Browsing by Author "Wu, Wen-Rang"

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Digital Predistortion for Concurrent Dual-band Transmitter Using a 2D LUT Based Method
(2015)
Cheng, Sheng-Lung
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Wu, Wen-Rang
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Peng, Chun-Hsien
;
Hsu, Chen-Jui
;
Liang, Paul
The digital predistortion (DPD) technique has been utilized in radio-frequency power amplifier linearization for its low cost and good performance. However, the conventional singleband OPO design is not applicable to the concurrent dual-band transmitters since the cross modulations are induced. The twodimensional (20) polynomial based OPO has been proposed as a remedy. Despite its good performance, the main drawbacks are the high computational complexity for the identification of the DPD coefficients and the high implementation complexity. It is known that the look-up-table (LUT) based method, which has been applied in conventional single-band transmitters, can effectively overcome the problems. In this paper, we consider a 20 LUT based DPD for the concurrent dual-band transmitters. First, we formulate a cost function from which the elements of the tables can be obtained through the optimization. Then, we propose an adaptive algorithm using the gradient-descent (GO) method to conduct the search. Moreover, we propose a practical method to implement the GO method which can significantly reduce the computational and implementation complexities. Finally, some measurement results are presented to demonstrate that the proposed algorithm has the satisfactory performance.
Method for Resolving Simultaneous Same-Row Access In Dual-Port 8T SRAM with Asynchronous Dual-Clock Operation
(2013-01-01)
Lien, Nan-Chun
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Chuang, Ching-Te
;
Wu, Wen-Rang
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電機資訊學士班
;
電子工程學系及電子研究所
This work proposes a novel Dual-Port (DP) 8T SRAM operation scheme. The scheme improves the Read stability and Write-ability, and allows asynchronous operation with arbitrary clock timing skew between two ports. It facilitates high performance, low-power and low VM1N with minimum device and area overhead. Postsimulation results show almost no timing penalty for simultaneous same-row access and the performance is almost the same as that for one port operation.