• Current Optics and Photonics
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• 제1권6호
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• pp.579-586
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• 2017

In this paper, we theoretically demonstrate that semiconductor optical amplifiers (SOAs) with strong wavelength dependence of gain and phase are capable of all-optical inverted and non-inverted wavelength conversion (WC) over a wide range, with the assistance of an optical filter. First, the gain dynamics and phase dynamics in a common quantum well (QW) SOA with the $In_{0.53}Ga_{0.47}As/In_{0.7322}Ga_{0.2678}As_{0.5810}P_{0.4190}$ material system are found to be strongly dependent on wavelength, which is mainly related to the wavelength dependence of the differential gain and the differential refractive-index change. Second, the wavelength dependence in an all-optical wavelength converter based on the QW SOA cascaded with a detuning band pass filter is studied. Simulations show that the quality of the converted signal has little dependence on the operation wavelength. Both inverted and non-inverted WC can be achieved, over a large wavelength range. Therefore, although the gain and phase change are strongly wavelength-dependent, the effects of this dependence can be erased by appropriate optical filtering.

• Journal of the Institute of Electronics Engineers of Korea SD
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• 제37권6호
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• pp.85-96
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• 2000

It is necessary that fully differential operational amplifier circuit should drive an external load in the VLSI design such as SCF(Switched Capacitor Filter), D/A Converter, A/D Converter, Telecommunication Circuit and etc. The conventional CMOS operational amplifier circuit has many problems according to CMOS technique. Firstly, Capacity of large loads are not able to operate well. The problem can be solve to use class AB stages. But large loads are operate a difficult, because an element of existing CMOS has a quadratic functional relation with input and output voltage versus output current. Secondly, Whole circuit of dynamic range decrease, because a range of input and output voltages go down according as increasing of intergration rate drop supply voltage. The problem can be improved by employing fully differential operational amplifier using differential output stage with wide output swing. In this paper, we proposed new current mirror has large output impedance and good current matching with input an output current and compared with characteristics for operational amplifier using cascoded current mirror. To obtain large output swing and low power consumption we suggest a fully differential operational amplifier. The circuit employs an output stage composed new current mirror and two amplifier stage. The proposed circuit is layout and circuit of capability is inspected through simulation program(SPICE3f).

• Journal of Power Electronics
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• 제14권4호
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• pp.806-813
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• 2014

Planar electromagnetic interference (EMI) filters are widely used to restrain the conducted EMI of switching power supplies. Such filters are characterized by small size, low parasitic parameters, and better high-frequency performance than the passive discrete EMI filter. However, EMI filter performance cannot be exactly predicted by using existing methods. Therefore, this paper proposes a method to use scattering parameters (S-parameters) for the measurement of EMI filter performance. A planar EMI filter sample is established. From this sample, the relationship between S-parameters and insertion gain (IG) of EMI filter is derived. To determine the IG under different impedances, the EMI filter is theoretically calculated and practically measured. The differential structure of the near-field coupling model is also deduced, and the IG is calculated under standard impedance conditions. The calculated results and actual measurements are compared to verify the feasibility of the theory.

• Journal of the Institute of Electronics Engineers of Korea SD
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• 제44권3호
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• pp.26-34
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• 2007

This Paper describes a chip design technique for body composition analyzer based on the BIA (Bioelectrical Impedance Analysis) method. All the functions of signal forcing circuits to the body, signal detecting circuits from the body, Micom, SRAM and EEPROMS are integrated in one chip. Especially, multi-frequency detecting method can be applied with selective band pass filter (BPF), which is designed in weak inversion region for low power consumption. In addition new full wave rectifier (FWR) is also proposed with differential difference amplifier (DDA) for high performance (small die area low power consumption, rail-to-rail output swing). The prototype chip is implemented with 0.35um CMOS technology and shows the power dissipation of 6 mW at the supply voltage of 3.3V. The die area of prototype chip is $5mm\times5mm$.

• International Journal of Aerospace System Engineering
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• 제7권2호
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• pp.6-12
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• 2020

The precise prediction of future position of satellite depends on the accurate determination of orbit, which is also helpful in performing orbit maneuvers and trajectory correction maneuvers. For estimating the orbit of satellite many methods are being used. Some of the conventional methods are based on (i) Differential Correction (DC) (ii) Extended Kalman Filter (EKF). In this paper, Differential Evolution (DE) is used to determine the orbit. Orbit Determination using DC and EKF requires some initial guess of the state vector to initiate the algorithm, whereas DE does not require an initial guess since a wide range of bounds for the design unknown variables (orbital elements) is sufficient. This technique is uniformly valid for all orbits viz. circular, elliptic or hyperbolic. Simulated observations have been used to demonstrate the performance of the method. The observations are generated by including random noise. The simulation model that generates the observations includes the perturbation due to non-spherical earth up to second zonal harmonic term.

• Journal of the Korean Institute of Telematics and Electronics S
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• 제34S권1호
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• pp.16-25
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• 1997

This paper shows the development of the high accuracy vehicle positioning algorithm using the differential technique in vehicle tracking systems form the existing vehicle position which is acquired from the global positioning system (GPS). The control center receives the satellite ephemerise data and pseudorange correction from the reference station, and vehicle position from the moving vehicle. The pseudorange is calculated with the satellite position and the vehicle position, and corrected by pseudorange correction. Using this corrected pseudorange and kalman filter, more improved vehicle positioning data were obtained.

• Proceedings of the IEEK Conference
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• 대한전자공학회 2002년도 ITC-CSCC -1
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• pp.86-89
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• 2002

A new design approach for realising low-power low-voltage high-Q high-order RE bandpass filter is proposed. Based on the gyrator-C inductor topology, a 2$\^$nd/-order biquadratic bandpass filter can be realised by adding a series capacitor to the input port of the gyrator. High-Q 2$\^$nd/-order and 4$\^$th/-order fully differential RF bandpass filters operating in the 2.4-㎓ ISM (Industrial, scientific and medical) frequency band under a 2-V single power supply voltage with low power dissipation are reported.

• Transactions of the Korean Society of Automotive Engineers
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• 제2권5호
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• pp.58-65
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• 1994

In order to reduce particulate emissions from diesel vehicles, mathematical model is established and analyzed on ceramic wall-flow monolith filter. A wall-flow monolith filter placed in the exhaust stream of a diesel engine can effectively limit the emission of diesel particulates through the monolith. The accumulated particulates can then be periodically combusted inside the monolith by directing hot gas to the monolith while normal engine exhaust is routed around the monolith system. The resulting low flow rates through the monolith require consideration of gas dynamics through the channels as well as particulate combustion to analyze this regeneration process. A mathematical model of the regeneration is formulated as a system of nonlinear partial differential equations describing the conservation of mass, momentum and energy. Numerical solutions are obtained by using a finite difference techniques for the spatial discretization. So we can use filter simulation program for the purpose of filter design and actual filter regeneration

• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제33권7호
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• pp.59-69
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• 2005

A position domain Hatch filter is proposed as an efficient carrier-smoothed-code processing algorithm for real-time kinematic differential global satellite navigation systems. The well-known range domain Hatch filter is newly interpreted with a stochastical point of view. The interpretation result is extended to derive the position domain Hatch filter. By a covariance simulation, it is shown that Hatch gain is, in general, more efficient than Kalman-type gain in carrier-smoothed-code processing and the proposed position domain Hatch filter is more advantageous than the conventional range domain Hatch filter if the visible satellite constellation changes during the positioning task.

• Journal of Power Electronics
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• 제16권3호
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• pp.1200-1208
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• 2016

Planar electromagnetic interference (EMI) filter has significant engineering significance to power electronic system integration and miniaturization. However, the value of differential mode capacitance cannot meet the demand of noise suppression because of the size limit of ceramics. In this case, the EMI filter of novel multilayers is recommended to address this issue. A novel integrated structure of EMI filter based on multilayer ceramic is proposed in this study. The inductance and capacitance of the new structure can be designed separately, which is an advantage in manufacturing. Insertion loss is measured more closely to the actual situation in this study, which is different from the condition where source and load impedances are both 50 Ω. In the process of designing a novel EMI filter, noise impedance is considered. Moreover, the prototype is created and applied to a small switching power supply, which verifies the effectiveness of the developed EMI filter.