• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.5
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• pp.217-221
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• 2005

A inductive voltage divider(IVD) is widely used as a ratio arm of precise impedance measurement bridges at low frequencies of audio frequency range and a well fabricated IVD has ratio error of $10^{-7}$ order without any calibration. Recently, the order of $10^{-8}$ of the best measurement uncertainty is needed for calibration and maintenance of impedance standards as national standards. In order to achieve that uncertainty, the IVD which is used for a ratio arm of precise impedance measurement bridge should be calibrated within the uncertain of order of $10^{-8}$ For this purpose, a ratio calibration bridge for IVDs has been developed. The measurement uncertainties of both inphase and quadrature of the bridge are analyzed less then $3{\times}10^{-8}$ respectively at 1 kHz and 25 V.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.10a
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• pp.127-130
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• 2003

An RSFQ (Rapid Single Flux Quantum) counter can be used as a frequency divider that was an essential part of a programmable voltage standard chip. The voltage standard chip is composed of two circuit parts, a counter and an antenna Analog signal of tens to hundreds ㎓ may be applied to a finline antenna part. This analog signal can be converted to the stream of SFQ voltage pulses by a DC/SFQ circuit. The number of voltage pulses can be reduced by 2n times when they pass through a counter that is composed of n T Flip-Flops (Toggle Flip-Flop). Such a counter can be used not only as a frequency divider, but also to build a programmable voltage standard chip. So, its application range can be telecommunication, high speed RAM, microprocessor, etc. In this work, we have used Xic, WRspice, and L-meter to design an RSFQ counter. After circuit optimization, we could obtain the bias current margins of the T Flip-Flop circuit to be above 31％ Our RSFQ counter circuit designs were based on the 1 ㎄/$\textrm{cm}^2$ niobium trilayer technology.

• Journal of electromagnetic engineering and science
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• v.8 no.3
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• pp.129-133
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• 2008

An integrated passive device(IPD) technology by semi-insulating(SI)-GaAs-based fabrication has been developed to meet the ever increasing needs of size and cost reduction in wireless applications. This technology includes reliable NiCr thin film resistor, thick plated Cu/Au metal process to reduce resistive loss, high breakdown voltage metal-insulator-metal(MIM) capacitor due to a thinner dielectric thickness, lowest parasitic effect by multi air-bridged metal layers, air-bridges for inductor underpass and capacitor pick-up, and low chip cost by only 6 process layers. This paper presents the Wilkinson power divider with excellent performance for digital cellular system(DCS). The insertion loss of this power divider is - 0.43 dB and the port isolation greater than - 22 dB over the entire band. Return loss in input and output ports are - 23.4 dB and - 25.4 dB, respectively. The Wilkinson power divider based on SI-GaAs substrates is designed within die size of $1.42\;mm^2$.

• JSTS:Journal of Semiconductor Technology and Science
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• v.7 no.4
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• pp.281-286
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• 2007

In this paper, sub-circuits for 24 GHz phase locked 100ps(PLLs) using $0.5{\mu}m$ SiGe HBT are presented. They are 24 Ghz voltage controlled oscillator(VCO), 24 GHz to 12 GHz regenerative frequency divider(RFD) and 12 GHz to 1.5 GHz static frequency divider. $0.5{\mu}m$ SiGe HBT technology, which offers transistors with 90 GHz fMAX and 3 aluminum metal layers, is employed. The 24 GHz VCO employed series feedback topology for high frequency operation and showed -1.8 to -3.8 dBm output power within tuning range from 23.2 GHz to 26 GHz. The 24 GHz to 12 GHz RFD, based on Gilbert cell mixer, showed 1.2 GHz bandwidth around 24 GHz under 2 dBm input and consumes 44 mA from 3 V power supply including I/O buffers for measurement. ECL based static divider operated up to 12.5 GHz while generating divide by 8 output frequency. The static divider drains 22 mA from 3 V power supply.

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.158-161
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• 1998

A precision high voltage generator for ion injection is implemented on HFZVS-PSCI (High Frequency Zero-Voltage-Switching Phase-Shift-Controlled Inverter). Some practical aspects of implementing precision high voltage generator with HFZVS-PSCI, such as a HFHV transformer, multiflier, and precision CR divider are discussed. The results show that the generator under the Phase-Shift-Controller has a fast dynamic response, low ripple voltage, and high accuracy.

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1368-1370
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• 1995

Lightning impulse voltage is essential to evaluate the insulation performance of electric power apparatus. Recently international standard(IEC-60) on high voltage measurement techniques are being revised. In the draft of this standard, a new calibration method is introduced and the accuracy of most industrial measuring systems is maintained by means of comparison test against the reference measuring systems. Intercomparison tests of dividers for lightning impulse measurement were carried out by KERI. The shielded resisitive divider with 700kV rating developed by KERI were done comparison test with PTB divider with 300kV rating which have the similar charateristics as that were circulated among the laboratories. This paper reports on the comparison test results with full lightning impulse voltages from 126kV to 240kV. It is demonstrated that KERI are capable of realizing the idea in the revision of the IEC standand, that is, to establish traceability.

• Proceedings of the IEEK Conference
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• 2000.11b
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• pp.208-211
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• 2000

This paper describes the design of a CMOS frequency synthesizer using programmable frequency divider with novel architecture. A novel architecture of programmable divider can be producted all of integer-N and fabricated by 0.65$\mu\textrm{m}$ 2-poly, 2-metal CMOS technology. Frequency synthesizer is simulated by 0.25$\mu\textrm{m}$ 2-poly, 5-metal CMOS technology. This circuit has settling time of 1.5${\mu}\textrm{s}$ and power consumption of 70㎽. Operating frequency of the frequency synthesizer is 820MHz∼l㎓ with a 2.5V supply voltage.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.233-236
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• 2005

Phase noise in a phase-locked-loop (PLL) is unwanted and unavoidable. It is a main concern in oscillation system especially PLL. The phase noise is derived in term of power spectrum density by using a reliable phase noise model. There are four noise sources being considered in this paper, which are generated by reference oscillator, voltage controlled oscillator, filter, and main divider. The major concern for this paper is the noise from the filter. Two types of second order low pass filter are used in the PLL system. Applying the mathematical phase noise model, the output noises are compared. The total noise from the passive filter is lower than the active filter at the offset frequency range between 1 Hz to 33 kHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.7
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• pp.620-624
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• 2016

In this paper we designed a current mode logic frequency divider to transmit a baseband amplitude modulated signal. From simulation result, we studied input and output waveforms according to the variation of input bias voltage. For the purpose of the verification of the study, we designed a current mode logic frequency divider at 1,400 MHz. The designed frequency divider operates between 100 MHz and 3,000 MHz, for -33 dBm input power. The circuit draws $I_{total}=30mA$ from $V_{DD}=3V$ supply, and the simulation result shows that an amplitude modulated signal at 1,400 MHz with the modulation index of 0.5 was successfully downconverted to 700 MHz.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1779-1781
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• 2003

For reliability of high voltage test results in test laboratory, traceability of measuring systems is to be needed. In this paper, it deals with traceability and uncertainty of AC voltage measuring system which is tested by comparison with reference divider.