外文翻譯---fir數(shù)字濾波器的設(shè)計(jì)-其他專業(yè)(編輯修改稿)
2025-02-24 09:15 本頁面
【文章內(nèi)容簡介】 n Example . Bellanger39。s Formula. Another simple formula advanced by Bellanger is given by [Bel81] Preliminary Considerations 12/)(3 )10(log2 10 ???? ??? ??ps spN. Its application is considered in Example . Hermann39。s Formula. The formula due to Hermann et al.[Her73] gives a slightly more accurate value for the order and is given by ??? ??????? 2/)( ]2/))[(,(,2ppspssps FDN ? ??? ? ）（ , Where ]6)(l o g5)(l o g4[l o g]3)(l o g2)(l o g1[),( 102101010210 aaaaaaD ppsppsp ??????? ??????? , And ]l o g[ l o g21),( 1010 spsp bbF ???? ??? , With a1=, a2= ,a3=, a4=, a5=, a6=, b1=, b2=. The formula given in Eq.() is valid for s???p . If sp ?? ? , then the filter order formula to be used is obtained by interchanging p? and s? in Eq.() and (). For small values of p? and s? , all of the above formulas provide reasonably close and accurate results. On the other hand, when the values of p? and s? are large, Eq.() yields a more accurate value for the order. A Comparison of FIR Filter Order Formulas Note that the filter order puted in Examples , and , using Eqs.(),(),and (), Respectively ,are all different. Each of these three formulas provide only an estimate of the required filter order. The frequency response of the FIR filter designed using this estimated order may or may not meet the given specifications. If the specifications are not met, it is remended that the filter order be gradually increased until the specifications are met. Estimation of the FIR filter order using MATLAB is discussed in Section . An important property of each of the above three formulas is that the estimated filter order N of the FIR filter is inversely proportional to the transition band width ( ps ??? ) and does not depend on the actual location of the transition band. This implies that a sharp cutoff FIR filter with a narrow transition ba
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