Browsing by Author "Yang, Mei-Hui"

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A dynamic phase-frequency recovery for power reduction in OFDM systems
(2007)
Yang, Mei-Hui
;
Yu, Jui-Yuan
;
Chen, Juinn-Ting
;
Lee, Chen-Yi
;
電子工程學系及電子研究所
A dynamic phase and frequency recovery (DPR & DFR) is proposed for power reduction and performance improvement. By the DPR, signal sampling rate is reduced from Nyquist rate (or higher) to the symbol rate, resulting in reduced ADC circuit power. By the DFR, data is recovered from less-interfered signals. In the MB-OFDM UWB system, the simulations show that the system improves 2.3 dB SNR and reduce 43.75% ADC power consumption with the proposed techniques.
An all-digital phase-frequency tunable clock generator for wireless OFDM communications systems
(2007)
Yu, Jui-Yuan
;
Chen, Juinn-Ting
;
Yang, Mei-Hui
;
Chung, Ching-Che
;
Lee, Chen-Yi
An all-digital clock generator is designed to enable the clock phase and frequency tuning dynamically during the wireless communications system is in operation. This phase-frequency tunable clock generator (PFTCG) provides 8 clock phases for selection and enables the ADC circuits sampling signals with lower frequency and better sampling phase, resulting in lower power consumption. The PFTCG provides the frequency tuning range +/- 150ppm centered at 5MHz, resulting in high performance due to smaller sampling clock offset. This PFTCG is simulated under the wireless body area network system, and shows a 6.3dB SNR improvement at BER=1 e(-3), and the. hardware is simulated with power 77.56 mu M in the standard process 90nm CMOS technology.