Browsing by Author "Chang, Yu-Yun"

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An OFDM-based 29.1Mbps 0.22nJ/bit Body Channel Communication Baseband Transceiver
(2015)
Tsai, Ping-Yuan
;
Chang, Yu-Yun
;
Hsu, Shu-Yu
;
Lee, Chen-Yi
;
電機學院
This paper proposes an energy-efficient transceiver for body channel communication. 16-QAM OFDM is adopted to enhance the data rate and ( 2,1,6) convolutional code is integrated to remain the transmission reliability, where the hard-decision Viterbi Decoder gives the coding gain by 2dB. The modulator of the transceiver provides two modes -high speed mode and low power mode. In the low power mode an uneven multi-level LINC architecture is adopted. The average-power based auto gain control is applied in the receiver to ensure the transmission quality under different paste distances and different users. The chip is implemented under 90nm CMOS technology with 5.2 mm(2) chip area. The data rate achieves 29.1Mbps with 6.349 mW power dissipation, resulting in 0.22nJ/b bit per energy.
Splay-to-Bend Transition-Free Reactive Monomer Modified Pi-Cell
(2009-05-01)
Chen, Szu-Fen F.
;
Chen, Huang-Ming P.
;
Chow, Liansing
;
Chang, Yu-Yun
;
Shieh, Han-Ping D.
A reactive monomer modified Pi-cell (RMM-Pi-cell) comprising a layer of liquid crystal (LC) reactive monomer on one surface was prepared to control the surface pretilt angle. The simulation results suggested that a transition-free Pi-cell can be prepared by asymmetrical cell with one 8 degrees pretilt angle and the other surface greater than 47 degrees when the cell gap was smaller than 4 mu m. The nematic reactive monomer layer has a molecular average tilt angle over 80 degrees which allowed the LC molecules to be arranged in a favored bend state in the asymmetrical cell. The critical voltages cannot be found in all 3-mu m RMM-Pi-cells. The cell retardation data confirmed the initial bend orientation with zero voltage applied. Moreover, the light leakage of dark state was reduced. The contrast ratio of RMM-Pi-cell was improved by a factor of 11 compared with an original Pi-cell without using compensation film.