• Journal of the Institute of Convergence Signal Processing
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• v.2 no.2
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• pp.55-61
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• 2001

In this paper, a synchronous reverse link DS-CDMA system with cdma2000 standard is simulated to analyze performance of system and to find the optimum power ratio between pilot channel and traffic channel. In the cdma2000 the pilot channel is used to estimate fading channel, in contract to IS-95 and it compensates phase variation of received signal due to channel environment. When the length of channel estimation is 31pcg symbols, we can find the optimum power ratio of pilot channel to traffic channel. And also we find Eb/No satisfying target FER when the power control is applied and analyze performance of system with multiuser transmission.

• Journal of IKEEE
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• v.2 no.1 s.2
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• pp.85-95
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• 1998

We consider two methods for the pilot signal transmission in DS/CDMA systems: Pilot channel method which is parallel to the data channel and pilot symbol method which is serial to the data channel. In this paper, we analyze the two methods. The performance of the two methods is shown to be dependent upon the added noise, fading, pilot symbol period and pilot channel power. Through the analysis, it is found that the performance of the pilot symbol method outperforms compared to the pilot channel method.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.609-611
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• 1996

Zero-Cross Detector makes pilot signal to control the power to CEDM(Control Element Drive Mechanism). Existing Zero-Cross Detectors has had a problem which can cause unexpected reactor trip resulted from fluctuating frequency of input signal coming from M/G Set. The existing Zero-Cross Detector can't work properly when power frequency is varying because it was designed to work under stable M/G Set operation, and produces wrong pilot signal and output voltage. In this report the Zero-Cross Detector is improved to resolve voltage fluctuating problem by using new devices such as digital noise filtering circuit, variable cycle compensator and alarm circuit. And through the performance verification it shows that new circuit is better than old one. If suggested detector is applied to plant, it is possible to use it under House Load Operation because stable voltage can be generated by new Zero-Cross Detector.

• ETRI Journal
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• v.28 no.5
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• pp.688-691
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• 2006

This letter addresses the superimposed pilot aided multiuser channel estimation for the uplinks of multi-input multi-output orthogonal frequency-division multiplexing systems. To mitigate the embedded-data effects on the performance of channel estimation, a novel combining algorithm is proposed. Optimal pilot symbols are developed with respect to the least square channel estimate's mean square error. The averaged sum-capacity lower bound is derived and simulated. Simulation results show that on a low signal-to-noise ratio regime, our proposed scheme achieves better performance and higher capacity than the conventional pilot aided approach.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.3
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• pp.1313-1318
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• 2011

This paper proposes a protocol integration system with multi-threading method for the ship electronic devices to solve problems with the compatibility. The proposed protocol integration system receives the different signals from each of the ships' devices through the RS-232 serial communication port and then divides the input signal into the field data. The required field data for standard signal composition are extracted from among these signal and these are combined in accordance with standard signal format. Thereafter, the protocol integration system transmits the processed standard signal to the auto pilot system through a single port.

• Journal of Broadcast Engineering
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• v.10 no.1 s.26
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• pp.31-42
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• 2005

ATSC DTV system uses FPLL block for acquiring the frequency synchronization. Because the FPLL uses only the pilot signal, the frequency convergence range becomes narrower and it takes a more time to acquire the frequency synchronization as the pilot is distorted. And the spectrum shape around the pilot makes an asymmetric convergence range between the positive frequency offset and the negative frequency offset. This paper proposes the algorithm that requires the Installation of the fitters at the both edges of a VSB spectrum and uses the signal power that passes these filters. The proposed algorithm complements the problems of the asymmetric convergence range and overcomes the performance degradation due to the distortion of a pilot level.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.11
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• pp.955-966
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• 2013

We propose two feedback interference cancellers(FICs) to improve the performance of the equalization digital on-channel repeater(EDOCR) with the FIC for the ATSC DTV broadcasting system. The FIC estimates the feedback channel between Tx. and Rx. antennas of the repeater by cross-correlating the reference signal and the feedback signal. Since there is a DC pilot which ruins the white property of the ATSC DTV signals, the FIC cannot estimate the feedback channel accurately. To solve the problem, the structural method which uses an additional DC pilot free reference for feedback channel estimation and the algorithmic method based on the digital signal processing which whitens the ATSC DTV signals and performs the feedback cancellation in the whitened signal domain. Simulation results show that the proposed two FICs show better feedback cancellation performance than the conventional FIC.

• Journal of the Korean GEO-environmental Society
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• v.20 no.4
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• pp.5-9
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• 2019

This paper is to provide the results of a pilot study of the usability and possibility of impact force response signal induced from impacting an object for the assessment of compressive strength of various materials (rock, concrete, wood, etc.) nondestructively. For this study, a device was devised for impacting an object and measuring the impact force. The impact was carried out by an initial rotating free falling impact and following repetitive impacts from the rebound action which eventually disappears. Wood and rock test specimens for different strengths were tested and an impact force response signal was measured for each test specimen. The total impact force signal energy which is assessed from integrating the impact force response signal was compared with the directly measured compressive strength for each specimen. The comparison showed that the total impact force signal energy has a direct relationship with the directly measured compressive strength and the results clearly indicated that the compressive strength of construction materials can be assessed nondestructively using total impact force signal energy which is assessed from integrating the impact force response signal induced from impacting an object.

• Journal of Korea Multimedia Society
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• v.13 no.11
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• pp.1667-1676
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• 2010

In this paper, we propose a packet scheduling algorithm that assigns different number of HS-PDSCH(High Speed Primary Downlink Shared Channel) to the service user according to the received signal to interference ratio of CPICH(Common Pilot Channel) and to the traffic characteristics. Assigned channel number is determined by the signal to interference ratio level from CPICH. The highest signal to interference ratio user gets the number of channels based on the signal to interference ratio table and the remained channels are assigned to the other level users. Therefore the proposed scheme can provide the similar maximum service throughput and higher fairness than existing scheduling algorithm. Simulation results show that our algorithm can provide the similar maximum service throughput and higher fairness than MAX C/I algorithm and can also support the higher service throughput than proportional fairness scheme.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.5C
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• pp.351-360
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• 2008

In cellular mobile radio systems with frequency reuse, the interference signals degrade the channel estimation and signal detection performance due to the low signal-to-interference ratio near coverage boundaries. When the preamble pilot sequences from different cells are orthogonal or located in disjointed positions, they can be used for multi-cell channel estimation and interference cancellation. In time-varying channels caused by Doppler spread, data pilot symbols are needed for channel estimations. However, data pilot symbols are usually located in identical positions for the overhead reduction, which degrades the channel estimation performance. In this paper, we demonstrate a significant amount of performance improvement is achieved by multiplying different pseudonoise(PN) sequences to the data pilot symbols from adjacent interference cells. In particular, for detection scheme using maximal ratio combining(MRC) and inter-cell spatial demultiplexing(ISD), quantitative performance gain of spectral efficiency for different values of Doppler frequency and interference power is presented.