• Proceedings of the KIEE Conference
• /
• 2003.07d
• /
• pp.2239-2241
• /
• 2003

A new RF control system of Pohang Accelerator Laboratory (PAL) storage ring is a subsystem upgraded PAL control system, which is based upon Experimental Physics and Industrial Control System (EPICS). There are 5 control components, Low Level RF System (LRS), Klystron System, Circulator System, Cavity System, Local Cooling Water System (LCW) at the storage ring of PAL. The new RF control system for the storage ring has been under development for one years, first versions of individual VME (Versa Module Europa) Input/output modules under construction and system integration begun. In this system, VMEbus-based hardware is widely used for front-end controllers (FDS), Input/output controller (IOC). A number of Programmable Logic Controller (PLC) and SUN workstations are also used for Operator Interfaces (OPI) in the control system. This paper describes the development VME I/O module to the new control system and how the design of this new system.

• Proceedings of the IEEK Conference
• /
• 2002.06c
• /
• pp.165-168
• /
• 2002

This paper has been designed and implemented of web security system using RF card A security mechanism that was proposed in this paper provides web services on card reader reads RF card of user only. In this paper, user authentication and server authentication was provided by challenge/response mechanism. Also, this system was provides confidentiality of communication messages.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
• /
• 2001.11a
• /
• pp.58-62
• /
• 2001

본 논문에서는 IMT-2000 통신방식 중 cdma-2000 방식의 시스템을 이용하여 이동통신 단말기 RF System에 미치는 위상 잡음의 영향성을 분석하였다. cdma-2000의 표준안인 TIA/EIA에서 권고한 IS-98-C 를 기초로 하여 위상 잡음 특성의 요구 조건을 유도하였다. 현재 상용화 된 부품을 이용하여 RF 시스템을 설계하여 위상 잡음 특성을 분석하였고 시스템에 가장 큰 영향을 미치는 oscillator의 위상 잡음의 양을 변화시켜 시스템에 미치는 영향을 Constellation Diagram과 Eye Diagram으로 제시 하였다.

• Proceedings of the IEEK Conference
• /
• 2008.06a
• /
• pp.149-150
• /
• 2008

In this paper, we propose a new RF education system using real module that engineer apply at actual companies and laboratories. The proposed system provides beginner and college students with a real effect of RF hardware education. The Optimized RF education system we present is made up of a real passive module, active module, mobile communication module, DSP based system.

• Journal of the Korea Society of Computer and Information
• /
• v.9 no.4 s.32
• /
• pp.179-184
• /
• 2004

Meter reading system, operated by meter staff who reads the meter and record consumption with handhold data terminals. can cause privacy intrusion, unread meter data, abnormal readings and excessive expenses of maintaining the system. To prevent the deterioration of customer service quality, Automatic Meter Reading system, which automatically recognizes meter readings and transmit reading data through wireless RF module, is designed. From collecting the reading data to managing statistics of customer's consumption information. this automatic meter reading system provides more accurate and fast information to customers. By designing this system, customer service satisfaction and reliability can be improve

• Current Optics and Photonics
• /
• v.3 no.4
• /
• pp.311-319
• /
• 2019

A hybrid free-space-optical/radio-frequency (FSO/RF) communication system is considered, with the help of amplify-and-forward (AF) relaying. We consider various weather conditions to investigate their effects on the system's performance. We begin by obtaining the cumulative distribution function and probability density function of the end-to-end signal-to-noise ratio for the AF dual-hop FSO communication system with RF backup link. Then, these results are used to derive closed-form expressions for the outage probability, average bit-error rate, and average ergodic capacity. The results show that the considered system efficiently employs the complementary nature of FSO and RF links, resulting in impressive performance improvements compared to non-hybrid systems.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.9 no.2
• /
• pp.327-332
• /
• 2008

New RF matcher module has been proposed in this paper for improvement of RF matcher in plasma etcher system using in semiconductor and display panel manufacturing process. New designed warm gear was used instead of bevel gear in new driving module, and control system was re-arranged with one-chip micro-process technique. The matching performance of new match module was improved in various process condition with reduction of backlash and matching time, and flexible motion of motor compared commercial match module. However this new type RF match module will improve the productivity in etching process of the mass production line.

• ETRI Journal
• /
• v.32 no.4
• /
• pp.503-511
• /
• 2010

WiBro radio frequency (RF) repeater is used for solving the problem of partial shadow areas in the wireless communication field that uses time-division duplexing (TDD) mode. In this paper, a method to efficiently generate TDD signals for WiBro RF repeater is proposed and its digital circuit is implemented. A TDD signal is detected from RF signals transmitted/received to/from RF repeater and then inputted again into the RF repeater, so that it can operate normally. First, the envelope of downlink signals is detected and then clamped to extract the basic form of a TDD signal using an operational amplifier circuit. Next, the TDD signal is generated by restoring and filtering the shape which has been distorted by the wireless channel. The algorithm and system to acquire TDD signal are developed with a goal to have simple but powerful functions with as little cost as possible. The proposed method is implemented as an RF-digital integrated system and verified through the experiments under the same condition as actual WiBro service environment.

• ETRI Journal
• /
• v.44 no.6
• /
• pp.966-976
• /
• 2022

Optical wireless communication, or free space optics, is a promising solution for backhauls in sixth-generation mobile systems. However, the susceptibility of optical links to weather conditions has led to FSO links being furnished with radio frequency (RF) backups. These Hybrid FSO/RF systems provide enhanced link availability but lead to RF resource wastage. Cognitive radio technology, in contrast, is well known for its optimal use of RF resources and may be combined with an FSO link to create a Cognitive Hybrid FSO/RF system. This work uses such a system to analyze a configuration for a mobile backhaul in sixth-generation mobile systems. This configuration can seamlessly coexist with established large scale RF cellular networks. The performance of this configuration is analyzed with respect to outage probability and average bit error by considering the impact of optical channel turbulence, misalignment loss, RF interference, and noise. Mathematical closed-form expressions are verified by simulations.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.60 no.12
• /
• pp.2286-2292
• /
• 2011

In this paper we present the design of Low Noise Amplifier(LNA), mixer and filter for RF front-end part of partial discharge monitoring system. The monitoring system of partial discharge in high voltage power machinery is used to prevent many kinds of industrial accidents, and is usually composed of three parts - sensor, RF front-end and digital microcontroller unit. In our study, LNA, mixer and filter are key components of the RF front-end. The LNA consists of common gate and common source-cascaded structure and uses the resistive feedback for broad band matching. A coupled line structure is utilized to implement the filter, of which size is reduced by the meander structure. The mixer is designed using dual gate structure for high isolation between RF and local oscillator signal.