hello, I am trying to evaluate a summation series from n=1:1:400. The expression inside the summation needs to be evaluated for various inputs L=0.5:0.1:3 and alpha=0:0.1:1. can any one help?thank you.

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M MAGHSUDI 2018-3-13

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https://ww2.mathworks.cn/matlabcentral/answers/388006-hello-i-am-trying-to-evaluate-a-summation-series-from-n-1-1-400-the-expression-inside-the-summatio

评论： Abraham Boayue 2018-3-14

the summation is (sum of all terms from n=1 to n=4000): q_loss(L,alpha)=-2∑Real((Q_n/2.π.n.j)*(1- .e^(2.π.n.j.alpha)) in which Q-n is given by: Q_n=(P_H (1-e^(-2.j.π.n.alpha) )+P_L (e^(-2.j.π.n.alpha)-e^(-2.j.π.n) ))/(2.π.n.j(j.Z_o.Zi.tan(w.L.zi/c)+R_v )). I would be grateful for any help. Thank you

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Abraham Boayue 2018-3-14

Check this code out. It might be useful, let me know if it works, if not, let me know what's wrong and we can fix it together.

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Answer 1

Abraham Boayue 2018-3-14

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https://ww2.mathworks.cn/matlabcentral/answers/388006-hello-i-am-trying-to-evaluate-a-summation-series-from-n-1-1-400-the-expression-inside-the-summatio#answer_309923

在 MATLAB Online 中打开

clear varianles;
close all;
n = 1:400;
L = 0.5:0.04:3;
alpha = 0:0.04:1;
N = length(n);
M = length(L);
C = length(alpha);
% Define constants (Just my test values)
w = 0.45;
c = 2.8;
Rv = 3.5;
Zo = 2;
Zi = 4;
Ph = 4.5;
Pl = 6.3;
[alpha,L] = meshgrid(alpha,L);
Q = zeros(M,C);
% code seem to be wirking well,but since 
% I have no idea what your function represents,
% I dont know what to expect. check it yourself
% and see. I may have defined some variables
% wrongly, varify the equations for the qs.
for i = 1:N
    phi = i*2*pi*n(i);
    q1 = Ph*(1-exp(-phi*alpha));
    q2 = Pl*(exp(-phi*alpha)-exp(-phi));
    q3 = phi*(i*Zo*Zi*tan(w*Zi*L)/c)+Rv;
    Qn = (q1+q2)./q3;
    qn = 1-exp(-phi*alpha);
    Q  = Q + real(Qn.*qn/phi); 
end
figure(1)
surf(alpha,L,Q) 
figure(2)
plot(Q,'linewidth',2)
grid
a = title('qloss(alpha,L)');
set(a,'fontsize',14);
a = ylabel('q');
set(a,'Fontsize',14);
a = xlabel('alpha,L');
set(a,'Fontsize',14);