Electronics and Telecommunications Research Institute

Yong Il Jun

Dae Woo Lee

Jae Kyoung Mun

Sang Choon Ko

Ho Young Kim

Chull Won Ju

Hee-Bum Jung

Jonghyurk Park

Kyu-Seok Lee

Chul Won Ju

The inventive concept relates to a system supplying a constant current direct current power to serial loads connected in series with one another. The inventive concept is constituted by a constant current source power supply unit outputting a predetermined direct current, a load connection unit having the same rated current characteristic as the constant current source, a load connection unit having a rated current characteristic smaller than the constant current source, a load connection unit having a rated current characteristic greater than the constant current source, a load connection unit having a rated current characteristic greater or smaller than the constant current source and a circuit controlling or protecting them.

Serial loading constant power supply system

An RF device is provided. The RF device includes a vibratile carbon nanotube having a nanotube natural frequency (f), a negative electrode fixed to a first end of the carbon nanotube, a vibratile tuning electrode having a variable resonance frequency and facing a second end of the carbon nanotube, and a positive electrode electrically connected to a first end of the tuning electrode. A second end of the tuning electrode is adjacent to the second end of the carbon nanotube, and the carbon nanotube vibrates at a carrier frequency according to an external electromagnetic wave having the carrier frequency, and the tuning electrode having variable resonance frequency characteristics amplifies distance variation between the second end of the carbon nanotube and the second end of the tuning electrode to increase an electron emission sensitivity according to field emission.

Radio frequency device comprising a vibratile carbon nanotube and a vibratile tuning electrode

Wired/wireless optical signal modulation and demodulation apparatuses and methods using an intensity modulation/direct detection method and an orthogonal frequency division multiplexing (OFDM) method are provided. A unipolar OFDM symbol frame is generated by determining the polarity of each of a plurality of sub-frames of a bipolar OFDM symbol frame which comprises both a plurality of positive pulses and a plurality of negative pulses, inverting the polarity of the sub-frames which are determined to be negative, delaying one of the positive sub-frame and a positive sub-frame obtained through the inversion by the duration of the sub-frames, and multiplexing the result of the delaying and whichever of the positive sub-frame and the positive sub-frame obtained through the inversion is not the result of the delaying. The unipolar OFDM symbol frame can guarantee high power amplification efficiency and high transmission power efficiency, and is robust against a multi-path channel environment. Therefore, the unipolar OFDM symbol frame can be used in various optical signal modulation/demodulation methods for wireless indoor broadband optical transmission devices, wired broadband optical transmission devices using multi-mode optical fibers, and radio-over-fiber devices which transmit baseband analog signals as optical signals.

Modulation and demodulation apparatuses and methods for wired/wireless communication system

Growing community of inventors

Daejeon, South Korea

Yong Il Jun