• Journal of information and communication convergence engineering
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• v.11 no.1
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• pp.56-61
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• 2013

Modern integrated circuits (ICs) are becoming an integrated parts of analog, digital, and radio frequency (RF) circuits. Testing these RF circuits on a chip is an important task, not only for fabrication quality control but also for tuning RF circuit elements to fit multi-standard wireless systems. In this paper, RF test circuits suitable for embedded testing are introduced: RF power detectors, power control circuits, directional couplers, and six-port reflectometers. Various types of embedded RF power detectors are reviewed. The conventional approach and our approach for the RF power control circuits are compared. Also, embedded tunable active directional couplers are presented. Then, six-port reflectometers for embedded RF testing are introduced including a 77-GHz six-port reflectometer circuit in a 130 nm process. This circuit demonstrates successful calibrated reflection coefficient simulation results for 37 well distributed samples in a Smith chart. The details including the theory, calibration, circuit design techniques, and simulations of the 77-GHz six-port reflectometer are presented in this paper.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.53 no.2
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• pp.94-99
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• 2004

In this paper, We design a RF control system capable of handling multiple POS thermal printers. The system has three parts including embedded master controller, RF controller and high-speed thermal printer. Specially the designed linux embedded controller has simple structure and high performance to connect the TCP/IP network. The effectiveness of the developed RF control system is shown by proposed food ordering system.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.6
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• pp.566-573
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• 2004

This paper describes the ubiquitous home network (uHome-net) testbed and LonRF intelligent devices based on LonWorks technology. These devices consist of Neuron Chip, RF transceiver, sensor, and other peripheral components. Using LonRF devices, a home control network can be simplified and most devices can be operated on LonWorks control network. Also, Indoor Positioning System (IPS) that can serve various location based services was implemented in uHome-net. Smart Badge of IPS, that is a special LonRF device, can measure the 3D location of objects in the indoor environment. In the uHome-net testbed, remote control service, cooking help service, wireless remote metering service, baby monitoring service and security ＆ fire prevention service were realized. This research shows the vision of the ubiquitous home network that will be emerged in the near future.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.10a
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• pp.583-584
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• 2022

Due to the development of drones, drone missions are performed in various fields, and BVLOS (Beyond Visual Line Of Sight) flight is performed in a wide area. Most drones operate through radio frequency (RF) communication and can only fly in a limited radius of about 1-2 km. To overcome this, in this paper, we propose a multi-communication protocol-based drone control system to control drones performing missions in BVLOS using RF and LTE (Long Term Evolution). The proposed system consists of a control unit and a drone unit. The control unit transmits one control signal generated from the remote controller through RF and LTE. The drone unit classifies the control signal transmitted through RF and LTE according to the priority of the communication protocol and delivers it to the FC (Flight Controller). Through the proposed control system, it is possible to overcome the RF communication distance limit and prevent the communication disconnection situation.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.255-258
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• 1996

This paper describes a DC voltage controller for the DC power supply which is constructed using the full-bridged MOS-FET DC-to-RF power inverter and rectifier. The full-bridged MOS-FET DC-to-RF inverter consisting of four MOSFET arrays and an output power transformer has a control function which is able to control the RF output power when the widths of the pulse voltages which are fed to four MOS-FET arrays of the fall-bridged inverter are changed using the pulse width control circuit. The power conversion efficiency of the full-bridged MOS-FET DC-to-RF power inverter was approximately 85 % when the duty cycles of the pulse voltages were changed from 30 % to 50 %. The RF output voltage from the full-bridged MOS-FET DC-to-RF inverter is fed to the rectifier circuit through the output transformer. The rectifier circuit consists of GaAs schottky diodes and filters, each of which is made of a coil and capacitors. The power conversion efficiency of the rectifier circuit was over 80 % when the duty cycles of the pulse voltages were changed from 30 % to 50 %. The output voltage of the rectifier circuit was changed from 34.7V to 37.6 V when the duty cycles of the pulse voltages were changed from 30 % to 50 %.

• Journal of the Korea Convergence Society
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• v.8 no.11
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• pp.85-91
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• 2017

This paper concerns the design of a matching module system enabling the RF signal to be harmonized between the new base stations (RRH) and the repeater in the same frequency band of the asynchronous transfer network. This matching system controls the RF Gain Control of the module while monitoring the quality of the quality. Additionally, the RF environment has been adapted accordingly to adjust the RF Gain Control to match the receiver characteristics of the relay. As a result of this study, we improved the quality of the interface between the new base stations and existing relays.

• Journal of Advanced Navigation Technology
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• v.18 no.5
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• pp.508-512
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• 2014

This paper suggests the control system and algorithm for auto and manual control of the streetlight using RF system. There are two control system in this auto control algorithm. One is group control, the other individual control. In case of group control, if a car is detected by the object detecting sensor of the system installed on the streetlight, it will turn on the light per group by transmitting the RF signal. The streetlight turns on separately when it detects people or a car parked on the shoulder in accordance with the individual control. Also, there is manual control algorithm that manager can check surrounding environment and condition of the streetlight by RF signal and various sensors. So, not only the proposed system reduce meaningless energy consumption, but also it offers convenience regarding maintenance and control of the streetlight.

• Development and Reproduction
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• v.16 no.1
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• pp.53-58
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• 2012

Circadian rhythmicity (e.g. secretory pattern of hormones) plays an important role in the control of reproductive function. We hypothesized that the alteration of feeding pattern via meal time shift/restriction might disrupt circadian rhythms in energy balance, and induce changes in reproductive activities. To test this hypothesis, we employed simple animal model that not allowing $ad$ $libitum$ feeding but daytime only feeding. The animals of $ad$ $libitum$ feeding group (Control) have free access to food for 4 weeks. The day feeding (=reverse feeding, RF) animals (RF group) have restricted access to food during daytime (0900-1800) for 4 weeks. After completing the feeding schedules, body weights, testis and epididymis weights of animals from both group were not significantly different. However, the weights of seminal vesicle (control : RF group = $0.233{\pm}0.014g$ : $0.188{\pm}0.009g$, $p$<0.01) and prostate (control : RF group = $0.358{\pm}0.015g$ : $0.259{\pm}0.015g$, $p$<0.001) were significantly lower in RF group animals. The mRNA levels of pituitary common alpha subunit ($C{\alpha}$; control : RF group = $1.0{\pm}0.0699$ AU : $0.1923{\pm}0.0270$ AU, $p$<0.001) and $FSH{\beta}$ (control : RF group = $1.0{\pm}0.1489$ AU : $0.5237{\pm}0.1088$ AU, $p$<0.05) were significantly decreased in RF group. The mRNA levels of ACTH were not significantly different. We were unable to find any prominent difference in the microstructures of epididymis, and there were slight alterations in those of seminal vesicles after 4 weeks of reversed feeding when compared to control samples. The present study demonstrates that the shift and/or restriction of feeding time could alter the pituitary gonadotropin expression and the weights of seminal vesicle and prostate in rats. These data suggest the lowered gonadotropin inputs may decrease androgen secretion form testis, and consequently results in poor response of androgen-dependent tissues such as seminal vesicle and prostate.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.2
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• pp.48-53
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• 2010

RC(Remote Control) is a technology that can efficiently control and transfer a variety of user commands to CEs. However, the existing RCs have been required various additional features such as communication between CEs, extension of communication range, low power-consumption and bi-directional communication according to the advent of new types of CE devices and its enhanced performance. Even though RC controller has many customers' requests, it is not a simple solution because most legacies work on IR-based RC. In this paper, we propose RF4CE-based Universal Remote Control Framework using Smartphone in order to solve the many constraints of IR legacies. The proposed R-URC system is designed by RF4CE platform which is a kind of de-facto standard for CE remote control communication. From the verification scenarios using various CEs and smart phone, we can see that the proposed R-URC shows the good practical usage in terms of contents sharing and smart CE control.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1568-1569
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• 2006

An electric probe is a conductor inserted into the plasma, by which plasma density and electron temperature can be deduced from the collected current (I) versus applied voltage (V) to the probe. In RF plasma the I-V characteristics of electric probe is distorted due to the RF fluctuation of plasma potential, so that it is hard to measure the real plasma parameters, especially the electron temperature. To eliminate the RF fluctuation, several compensation methods are developed such as RF compensation probe, peak-to-peak method, asymmetric double probe. By comparing proposed methods, a suitable method is to be introduced in determining electron temperatures in RF plasma.