针对不同方法提取面波基模式频散曲线精度问题,笔者分别采用τ-p变换、频率分解法、F-K变换、高分辨率线性拉东变换(High-Resolution Linear Radon Transform,简称HRLRT)对六层递增型地质模型合成瑞雷波记录进行频散能量成像,并按频散...针对不同方法提取面波基模式频散曲线精度问题,笔者分别采用τ-p变换、频率分解法、F-K变换、高分辨率线性拉东变换(High-Resolution Linear Radon Transform,简称HRLRT)对六层递增型地质模型合成瑞雷波记录进行频散能量成像,并按频散能量最大值拾取基模式频散曲线。为定量评价理论模型基模式频散曲线提取解与解析解的接近程度,引入了均方差与相关系数两种评价参数。评价结果表明,高分辨率线性拉东变换提取基模式频散曲线精度最高,均方差为11.167 8,相关系数为0.994 9;F-K变换提取基模式频散曲线精度最低,均方差为195.274,相关系数为0.515 2。展开更多
A three-part comb decimator is presented in this paper, for the applications with severe requirements of circuit performance and frequency response. Based on the modified prime factorization method and multistage poly...A three-part comb decimator is presented in this paper, for the applications with severe requirements of circuit performance and frequency response. Based on the modified prime factorization method and multistage polyphase decomposition, an efficient non-recursive structure for the cascaded integrator-comb （CIC） decimation filter is derived. Utilizing this structure as the core part, the proposed comb decimator can not only loosen the decimation ratio＇s limitation, but also balance the tradeoff among the overall power consumption, circuit area and maximum speed. Further, to improve the frequency response of the comb decimator, a cos-prefilter is introduced as the preprocessing part for increasing the aliasing rejection, and an optimum sin-based filter is used as the compensation part for decreasing the passband droop.展开更多
基金Supported by the China Postdoctoral Science Foundation （20080431379）.
文摘A three-part comb decimator is presented in this paper, for the applications with severe requirements of circuit performance and frequency response. Based on the modified prime factorization method and multistage polyphase decomposition, an efficient non-recursive structure for the cascaded integrator-comb （CIC） decimation filter is derived. Utilizing this structure as the core part, the proposed comb decimator can not only loosen the decimation ratio＇s limitation, but also balance the tradeoff among the overall power consumption, circuit area and maximum speed. Further, to improve the frequency response of the comb decimator, a cos-prefilter is introduced as the preprocessing part for increasing the aliasing rejection, and an optimum sin-based filter is used as the compensation part for decreasing the passband droop.
