[ÇóÖú] ʹÓÃË«×ÔÓɶȵÄËæ»ú¼õÁ¿¼¼Êõ£¨2DOF-RD£©·¨ÄâºÏ»ìµþµÄģ̬ÐźÅʱÄâºÏ²»Á¼µÄÎÊÌâ

%ÒÑ֪ʱ¼äÏòÁ¿t1Óë´øƵÂÊÏà½üµÄ»ìµþģ̬µÄË¥¼õÐźÅy
guess = [1,0.01,0.01,1,0.01,0.01,0];%δ֪²ÎÊýµÄ³õÖµ
guess_f = [0.1663,0.1862];%ÒÑÖªµÄÁ½Ä£Ì¬µÄƵÂÊHz
myFun = @(a,x) a(1)./sqrt(1-a(2)^2).*exp(-a(2).*guess_f(1).*x).*cos(sqrt(1-a(2)^2).*guess_f(1).*x-a(3))+a(4)./sqrt(1-a(5)^2)*exp(-a(5).*guess_f(2).*x).*cos(sqrt(1-a(5)^2).*guess_f(2).*x-a(6))+a(7);
[coeff,R1,J1,CovB1,MSE1] = nlinfit(t1,y,myFun,guess);%t1Ϊʱ¼äÏòÁ¿£¬yΪ´øƵÂÊÏà½üµÄ»ìµþģ̬µÄË¥¼õÐźÅ

%ÒÑ֪ʱ¼äÏòÁ¿t1Óë´øƵÂÊÏà½üµÄ»ìµþģ̬µÄË¥¼õÐźÅy
envelop = abs(hilbert(y));
envelop(1)=y(1);
guess = [1,0.01,1,0.01,0];%δ֪²ÎÊýµÄ³õÖµ
guess_f = [0.1663,0.1862];%ÒÑÖªµÄÁ½Ä£Ì¬µÄƵÂÊHz
myFun = @(a,x) a(1).*exp(-a(2).*x)+a(3).*exp(-a(4).*x)+a(5);%a(1)¡¢a(3)±íʾ·ùÖµ£¬a(2)¡¢a(4)±íʾ×èÄáÓëƵÂʵij˻ý
[coeff,R1,J1,CovB1,MSE1] = nlinfit(t1,envelop,myFun,guess);%t±íʾ×Ô±äÁ¿£¬y ±íʾÒò±äÁ¿£¬myfun¸ø¶¨µÄº¬ÓÐδ֪²ÎÊýµÄº¯Êý½á¹¹£¬guessδ֪²ÎÊýµÄ³õÖµ
zeta1 = abs(coeff(2)./guess_f(1));
zeta2 = abs(coeff(4)./guess_f(2));