• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.8
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• pp.1159-1168
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• 1993

The Switched-Capacitor Integrator(SCI) is a basic building block of Switched-Scpacitor Filter(SCF). But owing to the errors from the finite gain and bandwidth of op-amp on SCI, the most of SCP are limited to their applications. Although many of the compensation methods developed for active RC filters can be directly adapted to SCF, this is not true for the analysis of the effects of the op-amp dynamics on the filter response. The effect of finite op-amp gain is similar to the active RC filters. But SCF is more toter-ant of the finite op-amp bandwidth. In this paper, we have considered the errors of the finite gain and bandwidth of op-amp on SCI , and presented the simple and effective methods of compensating the errors of SCI due to the finite op-amp gain using the buffer circuit.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.7 no.1
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• pp.29-36
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• 1982

This paper investigates the utilization of the concept of FDNR first proposed by L. T. Bruton to eliminate the necessity of inductance in a network. A new FDNR with single OP-Amp is also introduces to simplify the network in this paper. The efficiency of the new contrivance is also proved through experimented confirmation of its frequency when applied to on active eliptic low pass filter.

• Journal of IKEEE
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• v.21 no.3
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• pp.248-251
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• 2017

In this paper, The proposed board is developed by EMI compliant Dash Camera with $360^{\circ}$ omni angle. The proposed board is designed by designing DM and CM input noise reduction circuit and applying active EMI filter coupling circuit. The DM and CM input noise reduction circuit design uses a differential op amp circuit to obtain the DM noise coupled to the input signal via the parasitic capacitance(CP). In order to simplify the circuit by applying the active EMI filter coupling circuit, a noise separator is installed to compensate the noise of the EMI source to compensate the CM and DM active filter simultaneously. In order to evaluate the performance of the board for the proposed EMI response, an authorized accreditation body has confirmed that the electromagnetic certification standard for each frequency band is satisfied.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.49-55
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• 2016

To separate the CM and DM noise in the EMI generated in various electrical electronic systems, passive and active separators have been researched. These separators are an important part of an effective active EMI-filter. The passive separator has some advantages, in that it is easy to realize at a low price and its structure is very simple. However, its major drawback is that its accurate inductor realization and accurate core selection are very difficult. The active separator is smaller in size and more accurate, but its main drawback is that an op-amp which has a broad band frequency response is necessary, its cost is high, and a DC power circuit is required. This paper compares the characteristics of EMI filters which apply the existing passive separator and proposed active separator. It was concluded that an active separator is needed for expensive and accurate equipment, whereas a passive separator is sufficient for inexpensive and general purpose EMI filters.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.7
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• pp.1579-1589
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• 1997

This paper introduces a monolithic chip 3.3V high-performance continuous-tune filter used in a CDP that can reconstruct the PDM or PWM signal output of a .SIGMA..DELTA. D/A converter. We also mentioned an active RC filter structure and filter order satisfying high-linearity and the design specification. In desigining the OP-AMP, using a structure that accepts some distortion we could reduce the chip area, and reducing the DC path using a new biascircuit gave us better power performance. The designed.SIGMA..DELTA. D/A converter post-processing filter does its smoothering operations and reconstructs the data without reducing the performance of the system.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1445-1456
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• 2011

This paper presents the research of Low Pass Filter(hereinafter called "LPF") which is the part of Chopper Gate Control Unit on the electric rolling stock. Chopper Gate Control Unit controling the propulsive equipments of electric rolling stock consists of several electronic parts, PCB, Power Supply, Gate Circuit Amp, Freon Cooling Device, and has been used the parts made by japan manufacturer Mitsubish. But these parts recently have been more broken down and slow down performance because of long-term use, deterioration. Most of the malfunctions are low performance of LPF. Furthermore, it is physically impossible to repair LPF. Because it is molding type part and no longer manufactured. Also it needs high cost for custom-building. Therefore, it is now making up for through self-developed LPF and operating on Busan metro 1st after on-board testing. This research performed the PS Pice simulation testing, analysis of self-developed LPF performance and the wave form characteristic by multi-function synthesizer, spectrum analyzer, oscilloscope.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.315-317
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• 1995

A simple drive circuit without position sensors for a switched reluctance motor is presented. The turn on and turn off points are determined by detecting the rate of change of the active phase current. The drive circuit consists of a current sensing resistor, RC filter, comparator, OP Amp, and OR gates. It is verified through the experiments that the switched reluctance motor with the proposed sensorless drive circuit is well operated in wide speed ranges.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.4B
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• pp.613-623
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• 2000

Digital TV tuner for 8-VSB modulation was developed with satisfying the requirements of ATSC. The double frequency conversion and the active tracking filter in the front-end were used to reduce interference of the adjacent channels and multi-channels, which suppress If beat and image band. However, it was impossible to get frequency mapping between tracking filter and first VCO(Voltage Controlled Oscillator) in the double conversion digital TV tuner differing from conventional NTSC tuner. This paper, therefore, suggests the available structure and a new method for automatic frequency selection by obtaining the mapping of frequency characteristic over tracking voltage and the combined hardware which compose of Micro-controller, EEPROM, D/A(Digital-to-Analog Converter), OP amp and switch driver to solve above problems.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.4
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• pp.473-477
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• 2015

In this paper, a commercial phosphorescent white light-emitting diode (WLED) visible light communication (VLC) system with an equalization circuit to achieve the high modulation bandwidth was designed and demonstrated. An analytical method to examine the performance of the equalizer was carried out using a general circuit-simulator, PSpice. The equalization circuit was composed of two passive filters with resisters and a capacitor and an active filter with an op-amp. Utilizing our post-equalization technology, the ~3.5 MHz bandwidth of phosphor WLED could be extended to ~25 MHz without using an optical blue-filter. In this VLC system with a single round-type WLED and a single PIN photo-diode, ASK data transmission up to 35 Mbps at a 1m free space distance was obtained. The resulting bit-error-rate was $7.6{\times}10^{-4}$, which is less than the forward error correction (FEC) limit of $3.8{\times}10^{-3}$.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.10
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• pp.629-636
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• 2016

This study presents the development of an acid resistance velocity sensor that is used for measuring velocity inside a copper sulfate plating bath. First, researchers investigated the acid resistance coating to confirm the suitability of the anti-acid sensor in a very corrosive environment. Then, researchers applied signal processing methods to reduce noise and amplify the signal. Next, researchers applied a pressure-resistive sensor with an operation amplifier (Op Amp) and low-pass filter with high impedance to match the output voltage of a commercial flowmeter. Lastly, this study compared three low-pass filters (Bessel, Butterworth and Chebyshev) to select the appropriate signal process circuit. The results show 0.0128, 0.0023, and 5.06％ of the mean square error, respectively. The Butterworth filter yielded more precise results when compared to a commercial flowmeter. The acid resistive sensor is capable of measuring velocities ranging from 2 to 6 m/s with a 2.7％ margin of error.