• MALSORI
• /
• no.53
• /
• pp.17-35
• /
• 2005

A New Method of Extracting the Filter Characteristics of the Nasal Cavity Using Homorganic Nasal-Stop Sequences: A Preliminary R eportHansang ParkThis study provides a new method of extracting the filter characteristics of the nasal cavity. Korean lenis stops are realized as voiced in the homorganic nasal-lenis stop sequences between vowels. Since the only difference between the two members of the homorganic nasal- lenis stop sequences, such as [mb], [nd], and [ g], is whether the passage to the nasal cavity is open or not, the subtraction of the LPC spectrum of the voiced stop from that of the preceding nasal leads to the filter characteristics of the nasal cavity of an individual speaker regardless of place of articulation. The results suggest that various attempts should be made to extract a robust filter characteristics of the nasal cavity by giving variation to LPC coefficients and by paying particular attention to speech samples. This study is significant in that it provides a preliminary report about a new method of extracting the filter characteristics of the nasal cavity.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.4 no.3
• /
• pp.164-167
• /
• 2003

In this study, we developed the mold for the plastic cavity filter which is a kind of a wireless communication device. Since the cavity filter is made of aluminium, the cost of fabrication is high and the production rate is low. But we can produce plastic cavity filter part by injection molding process with the mold which was designed by our team. The dimension and surface quality of plastic cavity filter was investigated by varying the molding method (conventional and MmSH process) and two different types of resin(PC/ABS and ABS). In case of ABS part, the shrinkage of the inner partition walls was decreased when we adopted MmSH method. The weight of both ABS and PC/ABS parts increased and the surface roughness decreased with MmSH process.

• The Bulletin of The Korean Astronomical Society
• /
• v.46 no.1
• /
• pp.37.3-38
• /
• 2021

Radiation pressure noise of photon and photon shot noise are quantum noise limitation in interferometric gravita-tional wave detectors. Since relationship between the two noises is position and momentum of the Heisenberg uncertainty principle, quantum non-demolition (QND) technique is required to reduce the two noises at the same time. Frequency dependent squeezing using a filter cavity is one of realistic solutions for QND measurement and experimental results show that its cutting-edge performance is sufficient to apply to the current gravitational wave detectors. A 300m filter cavity is under construction at adv-LIGO. KAGRA (gravitational wave detector in Japan) has also started international collaboration to build a filter cavity. Recently we joined the filter cavity project for KAGRA. Current status of squeezing and filter cavity research at KASI and details of the KAGRA filter cavity project will be presented.

• Journal of electromagnetic engineering and science
• /
• v.2 no.2
• /
• pp.100-104
• /
• 2002

A proper equivalent circuit model for coupling iris has been derived in order to compensate the length of cavity in a $TE_{011}$TEX> mode cylindrical cavity filter. A method to resolve the difference in bandwidth and feature or ripple systematically has been proposed. This method can be applied to other types of waveguide cavity filter.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.12 no.1
• /
• pp.173-179
• /
• 2012

In this study, cavity filter performing BPF function in Korea T-DMB system was designed by using of HFSS simulation tool, and we compared measured results with the simulated data. By simulation of HFSS that is magnetic and electric 3D simulating tool, we can save time and money maximumly by checking performances before actual filter implementation. Optimum conditions for the cavity filter were delivered based on the cylindrical waveguide characteristics. Measured results by implementation were compared with the simulation data.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.11 no.6
• /
• pp.157-162
• /
• 2011

In this study, we design and implement a cavity filter for the Korea T-DMB broadcasting transmitter station and repeater system. HFSS 3 dimensional field simulation tool is used for this study. T-DMB filter has to be high quality factor Q, and cavity filter is applying in T-DMB system due to high handling power. We use HFSS simulation tool for design to obtain exact resonant frequency with easy design. A cavity filter is implemented based on the simulated results, and test results are compared with simulations. Measured resonant frequency and bandwidth are 211.8MHz and 0.1MHz, and correspond with design values.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.10 no.6
• /
• pp.91-97
• /
• 2011

In this study, we design and implement a cavity filter for the Korea T-DMB broadcasting transmitter station and repeater system. HFSS 3 dimensional field simulation tool is used for this study. T-DMB filter has to be high quality factor Q, and cavity filter is applying in T-DMB system due to high handling power. We use HFSS simulation tool for design to obtain exact resonant frequency with easy design. A cavity filter is implemented based on the simulated results, and test results are compared with simulations. Measured resonant frequency and bandwidth are 211.8MHz and 0.1MHz, and correspond with design values.

• ETRI Journal
• /
• v.25 no.2
• /
• pp.133-139
• /
• 2003

We studied how the passive intermodulation (PIM) power arising in air cavity filters could be calculated and how the design of the filter could be optimized in order to reduce the amplitude of the PIM signal. To do this, using simulated results, we optimized the various parameters of a filter. PIM in an air cavity filter depends on the power dissipated in its cavities. A reduction of this power loss therefore decreases the PIM power in the air cavity filter. Our experimental results confirm that it is possible to design and produce air cavity filters that generate low PIM signals.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.9 no.6
• /
• pp.630-636
• /
• 2016

In this paper, a novel triple-mode cavity structure, designed for compactness and operating at 850 MHz, is analyzed. A cylindrical dielectric resonator is loaded into a metallic cylindrical cavity. Previous study has been focused on the analysis of the cylindrical dielectric resonator, but in this paper, the effect of the cylindrical metallic cavity has been analyzed. Enclosing the dielectric resonator inside the metallic cavity increases the resonant frequency of the dielectric resonator; however, this increases the quality factor and introduces the possibility of installing coupling screws. The principle of generation of triple-mode was investigated by parametric analysis. The generated triple-mode is TE011 mode and two orthogonally generated HEM121 modes. By adjusting the radius of the dielectric resonator, the height of the dielectric resonator, or the radius of the cylindrical metallic cavity, three modes could be coincided. However, the height of the metallic cavity keeps three modes separated. The mode characteristics of the proposed cavity are analyzed using a full-wave electromagnetic (EM) simulation. The proposed triple-mode cavity could be developed to triple-mode filter using a coupling screw, and the commercial application for the miniaturized filter below 1 GHz could be expected.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.22 no.6
• /
• pp.1251-1258
• /
• 1997

Generally, it is very important to study selective coupling between cavities of the filter structure using multimode cavity resonator. In this paper, we have manufactured 5-pole bandpass filter(BPF) using dual and triple-mode cavity resonator. To do so, we have derived the formulas for coupling coefficient about coupling between TE-modes from TM/TE-mode's tangential and lognitudinal field intensities each other. To implement the Chebyshev response, the intercabity slot combining dual-mode and triple-mode is designed to couple one H-field of TE-mode parallel to slot plate. In this paper, specially it is derived the formulas for T $E_{11p}$-mode from TE-modes, and determined after obtaining location and size of intercabity slot from the equation. In this ppaer, based on this result, we designed and implmented teh bandpass filter operated at the center frequency of 14.5GHz with a Chebyshev response. For the manufactured cavity filter, dual-mode and triple-mode cavity are resonted by two orthogonal T $E_{113}$-modes, and by two orthogonal T $E_{113}$-modes and one T $M_{012}$-mode, respecitively. The 2-stage 5-pole BPF proposed in this paper has the insertion loss of -2.32dB, the reflection loss of -15dB in the passband, and the out-or-rejection of -67dB.