湍流基于matlab kolmogorov结合次谐波补偿大气湍流相位屏【含Matlab源码 2178期】.zip

function phz=vkolmg(wvl,D,dz,N,CN,L0,l0) clc clear all close all CN=2*10^-17; dz=1000;% dz传输距离 N=512; wvl=808*10^-9;%波长 L0=10;% 外尺度 l0=0.1;% 内尺度 D=0.6; % D 相位屏尺寸 %N采样点数目 %L0 外尺度 l0 内尺度 CN常数 dz传输距离 delta=D/N; x=(-N/2:N/2-1)*delta; y=x; [X Y]=meshgrid(x,y); del_f=1/(N*delta); fx=(-N/2:N/2-1)*del_f; [kx ky]=meshgrid(2*pi*fx); k=2*pi/wvl; [th ka]=cart2pol(kx,ky); km=5.92/l0; k0=2*pi/L0; % r0=0.185*(wvl^2/(dz*CN))^(3/5); PSD_phi=0.033*CN*exp(-(ka/km).^2)./(ka.^2+k0^2).^(11/6); PSD_phi(N/2+1,N/2+1)=0; cn=2*pi*k.^2*dz.*PSD_phi*(2*pi*del_f).^2; phz_hi=ift2((randn(N)+1i*randn(N)).*sqrt(cn),1);%由于matlab本身的FFT算法的缘故，又cn为傅里叶变换展开的系数，此时del_f=1; figure(1); mesh(abs(phz_hi)-mean(abs(phz_hi(:))));axis tight; colorbar;title('phf'); figure(2); imagesc(abs(phz_hi)-mean(abs(phz_hi(:))));axis tight; colorbar;title('phf'); phz_hi=real(phz_hi); figure;imagesc(phz_hi);colorbar; title('FFT算法') %% 低频补偿 phz_lo=zeros(size(phz_hi)); for p=1:3 del_fp=1/(3^p*D); fx1=(-1:1)*del_fp; [kx1 ky1]=meshgrid(2*pi*fx1); [th1 k1]=cart2pol(kx1,ky1); km=5.92/l0; k0=2*pi/L0;%outscale frequency PSD_phi1=0.033*CN*exp(-(k1/km).^2)./(k1.^2+k0^2).^(11/6); PSD_phi1(2,2)=0; %random draws of Fourier coefficient cn1=2*pi*k.^2*dz.*PSD_phi1*(2*pi*del_fp).^2; cn1=(randn(3)+1i*randn(3)).*sqrt(cn1); SH=zeros(N); for ii=1:9 SH=SH+cn1(ii)*exp(1i*(kx1(ii)*X+ky1(ii)*Y)); end phz_lo=phz_lo+SH; end phz_lo=real(phz_lo)-mean(real(phz_lo(:))); phz=phz_hi+phz_lo; figure;imagesc(phz_lo);colorbar;title('低频补偿后') figure;imagesc(phz);colorbar;;title('低频补偿后FFT')