frequency exhaust noise of marine diesel engine is one of the most important noise sources in vessels. However, conventional absorptive silencers are limited because the absorptive material is not effective in low frequency range. In the paper, exhaust noise control of marine diesel engine has been studied by using the resonator type silencer, which was composed of concentric hole-cavity resonators. The acoustic performance of the resonator type silencer was verified by the insertion loss measurement considering flow effect. Consequently, its high performance, about $5{\sim}8dB$ noise reduction, in the low frequency range was confirmed by insertion loss measurements conducted in the ship.

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An Experimental Investigation on Noise Reduction Performance of the Absorption and the Resonance Type Duct Silencers (흡음형과 공명형 덕트 소음기의 소음저감 성능에 관한 실험적 고찰)

  • Lee, Young-Sup;Chung, Kwang-Seop;Lee, Dong-Hoon
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.22 no.12
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    • pp.897-901
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    • 2010
  • A silencer has been widely used for the purpose of suppressing the noises propagated from duct of air conditioning system. The absorption type silencer is usually applied to reduce the noise with high frequency bandwidth. On the order hand, the resonance type silencer is applied to reduce the noise with low-middle frequency bandwidth. The insertion loss of silencer is measured in the reverberation room. The cut-off frequency of reverberation room is 100 Hz. The insertion loss of absorption type silencer is more larger than that for resonance type silencer regardless of changing the flow velocity.

A Study on the Characteristics of Wide Band Matching Connector in Round Coaxial Lines (원형 동축 선로에서 광대역 매칭 커넥터의 특성 연구)

  • Kim, Byeong-Woo
    • Transactions of the Korean Society of Automotive Engineers
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    • v.20 no.5
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    • pp.152-157
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    • 2012
  • In this paper, smoothing plane connector have been proposed as the vehicle connector for the wireless access in vehicular environments (5.925GHz) communication. This smoothing plane connector is designed by considering the properties of critical parameter like smoothing distance of start to end point of contact area. The design simulation and results can be used to determine the most suitable smoothing plane wire dimensions for vehicle communication connector. The optimized WAVE connector inserted the smoothing plane wire has insertion loss less than-0.17dB at 5.925GHz. It provides 20% of insertion loss with good performance. Therefore, the simulated results can be effectively used for optimum design of high frequency connector for vehicle communication.

A Study on the Basic Shape of an MF Evaporator (MF증발기 기초 형상 설계에 관한 연구)

  • Park, Yong-Seok;Seong, Hong-Seok;Suh, Jeong-Se
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.18 no.6
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    • pp.39-44
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    • 2019
  • The evaporator is a key driver of an air conditioning system's efficiency. In this study, we study methods of maximizing the efficiency of a Massey Ferguson (MF) evaporator by measuring how the cooling performance of different shapes vary with temperature. We varied the tube insertion depth as well as the shape of the evaporator's header and tube. When we compare header shapes of "D", "Ellipse", and "Quadrangle" types, we find that the elliptical header creates the smallest pressure loss and the highest temperature difference. Between tube shapes of "Rectangular", "Projection", and "Circular" types, the "Projection" type tube creates the most temperature difference. We also investigated the depth of tube insertion in the header and find that tube insertion of 5 - 10 mm is feasible; we selected the depths of 5, 7, and 10 mm since they corresponded to approximately 30%, 50%, and 70% of the total width of the header. The tube insertion test demonstrated that a tube insertion depth of 7 mm creates the least pressure loss and the highest temperature difference. In conclusion, the optimal evaporator design uses an "Ellipse" type header, "Projection" type tube, and a tube insertion depth between 30 and 50% of the header width.

Design and Fabrication of Diplexer using Lumped Elements (집중 소자를 이용한 다이플렉서 설계 및 제작)

  • Park, Yong-Wook
    • The Journal of the Korea institute of electronic communication sciences
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    • v.7 no.1
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    • pp.9-14
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    • 2012
  • In this study, the diplexer used a separator or a combine of signals was designed and its characteristics were investigated. The diplexer consists of two fixed tuned bandpass filter such as low pass filter(LPF) and high pass filter(HPF) sharing a common part and was simulated. The diplexer with micro-strip structure was fabricated. The LPF of diplexer has insertion loss of -0.4 dB, return loss of -30 dB and 1.6 GHz cut-off frequency and HPF has insertion loss of -0.8 dB, return loss of -30 dB and 1.9 GHz cut-off frequency, respectively.

A Broadband Digital Step Attenuator with Low Phase Error and Low Insertion Loss in 0.18-${\mu}m$ SOI CMOS Technology

  • Cho, Moon-Kyu;Kim, Jeong-Geun;Baek, Donghyun
    • ETRI Journal
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    • v.35 no.4
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    • pp.638-643
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    • 2013
  • This paper presents a 5-bit digital step attenuator (DSA) using a commercial 0.18-${\mu}m$ silicon-on-insulator (SOI) process for the wideband phased array antenna. Both low insertion loss and low root mean square (RMS) phase error and amplitude error are achieved employing two attenuation topologies of the switched path attenuator and the switched T-type attenuator. The attenuation coverage of 31 dB with a least significant bit of 1 dB is achieved at DC to 20 GHz. The RMS phase error and amplitude error are less than $2.5^{\circ}$ and less than 0.5 dB, respectively. The measured insertion loss of the reference state is less than 5.5 dB at 10 GHz. The input return loss and output return loss are each less than 12 dB at DC to 20 GHz. The current consumption is nearly zero with a voltage supply of 1.8 V. The chip size is $0.93mm{\times}0.68mm$, including pads. To the best of the authors' knowledge, this is the first demonstration of a low phase error DC-to-20-GHz SOI DSA.

Acoustic test of the payload fairing of Korea satellite launch vehicle (소형 위성 발사체의 페이로드 페어링부에 대한 음향 가진 시험)

  • Park, S.H.;Seo, S.H.
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.220-223
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    • 2007
  • Acoustic test of the payload fairing of Korea satellite launch vehicle was conducted to verify the performance of acoustic protection system installed inside the payload fairing. This paper briefly introduces the acoustic test procedures and its results. Overall 148 dB acoustic loads were exerted on the payload fairing structures which mated with the upper stage structure of the launch vehicle. In order to verify the increase of insertion loss by the acoustic protection system, two kinds of test were performed. One is conducted with acoustic protection system and the other without acoustic protection system. Internal acoustic loads as well as external ones were measured and the measured insertion losses were compared with the requirement. The results showed that the acoustic protection system increases the insertion loss by more than 6 dB above 125 Hz. They also indicated that some design modification of Helmholtz resonator array is required to increase the insertion loss at a cavity resonant frequency.

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Optimal connection condition study of the plastic optical fiber connector for automobiles (자동차 광 네트워크용 POF 광커넥터 최적 접속 조건 연구)

  • Jung Eun-Joo;Kim Chang-Seok;Jeong Myung-Yung
    • Journal of the Korean Society for Precision Engineering
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    • v.23 no.3
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    • pp.61-68
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    • 2006
  • This paper is to investigate the influence of the endface quality on the loss characteristics of a plastic optical fiber(POF) connector and the stability of new designed sleeve for in-car network service. Using the parameters of the surface roughness and applied load, insertion loss of connector is measured. Endface condition for optimizing the connection is presented by the surface roughness satisfying loss criteria and the stress for minimizing the loss, $R_{rms}=8nm$ and 19 MPa, respectively. By vibration test and dynamic loss measurement, we show the stability of the new designed sleeve.

Design for Frequency Tripler Using Novel Bandpass Filter with Low Insertion Loss (낮은 삽입손실을 갖는 새로운 대역통과 필터를 이용한 주파수 3체배기 설계)

  • Min, Jun-Ki;Cho, Seung-Yong;Kim, Hyun-Jin;Kim, Yong-Hwan;Lee, Kyoung-Hak;Kim, Dae-Hee;Yun, Ho-Seok;Hong, Ui-Seok
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.31 no.10A
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    • pp.1031-1036
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    • 2006
  • This paper proposes a novel BPF structure with less insertion loss and small size instead of the existing coupled line BPF for the output of the tripler using APDP (Anti-Parallel Diode Pair). This proposed BPF consists of the interdigital capacitor and spiral open stub. The proposed BPF has the insertion loss of less than 0.7dB within the band $(16.41{\sim}19.23GHz)$. The conversion loss of the tripler is about $16.6{\sim}18.5dB$ $(flatness<{\pm}1dB)$ at $5.72{\sim}6.28GHz$ of fundamental frequency. Its fundamental frequency and the fifth harmonic suppression characteristic at 6GHz are -32.16dBc and -44.6dBc, respectively And its phase noise attenuation characteristic is about 9.5dB at 100kHz.