• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.157-159
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• 2010

Most digital cameras apply a Charge Coupled Device(CCD) Sensor or a Complementary Metal Oxide Semiconductor(COMS) Sensor. And the images captured these sensors include unwanted noises. In this paper, we proposed a method of the Noise Reduction(NR) about noise reduction or recovery in the image. The proposed NR method is related to Bandwidth of the Low Pass Filter(LPF). For improvement of NR, we were changing the filter coefficient of the LPF. The results of simulations with various filter coefficients, [1 2 1] in the LPF and [-1 2 -1] in the High Pass Filter(HPF) have ideal frequency bandwidth and high performance. We proposed a filter coefficient [1 2 1] and [-1 2 -1] in the LPF and the HPF respectively.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.2 no.2
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• pp.115-121
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• 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.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.1
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• pp.7-11
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• 2002

A novel microstrip type law-pass filter using thin or thick film resistors is proposed to efficiently eliminate harmonic spurious response in stop-band. The proposed low-pass filter shows the spurious suppression enhancement of 20 dB over a conventional one. The designed low-pass filter could be used as a harmonic rejection filter of a local oscillator for Ku-band satellite payload system.

• Journal of the Korean Institute of Telematics and Electronics
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• v.4 no.1
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• pp.13-21
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• 1967

A low pass filter is synthesized with R, C and negative impedance converters(NIC). The filter has a 4-th order elliptic function, which gives best magnitude approximation with equi-ripple characteristics both in pass and stop band. And experimental investigations have been made on the effect of the anticipated deviation of the NIC conversion factor and of possible loaded operation. Through the study, it has been cocluded that: 1. For minimum pole-zero sensitivity with respect to the NIC conversion factor, the network of a parallel RC-NIC configuration is preferable and the Horowitz polynomial decomposition method is applied in the synthesis procedure. 2. A few percentage variation of the NIC conversion factor changes the frequency and amplitude characteristics of the filter by nearly negligible amount. 3. With a load resistance below the critical value, the filter turns into an oscillator.

• 한국정보통신설비학회:학술대회논문집
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• 2003.08a
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• pp.293-295
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• 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.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.2
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• pp.180-184
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• 2010

In this paper, the filter design and simulation are performed to construct the multi-channel cardiac activation main amplifier. The main amplifier consists of sample and holder, variable high pass filter, notch filter, variable low pass filter. The general 64 channel configuration is expanded into 128 channels to enhance the spatial resolution and the filter is designed for 128 channels cardiac activation main amplifier.

• JSTS:Journal of Semiconductor Technology and Science
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• v.10 no.4
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• pp.282-291
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• 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.

• Proceedings of the Acoustical Society of Korea Conference
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• 1994.06a
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• pp.931-936
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• 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.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.5
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• pp.185-189
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• 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
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• v.17 no.5
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• pp.99-111
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• 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.