• Journal of IKEEE
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• v.3 no.1 s.4
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• pp.11-21
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• 1999

This paper has been proposed a structure composed of FIRs and IIR filters as digital interpolation filter to integrate the off-chip analog low-pass filter of audio DAC. The passband ripple (>$0.41{\times}fs$), passband attenuation(>at$0.41{\times}fs$) and stopband attenuation(<$0.59{\times}fs$) of the ${\Delta}{\Sigma}$ modulator output using the proposed digital interpolation filter had ${\pm}0.001[dB]$, -0.0025[dB] and -75[dB], respectively. Also the inband group delay was 30.07/fs[s] and the error of group delay was 0.1672%. Also, the attenuation of stopband has been increased -20[dB] approximately at 65[kHz], out-of-band. Therefore the RC products of analog low-pass filter on chip have been decreased compared with the conventional digital interpolation filter structure.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2003.06a
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• pp.247-250
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• 2003

디지털 2차 적응 IIR 대역 통과 필터의 진폭 특성을 해석, 적응 계수와 입력 신호의 중심 주파수 그리고 극의 각과의 관계를 해석하고, 적응 계수의 경계를, 기존에 발표된 세 알고리즘을 예로 들어, 평가하였다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.9
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• pp.924-930
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• 2003

In this paper, a novel miniaturized microstrip duplexer with attenuation pole is proposed. A three-pole microstrip CT(Cascade Trisection) two bandpass filters have each asymmetrically prescribed transmission zero are design and fabrication. This CT bandpass filter changes coupling structure, which not only shifts the location of attenuation poles but also improves skirt characteristics. The duplexer results of measurement with the cross coupling CT bandpass filters has been yielded better isolation and sharper skirt behavior than that with a conventional bandpass filter. The results of measurement are almost similar to those of simulation results.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.2
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• pp.13-18
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• 2001

In this paper, a four-pole quasi-elliptic function bandpass filter of 1.95GHz center frequency with 60 MHz bandwidth for IMT-2000 using miniaturized square SIR(Stepped Impedance Resonator) is designed and fabricated. The simulation of NUFDTD(Nonuniform Finite Difference Time Domain) is used to design the resonator and to calculate the coupling coefficient of three basic structures. The size reduction of miniaturized square SIR resonator is about more than 50% compare with a square open loop resonator. Bandpass filter using this resonator shows good microwave characteristic with the harmonic suppression of about 19dB. The results of measurements are almost similar to those of simulation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.4
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• pp.630-638
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• 2001

This paper has been proposed a structure composed of FIRs and IIR filters as digital decimation filter to compensate the drooping inband on the high precision AU chips. The area of chip has been reduced compared with the conventional structure because the RAM and MAC is reduced. The passband ripple$(\leq\; 0.4535 \times fs)$, passband attenuation(at $\; 0.4535 \times fs$ and stopband attenuation$(\geq\; 0.59\times fs)$ of the 6th-order $\Delta\Sigma$ modulator and digital decimation filter had $\pm0.0007[dB]$, -0.0013[dB] and -110[dB] respectively. Also the inband group delay, which was almost same compared with the conventional digital decimation filter structure, was 30.07/fs[s] band the error of group delay was 0.1672%.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.6 s.121
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• pp.639-647
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• 2007

This paper proposed the novel method that can realize the parallel coupled line(PCL) band-pass filter with directly coupled feeding structure by means of transforming the first and last PCL sections of the conventional PCL band-pass filter into K-inverters, then substituting T-type equivalence for K-inverter. The proposed method supplies simple design formulae and can considerably reduce time and efforts needed to optimize filter performance when compared to reported methods using external Q or equivalent parameters. On the basis of the proposed method, the band-pass filter using directly coupled feeding structure and having 18% fractional bandwidth was designed and fabricated. The validity of proposed method was proven by the measured result.

• ETRI Journal
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• v.14 no.4
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• pp.249-257
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• 1992

인버터를 이용한 대역 통과 필터를 설계할 때, 기존에 사용하던 기하평균 방법은 인버터의 이미턴스가 주파수에 대해 일정하다고 생각한 가정때문에 대역폭률이 10% 이상인 광대역 필터에서 대역폭과 중심주파수가 잘 맞지 않게 된다. 이에 대한 보완으로 Cohn은 새로운 함수를 제안하였는데, 이 함수도 coupling 방법에 따른 사용상의 제약을 갖고 있다. 본 고에서는 coupling 방법에 관계없이 광대역 필터를 설계할 수 있는 새로운 변환 함수를 제시하였으며 컴퓨터 시뮬레이션을 통해 기존의 함수들보다 더 정확하다는 것을 확인하였다.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.1273-1278
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• 2005

In this thesis, a 2 stage 6-pole bandpass filter(BPF) is designed and implemented by using triple-mode cavity for satellite payload system. The BPF has a 100MHz bandwidth at the center frequency of 14.5GHz(Ku-band) and the response of the filter is the Chebyshev function. The cavity filter uses two orthogonal $TE_{113}$ modes and one $TM_{012}$ mode. The coupling between the adjacent cavityes(intercavity coupling) results in a Chebyshev response and is accomplished by only H-filed component of TE modes. The size and location of intercavity slot is determined by the coupling equation from E- and H-field of TE and TM resonant modes in circular cavity. The 2-stage 6-pole triple-mode cavity BPF has the insertion loss of 2.4dB and the reflection loss of 15dB in the passband. The triple-mode BPF proposed in this thesis can be used as channel filters for satellite payload system and can minimize filter assembly in general wireless communication system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.4
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• pp.636-644
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• 2009

This paper presents a compact, low insertion loss, sharp rejection and wide band microstrip band pass filter that is composed rectangular loop resonator and step-impedance-open-stub(SIOS) for wireless data communication. The SIOS can be reduce length about 30% more than general $0.25{\lambda}$ stub. And the stub can the advantage of tuning impedance magnitude. In order to demonstrate agrement of this paper prove, the optimized wide band pass filters are realized and experimented. A transmission line model used to calculate the frequency response of the new filters shows good agreement with measurements. The filter has 3dB fractional bandwith of 52.5%(3.267GHz), an insertion loss of better than 0.33dB from 4.587GHz to 7.854GHz, and two rejection of greater than 30dB within 221MHz$(4.366GHz{\sim}4.587GHz)$ at low frequency band, 181MHz$(7.854GHz{\sim}8.035GHz)$ at high frequency band. Maximum rejection characteristics of the filter are -54dB at low frequency and -60dB at high frequency.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.9
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• pp.1033-1038
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• 2015

Complementary Filter is commonly used in signal processing method for real-time position measurement. Butterworth filter characteristic has a uniform gain in the pass band, the blocking band has a good blocking characteristics. Therefore, we propose a method of designing a complementary filter having a characteristic of Butterworth filter characteristic. By setting the appropriate filter coefficients in the simulation it appears to improve the performance of the filter. In the experiment it shows a real-time signal processing is possible by using the calculated filter coefficients in the simulation.