A Recursive Nonlinear Filter for Sigma-Delta Modulator
碩士 === 國立中正大學 === 通訊工程研究所 === 91 === In this thesis, the research topic focuses on nonlinear filter for the first-order sigma-delta modulator. As the input of first-order sigma-delta modulator is a constant signal, its output sequence can be simplified iteratively into new shorter sequence by the re...
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| Format: | Others |
| Language: | zh-TW |
| Published: |
2003
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| Online Access: | http://ndltd.ncl.edu.tw/handle/57890434108319268930 |
| Summary: | 碩士 === 國立中正大學 === 通訊工程研究所 === 91 === In this thesis, the research topic focuses on nonlinear filter for the first-order sigma-delta modulator. As the input of first-order sigma-delta modulator is a constant signal, its output sequence can be simplified iteratively into new shorter sequence by the recursive formula. Then the final-derived sequence will be found and utilized. We design a nonlinear filter “Recursive Sequence-Extension Filter” to reduce quantization noise efficiently by the inverse transformation of the final-derived sequence and to converge the input estimation by the basic averaging method consequently. Experiments show the signal-to-noise ratio (SNR) performance of the proposed “Recursive Sequence-Extension Filter” without complex computation cost is almost the same as that of the O(NlogN) algorithm in unknown modulator’s initial state. Besides, the proposed filter has been easily verified and implemented by FPGA.
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