• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.106-109
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• 1998

Wireless communication systems, in particular, must operate in a crowded electro-magnetic environmnet where in-band undesired signals are treated as noise by the receiver. These interfering signals are often random but not Gaussian Due to nongaussian noise, the distribution of the observables cannot be specified by a finite set of parameters; instead r-dimensioal sample space (pure noise samples) is equiprobably partitioned into a finite number of disjointed regions using quantiles and a vector quantizer based on training samples. If we assume that the detected symbols are correct, then we can observe the pure noise samples during the training and transmitting mode. The algorithm proposed is based on a piecewise approximation to a regression function based on quantities and conditional partition moments which are estimated by a RMSA (Robbins-Monro Stochastic Approximation) algorithm. In this paper, we develop a diversity combiner with modified detector, called Non-Linear Detector, and the receiver has a differential phase detector in each diversity branch and at the combiner each detector output is proportional to the second power of the envelope of branches. Monte-Carlo simulations were used as means of generating the system performance.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.421-422
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• 2008

In this paper, CMOS RF front-end circuits for an L1/L5 dual-band global positioning system (GPS)/Galileo receiver are designed in $0.13\;{\mu}m$ CMOS technology. The RF front-end circuits are composed of an RF single-to-differential low noise amplifier, an RF polyphase filter, two down-conversion mixers, two transimpedance amplifiers, a IF polyphase filter, four de-coupling capacitors. The CMOS RF front-end circuits provide gains of 43 dB and 44 dB, noise figures of 4 dB and 3 dB and consume 3.6 mW and 4.8 mW from 1.2 V supply voltage for L1 and L5, respectively.

• International journal of advanced smart convergence
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• v.7 no.2
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• pp.47-54
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• 2018

This paper is a study on implementation of the golf play advice system which provides advice to golfers through mobile devices. The system consists of a mobile unit consisting of a GPS receiver, a data transmitter and receiver, and a display unit, and a server unit composed of a database and advice generator. The advice generator that provides advices to the users, generates advices with IF-THEN rule-based reasoning method. The reasoning module utilizes golfer's personal records and various information in the database of the server unit. This system provides the advice to the users who play on the golf course through mobile devices, so that it is possible to provide various information similar to the screen golf using the computer simulating technology in the outdoor golf course.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.4
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• pp.598-603
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• 1990

This study evaluates the performance of an optical receiver for binary phase shift keying (BPSK) signals in the presence of short noise originating from the photo diode and phase noise of the optical source. The case of using I.O. hybrid compare with the fiber optic hybrid to mix received optical signal and laser local oscillator signal. The impact of these noise is minimized if loop natural frequency and power split ratio between data and carrier recovery branch are choosen optimally. Then it is obtained that required laser linewidt to achieve a BER of 10**-9. The results are the same except theat in case of using the fiber optic hybrid the required optical power is twice as much as the I.O. hybrid.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.399-403
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• 2006

Software-based GNSS receivers have the great advantage in flexibility compared with conventional receivers. But it has some problems to processing IF level Signal RAW data, need long time to process long term data and TTFF is long because the process is too slow. So this time, we concentrated on the signal acquisition, and examined the speedup technique. Using this technique, the acquisition was speedup dramatically, and signal-to-noise ratio was improved.

• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.5
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• pp.591-596
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• 1986

A binary continuous phase frequency shift keying (CPFSK), whose phase is a continuous function of time and instantaneous frequency is constant, is a bandwidth efficient constant envelope signalling scheme. A transmitting signal is formed by combined coding of a convolutional encoder and a binary CPFSK modulator. The signal is transmitted throuth additive white Gaussian noise(AWGN) channel. If the received signal is detected by a coherent maximum likelihood(ML) receiver, error probability can be expressed approximately in terms of minimum Euclidean distance. We propose rate 2/4 codes for the improvement of error performance without increating the data rate per bandwidth and the receiver complexity. Its minimum Euclidean distances are compared with those of rate \ulcornercodes as a function of modulation index and observation interval.

• ETRI Journal
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• v.46 no.2
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• pp.238-249
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• 2024

Equivalent-time sampling can improve measurement or sensing systems because it enables a broader frequency band and higher delay resolution for periodic signals with lower sampling rates than a Nyquist receiver. Meanwhile, a digital down-conversion (DDC) technique can be implemented using a straightforward radio frequency (RF) circuit. It avoids timing skew and in-phase/quadrature gain imbalance instead of requiring a high-speed analog-to-digital converter to sample an intermediate frequency (IF) signal. Therefore, when equivalent-time sampling and DDC techniques are combined, a significant synergy can be achieved. This study provides a parameter design methodology for optimal equivalent-time sampling using DDC.

• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.667-670
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• 2004

In this paper, we have presented the improved IF transceiver architecture and the implementation and experimental results on re-configurable transceiver based on digital IF for multiple wideband OFDM/TDD base stations for high-speed portable internet-service in which is issued Korea. The implemented IF transceiver has been designed to support multiple frequency allocations and multiple standards by only modifying the programmable software not its hardware like as the software-defined-radio concept. Also, the digital complex quadrature modulation technique has been used for the digital IF transmitter, which is able to combine multiple frequency bands in digital processing block not RF block and to reject the image frequency signals. And the bandpass sampling technique has been used for the digital IF receiver to reduce the sampling rate of ADC. This paper has shown the experiment results on the frequency response and constellation on the base-station implemented using the modified IEEE 802.16a/e physical layer channel structure based on OFDM/TDD.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.2
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• pp.473-480
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• 2013

In this paper, location recognition algorithm is developed to improve the accuracy using improve Trilateration. The location recognition algorithm is first calculate the location refer to the measured signal power. Error can be occurred when measure distance with arranged node in specific location. If the distance data is received from node (receiver, coordinator), Node selected for location calculation is defined through section. If the distance data is received from node (receiver, coordinator), Node selected for location calculation is defined through section. Second, we apply algorithm of section filtering. If there are 4 sections in node, we consider 1 section to 6 location recognition coordinates. A special characteristic drawback of RF is that the actual distance is actually farther than the calculated received distance data. This is error is incurred when the signal strength increases. We reduce the location recognition error by applying an improved algorithm as secondary after filtering primary through section filtering.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.6
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• pp.161-167
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• 2017

Recently, small radar has been reduced in size and power consumption to cope with various operating environments. It also requires the development of a small millimeter wave radar with high range resolution to disable the system of target with a single strike. In this paper, we design and implement a signal processor that can be used in small millimeter wave radar. The signal processor for the small millmeter wave radar is designed with a digital IF(Intermediate Frequency) receiver and DFT(Discrete Fourier Transform) module capable of real time FFT operation for miniaturization and low power consumption. Also it was to leverage the FPGA(Field Programmable Gate Array) and DAC(Digital Analog Converter) as a means for correcting the distortion of signals that can occur in the receive path of the small millimeter wave radar to create a RF signal that is used by the system. Finally, we verified the signal processor presented through performance test