• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.2
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• pp.130-134
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• 2008

This paper presents a clock and data recovery(CDR) using a quarter-rate technique. The proposed CDR helps reduce the VCO frequency and is thus advantageous for high speed application. It can achieve a low jitter operation and extend the pull-in range without a reference clock. The CDR consists of a quarter-rate bang-bang type phase detector(PD) quarter-rate frequency detector(QRFD), two charge pumps circuits(CPs), low pass filter(LPF) and a ring voltage controlled oscillator(VCO). The Proposed CDR has been fabricated in a standard $0.18{\mu}m$ 1P6M CMOS technology. It occupies an active area $1{\times}1mm^2$ and consumes 98 mW from a single 1.8 V supply.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.3
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• pp.445-453
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• 2000

In this paper, the method of designing an active inductor for MMIC is proposed. The proposed tunable active inductor is composed of a cascade FET with feedback capacitors and resistors. Because of a very low series resistance in the proposed inductor, a very high Q factor can be obtained. Also it has an excellent characteristics suitable for high frequency band. The inductance value can be changed by controlling feedback capacitors, resistors and a bias voltage respectively. When the feedback resistor and parallel resistor within circuits are varied, the inductance value is changed from 0.2 nH to 1.7 nH in the range 1 to 15 GHz. Also we designed bandpass filter using the proposed active inductor and it shows the insertion loss of 0.4 dB and return loss, 20 dB.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.7
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• pp.791-794
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• 2014

In this work, a 300 GHz imaging detector has been developed and image has been acquired in a 65-nm CMOS technology. The circuit was designed based on the square-law of MOSFET devices. The fabricated detector exhibits a maximum responsivity of 2,270 V/W and minimum NEP of $38pW/Hz^{1/2}$ at 285 GHz, and NEP< ${\sim}200pW/Hz^{1/2}$ for 250~305 GHz range. The chip size is $400{\mu}m{\times}450{\mu}m$ including the probing pads and a balun, while the core of the circuit occupies only $150{\mu}m{\times}100{\mu}m$.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.4
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• pp.347-350
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• 2017

In this paper, we implemented a real-time 2.4 GHz direction finding system using a time-modulated array(TMA) and an Universal Software Radio Peripheral(USRP). Our system consists of two commercial monopole antennas, self-designed switch board, and an USRP, and it is controlled using LabVIEW program in real-time. From measured results, it is verified that our system can exactly detect the incident angle within 4 degree in the range of 30 degree. Our direction finding system has advantages of a simple hardware architecture than conventional one with multiple receivers, and a simple algorithm only by using a main lobe and a first side-lobe of switching frequency.

• Journal of the Korean Institute of Gas
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• v.12 no.1
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• pp.31-35
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• 2008

Natural gas vehicles are being applied to city buses for improving air quality in metropolitan and have proved the effective way to reduce the pollutant emissions. Liquified Natural Gas(LNG) has also attempted a vehicle fuel in order to raise the fuel storage density that is a disadvantage of Compressed Natural Gas(CNG). This paper described insulation characteristic of a LNG storage tank. From the results, adiabatic coefficient of a tested tank was around $40J/h{\cdot}^{\circ}C{\cdot}m^2$ and it was the lower level than gas safety regulation limit. Two experimental methods were adopted to justify the evaluation results and they were revealed that the results were very similar to each other. Also, through testing relief valve operation characteristic it was investigated venting amount of boiled off gas.

• The Journal of the Korea Contents Association
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• v.13 no.11
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• pp.541-550
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• 2013

Generally in case of tablet PC's, the Windows 8 is used to support various functions or development convenience, however it cannot support real-time processing. In addition, existing commercial solutions and RTiK has a problem to support real-time processing due to impossibility of getting APIC timer count value which is used to generate timer interrupt separated from that of Windows. Thus, in this paper, we set the initial APIC count value using MSR_FSB_FREQ to support real-time processing on the Windows 8-based tablet PC's. Additionally, we deal with designing and implementing RTiK+ providing real-time processing to guarantee interrupt periods by controlling C-State which is used for low power techniques. To evaluate the performance of the proposed RTiK+, we measured the periods of generated real-time threads using RDTSC instructions which return the number of CPU clock ticks, and verified that RTiK+ operates correctly within the error ranges of 1ms.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.6
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• pp.529-534
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• 2014

Pyrotechnic devices are widely used for space appendages. However, a cube satellite requirements do not permit the use of explosive pyrotechnic device. A nichrome burn wire release has typically been used for holding and release of deployable appendages of the cube satellite due to its simplicity and low cost. However, relatively low mechanical constraint force and system complexity for application of multi-deployable systems are disadvantages of the conventional mechanism. To overcome these drawbacks, we developed a hinge driving segmented nut type holding and release mechanism based on the nichrome burn wire release. The functional performance of the mechanism has been verified through release function test, static load test and shock level measurement test.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.904-907
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• 2013

Demand Controller is a control device that if current electric power consumption seems to exceed the targeted amount of electric power, block the connected load devices. When this ON/OFF way is applied to electric power management of electric furnace, start and stop operation of inverter and an electric heater which supplying electric power is being performed repeatedly. This has a problem of life-shortening of inverter and an electric heater by electrical damage. In addition, when electric power supplying is blocked, attemperation is not allowed until return to normal operation condition. In this paper, we develop power management system for electric furnace using the electric furnace remote controller. This system provides the automatic control for approved electric power to electric furnace organically and prevent electric damage of inverter and an electric heater through continuous electric power supply within the targeted amount of electric power.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.6
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• pp.849-854
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• 2018

Radio base stations, which are widely distributed across large areas, have many difficulties in managing them. Unmanned radio base stations in remote mountains are having a hard time accessing them in case of emergencies. Major telephone service providers only remotely control incoming and outgoing information and local small business partners responsible for maintaining actual facilities do not possess such technologies, so they are each checked during field visits. In this study, in order to process the sensor raw data and smoothing, we apply the particle filters and confirmed that the performance of sensor data accuracy is increased. Integrated system using temperature, humidity, fire condition, and power operation at a wide range of radio base stations under the real-time monitoring status is operated well. It show that all of the status of base station are monitored at the remote office using the cloud server through internet networking.

• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.2
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• pp.202-208
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• 2001

A Switched Reluctance Motor(SRM) has double salient poles structure and the phase windings are wound in stator. SRM hase more simple structure that of other motor, thus manufacture cost is low, mechanically strong, reliable to a poor environment such as high temperature, and maintenance cost is low because of brushless. SRM needs position detector to get rotator position information for phase excitation and tachometer or encoder for constant speed operation. But, this paper doesn\`s use an encoder of high cost for velocity measurement of rotator. Instead of it, the algorithm for position detection and velocity estimation from simple slotted disk has been proposed and developed. To implement variable speed digital control system with velocity estimation algorithm, the TMS320F240-20MIPS fixed point arithmetic processor of TI corporation is used. The experimental results of the developing system are enable to control speed with wide range, not only single pulse, hard chopping mode and soft chopping, ut also variable speed control, and advance angle control.