• Title/Summary/Keyword: Tuneable Filter

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Implementation of Tuneable Filter Using CPW Coupled Line and Varactor Diode

  • Park, Jeong-Heum
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.20 no.9
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    • pp.40-44
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    • 2006
  • This study investigated a new tuneable bandpass filter based on coplanar waveguide coupled line structure, and using the varactor diode for tuning the center frequency of the filter. The filter was designed by a commercial simulator and had a tuning range of 180[MHz] from 0.95[GHz] to 1.13[GHz]. The filter acceptable values regarding the insertion loss was less than 3[dB] and its return loss greater than 12[dB]. The figure of merit of the implemented tuneable filter increased with the reverse bias voltage up to 14[V] on the varactor diode. The proposed filter has a promising future as it can be used in integration processes and in various materials as substrate.

Optical performance monitoring in 16CH WDM system, using FFP-TF (FFP-TF를 활용한 OPM의 16CH WDM시스템 광 성능 모니터링)

  • 이동선
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.28 no.8A
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    • pp.657-662
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    • 2003
  • The OPM(optical performance monitoring module) is needed in order to monitor optical performance. the most importance of OPM is to measure the wavelength of optical signal. In the past time, it was very difficult to get the wavelength value because they used pilot tone. Since then, using AWG(arrayed waveguide grating) and AOTF(acousto optic tuneable filter), the wavelength and the transmission qualify for multi channel signal have been monitored. In this paper, we chose the fiber fabry-perot wavelength variable filter which be evaluated for optical resolution ability to excellent, so that FBG(fiber bragg grating) was used for setting reference wavelength because chose a wavelength variable filter.

Implementation and Verification of Linear Phase filter with Variable Cutoff Frequency for PCM/FM transmission (PCM/FM 전송을 위한 가변 컷오프 주파수 특성의 선형위상 필터 구현 및 검증)

  • Lee Sang-Rae;Ra Sung-Woong
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.31 no.7C
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    • pp.713-724
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    • 2006
  • The purpose of this study is to design, implement and verify the pre-modulation filter with the variable -3dB cutoff frequency and linear phase response for bandlimiting the allocation of radio frequency bandwidth for PCM/FM transmission. For the design of this required filter, the digital FIR filter, DAC system and tuneable 2nd order LPF have been constructed and simulated according to the attenuation characteristic requirement of the amplitude frequency response by each stage. From these results, we have implemented the filter and verified the analog conversion hardware part which is composed of DAC system and tuneable 2nd order LPF for the interpolation of the discrete sequences. Especially this paper proposes and carries out the verification processes using the tone generator and the calibration procedures for more precise frequency response of the filter.

Characterization of Ferroelectric Thin Film in Microwave Region (마이크로파대에서의 강유전 박막 유전 특성 평가)

  • Park, Jeong-Heum
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.10
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    • pp.1061-1067
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    • 2004
  • In this study, ferroelectric (Ba,Sr)TiO$_3$ and high temperature superconductor YBCO thin films were fabricated by PLD (Pulsed Laser Deposition) method and tuneable bandstop filters were implemented with two different IDC(Interdigital Capacitance) gap patterns, 20${\mu}{\textrm}{m}$ and 30${\mu}{\textrm}{m}$ using these two thin film layers. The resonant frequency was changed by DC bias voltage. By comparing measured results with simulation, the dielectric properties of ferroelectric thin film have been extracted. The permittivity was 820 ~ 900 at 30 K and had an acceptable error range but the loss tangent had a great difference, 0.018 in 30${\mu}{\textrm}{m}$ IDC gap pattern and 0.037 in 20 ${\mu}{\textrm}{m}$.

Fabrication and characterization of optical fiber fabry-perot tunable filter for WDM transmission (WDM 전소용 광섬유 fabry-perot 가변 광필터의 제작 및 특성 분석)

  • 김윤중;김창민;김명진;윤대원
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.35D no.3
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    • pp.70-81
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    • 1998
  • Fiber-Fabry-Perot (FFP) tunable filters, the essential component of WDM transmission, were designed, fabricated and characterized. Multi-layered thin film mirrors that consists of an optical collimater's corss section as a substrate and TiO$_{2}$SiO$_{2}$ alternating multi-layered films as a filter wer designed by means of the transfer matrix method. Fabricated mirrors showed the high reflectivity over around 98% as expected. After fabricating the tuneable filters using PZT, we measured FSR, FWHM, finesse , crosstalk and insertion loss, confirming that the built devices satisfied the optical filter's specifications required in the SEDM transmission systems.

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Performance Comparison of Channelization Schemes for Flexible Satellite Transponder with Digital Filter Banks (디지털 필터뱅크 기반 플렉서블 위성중계기를 위한 채널화 기법의 성능비교 연구)

  • Lee, Dong-Hun;Kim, Ki-Seon
    • Journal of the Korea Institute of Military Science and Technology
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    • v.13 no.3
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    • pp.405-412
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    • 2010
  • The purpose of this paper is to compare complexity and to assess flexibility of competing transponder architectures for satellite communication services. For performance comparison, we consider three channelization techniques: digital down converter(DDC) based on the use of the cascaded integrator-comb(CIC) filter, tuneable pipeline frequency transform(T-PFT) based on the tree-structure(TS) and variable oversampled complex-modulated filter banks(OCM-FB) based on the polyphase FFT(P-FFT). The comparison begins by presenting a basic architecture of each channelization method and includes analytical expressions of the number of multiplications as a computational complexity perspective. The analytical results show that DDC with CIC filter requires the heavy computational burden and the perfect flexibility. T-PFT based on the TS provides the almost perfect flexibility with the low complexity over DDC with the CIC filter for a large number of sub-channels. OCM-FB based on the P-FFT shows the high flexibility and the best computational complexity performance compared with other approaches.

Linear Interrogation of Distributed Fiber Grating Temperature Sensor Network using a Fabry-Perot ITU Filter (Fabry-Perot ITU 필터의 기준파장을 이용한 분배형 광섬유 격자 온도센서의 선형복조)

  • Park, Hyoung-Jun;Song, Min-Ho
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.21 no.7
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    • pp.54-60
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    • 2007
  • We constructed a fiber-optic temperature sensor system using a sensor array with 15 fiber Bragg gratings for distributed temperature monitoring in electrical power systems. A polynomial fitting algorithm was used to compensate the nonlinear action of the MEMS tuneable wavelength filter used for Bragg wavelength demodulation Fixed passband wavelengths from a Fabry-Perot ITU filter were used as reference wavelengths for the fitting algorithm which obtained constant accuracy regardless of the wavelength scanning range and frequency. About 0.18[%] of linearity error compared to reference thermocouple thermometer has been obtained in the preliminary experimental results.