• Title/Summary/Keyword: Dual filters

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Design of Dual-Mode Digital Down Converter for WCDMA and cdma2000

  • Kim, Mi-Yeon;Lee, Seung-Jun
    • ETRI Journal
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    • v.26 no.6
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    • pp.555-559
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    • 2004
  • We propose an efficient digital IF down converter architecture for dual-mode WCDMA/cdma2000 based on the concept of software defined radio. Multi-rate digital filters and fractional frequency conversion techniques are adopted to implement the front end of a dual-mode receiver for WCDMA and cdma2000. A sub-sampled digital IF stage was proposed to support both WCDMA and cdma2000 while lowering the sampling frequency. Use of a CIC filter and ISOP filter combined with proper arrangement of multi-rate filters and common filter blocks resulted in optimized hardware implementation of the front end block in 292k logic gates.

Image Restoration in Digital Radiography Using Dual Sensor Wiener Filer (이중센서 위너필터를 이용한 디지탈 라디오 그라피 영상 복원)

  • Lee, Tae-Soo;Park, Kwang-Suk;Min, Byoumg-Goo;Lim, Jeong-Gee;Han, Man-Chung
    • Journal of Biomedical Engineering Research
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    • v.10 no.3
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    • pp.293-302
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    • 1989
  • A Dual Sensor Wiener Filter technique was used to improve the image quality of the scanning type digital radiographic system (resolution and SNR). In this method, two images were acquried simultaneously using two sensors with high and low resolution and SNR values. Using the cross Power spectrum between dual sensor outputs of the same chest radiographic image. we design a new type of Wiener Filter and implement it with fast algorithm. We compared the performance of this new dual sensor filter with conventional single sensor filters (Wiener Filter and Parametric Projec- tion Filter) . In simulation studies, it is shown that this new method has SNR improvement of 1-3 dB better than conventional filters.

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A 20 GHz low-loss dual - mode channel filter using mode matching method (모드정합법을 이용한 20GHz 저손실 이중모드 채널여파기)

  • 정근욱;이재현;유경완;강성춘
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.34D no.10
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    • pp.53-59
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    • 1997
  • In this paper, we present a 20 GHz low-loss dual-mode channel filter designed by using mode matching method. The performance of dual-mode channel filter mainly depends on iris characteristics. Therefore the exact design of iris is the key point to get good frequncy response of the filter. MOde matching technique is widely used ot design several kinds of waveguide filters because it is simple in theory and can easily calculate the scattering matrices at the discontinuities with simple structure like iris coupled filters. Additionally the effect for finite thickness of the iris in the dual-mode cavity iflter is analyzed by te full-wave method, providing the exact filter implementation without trial and error.

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A Method for Improving Stopband Characteristics of a Dual-Band Filter

  • Lee, Ja-Hyeon;Lim, Yeong-Seog
    • Journal of electromagnetic engineering and science
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    • v.11 no.3
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    • pp.186-191
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    • 2011
  • This paper presents a simple and effective method for improving stopband rejection characteristics of previously studied dual-band filters. Small electric couplings were applied to the symmetrically positioned shunt resonators, which divided each transmission zero into two transmission zeros without any effect on passbands. We were able to achieve improved stopband rejection characteristics by these additional transmission zeros. For the filter application, we designed a dual-band filter with improved stopband characteristics using microstrip quasi-lumped elements. The electric couplings that control the location of transmission zeros are controlled by the distance between symmetric open stubs of the filter. The filter was fabricated with a relative dielectric constant of 3.5 and a thickness of 0.76 mm. The fabricated filter has a small size ($14.6{\times}13.2{\times}0.76$ mm) and a low insertion loss when compared with conventional filters.

Compact and Low Insertion Loss Dual-Mode Resonator and Its Applications for Switchable Filters (낮은 삽입손실을 갖는 소형 이중모드 공진기와 스위치 기능을 가진 여파기로의 응용)

  • 성영제;김보연;이건준;김영식
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.15 no.3
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    • pp.301-310
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    • 2004
  • In this paper, a compact dual-mode filter structure without coupling gaps is proposed. The novel design is achieved by embedding a pair of equal crossed slots and spur-lines. Without coupling gaps between feed lines and patch resonator, the new filter can provide low insertion loss. It is found that this design has wide coupling range for dual-mode operation. It means that these characteristics of the proposed filter can reduce uncertainty in fabrication. By using two PIN diodes mounted inside a pair of spur-lines, the proposed structure works as a switchable filter. Also, it has a size reduction of about 34.7 %, compared with conventional dual-mode filters.

Design and Implementation of Open-Loop Clock Recovery Circuit for 39.8 Gb/s and 42.8 Gb/s Dual-Mode Operation

  • Lim, Sang-Kyu;Cho, Hyun-Woo;Shin, Jong-Yoon;Ko, Je-Soo
    • ETRI Journal
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    • v.30 no.2
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    • pp.268-274
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    • 2008
  • This paper proposes an open-loop clock recovery circuit (CRC) using two high-Q dielectric resonator (DR) filters for 39.8 Gb/s and 42.8 Gb/s dual-mode operation. The DR filters are fabricated to obtain high Q-values of approximately 950 at the 40 GHz band and to suppress spurious resonant modes up to 45 GHz. The CRC is implemented in a compact module by integrating the DR filters with other circuits in the CRC. The peak-to-peak and RMS jitter values of the clock signals recovered from 39.8 Gb/s and 42.8 Gb/s pseudo-random binary sequence (PRBS) data with a word length of $2^{31}-1$ are less than 2.0 ps and 0.3 ps, respectively. The peak-to-peak amplitudes of the recovered clocks are quite stable and within the range of 2.5 V to 2.7 V, even when the input data signals vary from 150 mV to 500 mV. Error-free operation of the 40 Gb/s-class optical receiver with the dual-mode CRC is confirmed at both 39.8 Gb/s and 42.8 Gb/s data rates.

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Network Parameters of 6-Pole Dual-Mode Singly Terminated Elliptic Function Filter (6차 단일종단 이중모드 타원응답 필터의 회로망 파라미터 추출에 관한 연구)

  • Lee, Juseop;Uhm, Man-Seok;Yom, In-Bok;Lee, Seong-Pal
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.28 no.7A
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    • pp.557-562
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    • 2003
  • An output multiplexer of manifold type is widely used in a recent satellite transponder for its mass and volume reduction. For correct operation, the filters of such a multiplexer must be singly terminated. In this paper, a simple synthesis method of a 6-pole dual-mode singly-terminated filter is described. From the transfer function of the filter, network parameters such as in/output terminations and coupling coefficients are obtained easily without complicated matrix algebra such as orthogonal projection and similarity transformation. Two different-structure filters are taken into consideration and the network parameters of each filter have been extracted from the same transfer function. It is shown that the responses of two filters are same to each other since their network parameters are obtained from the same transfer function. The method described in this paper can be applied to the other degree singly terminated filter.

Harmonic Suppressed Dual-Band Bandpass Filter with Independently Tunable Center Frequencies and Bandwidths

  • Chaudhary, Girdhari;Jeong, Yongchae;Lim, Jongsik
    • Journal of electromagnetic engineering and science
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    • v.13 no.2
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    • pp.93-103
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    • 2013
  • This paper presented a novel approach for the design of a tunable dual-band bandpass filter (BPF) with independently tunable passband center frequencies and bandwidths. The newly proposed dual-band filter principally comprised two dual-mode single band filters using common input/output lines. Each single BPF was realized using a varactor-loaded transmission line resonator. To suppress the harmonics over a broad bandwidth, a defected ground structure was used at the input/output feeding lines. From the experimental results, it was found that the proposed filter exhibited the first passband center frequency tunable range from 1.48 to 1.8 GHz with a 3-dB fractional bandwidth (FBW) variation from 5.76% to 8.55%, while the second passband center's frequency tunable range was 2.40 to 2.88 GHz with a 3-dB FBW variation from 8.28% to 12.42%. The measured results of the proposed filters showed a rejection level of 19 dB up to more than 10 times the highest center frequency of the first passband.

Pilot-Scale Evaluation of Granular Filters Using Particle Distribution Analysis (여재구성에 따른 탁질입자 제거특성 및 효율 비교)

  • Ahn, Jong-Ho;Yoon, Jae-Heung
    • Journal of Korean Society of Environmental Engineers
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    • v.22 no.5
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    • pp.919-926
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    • 2000
  • The experiment in this study was conducted as a part of an effort to evaluate filter performance with pilot-filters consisting of one mono-media and two dual-media columns. Particle distribution analysis using a particle counter is more sensitive and better than turbidity analysis in observing particle detachments and a breakthrough. In sand media filters having 1.5 m of available head, caution is needed in the head loss of the late stages of filtration, and for dual-media filters, appropriate media configuration and effluent Quality monitoring should be used for preventing the final breakthrough. Also the time of particle breakthrough in the dual media filter can be deferred by increasing bed depth, and it is necessary to use a filtration aid prior to filtration to prevent breakthrough of these intermediate sized particles in high filtration rate.

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A Study on Design of Dual-Bandpass Filters for Wireless LAN (무선 LAN용 이중 대역통과 필터의 설계에 관한 연구)

  • Jeon, Mi-Hwa;Kim, Eun-Mi;Kim, Dong-Il;Jeon, Joong-Sung;Kim, Min-Jung
    • Journal of Navigation and Port Research
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    • v.32 no.6
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    • pp.481-487
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    • 2008
  • Ship's wireless LAN was in the limelight as equipment of ease, cost reduction, various func tion al i ty. In the paper, a dual-bandpass filter for wireless LAN has proposed, which was designed by using dual-mode square loop resonator with square patch in compliance with 2.4 GHz and 5 GHz band of wireless LAN. The dual-bandpass filter could be designed by adjusting sizes of one perturbation element and three of reference elements in compliance with the frequency bands of 2.4 GHz and 5.8 GHz, Furthermore, new dual-bandpass filter was also designed by adjusting stopband of using open stubs in compliance with the frequency bands of 2.4 GHz and 5.2 GHz. The measured results for the fabricated dual-bandpass filters agreed well with the simulated ones, and hence, it was confirmed that the proposed design method is valid.