• Proceedings of the IEEK Conference
• /
• 1999.11a
• /
• pp.63-66
• /
• 1999

Echo and near-end crosstalk(NEXT) can be generated in two-wire duplex transmission. In this paper investigates how to cancel echoes of high speed communication. A pipeline algorithm is used to remove the echoes that high speed communication. It is least mean squared(LMS) algorithm based on the relaxed look-ahead concept, is focused on the pipelined LMS, and its performance is compared to that of the serial LMS algorithm. And we design pipelined adaptive filtering. In advanced of the hardware implementation with VHDL code the performance of pipelined LMS algorithm is verified by the computer simulation.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.21 no.8
• /
• pp.2033-2042
• /
• 1996

In this papre, we describe a recently implemented echo canceller for digital cellular communication of Code Division Multiple Access(CDMA) that features time sharing of digital signal processor(DSP) over four channels in one DSP to reduce per channel costs. In the Public Land Mobile Network(PLMN), it is important to cancel the echo reflected from the Public Switched Telephone Network(PSTN) side. In case of digital mobile system, the round-trip delay of the echo is in excess of about 180 milliseconds due to frame-by-frame voice coding. It is necessary to cancel the echo in PLMN. We have developed a multi-channel echo canceller tht operates with Time Switch Module in a Mobile Switching Center(MSC). The general echo canceller needs PCM trunk interface circuits and the tone detection and disabling circuits, but the multi-channel echo canceller linked with Time Switch Module does not need them. Therefore we could develop the effective and economical echo canceller.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.12 no.5
• /
• pp.906-911
• /
• 2008

This paper designed Simulik Model to cancel the carrier frequency offset in OFDM using CORDIC Algorithm and evaluated its performance. And Simulink Model compared with Xilinx System Generator Model for FPGA implementation. As a result of simulation, we confirmed that both model is error free by CORDIC when offset frequency is lower than $10^5MHz$. Also, we verified the performance through Hardware Co-simulation with Xilinx Spartan3 xc3s1000 fg676-4 Target Device, and timing analysis and resource estimation.

• 한국항공운항학회:학술대회논문집
• /
• 2007.06a
• /
• pp.11-12
• /
• 2007

• Journal of the Institute of Electronics and Information Engineers
• /
• v.50 no.7
• /
• pp.225-230
• /
• 2013

In a bandpass sampling (BPS), the frequency of the sampler is lower than that of the signal being sampled. In this method, the baseband spectrum directly appears by the sampling operation, so that it is not necessary to use any frequency down-converter, which makes the receiver's hardware simpler. The second-order BPS uses two identical BPS samplers, of which sampling times are offset by each other. By exploiting the relationship between two sampled signals, it can be possible to cancel the aliased signal component or the interference due to the bandpass sampling. In order to cancel the interference, an interpolant filter is used to manipulate the phase characteristics of the BPS sampled signal. In this paper, it is introduced a multiband interpolant filter which can simultaneously cancel multiple interference signals that have been aliased from multiple frequency bands. In case of no need of interference cancellation, another method is suggested to enhance the signal quality by 3dB. A computer simulation has been performed, and the feasibility of the suggested methods has been verified.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.16 no.6
• /
• pp.542-553
• /
• 2011

A magnetic cable that can safely deliver high frequency AC electric power in flammable or sensitive workplaces by preventing from arcs and electric shocks is firstly proposed in this paper. Several new magnetic cable structures with magnetic shields, which are composed of such cancel coil, cancel copper plate, and cancel copper pipe, were compactly implemented by considering and analyzing fringe field and thus the parallel leakage flux is drastically reduced. The output power and efficiency of a prototype magnetic cable with 1.5 m length and 5 cm gap were measured as 353.8W and 68%, where the source current and switching frequency were 10 $A_{rms}$ and 20 kHz, respectively. The proposed magnetic cables are fully analyzed and verified by finite-element method (FEM) simulations and experiments. The results are in a good agreement.

• Journal of Digital Convergence
• /
• v.8 no.2
• /
• pp.147-160
• /
• 2010

Internet shopping mall business has taken its place as a major form of e-commerce and is evolving constantly. At the same time, disputes of various kinds are also arising in proportion to the evolution. A typical example is when a consumer purchased a product from an internet shopping mall and the seller wants to cancel or withdraw the sales contract saying that he miswrote the price or other important information when posting the product on the internet. It's about the error on the seller's part. Civil Law Chapter 109, legal principles on errors, appears to assume the case of natural declaration of intention. It was observed that legal principles on errors defined by the Civil Law are also applied in internet shopping malls, where declaration of intention is made electronically. In transactions involving internet shopping malls, where the seller's indication and advertisement constitutes an inducement to offer, the seller may cancel a contract concluded by the consumer's offer and the seller's acceptance if the seller finds errors on his part, and adequacy of the cancellation should be judged depending on specific cases. That is, the judgment of the important ground that comprises prerequisites for cancellation and presence of negligence may depend on how much difference there is between the normal price and the posted price on a specific case. Also, considering the cases where negligence was not perceived on the seller's miswriting of the price, the seller may cancel the transaction in a similar situation.

• 한국항공운항학회:학술대회논문집
• /
• 2005.11a
• /
• pp.11-14
• /
• 2005

• Proceedings of the Korean Institute of Communication Sciences Conference
• /
• 2006.07a
• /
• pp.531-531
• /
• 2006

• 제어로봇시스템학회:학술대회논문집
• /
• 2002.10a
• /
• pp.62.6-62
• /
• 2002

$\textbullet$ Introduction $\textbullet$ Problem Formulation $\textbullet$ Feedback Linearizing Controller Design $\textbullet$ Fuzzy System to Cancel System Uncertainty $\textbullet$ Adatptive Fuzzy Sliding Mode Controller Design $\textbullet$ Simulations $\textbullet$ Conclusions