• Title/Summary/Keyword: bandpass filter

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다채널 표면 플라즈몬 공명 영상장치를 이용한 자기조립 단분자막의 표면 분석

  • Pyo, Hyeon-Bong;Sin, Yong-Beom;Yun, Hyeon-Cheol
    • 한국생물공학회:학술대회논문집
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    • 2003.04a
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    • pp.74-78
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    • 2003
  • Multi-channel images of 11-MUA and 11-MUOH self-assembled monolayers were obtained by using two-dimensional surface plasmon resonance (SPR) absorption. Patterning process was simplified by exploiting direct photo-oxidation of thiol bonding (photolysis) instead of conventional photolithography. Sharper images were resolved by using a white light source in combination with a narrow bandpass filter in the visible region, minimizing the diffraction patterns on the images. The line profile calibration of the image contrast caused by different resonance conditions at each points on the sensor surface (at a fixed incident angle) enables us to discriminate the monolayer thickness in sub-nanometer scale. Furthermore, there is no signal degradation such as photo bleaching or quenching which are common in the detection methods based on the fluorescence.

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DESIGN AND FABRICATION OF S-BAND DIPLEXER FOR LEO TT&C APPLICATION (저궤도 위성 관제용 S-대역 다이플렉서 설계 및 제작)

  • Ahn, Sang-Il;Park, Dong-Chul
    • Journal of Astronomy and Space Sciences
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    • v.24 no.4
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    • pp.397-408
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    • 2007
  • Diplexer is one of core devices needed to communicate with satellite using single ground antenna by separating uplink and downlink signal. This paper presents the design of the S-band diplexer for LEO TT&C application, especially for KOMPSAT (KOrea Multi-Purpose SATellite). To cope with requirements such as high handling power, low insertion loss, air-cavity resonator with high quality factor was considered as one of design drivers. Design was started with predicting unloaded Q and equivalent circuit from the structure of air-cavity resonator. For the convenience of adjustment, the coupling factor placed between resonators was estimated from COTSEM (Electro-Magnetic) simulator, EESOF $ADS^{TM}$, and expressed with 2-order polynomial regression. To improve the isolation between transmitting part (Tx) and receiving part (Rx), the inductive and capacitive attenuation poles were inserted between $4^{th}\;and\;6^{th}$ resonator respectively. The fabricated diplexer consists of two bandpass filters and each filter has eight resonants. From the measurement, it was shown that major requirements such as 0.5dB of insertion loss, 20dB of return loss and 100dB of isolation were fully satisfied within passband.

Design of PCB Embedded Balanced-to-unbalanced WiMax Duplexer Using Coupled LC Resonators (WiMAX 응용을 위한 결합 공진기 기반의 PCB 내장형 평형신호 듀플렉서의 설계)

  • Park, Ju-Y.;Park, Jong-C.;Park, Jae-Y.
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.1587_1588
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    • 2009
  • In this paper, PCB embedded balanced-to-unbalamced duplexer using coupled LC resonator was introduced for low cost dualband WiMax front-end-module application. In order to obtain the function of bandpass filter and balun transformer, proposed duplexer was configured by using magnetically coupled LC resonator. Out-of-band suppression was enhanced by applying two m-Derived transform circuits to obtain transmission zeros at 2GHz and 4.8GHz. In order to reduce the size of embedded duplexer, BaSrTiO3 (BST) composite high Dk RCC film was applied to improve the capacitance density. This high Dk film provided the capacitance density of 12.2 pF/mm2. The simulation results shows that fabricated duplexer had an insertion loss of 2.9dB and 5.5dB and return loss of 15dB and 16dB for 2.5GHz~2.6GHz and 3.5GHz~3.6GHz, respectively. The maximum magnitude and phase imbalance were 0.01dB and 0.17dB, and 1degree and 2degree in its passband, respectively. The out-of-band suppression was observed approximately 29dB and 40dB below 1.9GHz and over 4.5GHz, respectively. It has a volume of 6 mm $\times$ 7 mm $\times$ 0.7 mm (height).

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A Study on Hybrid Split-Spectrum Processing Technique for Enhanced Reliability in Ultrasonic Signal Analysis (초음파 신호 해석의 신뢰도 개선을 위한 하이브리드 스플릿-스펙트럼 신호 처리 기술에 관한 연구)

  • Huh, H.;Koo, K.M.;Kim, G.J.
    • Journal of the Korean Society for Nondestructive Testing
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    • v.16 no.1
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    • pp.1-9
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    • 1996
  • Many signal-processing techniques have been found to be useful in ultrasonic and nondestructive evaluation. Among the most popular techniques are signal averaging, spatial compounding, matched filters and homomorphic processing. One of the significant new process is split-spectrum processing(SSP), which can be equally useful in signal-to-noise ratio(SNR) improvement and grain characterization in several specimens. The purpose of this paper is to explore the utility of SSP in ultrasonic NDE. A wide variety of engineering problems are reviewed, and suggestions for implementation of the technique are provided. SSP uses the frequency-dependent response of the interfering coherent noise produced by unresolvable scatters in the resolution range cell of a transducer. It is implemented by splitting the frequency spectrum of the received signal by using gaussian bandpass filter. The theoretical basis for the potential of SSP for grain characterization in SUS 304 material is discussed, and some experimental evidence for the feasibility of the approach is presented. Results of SNR enhancement in signals obtained from real four samples of SUS 304. The influence of various processing parameters on the performance of the processing technique is also discussed. The minimization algorithm, which provides an excellent SNR enhancement when used either in conjunction with other SSP algorithms like polarity-check or by itself, is also presented.

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Analysis of Galileo GIOVE-A E1 Signal and RF Front-End Bandwidth Effects (갈릴레오 GIOVE-A E1 신호 분석 및 RF 프론트엔드 대역폭 영향 분석)

  • Lee, Byung-Hyun;Im, Sung-Hyuck;Jee, Gyu-In;Ko, Sun-Jun
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.36 no.8
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    • pp.767-773
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    • 2008
  • Galileo is a new civil Global Navigation Satellite System(GNSS) developed by Europe. GIOVE-A, a satellite to test Galileo system performance, transmits navigation signal on orbit. Evaluation of Galileo system and development of Galileo receiver needs to analyze GIOVE-A signals. In this paper, we received GIOVE-A signals and processed it using GIOVE-A Interface Control Document(ICD). Signal acquisition, tracking and navigation message decoding made grasping current signal status possible. Bandwidth increase by BOC modulation is one of the difference from GPS. Therefore, we investigated feasibility of conventional GPS L1 RF front-end to receive GIOVE-A E1 signal by evaluation of receiving performance of navigation signal on each bandpass filter of RF front-end.

Improvement of DTMF Tone Detection in ARS System (자동응답시스템에서 DTMF신호음 검출 개선에 관한 연구)

  • Kim, Hee-Dong;Kim, Je-Woo;Hong, Young-Jin
    • The Journal of the Acoustical Society of Korea
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    • v.15 no.6
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    • pp.110-116
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    • 1996
  • In this paper a novel method improving the accuracy of DTMF tone reception in ARS system is proposed. ARS system should allow users to generate DTMF signals while it is sending voice guidance. It is not unocmmon, in this case, that a portion of transmitting voice signals cross-talks to the receiving channel and it often results in interfering with the receiving DTMF signals. Serious degradations including DTMF tone missing, false alarm and so forth have been introduced for the above reason. To overcome this phenomena, we have proposed a way eliminating the frequency spectra representing DTMF signals bands from the transmitting voice signal by using notch filters. This method also employs bandpass filters of which the frequency responses are reciprocal to those of the notch filters incorporated with the DTMF receiver. It is shown that a drastic improvement has been achieved with respect to the DTMF tone detection with little deterioration of voice guidance quality.

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Design of a Metamaterial-Based Low-Profile Antenna Mounted on LEO/Cube Satellites (저궤도 큐브위성 탑재용의 메타물질형 저자세 안테나의 설계)

  • Han, Dajung;Lee, Changhyeong;Park, Heejun;Lee, Jihye;Kahng, Sungtek
    • Journal of Satellite, Information and Communications
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    • v.12 no.1
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    • pp.94-100
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    • 2017
  • In this paper, we suggest a design method of a metamaterial-based low-profile antenna working at 425 MHz for LEO/Cube satellites. Satellites play an important role in linking th remote nodes in a wireless communication network and covering wide areas of the globe. Especially, an increasing number of universities or individuals aspire having their own satellites and build low-budget structures such as cube satellites in LEO and the ways to reduce the sizes of their satellites. Since the antenna occupies a major portion of the satellite surface, the antenna should be miniaturized for lighter weight. The proposed metamaterial low-profile antenna, unlike the conventional patch antenna, produces such a zeroth-order resonance to create an omnidirectional radiation pattern. Also, it is connected to a UHF waveguide bandpass filter as the feeding system to examine the possible change in the situation that the antenna is combined with the system. The performances of the monopole and proposed metamaterial antennas are compared to one another.

A Study on Implementation and Performance Evaluation of Wideband Receiver for the INMARSAT-B Satellite Communications System (INMARSAT-B형 위성통신용 광대역 수신단 구현 및 성능평가에 관한 연구)

  • 전중성;임종근;김동일;김기문
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.5 no.1
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    • pp.166-172
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    • 2001
  • A RF wideband receiver for INMARSAT-B satellite communications system was composed of low noise amplifier and high gain amplifier, The low noise amplifier used to the resistive decoupling circuit for input impedance matching and self-bias circuits for low noise. The high gain amplifier consists of matched amplifier type to improve receiver gain. The active bias circuit can be used to provide temperature stability without requiring the large voltage drop or relatively high-dissipated power needed with a bias stabilization resistor. The bandpass filter was used to reduce a spurious level. As a result, the characteristics of the receiver implemented here show more than 60 dB in gain and less than 1.8:1 in input and output voltage standing wave ratio(VSWR), especially the carrier to noise ratio which is input signal level -126.7 dB m at 1537.5 MHz is a 45.23 dB /Hz at a 1.02 kHz.

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Advanced Synchronous Reference Frame Controller for three-Phase UPS Powering Unbalanced and Nonlinear Loads (3상 무정전 전원장치에 적합한 새로운 구조의 동기좌표계 전압제어기)

  • Hyun Dong-Seok;Kim Kyung-Hwan
    • The Transactions of the Korean Institute of Power Electronics
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    • v.10 no.5
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    • pp.508-517
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    • 2005
  • This paper describes a high performance voltage controller for 3-phase 4-wire UPS (Uninterruptible Power Supply) system, and proposes a new scheme of synchronous reference frame controller in order to compensate for the voltage distortions due to unbalanced and nonlinear loads. Proposed scheme can eliminate the negative sequence voltage component due to unbalanced loads and also reduce the harmonic voltage component due to non-linear loads, even when the bandwidth of voltage control loop is a very low. In order to compensate for the effects of unbalanced loads, the synchronous reference frame controller with the positive and negative sequence computation block is proposed, and the synchronous frame controller with a bandpass filter is proposed to compensate for the selected harmonic frequency of output voltage. The effectiveness of the proposed scheme has been investigated and verified through computer simulations and experiments by a 30kVA UPS.

Imaging of self-assembled monolayers by surface plasmon microscope (표면 플라즈몬 현미경을 이용한 자기조립 단분자막의 이미징)

  • 표현봉;신용범;윤현철;양해식;김윤태
    • Korean Journal of Optics and Photonics
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    • v.14 no.1
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    • pp.97-102
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    • 2003
  • Multi-channel images of 11-MUA(11-Mercaptoundecanoic acid) and 11-MUOH(11-Mercaptoundecanol) self-assembled monolayers were obtained by using two-dimensional surface plasmon resonance (SPR) absorption. The patterning process was simplified by exploiting direct photo-oxidation of thiol bonding (photolysis) instead of conventional photolithography. Sharper images were resolved by using a white light source in combination with a narrow bandpass filter in the visible region, minimizing the diffraction patterns on the images. The line profile calibration of the image contrast caused by different resonance conditions at each point on the sensor surface (at a fixed incident angle) enables us to discriminate the monolayer thickness in nanometer scale. Furthermore, there is no signal degradation such as photo bleaching or quenching, which are common in the detection methods based on fluorescence.