• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.14 no.4
• /
• pp.393-400
• /
• 2003

This paper deals with the design and manufacturing technique of EQM(Engineering Qualification Model) of input multiplexer(IMUX) for the Ku-band satellite transponder. Channel dropping method by circulator chain structure is adopted for demultiplexing each channel. External equalizers are attached behind channel filters fur reduction of group delay variation and amplitude variation simultaneously. Both channel filters and equalizers adopted dual-mode technique in design f3r mass and volume reduction. Channel filters are designed to have 8-pole elliptic response and equalizers to be of 2-pole reflection type. For good temperature stability characteristics, INVAR36 material is used for channel filters and external equalizers. Vibration test, Thermal Vacuum Test, and EMC test have been performed on input multiplexer and it is shown to be suitable for Ku-band satellite transponder.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2015.10a
• /
• pp.889-893
• /
• 2015

In this work, the characteristics of GIDL current in nanowire GAA MOSFET with different channel width and hot carrier stress. When the gate length is fixed as a 250nm the GIDL current with different channel width of 10nm, 50nm, 80nm, and 130nm have been measured and analyzed. From the measurement, the GIDL is increased as the channel width decreaes. However, the derive current is increased as the channel width increases. From measurement results after hot carrier stress, the variation of GIDL current is increased with decreasing channel width. Finally, the reasons for the increase of GIDL current with decreasing channel width and r device. according to hot carrier stress GIDL's variation shows big change when width and the increase of GIDL current after hot carrier stress are confirmed through the device simulation.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.29A no.3
• /
• pp.1-7
• /
• 1992

This paper discusses the self-adaptive equalization technique which has adaptibility to channel characteristics varation without training sequence. The criterion function used in this paper is based on the concept of cumulant matching. This function can be applied to nonminimum phase channel, and we can verify the fact that if the constrained condition is satisfied. this criterion has no local optimum. As the adaption algorithm, the normalized gradient-searching technique is used. Simulations verify the performance of our method in case of 8PAM, 8PSK(CCITT V.27), 16QAM(CCITT V.29) sources and three type nonminimum phase channels.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1999.11a
• /
• pp.461-463
• /
• 1999

In this paper, we have systematically investigated the variation of electrical characteristics with back-gate bias of n-channel SOI MOSFET\\`s. When positive bias is applied back-gate surface is inverted and back channel current is increased. When negative bias is applied back-gate surface is accumulated but it does not affect to the electrical characteristics.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.31 no.8A
• /
• pp.745-751
• /
• 2006

The transmitter requires knowledge of the channel status information in order to adopt the adaptive modulation and coding scheme(AMC) for OFDM system. But in the outdoor environment which the users have high mobility, the channel status information from the users is outdated, so that it induces the degradation of system throughput and packet error rate(PER) performance. To solve this problem, researches about applying channel prediction technique to the AMC scheme have been proceeded. Most channel prediction techniques assume that there is no channel variation in the predefined time duration, e.g., a slot. As a result, those techniques cannot compensate the degradation of PER performance resulting from the rapid variation of channel during the slot duration. This paper introduces a novel channel prediction technique for OFDM/FDD system to support adaptive modulation and coding scheme over rapidly time-varying multipath fading channel. The proposed channel prediction technique considers the time-varying nature of channel during the slot duration. Simulation results show that the AMC scheme of OFDM/FDD system utilizing the proposed channel prediction technique can guarantee the target PER of 1% without any loss of system throughput compared with the case supported by the conventional channel prediction under ITU-R Veh A 30km/h.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.17 no.11
• /
• pp.1290-1298
• /
• 1992

In this paper, the Poisson's equation is solved two-dimensionally without employing any fitting parameters, and the model formulation of a short-channel MOSFET is accomplished fully analytically. It automatically derives a very accurate drain current expression that can be used simultaneously for strong inversion, subthreshold, and saturation regions. Furthermore, this model gives a unified explanation for the short-channel effect, the body effect, the DIBL effect, and even the variation of the effective carrier mobility. The obtained expression of the threshold voltage also includes the dependence on the oxide thickness, the n+ junction depth, and temperature.

• Journal of Ship and Ocean Technology
• /
• v.4 no.2
• /
• pp.24-37
• /
• 2000

The purpose of this paper is to study the upstream waves in front of an advancing arbitrary hull shape in a restricted water channel. Conventionally, in a restricted water channel, shallow water effects are amplified because of the finite water depth and width. When the effects of shallow water and the restricted channel width are severe, upstream waves propagate forward from the fore-body of the advancing hull. In this study, numerical simulations are carried out for the relevant analysis of the flow phenomena by the draft variation of advancing hull in a restricted water channel. Numerical simulations are done with a finite-difference method based on the MAC scheme in a rectangular grid system.

• Transactions on Electrical and Electronic Materials
• /
• v.7 no.3
• /
• pp.99-102
• /
• 2006

The electrical characteristics of CMOS inverter with LDMOSFET are studied for high power and digital circuit application by using two dimensional MEDICI simulator. The simulation is done in terms of voltage transfer characteristic and on-off switching properties of CMOS inverter with variation of channel length and channel doping levels. The channel which surrounds a junction-type source in LDMOSFET is considered to be an important parameter to decide a circuit operation of CMOS inverter. The digital logic levels of input voltage show to increase with increase of n-channel length and doping levels while the logic output levels show to the almost constant.

• Journal of Environmental Science International
• /
• v.9 no.5
• /
• pp.375-384
• /
• 2000

It is very important to interprete and simulate the variation of phytoplankton maximum region for the prediction and control of red tide. This study was composed of two parts first the hydrodynamic simulation such as residual current and salinity diffusion and second the ecological simulation such as phytoplankton distribution according to freshwater discharge and pollutant loads. Without the Nakdong river discharge residual current was stagnated in inner side of this estuary and surface distribution of salinity was over 25psu. On the contrary with summer mean discharge freshwater stretched very far outward and some waters flowed into Chinhae Bay through the Kadok channel and low salinity extended over coastal sea and salinity front occurred. From the result of contributed physical process to phytioplankton biomass the accumulation was occurred at the west part of this estuary and the Kadok channel with the Nakdong river discharge. When more increased input discharge the accumulation band was transported to outer side of this estuary. The frequently outbreak of red tide in this area is caused by accumulation of physical processes. The phytoplankton maximum region located inner side of this estuary without the Nakdong river discharge and with mean discharge of winter but it was moved to outer side when mean discharge of the Nakdong river was increased. The variation of input concentration from the land loads was not largely influenced on phytoplankton biomass and location of maximum region. When discharge was increased phytoplankton maximum region was transferred to inner side of the Kadok channel. ON the other hand when discharge was decreased phytoplankton maximum region was transferred to inner side of this estuary and chlorophyll a contents increased to over 20$\mu\textrm{g}$/L Therefore if any other conditions are favorable for growth of phytoplankton. decreas of discharge causes to increase of possibility of red tide outbreak.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.15 no.3
• /
• pp.205-210
• /
• 2022

A novel OLED pixel circuit is proposed in this paper that uses only n-type thin-film transistors(TFTs) to improve the luminance non-uniformity of the AMOLED display caused by the threshold voltage variation of an OLED driving TFT. The proposed OLED pixel circuit is composed of 6 n-channel TFTs and 2 capacitors. The operation of the proposed OLED pixel circuit consists of the capacitor initializing period, threshold voltage sensing period of an OLED·driving TFT, image data voltage writing period, and OLED·emitting period. As a result of SmartSpice simulation, when the threshold voltage of·OLED·driving TFT varies from 1.2 V to 1.8 V, the proposed OLED pixel circuit has a maximum current error of 5.18 % at IOLED = 1 nA. And, when the OLED cathode voltage rises by 0.1 V, the proposed OLED pixel circuit has very little change in the OLED current compared to the conventional OLED pixel circuit. Therefore, the proposed pixel circuit exhibits superior compensation characteristics for the threshold voltage variation of an OLED driving TFT and the rise of the OLED cathode voltage compared to the conventional OLED pixel circuit.