function?Fresnel_demo（）
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%?此文件為菲涅爾積分演示程序（菲涅爾積分是求線性調頻信號頻譜的必要手段）
%?輸入自變量x調用菲涅爾積分函數，分別獲得實部和虛部
%?輸出三個figure演示菲涅爾積分的空間特征
%?參考文獻：國鵬.基于單脈沖技術的雷達三維成像[D].北京:北京航空航天大學.2008.pp35-36
%?樊文貴/北京航空航天大學電子信息工程學院
%?5/12/2014
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
x=0:0.02:10;????????????%輸入自變量數據
[CS]=Fresnel_init（x）;??%調用菲涅爾積分

%%?分別獲得積分實部和虛部
figure（1）;
plot（xC‘b‘‘linewidth‘2）;hold?on;
plot（xS‘r‘‘linewidth‘2）;hold?off;
title（‘C（x）與S（X）震蕩曲線‘）;
legend（‘C（x）‘‘S（x）‘）;
grid?on;

%%?以x為自變量獲得二維菲涅爾積分曲線
figure（2）;
plot（CS‘linewidth‘2）;
title（‘二維菲涅爾積分曲線‘）;
grid?on;

%%?以x為自變量獲得空間菲涅爾積分曲線
figure（3）;
n=zeros（length（x））;
plot3（xCS‘b‘‘linewidth‘2）;hold?on;
%%繪三維圖形比較費時間
%?plot3（nCS‘k‘‘linewidth‘2）;hold?on;
%?plot3（xnS‘r‘‘linewidth‘2）;hold?on;
%?plot3（xCn‘y‘‘linewidth‘2）;hold?off;
grid?on;xlabel（‘x‘）;ylabel（‘C（x）‘）;zlabel（‘S（x）‘）;
title（‘空間菲涅爾積分曲線‘）;
end

function?[CS]?=?Fresnel_init（t）
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%?菲涅爾積分函數
%?利用符號表達式求得菲涅爾積分表示
%?利用替換函數將符號替換為數值并利用vpa函數求得對應數值解
%?輸入?x?積分上限
%?輸出?C?積分值實部
%??????S?積分值虛部
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
syms?x;??????????????????????????????????%設置表達式變量
freint=int（exp（1i*pi*x.^2/2）x0x）;?????%求得0~x的菲涅爾積分
fr=vpa（subs（freint‘x‘t）8）;????????????%利用VPA（）函數獲得解析解
C=real（fr）;??????????????????????????????%獲得實部
S=imag（fr）;??????????????????????????????%獲得虛部
end

?屬性????????????大小?????日期????時間???名稱
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?????文件???????1884??2014-05-12?10:53??菲涅爾積分\Fresnel_demo.m

?????文件??????47424??2014-05-12?11:16??菲涅爾積分\菲涅爾積分.docx

?????目錄??????????0??2014-05-12?11:17??菲涅爾積分

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