• Journal of Sensor Science and Technology
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• v.24 no.4
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• pp.252-257
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• 2015

This paper proposes a single slope A/D converter (SSADC) that is possible to process the signal of the ultraviolet, visible and infrared rays with a single chip. And the proposed SSADC is a type of single channel ADC. In the conventional SSADC, it is possible to process the only one signal with a kind of the sensor because the speed of the operating frequency and the slope of ramp signal generated by the ramp generator are fixed. In order to improve the disadvantages, a ramp generator which has variable slope in ramp function is designed and $3{\times}1$ MUX(multiplexer) is adopted so that we can change the speed of the operating frequency and the slope of ramp signal. Therefore, the multiple signal processing of the wanted sensors can be possible. The designed circuit is layout by the $0.35-{\mu}m$ CMOS 2-poly 4-metal technology process and is checked through DRC and LVS tools.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.2
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• pp.138-141
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• 2018

In this paper, we describe the designed digital waveform of a linear frequency-modulated (FM) chirp signal using field-programmable gate arrays (FPGAs) for image radar, and this signal is modulated with an I-Q modulator, and multiplied by 24 frequency multipliers to obtain a 94-GHz W-band wideband chirp generator. The developed chirp generator is an FM signal with a 94-GHz carrier frequency and a 960-MHz bandwidth, and the flatness is less than 1.0 dB at intermediate frequency (IF) (3.9 GHz), 2.0 dB in the W-band, and it has a 0.3-W output power in the W-band.

• Journal of Electrical Engineering and Technology
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• v.9 no.6
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• pp.2114-2117
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• 2014

Joint pain is generally a common disorder not only for the old aged people but also for the immunocompromised patients. The present proposed study reveals the presence of inflammatory diseases in joint generally diagnosed by removing synovial fluid and changes in the volume and composition are examined for the presence of WBC and crystals. This study implement a non-invasive approach to identify the changes in joint fluid by measuring the changes in electrical property of the synovial tissue under the influence of electrical current signal with frequency range between 100 kHz to 300 kHz. The response of tissue for the current signal was measured in terms of potential drop across the tissue. The hardware system design consists of input and output sections. The input section which applies current signal to upper limb joint region is made of ICL8038 function generator IC with amplifier and voltage to current converter. The output section picks voltage variation using metal surface electrode, amplifier, ADC, PIC microcontroller and LCD interface. 100 patient inclusive of normal and disease affected patients where examined for upper limb synovial fluid variation and inflammatory diseases were identified.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.785-786
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• 2017

Recently, interest in AMOLED (Active Matrix OLED) panels has been growing with the development of displays used in each device. Therefore, the demand for the inspection equipment required for production is spreading, and therefore, efficient design is required to operate a plurality of signal generators. In this paper, we propose a central server management system for signal generators. The proposed system includes a method for driving an AMOLED panel, and the timing and power setting results are presented. Thus, it is possible to cope with loss or alteration of data, and it is believed that stable and smooth communication is possible.

• ETRI Journal
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• v.36 no.6
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• pp.924-930
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• 2014

This paper presents a $0.13{\mu}m$ CMOS 3-level envelope delta-sigma modulation (EDSM) RF signal generator, which synthesizes a 2.6 GHz-centered fully symmetrical 3-level EDSM signal for high-efficiency power amplifier architectures. It consists of an I-Q phase modulator, a Class B wideband buffer, an up-conversion mixer, a D2S, and a Class AB wideband drive amplifier. To preserve fast phase transition in the 3-state envelope level, the wideband buffer has an RLC load and the driver amplifier uses a second-order BPF as its load to provide enough bandwidth. To achieve an accurate 3-state envelope level in the up-mixer output, the LO bias level is optimized. The I-Q phase modulator adopts a modified quadrature passive mixer topology and mitigates the I-Q crosstalk problem using a 50% duty cycle in LO clocks. The fabricated chip provides an average output power of -1.5 dBm and an error vector magnitude (EVM) of 3.89% for 3GPP LTE 64 QAM input signals with a channel bandwidth of 10/20 MHz, as well as consuming 60 mW for both channels from a 1.2 V/2.5 V supply voltage.

• IEIE Transactions on Smart Processing and Computing
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• v.4 no.4
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• pp.258-264
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• 2015

The first 77 GHz transceiver that applies a heterodyne structure-based linear frequency modulation-frequency shift keying (LFM-FSK) front-end module (FEM) is presented. An LFM-FSK waveform generator is proposed for the transceiver design to avoid ghost target detection in a multi-target environment. This FEM consists of three parts: a frequency synthesizer, a 77 GHz up/down converter, and a baseband block. The purpose of the FEM is to make an appropriate beat frequency, which will be the key to solving problems in the digital signal processor (DSP). This paper mainly focuses on the most challenging tasks, including generating and conveying the correct transmission waveform in the 77 GHz frequency band to the DSP. A synthesizer test confirmed that the developed module for the signal generator of the LFM-FSK can produce an adequate transmission signal. Additionally, a loop back test confirmed that the output frequency of this module works well. This development will contribute to future progress in integrating a radar module for multi-target detection. By using the LFM-FSK waveform method, this radar transceiver is expected to provide multi-target detection, in contrast to the existing method.

• Wind and Structures
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• v.21 no.4
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• pp.443-460
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• 2015

In this paper, an integrator based method to estimate the effective wind speed in wind turbine systems is proposed. First, the aerodynamic torque was accurately estimated through a proportional gain based observer where the generator speed is the measured output of the system. The torque signal contains not only useful frequencies of the wind, but also high frequencies and the ones due to structural vibration. The useful information of the wind signal is low frequency. A spectral analysis permitted the determination of the useful frequencies. The high frequencies were then filtered before introducing the torque signal in the wind speed observer. The desired effective wind speed was extracted through an integrator based observer using the previously estimated aerodynamic torque. The strength of the method is to avoid numerical solutions used in literature of the wind speed estimation. The effectiveness of the proposed wind speed estimator and its use to control the generator speed has been tested under turbulent situations using the FAST software (Fatigue, Aerodynamics, Structures, and Turbulence), for large scale Megawatt turbine.

• Journal of the Korea Institute of Military Science and Technology
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• v.24 no.4
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• pp.368-373
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• 2021

This paper presents a method of independent pulse repetition frequency(PRF) generation and control for frequency phase calibration on mono-pulse radar at a remote location. In order to generate an independent PRF signal of 320[Hz], pulse width modulation(PWM) of 16-bit timer/counter was applied. For a precision control of PRF signal, 16-bit timer/counter interrupt was changed for each period. Therefore, average frequency of PRF could be controlled by 0.0001[Hz]. To calibrate a frequency phase of mono-pulse radar at a remote location, the proposed PRF generator with a precision control of frequency was used regardless of receiving PRF signal from a radar. For the verification of the proposed PRF generator, theoretical analysis and experimental results are included.

• Journal of Satellite, Information and Communications
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• v.12 no.4
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• pp.72-77
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• 2017

The Satellite Based Augmentation System (SBAS) broadcasts to users integrity and correction information for Global Navigation Satellite System (GNSS) such as GPS and GLONASS using geostationary orbit (GEO) satellites. In accordance with the recommendation of the International Civilian Aeronautical Organization (ICAO) to introduce SBAS until 2025, a Korean SBAS system development / construction project is underway with the Ministry of Land, Transport and Maritime Affairs. Korea Augmentation Satellite System (KASS) is a high precision GPS correction system which is composed of KASS Reference Station (KRS), KASS Processing Station (KPS), KASS Uplink Station (KUS), KASS Control Station (KCS) and GEO satellites. In this paper, we provided the conceptual design of the KASS uplink station, which is composed of the Signal Generator Section (SGS) and the Radio-Frequency Section (RFS), and interface between the KASS ground sector and the GEO satellite.

• Journal of IKEEE
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• v.25 no.4
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• pp.721-727
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• 2021

This paper proposes a UWB (Ultar-wideband) impulse generator using the gated ring oscillator. The oscillator and PLL circuits which generate a several GHz LO signal for the conventional architecture are replaced with the gated ring oscillator. Therefore, the system complexity is decreased. The proposed architecture controls the duty of enable signal, which is used for the head switch of ring oscillator. The control of the duty enables to tun off the oscillator during the guard interval and stop wasting the power consumption. The pulse shaping method using the counter makes the small side lobe and preserves the bandwidth regardless of the change on the center frequency. Designed UWB impulse generator could change the center frequency from 6.0 GHz to 8.8 GHz with a digital bit control, while it preserves the bandwidth as about 1.5 GHz.