• Title/Summary/Keyword: multi-band filter

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A Filter Synthesis Method for Multi-Band Filter Design (다중 대역 필터 설계를 위한 필터 합성법)

  • Lee, Hye-Sun;Lee, Ja-Hyeon;Lim, Yeong-Seog
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.21 no.11
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    • pp.1259-1268
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    • 2010
  • In this paper, we presented a new LC prototype synthesis method for the multi-band filter. For synthesis a multi-band filter with the required frequency response, we proposed the diagram of poles and zeros, also, we proposed the optimization process for finding the combination of optimized poles and zeros. From the transfer and reflection functions calculated from poles and zeros, we performed the quasi-elliptic LC prototype synthesis of multi-band filter. Using the proposed LC prototype synthesis method of multi-band filter, dual-band filter operating at GSM(880~960 MHz) and ISM(2,400~2,500 MHz) and triple-band filter operating at GSM(880~960 MHz) and ISM(2,400~2,500, 5,725~5,850 MHz) were designed and fabricated.

Reduction Algorithm of Environmental Noise by Multi-band Filter (멀티밴드필터에 의한 환경잡음억압 알고리즘)

  • Choi, Jae-Seung
    • Journal of the Korea Society of Computer and Information
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    • v.17 no.8
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    • pp.91-97
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    • 2012
  • This paper first proposes the speech recognition algorithm by detection of the speech and noise sections at each frame, then proposes the reduction algorithm of environmental noise by multi-band filter which removes the background noises at each frame according to detection of the speech and noise sections. The proposed algorithm reduces the background noises using filter bank sub-band domain after extracting the features from the speech data. In this experiment, experimental results of the proposed noise reduction algorithm by the multi-band filter demonstrate using the speech and noise data, at each frame. Based on measuring the spectral distortion, experiments confirm that the proposed algorithm is effective for the speech by corrupted the noise.

Compact Spatial Triple-Band-Stop Filter for Cellular/PCS/IMT-2000 Systems

  • Kim, Dong-Ho;Yeo, Jun-Ho;Choi, Jae-Ick
    • ETRI Journal
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    • v.30 no.5
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    • pp.735-737
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    • 2008
  • We propose a novel spatial multi-band-stop filter using modified multiple loop array elements to block electromagnetic waves or signals of mobile phones in public facilities. It operates at the following frequency bands: Korean cellular (824 MHz to 894 MHz), Personal Communication Service (PCS) (1.75 GHz to 1.87 GHz), and IMT-2000 (1.92 GHz to 2.17 GHz). Two frequency selective surfaces with modified multiple-loop elements are printed on the top and bottom of a pair-glass pane, which is a pair of glass panes with an air gap between them. A modified multiple-loop element with a meander line is used to make the size of the filter compact. The simulated and measured results show good agreement, which confirms the usefulness of the proposed tri-band spatial filter.

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A half subcarrier guard band spectrum assignment scheme for multi-user FBMC systems

  • Huang, Wei;Xu, Hongbo;Li, Zhongnian
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.16 no.1
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    • pp.350-364
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    • 2022
  • Traditionally, in multi-user multi-carrier systems, the neighboring subband will be gapped by one subcarrier, which is set as guard band to reduce multiple access interference (MAI) between neighboring subbands. The empty subcarrier for guard band will degrade the spectral efficiency of the whole system. In order to enhance the spectral efficiency of multi-user filter bank multiple carrier (FBMC) systems, a new subband allocation method is introduced, in which the neighboring subband is gapped by half subcarrier instead of one subcarrier. Meanwhile, in order to implement the proposed resource allocation scheme, an optimized FBMC prototype filter is designed to decrease the inter-subband interference to the neighboring subband. The detailed simulations about the comparison between the proposed spectrum assignment and traditional FBMC are given, as well as the performance in the different interference scenarios. The simulation results show that the combination of the proposed spectrum assignment scheme and the optimized filter has better performance compared to the traditional scheme. The proposed scheme can be used in the system which serves massive users to get higher spectrum efficiency.

A New Design of Trisection Band-Pass Filter Based on Electromagnetic Simulation (EM 시뮬레이션을 기반으로 한 트라이섹션 대역 통과 여파기의 새로운 설계)

  • Kim, So-Su;Yeom, Kyung-Whan
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.22 no.12
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    • pp.1086-1096
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    • 2011
  • In this paper, we present the trisection band-pass filter with a transmission zero at 2.63 GHz, which has a center frequency of 2.44 GHz, relative bandwidth of 5 %, and return loss of 18 dB, based on a multi-port ElectroMagnetic simulation. The coupling matrix for the trisection filter is calculated and this filter is transformed into band-pass filter prototype through a lossless 2-port circuit transformation. The J-inverter values and slope parameters of each individual resonator are computed using an EM simulation Y-parameters of the filter with multi port. The dimensions of desired filter are determined by matching the computed J-inverter and susceptance slope parameters to those of the prototype band-pass filter. Undesired cross-couplings are found to occur which does not appear in the prototype trisection filter. To overcome the problem of undesired couplings, the filter was optimized to satisfy the same frequency response of prototype filter. The validity of the proposed design method was verified through the implementation of the designed and optimized filter.

Multi-harmonic Suppression Band-Pass Filter for Communication System

  • Zhang, Wenmei;Han, Liping;Ma, Runbo;Mao, Junfa
    • ETRI Journal
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    • v.29 no.4
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    • pp.533-535
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    • 2007
  • For the purpose of decreasing intermodulation distortion, a new multi-harmonic suppression band-pass filter based on a microstrip radial stub is studied. Compared with traditional resonator filters, the new filter can suppress the second, third, and even fourth harmonics directly. The dimension of the filter is about $0.3\;{\lambda}_{g^0}{\times}0.13\;{\lambda}_{g^0}$ (${\lambda}_{g^0}$ is the guiding wavelength at the resonant frequency). Only one gap was introduced, so lower insertion loss can be obtained. Basic agreement between the measured and simulated results has been achieved.

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Broad Dual-band Metamaterial Filter with Sharp Out-of-band Rejections

  • Qi, Limei;Shah, Syed Mohsin Ali
    • Current Optics and Photonics
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    • v.2 no.6
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    • pp.629-634
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    • 2018
  • A broad dual-band terahertz metamaterial filter with sharp out-of-band rejections is designed and demonstrated. The center frequencies of the first and the second bands occur at 0.35 THz and 0.96 THz with 3 dB relative bandwidth of 31% and 17%, respectively. Results are measured using a THz time-domain spectroscopy system that shows agreement with simulations. Physical mechanisms of the broad dual-band resonance are clarified based on transmissions of different structures and surface current density distributions. Influence of structure parameters on the transmission characteristics are discussed. Symmetry of the structure ensures the filter polarization independence at normal incidence. These results supported by the design of the filter could find applications in broad multi-band sensors, terahertz communication systems, and other emerging terahertz technologies.

Design and Fabrication of SiO2/TiO2 Multi Layer Thin Films on Silicon Encapsulation of LED Deposited by E-beam Evaporation for NIR Narrow Band Pass Filter Application (NIR 협대역 투과 필터 응용을 위한 LED 실리콘 봉지재 위에 직접 E-beam으로 증착 된 SiO2/TiO2 다층 박막 설계 및 제작)

  • Kim, Dong Pyo;Kim, Kyung-Seob;Kim, Goo-Cheol;Jeong, Jung-Chae
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.35 no.2
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    • pp.165-171
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    • 2022
  • The SiO2/TiO2 multilayer thin films used for narrow band pass filter were fabricated using E-beam evaporation method. The narrow band pass filter was used to enhance the resolution of spectroscopy and sensor applications with near infrared (NIR) light source. The narrow band pass filter with multilayer thin films were designed with Essential Macleod program. The multilayers of SiO2/TiO2 with 32 layers were deposited on the silicon encapsulation of IR with peak wavelength (λp) of 660 nm and NIR LEDs with λp of 830 nm, 880 nm, and 955 nm. After NIR light passed through the narrow band pass filter, the full width of half maximum of 33.4~48.6 nm became narrow to 20~24 nm owing to the absorption of photons with short or long wavelength of designed band of 20 nm. The SiO2/TiO2 band pass filter fabricated in this study can be used for sensor, optoelectronics, and NIR spectroscopy applications.

A study on the multi-point signal detection, using Passive band-pass filter in FBG Hydrophone (FBG(Fiber Bragg Grating) Hydrophone에서 Passive Band-Pass Filter를 사용한 다중점 신호 검출에 관한 연구)

  • Kim, Kyung-Bok;Kwack, Kea-Dal
    • Journal of Sensor Science and Technology
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    • v.9 no.4
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    • pp.307-315
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    • 2000
  • To set up the arrays system of FBG(Fiber Bragg Grating) Hydrophone sensor and realize the multi-point signal detection for the wide scope underwater, using WDM(Wavelength Division Multiplexing) method and Passive band-pass filter system, underwater acoustic signal detection of the newly designed two FBG Transducers is successfully experimented. As a result of the experiment, it was possible each signal with different frequent signals is detected for the multi-point up to 1.3KHz in underwater. We can, therefore, prove the possibility on the system design of Hydrophone sensor arrays, using the newly made FBG Transducers.

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A Design Method for Third-Band FIR Filters of Equi-Ripple Passband (균일 리플 통과대역 응답을 갖는 1/3 밴드 FIR 필터의 설계)

  • Moon Dong-Wook;Kim Lark-Kyo
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.54 no.9
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    • pp.570-576
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    • 2005
  • In FIR (Finite Impulse Response) filter applications, Nth-band FIR digital filters are known to be important due to their reduced computational requirements. The conventional methods for designing FIR filters use iterative approaches such as the well-known Parks-Mcclellan algorithm. the Parks-Mcclellan algorithm is also used to design Nth-band FIR digital filters. But a disadvantage of the Parks-McClellan algorithm Is that it needs a good amount of design time. This paper describes a direct design method for third-band FIR Filters using Chebyshev polynomial, which provide a reduction in design time over indirect methods such as the Parks-McClellan algorithm. The response of the resulting filter is equi-ripple in passband. The proposed method of design produces a passband response that is equi-ripple to within a minuscule error, compare to that of the Parks-McClellan algorithm.