• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.9
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• pp.60-65
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• 2009

In this paper, we present a compact Ultra-Wideband band-pass later with notched band at fireless-LAN band using a band-pass and band-notch filter. The structure of our proposed band-pass filter is very simple, and the DGS(Defected Ground Structure) structure is used to get the low-pass filter characteristic, and an embedded open-stub structure is used to get the notched filter. Our proposed band-pass filter can be much smaller than a cascaded filter. As a result of measurement, the insertion loss is less than 0.7dB throughout the pass-band of $2.21GHz{\sim}10.92GHz$, the return loss is more than 17dB and the group delay maximum variation is 0.24ns and a notched band is at $5.3GHz{\sim}5.7GHz$.

• Journal of the Korean Association of Geographic Information Studies
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• v.19 no.1
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• pp.154-166
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• 2016

This study aims to contribute to better understanding the effects of the changes in the parameter values of GroundFilter algorithm(GF), which performs filtering process, and of GridsurfaceCreate algorithm(GC), which creates regular grid, provided in Fusion software on the accuracy of elevation of the final LiDAR-DEM products through comparative analysis. In order to test whether there are significant effects on the accuracy of the final LiDAR-DEM products due to the changes of GF(1, 3, 5, 7, 9) parameter levels and GC(1, 3, 5, 7, 9) parameter levels, two-way ANOVA is conducted based on residuals. The residuals are calculated using the differences between each sample plot's paired field-measured and DEM-derived elevation values given each individual GF and GC level. After that, Tukey HSD test is conducted as a post hoc test for grouping the levels. As a result of two-way ANOVA test, it is found that the change in the GF levels significantly affects the accuracy of LiDAR-DEM elevations(F-value : 27.340, p < 0.01), while the change in the GC levels does not significantly affect the accuracy of LiDAR-DEM elevations(F-value : 0.457). It is also found that the interaction effect between GF and GC levels is not likely to exist(F-value : 0.247). From the results of the Tukey HSD test in the GF levels, GF levels can be divided into two groups('7', '5', '9', '3' vs '1') by the differences of means of residuals. Given the current conditions, LiDAR-DEM can achieve the best accuracy when the level '7' and '3' are given as GF and GC level, respectively.

• Journal of Broadcast Engineering
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• v.17 no.3
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• pp.480-490
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• 2012

When interpolating chrominance signal, the H.264/AVC standard uses linear interpolation. In this paper, we suggest more effective method that uses a high precision filter, 6-tap FIR filter, 2-tap linear filter for chroma interpolation. The experimental result shows that the proposed method achieves the BD-Rate decrease without the PSNR decrease compared with Jm11.0kta2.7. The maximum BD-rate improvements on Y component are 1.3%, those of Cb and Cr components are 19.8%, 25.0%, respectively. The average BD-rate improvements on Y component are 0.5%, those of Cb and Cr components are 6.1%, 6.9%, respectively.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.7
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• pp.26-31
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• 2005

In this paper, a small BPF(band pass filter) is designed using new probe type for wireless communication system. The dielectric resonator is used high Q ceramics for low loss characteristic. In order to provide a band pass filter which can be reduced in dimension, can be reduced in height, and can be surface-mounted. The filter was fabricated using $TE_{01{\delta}}$ mode dielectric resonator. The input/output probes are attached to coner portion of the rectangular metal cavity. Results of the manufactured filter($12{\times}12{\times}8[mm]$) show that the center frequency is 9.95358[GHz], the insertion loss is -1.9[dB], the 3[dB]_bandwidth is 14.9[MHz], and the loaf Q is 664.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.5
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• pp.1-9
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• 1989

In binary digital transmission system the band-limiting is required for the better transmission efficiency. But in the case of band-limiting the intersymbol-interference (ISI) usually takes place. In this paper, in an attempt to design band-limiting filter which has minimum ISI and maximum stop-band loss, first, making use of analog filter by combining Binary Transversal Filter (BTF) and analog filter (4th Butterworhfilter), we found the value that minimizes ISI phenomenon by getting step response of rectangular pulse resulting from BTF in time domain. Second, we found filter characteristic we want to in frequency domain for band-limiting and minimized the error. And then we obtained resistor value (Tap coefficient) in order to design algorithm for optimum filter. Also we showed the example of simulation in case we established the resistors with 3,5 and 7 respectively. With 7 resistors set, we identified that the ripple of about minus 30dB was taken place.

• Journal of electromagnetic engineering and science
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• v.16 no.1
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• pp.7-12
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• 2016

This paper presents the design of a negative group delay circuit (NGDC) using the filter synthesis approach. The proposed design method is based on a frequency transformation from a low-pass filter (LPF) to a bandstop filter (BSF). The predefined negative group delay (NGD) can be obtained by inserting resistors into resonators. To implement a circuit with a distributed transmission line, a circuit conversion technique is employed. Both theoretical and experimental results are provided for validating of the proposed approach. For NGD bandwidth and magnitude flatness enhancements, two second-order NGDCs with slightly different center frequencies are cascaded. In the experiment, group delay of $5.9{\pm}0.5ns$ and insertion loss of $39.95{\pm}0.5dB$ are obtained in the frequency range of 1.935-2.001 GHz.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.7
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• pp.709-716
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• 2013

A fan filter unit (FFU) is a device which supplies clean air from the ceiling in a clean room. With an increase in its size, velocity variation occurs within the exhaust plane and this damage the product quality or productivity. Hence, a guide vane is installed inside the device to enhance the velocity uniformity. Because the vane reduces the flow rate for a given pumping power, an optimum design is required to achieve velocity uniformity while minimizing the flow rate reduction at the same time. To find a geometry that satisfies these requirements, a series of numerical simulations has been conducted while changing the angle and length of the guide vanes. By changing the geometry of the side guide vane, the velocity uniformity increased by 3.7% and the flow rate decreased by 1.5%. For the center guide vane, the velocity uniformity increased by 2.9% and the flow rate decreased by 0.7%.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.9
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• pp.1065-1072
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• 2012

In this paper, the method of design of the waveguide band-pass filter and limiter in radar system is proposed. First, we design a self-resonant iris, which can behave as a band-pass filter by mounting the PIN diode on the iris. When low power microwave is incident on the proposed element, the element behaves as a band-pass filter. Under a high power microwave condition, however, the element behaves as a limiter having wide band stop characteristics. The fabricated element has a pass band with -0.7 dB insertion loss at 10 GHz under the low power condition and isolation about 25 dB under the high power condition.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.7
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• pp.455-463
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• 2001

In this Paper, an approximate processing method is proposed and tested. The proposed method uses variable CSD (VCSD) coefficients which approximate filter stopband attenuation by controlling the precision of the CSD coefficient sets. A decimation filter for Audio Codec '97 specifications has been designed having processor architecture that consists of program/data memory, arithmetic unit, energy/level decision, and sinc filter blocks, and fabricated with 0.6${\mu}{\textrm}{m}$ CMOS sea-of-gate technology. For the combined two halfband FIR filters in decimation filter, the number of addition operations were reduced to 63.5%, 35.7%, and 13.9%, compared to worst-case which is not an adaptive one. Experimental results show that the total power reduction rate of the filter is varying from 3.8 % to 9.0 % with respect to worst-case. The proposed approximate processing method using variable CSD coefficients is readily applicable to various kinds of filters and suitable, especially, for the speech and audio applications, like oversampling ADCs and DACs, filter banks, voice/audio codecs, etc.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.203-206
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• 2003

Thermo-optic tunable filter, with 4-pairs of H/L layers for DBR, was designed and fabricated. The transmittance characteristics of the filter were measured. Additionally, heating system and temperature sensor system were used in order to observe property of the filter by thermo-optic effect. The tuning efficiency of the filter was measured to be 0.144nm/K$^{-1}$ showing the tuning range of 9.4nm for the temperature variation of 64.7$^{\circ}C$. Filter, lens and fiber were aligned by micro-optical bench.