• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2002.11a
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• pp.82-85
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• 2002

본 논문에서는 접지면에 어퍼쳐를 갖는 협대역 hairpin-comb 대역 통과 여파기를 제안하였다. Hairpin-comb 공진기는 두 공진기 사이의 간격이 매우 좁더라도 약한 커플링을 유지하는 특성이 있으므로 협대역 대역통과 여파기 제작시 여파기의 전체적인 크기를 작게 할 수 있는 장점이 있다. 그러나 일반적인 마이크로스트림에서는 공진기 사이가 최소한의 거리가 되더라도 커플링이 너무 미약하여 사용할 수 없다, 그러므로 접지면의 어퍼쳐를 사용하여 약한 커플링을 보상함으로써 일반 마이크로 스트립에서도 협대역을 대역통과 여파기를 제작할 수 있었다. 또한 공진기 사이의 거리변환 없이 어퍼쳐의 크기에 의해서 커플링을 조절함으로써 전체 여파기의 크기를 고정시킨 상태에서 대역폭을 조절할 수 있는 장점이 있다. 본 논문에서는 중심 주파수가 1.78 ㎓ 이고 대역폭이 62MHz(3.5%)인 여파기를 제작하였다.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.11
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• pp.141-148
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• 2012

A design of a 32-bit fourth-stage decimation filter decimation filter used in sigma-delta analog-to-digital (A/D) converter is proposed in this work. A four-stage decimation filter with down-sampling factor of 512 and 32-bit output is developed. A multi-stage cascaded integrator-comb (CIC) filter, which reduces the sampling rate by 64, is used in the first stage. Three half-band FIR filters are used after the CIC filter, each of which reduces the sampling rate by two. The pipeline structure is applied in the CIC filter to reduce the power consumption of the CIC. The Canonic Signed Digit (CSD) arithmetic is used to optimize the multiplier structure of the FIR filter. This filter is implemented based on a semi-custom design flow and a 130nm CMOS standard cell library. This decimation filter operates at 98.304 MHz and provides 32-bit output data at an audio frequency of 192 kHz with power consumption of $697{\mu}W$. In comparison to the previous work, this design shows a higher performance in resolution, operation frequency and decimation factor with lower power consumption and small logic utilization.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.405-408
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• 2015

While the oversampling sigma-delta ADCs are known to have high resolution, they often suffer from SNDR losses when operated at a very high data clock. This paper presents a design and implementation of a decimation filter that provides minimum distortion at passband for high-speed sigma-delta ADC. The proposed digital decimation filter employs a butterworth structure, which is a type of an IIR filter. To evaluate the performance of the proposed decimation filter, we implemented a 1-bit, third-order, OSR=64 sigma-delta modulator followed by the proposed decimation filter. Using the simulation ad measurement, we compared the performance of the proposed decimation filter with a conventional CIC(cascaded integrator comb) decimation filter, which is commonly used in most sigma-delta ADCs. The measurement results show that the proposed decimation filter presents substantially lower distortion at passband and thus can provide must higher SNDR.

• Proceedings of the Acoustical Society of Korea Conference
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• 1998.06e
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• pp.3.2-6
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• 1998

본 논문에서는 실측된 실내 충격 응답을 모델링하여 실내 잔향 필터 설계를 시도하였다. 급강하법(steepest descent method)을 이용하여 측정된 실내 충격 응답을 4개의 콤 필터(comb filter)와 2개의 올패스 필터(allpass filter)로 이루어진 잔향 필터로 모델링하여, 잔향 필터의 계수를 결정하였다.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.4 s.304
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• pp.153-158
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• 2005

In this paper, a filter is proposed to compensate droop of the CIC filter for SDR. The proposed compensation filter has almost linear-phase characteristic, requires low operational complexity, and is cost-effective due to its second-order characteristic and lowest operational rate in the baseband.. Especially, it compensates droop in the passband with little performance degradation in the stopband. It is shown, by a design example and its performance analysis, that the proposed compensation method gives performance enhancement in communication systems. It is also shown that the proposed method is superior to conventional ones in view of memory usage and computational load.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.11
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• pp.2649-2655
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• 2015

While the oversampling sigma-delta ADCs are known to have high resolution, they often suffer from SNDR losses when operated at a very high data clock. This paper presents a design and implementation of a decimation filter that provides minimum distortion at passband for high-speed sigma-delta ADC. The proposed digital decimation filter employs a butterworth structure. To evaluate the performance of the proposed decimation filter, we implemented a 1-bit, third-order, OSR=64 sigma-delta modulator followed by the proposed decimation filter. Using the simulation ad measurement, we compared the performance of the proposed decimation filter with a conventional CIC(cascaded integrator comb) decimation filter, which is commonly used in most sigma-delta ADCs. The measurement results show that the proposed decimation filter presents substantially lower distortion at passband and thus can provide must higher SNDR.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.8
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• pp.1753-1758
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• 2012

This paper introduces analog FIR filters based on a distributed amplifier and analyzes the proposed filter's characteristics. A simple design method of an analog FIR filter based on the digital filter design technique is also introduced. The proposed analog FIR filters are a moving average(MA) and a comb type filters with no multiplier. This simple structures of the proposed filters may enable to operate at multi-GHz frequency range and applicable to combine a filter and an amplifier of RF system. The proposed analog FIR filters were implemented with standard $0.18{\mu}m$ CMOS technology. The designed GHz analog FIR filters are simulated by Cadence Spectre and compared to the results of digital FIR filters obtained from MATLAB simulations. From the simulation results, the characteristics of the proposed analog FIR filters are fairly well matched with those of digital FIR filters.

• Journal of Industrial Technology
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• v.28 no.B
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• pp.239-244
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• 2008

We have realized the swept source optical coherence tomography(SS-OCT) by using the self-fabricated wavelength swept laser(wavelength tuning range : 80nm, line-width : 0.12nm, wavelength sweeping rate : 50Hz). In addition, we have used the dual balanced detector that could make a mirror image in OCT display suppressed. We can also fabricate the comb filter of Michelson interferometer type for fast-signal processing in OCT. Using this SS-OCT system for measuring an mirror, a 1mm-depth glass and an onion, we confirmed that the in vivo epidermal cross-sectional images for them can be obtained appropriately.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2016.11a
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• pp.163-164
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• 2016

이전까지 많은 연구자들은 적응 신호처리(Adaptive Signal Process)를 이용한 잡음 제거 방법을 연구해 왔다. 그러나, 최근 발전하고 있는 멀티콥터는 프로펠러 모터의 RPM(Revolution Per Minute)이 실시간으로 변하기 때문에 적응 신호처리를 이용하여도 깔끔한 결과를 얻어 내기가 어렵다는 한계가 존재한다. 또한, 특정 주파수를 기준으로 형성되는 고조파(Harmonics)는 적응 알고리즘인 (N)LMS 를 이용한 예측에서 오차를 발생시키는 문제를 발생시킨다. 따라서, 본 논문에서는 멀티콥터를 이용한 음향 취득에 대한 소음 저감 방법으로 회전 속도계(Tachometer), 콤 필터(Comb Filter), NLMS 알고리즘(Normalized Least Mean Square Algorithm)을 이용한 방법을 제안한다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.3
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• pp.11-17
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• 2010

Multi-standard, multi-band, multi-service system to ensure a flexible interface between the SDR (Software Defined Radio) technology for the implementation of the Stability and Low-Power, Low-Calcualrion DDC (Digital Down Conversion) technology is essential. DDC technology consists of a digital channel filter. This is a typical digital filter because of the limited fisheries are vulnerable to overflow and rounding errors are drawbacks. In this paper, we overcome this disadvantage, we propose the structure of the DDC. The way WDF (Wave Digital Filter) Structural rounding error due to the structural resistance to noise. Therefore, This is the useful structure when the filter coefficients's word length is short. In addition, since IIR filters based on FIR filters based on the amount of computation is reduced because fewer than filter's tap. The proposed structure is used in DDC that CIC (Cascaded Integrator Comb) filter, WDF, IFOP (Interpolated Fourth-Order Polynomials) were analyzed with respect to, the results were confirmed by computer simulation.