• 한국정보통신학회:학술대회논문집
• /
• 한국해양정보통신학회 2010년도 춘계학술대회
• /
• pp.157-159
• /
• 2010

대부분의 디지털 촬영 장치는 Charge Coupled Device(CCD) 또는 Complementary Metal Oxide Semiconductor(CMOS) 센서를 사용한다. 이러한 센서를 통해 촬영된 영상 정보에는 원하지 않는 잡음이 포함되어있다. 본 논문은 영상의 잡음 제거 및 영상 정보의 회복을 위한 기법인 잡음 제거(Noise Reduction, NR)에 관한 것이다. 제안한 NR 방법은 저역통과 필터(Low Pass Filter, LPF)의 대역폭을 고려한 잡음 제거 방법에 관한 것으로, NR의 성능개선을 위하여 MSF 연산에 사용되는 LPF의 필터 계수를 통한 시뮬레이션을 수행하였다. 필터 계수가 갖는 주파수 대역폭의 특성을 고려한 시뮬레이션 결과, MSF 연산에 적용되는 LPF와 고역통과 필터(High Pass Filter, HPF)의 필터 계수가 [1 2 1]과 [-1 2 -1]인 경우 가장 이상적인 주파수 대역폭을 나타내며, NR의 성능 또한 우수함을 확인하였다. 시뮬레이션 결과를 통하여, MSF를 수행함에 있어서 LPF와 HPF의 필터 계수를 [1 21]과 [-1 2 -1]로 제안하였다.

• International Journal of Fuzzy Logic and Intelligent Systems
• /
• 제2권2호
• /
• pp.115-121
• /
• 2002

This paper presents an evolutionary design of digital IIR filters using the genetic algorithm (GA) with modified genetic operators and real-valued encoding. Conventional digital IIR filter design methods involve algebraic transformations of the transfer function of an analog low-pass filter (LPF) that satisfies prescribed filter specifications. Other types of frequency-selective digital fillers as high-pass (HPF), band-pass (BPF), and band-stop (BSF) filters are obtained by appropriate transformations of a prototype low-pass filter. In the GA-based digital IIR filter design scheme, filter coefficients are represented as a set of real-valued genes in a chromosome. Each chromosome represents the structure and weights of an individual filter. GA directly finds the coefficients of the desired filter transfer function through genetic search fur given filter specifications of minimum filter order. Crossover and mutation operators are selected to ensure the stability of resulting IIR filters. Other types of filters can be found independently from the filter specifications, not from algebraic transformations.

• 한국전자파학회논문지
• /
• 제13권1호
• /
• pp.7-11
• /
• 2002

본 논문에서는 저지대역에서 하모닉과 불요특성을 효과적으로 제거하기 위한 목적으로 박막 혹은 후박 저항을 이용한 새로운 형태의 마이크로스트립 형태의 저역통과 필터를 제안한다. 제안한 필터는 기존의 마이크로스트림형태의 저역통과 필터에 비해 20dB 이상의 불요파 제거 효과를 보인다. 설계된 저역통과 필터는 Ku 대역 위성중계기용 국부발진기의 하모닉 제거 필터로 사용되어질 수 있다.

• 대한전자공학회논문지
• /
• 제4권1호
• /
• pp.13-21
• /
• 1967

RC-NIC LPF 설계를 해석적으로 하는 방법을 취급하였으며 4차 타원함수특성을 갖도록 실제LPF를 설계하여 실험적으로 그 동작특성을 고찰하였다.

• 한국정보통신설비학회:학술대회논문집
• /
• 한국정보통신설비학회 2003년도 하계학술대회
• /
• pp.293-295
• /
• 2003

In this paper, planar harmonic rejection low-pass filter is proposed to effectively suppress spurious response in stop-band. For suppress the unwanted signal such as spurious and harmonics, we presented a new design method controlled the higher order modes. The proposed low-pass filter was shown to suppress the spurious response by more than $20{\sim}40dB$ compared with conventional microstrip low-pass filters. The filter is evaluated by experiment and simulation with good agreement and shown to have attractive properties such as wide stop band range and low insertion loss.

• 한국전자통신학회논문지
• /
• 제5권2호
• /
• pp.180-184
• /
• 2010

본 논문에서는 다중 채널 심장 전기도 주 증폭기의 중요한 부분인 필터를 설계하고 시뮬레이션을 통하여 성능을 분석하였다. 주 증폭기는 샘플/홀더, 가변 고역통과 필터, 노치 필터, 가변 저역통과 필터로 구성된다. 필터는 기존의 64 채널의 공간 분해능을 향상시키기 위하여 128채널을 고려하여 설계되었다.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제10권4호
• /
• pp.282-291
• /
• 2010

This paper presents a full-CMOS transmitter and receiver for VDSL2 systems. The transmitter part consists of the low-pass filter, programmable gain amplifier (PGA) and 14-bit DAC. The receiver part consists of the low-pass filter, variable gain amplifier (VGA), and 13-bit ADC. The low pass filter and PGA are designed to support the variable data rate. The RC bank sharing architecture for the low pass filter has reduced the chip size significantly. And, the 80 Msps, high resolution DAC and ADC are integrated to guarantee the SNR. Also, the transmitter and receiver are designed to have a wide dynamic range and gain control range because the signal from the VDSL2 line is variable depending on the distance. The chip is implemented in 0.25 ${\mu}m$ CMOS technology and the die area is 5 mm $\times$ 5 mm. The spurious free dynamic range (SFDR) and SNR of the transmitter and receiver are 67.5 dB and 41 dB, respectively. The power consumption of the transmitter and receiver are 160 mW and 250 mW from the supply voltage of 2.5 V, respectively.

• 한국음향학회:학술대회논문집
• /
• 한국음향학회 1994년도 FIFTH WESTERN PACIFIC REGIONAL ACOUSTICS CONFERENCE SEOUL KOREA
• /
• pp.931-936
• /
• 1994

Although an ideal low-pass filter is not physically realizable, it can be approximated on the basis of time reversal techniques. In this paper, we describe a method to approximately implement the ideal low-pass filter and apply it to the pitch extraction system. Experimental results show that our method is effective to estimate the fundamental frequency of the speech signal.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제54권5호
• /
• pp.185-189
• /
• 2005

This paper focuses on the design for Rx/Tx switch module of GSM(global standard mobile) band, characterization of a miniature, low power and dual-band implementation of the front-end switch module with low-pass filer And the effort to make agreement between the simulated design and the measured data for these solutions takes the place through accumulated design and manufacturing data library. We present the design, modeling and measurement of switch module integrating GSM Rx/Tx switching circuit and LPF(low pass filter) on a LTCC(low temperature co-fired ceramic) substrate. For GSM application, insertion and return loss of the low pass filter designed was less than 0.3 dB which was less than 12.7 dB at 900 MHz. The LTCC switch module contained 10 embedded passives and 3 surface mount components integrated on 4.6$\times$4.8$\times$1.2 mm, 6-layer multi-layer integrated circuit. The insertion loss of switch module measured at 900 MHz was 11 dB. In both of the design approach yielded excellent agreement between measured and simulated results.

• Journal of Advanced Marine Engineering and Technology
• /
• 제17권5호
• /
• pp.99-111
• /
• 1993

In this paper, the current waveform and dynamic characteristics of the proposed system which is composed of a full bridge inverter and low pass LC filter is investigated through the results of computer simulation and experiment to find out the good performance of variable speed AC motor. By the experiment results, it is confirmed that the load current of pseudo sine waves is to be got by the proposed low pass LC filter and the speed of single phase AC motor driven by a full bridge inverter can be smoothly controlled by use of digital PID controller.