• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.392-394
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• 2019

Tunnels and subterranean roads, which are representative evacuation facilities for national or regional disasters, have radio relay broadcasting facilities for legal reasons and convenience reasons. However, this system is limited to radio broadcasting and it is impossible to effectively communicate disaster or emergency situations that occur locally due to broadcasting of national broadcasting without DMB broadcasting. In order to improve this, we construct a remote disaster broadcasting system at each regional disaster station and implement a system to transmit it to each tunnel using internet or LTE network. The system in the tunnel transmits the emergency broadcasting signal through the existing relay equipment through the modulator which decodes the SMS, the media file, the real time broadcasting or the image received by the digital signal and converts it into FM and DMB frequency. The method proposed and implemented in this study can be used to provide efficient information and remote field control in case of emergency in tunnel and underground roadway.

• Archives of design research
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• v.12 no.4
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• pp.201-209
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• 1999

Feb. 11. 1997, Korean Government announced FM Radio Broadcasting and TV Terrestrial TV Broadcasting will be changed to digital format in year 2001, and all Korean Broadcasting except AM Radio and Microwave will be changed to digital format before 2010. In spite of IMF economic crisis, the Digitizing is the one of the hot issue in TV Broadcasting area. The narrow view of the Digitizing the Broadcasting is a technical development from the analogue to digital, but the extended view of it means not only the technical development but the revolution in the concept of TV and service area, relationship between sender and receiver, structure of TV Industry. Thus Digitizing the Broadcasting shifts paradigm and eventually it cause a big change in the advertising creative. The digital TV could be a very encouraging technical development for the consumers convenience because of the multiple choice in the channels and interactive services which leads us to the multimedia service through the TV . On the other hand, multimedia and multi-channel, interactivity implicate a big uncertainty and risk, This research paper is about the technical aspects and social aspects of digital TV and its influence of the marketing and TV advertising creative.

• International Journal of Internet, Broadcasting and Communication
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• v.9 no.2
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• pp.58-63
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• 2017

The sound we hear is transmitted through the atmosphere. However, both the sound we want to hear and the surrounding sound are mixed, and noise is generated, and the sound is not clearly transmitted due to factors such as distance. In particular, in closed spaces like buildings, it is often difficult to hear sounds from outside because of the sound of reflection. People with hearing impairments, such as the elderly and the deaf, have a hard time hearing the sounds they want to hear. Thus, we are developing a hearing aid that can detect radio waves. To this end, we propose the development of a hearing aid that uses FM radio and Bluetooth. These devices are expected to be useful not only for the elderly and the deaf but also in situations where information is transmitted to a large number of people, such as students and tourists, in a large space. The main purpose of this device is to enable users to hear sound correctly without blind spots.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2012.07a
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• pp.178-180
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• 2012

본 논문에서는 유럽의 디지털 라디오 전송 규격인 DRM(Digital Radio Mondiale)의 Band II 대역 전송 모드인 모드 E의 전송률 향상 기법을 제안한다. DRM 모드 E는 FM 방송과의 동시방송 등의 문제를 고려하여 100kHz 대역폭에서 186kbps의 전송률을 제공한다. 하지만, 이 전송률은 모바일TV 등 멀티미디어 서비스를 제공하기 위해서는 부족하기 때문에 전송률의 향상이 요구된다. 논문에 제안된 전송률 향상기법은 기존의 DRM 모드에 변조방식 및 부호방식을 추가하는 방식으로 최대 350kbps의 전송률 제공이 가능하며, FAC(Fast Access Channel)의 예약필드에 신규 방식에 대한 정보를 전송함으로써 기존 시스템과 호환성을 유지할 수 있다. 모의실험 결과에서, AWGN(Additive White Gaussian Noise) 채널의 비트오류율 le-4를 기준으로 223kbps의 전송을 위해서는 13dB의 SNR(Signal-to-Noise Ratio)이 요구되며, 351kbps의 전송률 제공을 위해서는 약 18dB의 SNR이 요구됨을 확인할 수 있다. 또한, 다중경로 페이딩 채널환경에서 부호율이 1/2인 경우에는 이동속도보다는 지연확산이 성능에 영향을 주지만, 부호율이 1/2 보다 크며 150Km/h이상 증가하면 오류마루가 발생함을 확인할 수 있다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.7C
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• pp.713-724
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• 2006

The purpose of this study is to design, implement and verify the pre-modulation filter with the variable -3dB cutoff frequency and linear phase response for bandlimiting the allocation of radio frequency bandwidth for PCM/FM transmission. For the design of this required filter, the digital FIR filter, DAC system and tuneable 2nd order LPF have been constructed and simulated according to the attenuation characteristic requirement of the amplitude frequency response by each stage. From these results, we have implemented the filter and verified the analog conversion hardware part which is composed of DAC system and tuneable 2nd order LPF for the interpolation of the discrete sequences. Especially this paper proposes and carries out the verification processes using the tone generator and the calibration procedures for more precise frequency response of the filter.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.05a
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• pp.178-182
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• 2000

During the past five years, there has born tremendous interest worldwide in the possibility of exploiting chaos in wideband communication systems. Many different demodulation techniques have been proposed up to date. They can be divided into two basic categories. In the first approach, like the conventional coherent demodulation techniques, the chaotic signal has to be recovered from the received noisy signal by synchronization. However, the chaotic synchronization techniques published to data are so sensitive to the channel noise and distortion that these techniques can not be used in radio communications. In the second approach, the demodulation is carried out nonsynchronization. This paper surveys the different chaotic communication techniques that can be implemented nonsynchronization and compares the threshold and BER of the different methods. Finally, FM-DCSK is introduced the first step for apply to wideband chaos digital CDMA, where the data is not limited by the inherent nonperiodic property of the chaotic signal.

• Proceedings of the IEEK Conference
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• 2000.06e
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• pp.113-116
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• 2000

In this paper presents the portable wireless ECG data detection and diagnosis system based on discreet wavelet transform. An algorithm based on wavelet transform suitable for real time implementation has been developed in order to detect ECG characteristics. In particular, QRS complex, S and T waves may be distinguished form noise, baseline drift or artifacts. Proposed telemetry system that a transmitting media using radio frequency(RF) for the middle range measurement of the physiological signals and receiving media using optical for electromagnetic interference problem. A standard hi-directional serial communication interface between the telemetry system and a personal computer or laptop, allows read-time controlling, diagnosing and monitoring of system. A portable telemetry system within a size. of 65${\times}$125${\times}$45mm consists of three parts: a digital signal processing part for physiological signal detect or diagnose, RF transmitter for data transfer and a optical receiver for command receive. Advantages of proposed telemetry system is wireless middle range(50m) FM transmission, reduce electromagnetic interference to a minimum. which enables a comfortable diagnosis system at home.

• Journal of Electrical Engineering and Technology
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• v.9 no.2
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• pp.771-776
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• 2014

In this paper, an agile programmable chirp spread spectrum generator for wideband frequency-jamming applications from 20 MHz to 3 GHz is proposed. A frequency-mixing architecture using two voltage-controlled oscillators is used to achieve a wideband operating frequency range, and the direct digital synthesizer (DDS)-based chirping method with a two-point modulation technique is employed to provide a programmable and consistent chirp bandwidth. The proposed signal generator provides the various programmable FM signals from 20 MHz to 3 GHz with a modulation bandwidth from 0 to 400 MHz. The prototype successfully demonstrates arbitrary sequential jamming operation with a fast band-to-band hopping time of < 10 ${\mu}sec$.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.10
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• pp.1001-1008
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• 1991

.In this paper the efficient clock recovery algorithm is proposed to regenerate the manchester code at the system using the Manchester encoding scheme such as LAN. Mobile communication and digital communication systems. The proposed clock recovery circuit recovers the clock using the two times of the same original transmitted frequency can be completely recovered. The implementation of the proposed clock recovery circuit and the interpretation of test results prove the validity of the proposed algorithm.

• Journal of Broadcast Engineering
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• v.14 no.3
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• pp.332-341
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• 2009

Terrestrial digital multimedia broadcasting(T-DMB) is one of mobile broadcasting services, and the commercial service was started in December 2005 in Korea. The performance targets of T-DMB are providing VCD(video CD) quality video and FM radio quality audio. In recent years, the researches for providing high quality video or audio service on T-DMB environments have been being carried out. To provide high-quality video or audio service, some additional data should be transmitted to the receiver as well as T-DMB video and audio data. Since the data rate for one T-DMB program is low, it is important to transmit the additional data at a low bit rate. In this paper, we propose a packetizing method for efficient transmission of the additional data to provide multichannel audio service on T-DMB environment.