• Journal of the Institute of Electronics Engineers of Korea TE
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• v.42 no.3
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• pp.39-44
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• 2005

In this paper, we use the 5-ary frequency shift keying method for robust powerline communication. To transmit the data by the 3-ary carrires among 5-ary carrirers and three carriers are 115kHz, 120kHz and 125kHz. Each time of three carrires is 0.33ms and total transmitting time duration from zero crossing point has 1ms. We use the dummy carriers which are 50kHz and 350kHz for monitoring the powerline channel state, dummy signal duration is received during 1ms. Experimentation result is shown that the implemented PLC transceiver has better than chirp transceiver at the capacitive load testing in spite of low transmission power.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.1
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• pp.22-31
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• 1999

The conventional RZ-SSB demodulator consists of a limiter, FM demodulator and a linearizer. Since the conventional linearizer which cancels the high-order distortions must include Hilbert transformer, the performance of the demodulator are determined by the Hilbert transformer which is very complicated to realize in aeronautical telecommunication. This paper describes a method of designing RZ-SSB demodulator without Hilbert transformer. Since avionics systems are able to eliminate the inherent disadvantages in RZ-SSB, the results of this paper suggest that the RZ-SSB demodulator without Hilbert transformer is suitable for aeronautical telecommunication transceiver systems used in HF band.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.168-171
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• 2003

As vehicles are more intelligent for convenience and safety of drivers, the in-vehicle networking systems and smart modules are essential components for intelligent vehicles. However, for the smart module to widely apply to the IVN systems, two problems are considered as follows. Firstly, because it is very difficult that transducer manufacturers developed the smart module that supports the existing all IVN protocols, the smart module must be independent to the type of networking protocols. Secondly, when the smart module is exchanged due to its failure, it is necessary how the transducer is only exchanged without exchange of the microprocessor and network transceiver. This paper deals with the IEEE 1451 based smart module that describes the digital interface between a network transceiver and sensor module. Finally. efficiency of the IEEE 1451 based smart module was evaluated on the experimental model.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.2
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• pp.83-91
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• 2012

An RF energy detector for spectrum sensing in TV white space transceiver is presented. It is based on an RF active filtering technique that comprises a low-noise amplifier with a frequency-translation high-pass filtering feedfoward loop, which attenuates the unwanted sideband energy and only passes the wanted band energy. Unlike the conventional architecture, a new architecture that can attenuate both sidebands at the same time is proposed. A simplified system modeling method is presented to assess the non-ideality effects on the RF energy detector performances. System behavioral simulations demonstrate that the proposed architecture can be instrumental for realizaing a RF energy detector circuit in CMOS.

• Korean Journal of Optics and Photonics
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• v.15 no.4
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• pp.349-354
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• 2004

As a transmitter sub-assembly in the XFP(10 Gb/s Small Form Factor Pluggable) transceiver module, a transmitter optical sub-assembly(TOSA) is designed, fabricated and characterized in view of electrical and thermal performances. For a low-cost and compact packaging TOSA, the bias-tee and the matching resistor are monolithically integrated on the AlN sub-mount and a newly designed coplanar waveguide is drawn in the TO-stem. All optoelectronic components packaged in the TOSA are modeled by the equivalent circuit, which helps to improve and characterize the TOSA performance. The fabricated TOSA shows the -3㏈ bandwidth as high as 11 GHz at an elevated temperature of 85$^{\circ}C$.

• Journal of Korea Society of Digital Industry and Information Management
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• v.9 no.2
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• pp.81-87
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• 2013

In this paper, we present an implementation of Long Term Evolution (LTE) Uplink (UL) system on a Software Defined Radio (SDR) platform using a conventional Personal Computer (PC), which adopts Graphic Processing Units (GPU) and Universal Software Radio Peripheral2 (USRP2) with URSP Hardware Driver (UHD) for SDR software modem and Radio Frequency (RF) transceiver, respectively. We have adopted UHD because UHD provides flexibility in the design of transceiver chain. Also, Cognitive Radio (CR) engine have been implemented by using libraries from UHD. Meanwhile, we have implemented the software modem in our system on GPU which is suitable for parallel computing due to its powerful Arithmetic and Logic Units (ALUs). From our experiment tests, we have measured the total processing time for a single frame of both transmit and receive LTE UL data to find that it takes about 5.00ms and 6.78ms for transmit and receive, respectively. It particularly means that the implemented system is capable of real-time processing of all the baseband signal processing algorithms required for LTE UL system.

• Journal of the Korean Institute of Telematics and Electronics
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• v.9 no.5
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• pp.19-26
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• 1972

A newly developed quartz frequency modulator utili3ing a V. V. C. diode is briefly described. Its electrical characteristics-including modulation linearity, modulation distortion, and carrier frequency stability depending upon the variation of the environmental temperature and the applied power voltage, etc.-are suitable for the modulator of a mobile or a portable F.M. transmitter according to the experimental results. The excellent over-all electrical characteristics were proved from the experimental development of the two kinds of transceivers. One is the single channal transceiver which contains a direct frequency modulator at the carrier frequency of 52.750 MHg. The other is the dual channel transceiver (the frequencies are selected from about 40 channels without tuning adjustment) whose operational frequency is composed of a modulated frequency of 10.7 MHz and the frequency generated at a channel control oscillator, As mentioned above, it is realized that the electrical characteristics of this modulation method are suitable for portable F. M. transceivers.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.1
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• pp.148-154
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• 2005

This paper deals with performance degradations caused by RF I/Q impairments such as amplitude mismatch and phase mismatch in W-CDMA user equipment which uses QPSK(Quadrature Phase Shift Keying) modulation. The impacts of I/Q impairments on the BER(Bit Error Rate) are analyzed by using the variations of adjacent symbol distance. The BER versus amplitude mismatch and phase mismatch with QPSK constellation is reviewed through Matlab simulation. Performance degradation produced by RF I/Q impairments is measured with the implemented RF transceiver and modulation/demodulation test equipments through EVM(Error Vector Magnitude). The minimum performance requirements of amplitude mismatch and phase mismatch in W-CDMA user equipment are presented from the point of hardware implementation and the test method of the impairments is also included.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.3
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• pp.93-98
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• 2005

Silicon bipolar transistors (Si-BJT) are widely used in the telecommunication system such as short range wireless control and wireless indoor voice communication system. New modeling method for the internal current source model of Si-BJT is proposed. The proposed method based on new thermal resistance extraction method and new analytical expressions for the current source parameters of Si-BJT. The proposed method can directly extract the model parameters without any optimization procedure which is adopted in the conventional modeling method. The proposed method is applied to 5 finger $0.4\times20[{\mu}m^2]$ and the model shows good prediction of the measured data in $3[\%]$ of errors proving the validity of this method.

• Journal of Advanced Navigation Technology
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• v.9 no.2
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• pp.93-102
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• 2005

This paper presents an interface configuration between Access Point(AP) and Radio Over Fiber (ROF) transceiver for the wireless internet system. The wireless internet could provides 60km/h mobility and 50Mbps IP based data services for each mobile terminal. Thus, cost effective cell infrastructure is inevitably required. This paper suggests an interface configuration between AP and passive integrated picocell(PIP) involving ROF links. Nonlinear characteristics of ROF link using a typical FP transceiver are measured for wireless internet applications.