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

As the demand for higher data-rate chip-to-chip communication such as memory-to-controller, processor-to-processor increases, low cost high-speed serial links\ulcorner become more attractive. This paper describes a 0.25-fm CMOS 1.6Gbps/pin 4-level transceiver using Stub Series Terminated Logic for high Bandwidth. For multi-gigabit/second application, the data rate is limited by Inter-Symbol Interference (ISI) caused by channel low pass effects, process-limited on-chip clock frequency, and serial link distance. The proposed transceiver uses multi-level signaling (4-level Pulse Amplitude Modulation) using push-pull type, double data rate and flash sampling. To reduce Process-Voltage-Temperature Variation and ISI including data dependency skew, the proposed high-speed calibration circuits with voltage swing controller, data linearity controller and slew rate controller maintains desirable output waveform and makes less sensitive output. In order to detect successfully the transmitted 1.6Gbps/pin 4-level data, the receiver is designed as simultaneous type with a kick - back noise-isolated reference voltage line structure and a 3-stage Gate-Isolated sense amplifier. The transceiver, which was fabricated using a 0.25 fm CMOS process, performs data rate of 1.6 ~ 2.0 Gbps/pin with a 400MHB internal clock, Stub Series Terminated Logic ever in 2.25 ~ 2.75V supply voltage. and occupied 500 * 6001m of area.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.8 no.1
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• pp.1-11
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• 1983

The object of this paper is to investigate a PCM telemetry system which is designed and constructed in individual modules for an airborne remote measurement system for the first time in Korea. The time division multiplexing PCM encoder has maximum allowable input channels 64 words/frame, 140kbits/sec bit rate. 200frames/sec and 10 bits/wod resolution. And the transmitting unit is designed for 2.2-2.3GHz(s-band) telemetry frequency band, PCM/FM modulation. The Study of airborne PCM telemtry system contribute to develop a device which can acquire various technical data of newly developing flying vehicles by remote measurement. The performance of the proposed system has been verified through a seguence of tests.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.7
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• pp.335-343
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• 2006

We have designed the system that measure one channel ECG by two electrode and extract real-time EDR with more related resipiration and comportable to subject by using conductive textile. On the assumption that relation between RL electrode and potential measurement electrode is coupled with RC connected model, we designed RL drive output to feedback two electrode for reduction of common mode signal. The conductive textile which was used for two ECG electrode was offered more comfort during night sleep in bed than any other method using attachments. In the method of single-lead EDR, R wave point or QRS interval area could be used for EDR estimation in traditional method, it is, so to speak, the amplitude modulation(AM) method for EDR. Alternatively, R-R interval could be used for frequency modulation(FM) method based on Respiratory Sinus Arrhythmia(RSA). For evaluation of performance on AM EDR and FM EDR from 14 subject, ECG lead III was measured. Each EDR was compared with both temperature around nose(direct measurement of respiration) and respiration signal from thoracic belt(indirect measurement of respiration) on mean squared error(MSE), cross correlation(Xcorr), and Coherence. The upsampling interpolation technique of multirate signal processing is applied to interpolating data instead of cubic spline interpolation. As a result, we showed the real-time EDR extraction processing to be implemented at micro-controller.

• Journal of Broadcast Engineering
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• v.21 no.5
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• pp.726-738
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• 2016

This study analyzed the properties of VHF band and suggested an efficient VHF band application plan for digital radio and UHDTV broadcasting through the experiment by the house T-DMB device in practical user environment. In order to find an efficient frequency band for digital radio broadcasting, this study examined first, to check the times of drop-out receive occurring in the audible area using a DMB/FM CAR Radio for T-DMB that has the characteristics of DAB. Second, this article explored the phenomenon of feedback loops in the same channel using a T-DMB house gap filler transmitting the signal by the same OFDM modulation scheme with UHDTV for configuring suitable SFN transmission network of the UHDTV broadcasting. Based on these experiments, this study suggested a suitable VHF band for digital radio and an efficient utilization of the VHF frequency band for the SFN network configuration of UHDTV.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.2
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• pp.168-180
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• 1992

Commumication technology has been continuously developed to overcome the distance and time for the transmission of information to the human society. Wireless mobile communication, which had been used mostly in the military and police is widely used these days for enterprise and individuals. Therefore the domestic usage of the advanced mobile phone service are progressively gaining wide popularity. The modulation techniques used usually in mobile communications were the analog techniques such as AM and FM, but they are getting replaced by the digital techniques, However, the major disadvantage of the digital communications is the increase of the transmission bandwidth. Therefore, it is very important to use efficiently the limited frequency bandwidth. The domestic research and development on the subject seems quite limited and in order to establish the technology of the digital mobile communications. This thesis presents the design of the frequency hopping synthesizer providing 124 channels with a channel spcing of 200KHz. VCD used in the synthesizer employs a semi-rigid cable for higher purity of signal spectrum, and a hybrid pgase detector is realized with a sample hold phase detector in conjuction with a tri-state phase detedctor.

• Korean Journal of Audiology
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• v.18 no.3
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• pp.105-111
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• 2014

Assistive listening devices (ALDs) refer to various types of amplification equipment designed to improve the communication of individuals with hard of hearing to enhance the accessibility to speech signal when individual hearing instruments are not sufficient. There are many types of ALDs to overcome a triangle of speech to noise ratio (SNR) problems, noise, distance, and reverberation. ALDs vary in their internal electronic mechanisms ranging from simple hard-wire microphone-amplifier units to more sophisticated broadcasting systems. They usually use microphones to capture an audio source and broadcast it wirelessly over a frequency modulation (FM), infra-red, induction loop, or other transmission techniques. The seven types of ALDs are introduced including hardwire devices, FM sound system, infra-red sound system, induction loop system, telephone listening devices, television, and alert/alarm system. Further development of digital wireless technology in hearing instruments will make possible direct communication with ALDs without any accessories in the near future. There are two technology solutions for digital wireless hearing instruments improving SNR and convenience. One is near-field magnetic induction combined with Bluetooth radio frequency (RF) transmission or proprietary RF transmission and the other is proprietary RF transmission alone. Recently launched digital wireless hearing aid applying this new technology can communicate from the hearing instrument to personal computer, phones, Wi-Fi, alert systems, and ALDs via iPhone, iPad, and iPod. However, it comes with its own iOS application offering a range of features but there is no option for Android users as of this moment.

• Journal of Broadcast Engineering
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• v.24 no.3
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• pp.485-494
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• 2019

A software-driven real-time frequency de-modulator is implemented with the aid of universal-serial-bus (USB) type software defined radio dongle. An analog stereo frequency modulation (FM) broadcast signal is down-converted to the basedband analog signal then converted to digital bit streams in the USB dongle. Computer software such as Matlab, Python, and GNU Radio manipulates the incoming bit streams with the technique of digital signal processing. Low pass filtering, band pass filtering, decimation, frequency discriminator, double sideband amplitude demodulation, phase locked loop, and deemphasis function blocks are implemented using such computer languages. Especially, GNU Radion is employed to realize the real-time demodulator.

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.4
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• pp.256-264
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• 2018

This paper proposes a three-bridge LLC resonant converter with auxiliary switches for a wide output voltage control range. This converter can be controlled in two ways to achieve a wide controllable output voltage control range of $V_o$ to $3V_o$. The first control mechanism is achieved through the pulse width modulation (PM) of the auxiliary switches and primary switching devices, while the second control mechanism is achieved through the frequency modulation (FM) of the primary switching devices that are configured to operate in the full-bridge switching mode when the auxiliary switches are turned off. The feasibility of using the proposed converter is verified by the results of an experiment with a 2kW prototype.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.9
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• pp.2280-2288
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• 2014

The conventional dimming control methods of LED (Light-emitting dioades) include Analog, PWM (Pulse Width Modulation), and FM (Frequency Modulation) Control. Analog dimming is controlled by adjusting forward current of Power LED. Although Analog dimming is possible to control linearly the brightness levels on a whole range (0%~100%), it comes into existence a variation of wavelength by changing the Power LED's forward current. PWM dimming has achieved by varying in duty of full current flowing to the Power LED. Generally, PWM dimming doesn't make variation of wavelength but have difficulty with adjusting the linear brightness level between 0% and 10%. FM dimming method is on the same wavelength as PWM dimming, however, it has problem of flickering at low level of dimming. This paper propose a efficient dimming control method of Power LED in order to overcome the disadvantages of the above mentioned methods. We apply to Analog method in low level of dimming control and use PWM method in dimming range from 10% to 100%. For the experiment, we design and implement a circuit and test the proposed method. Consequently, we can control the linear brightness of Power LED across the whole range and get the constant wave at different dimming level. The experimental results show the benefits of the proposed method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.7
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• pp.607-615
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• 2016

This study concerns the transmission of energy and data using induced electromotive force. Due to the requirements of weapon systems, most arms are kept in an armory for a very long time before being used. During this time, the reserve battery, which serves mostly as a power supply for the electronic fuze, can be degraded, thus causing problems when it is actually needed. We attempt to solve the various problems associated with the old fuze system caused by long-term storage by using the 'induction power' transmitted from another device just before its operation, instead of using 'built-in power'. We tried to find the best carrier frequency to communicate with the system by induced electromotive force. Also, we changed the communication method for transmitting the 'induction power' from 'FM/AM modulation' to 'Duty ratio modulation', which can transmit a large amount of data in a short time. Through experiments, it was demonstrated that the induction coil can replace the reserve fuze's battery without any problem, thus confirming the possibility of using an induction coil as the power supply source of the electronic fuze.