【电路综合】基于简化实频的SRFT微带线切比雪夫低通滤波器matlab设计.zip

function [F G g]=Denom_Cheby(n,eps_sq,alfa) % All the results are obtained in lambda square domain. % Given n and alfa Compute G % Here computations are carried out in several steps % Step 1: find if n is odd or even. % Step 2: if n is odd % x=lambda^2 %--------------------------- Tn=poly_cheby (n); Y=[alfa*alfa 0];%Y=alfa^2*x; Row vector z=[1 -1];%[x-1]; Row Vector n1=length(Tn); % check if n is odd or even k=n1/2;k=fix(k); % n is odd case if n>1 if abs((k-n1/2))==0;%n is odd nT=n1/2;T=poly_oddterms(Tn); %Chebyshev poly with odd terms % Y loop; A=[T(1)]; for i=1:nT-1;% Start Y loop B=[T(i+1)];%polynomial C=conv(A,Y);%C=AY C=vector_sum(C,B);%C=AY+B A=C;% Row vector end;%for loop ends here T=C; % (x-1) loop A=[T(nT)]; for i=1:nT-1 B=T(nT-i)*poly_xn(i);%B=T(i+1)*Y A=conv(A,z); C=vector_sum(A,B); A=C; end;% for loop ends here G1=C; G2=conv(G1,G1); Z3=eps_sq*Y; G3=conv(G2,Z3); end;%if n is odd loop ends here %-------------------------------------- % if n is an even integer if abs((k-n1/2))>0; % n is even nk=n/2; T=poly_eventerms(Tn);%Chebyshev poly with even terms % Y loop; A=[T(1)]; for i=1:nk;% Start Y loop B=[T(i+1)];%polynomial C=conv(A,Y);%C=AY C=vector_sum(C,B);%C=AY+B A=C;% Row vector end;%for loop ends here T=C; % z loop A=[T(nk+1)]; for i=1:nk B=T(nk-i+1)*poly_xn(i);%B=T(nk-i+1)*Y A=conv(A,z); C=vector_sum(A,B); A=C; end;% for loop ends here G1=C; G2=conv(G1,G1); G3=conv(G2,[eps_sq]); end % end of n=even ineger loop end %n=1 case if n==1 G3=eps_sq*Y; end % F=[1]; for i=1:n F=conv(F,z); end G=vector_sum(F,G3); % % Construction of g(lambda) r=roots(G); zr=sqrt(r); g1=abs(G(1)); g1=sqrt(g1); g=g1*poly(-zr); return