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Asked by Jordi on 8 May 2013

Hi, I have this problem and i don't know why it appears:

??? Subscript indices must either be real positive integers or logicals.

Error in ==> SumaSin at 27 sin(1) = A(1)*sin(2*pi*f(1)*tt) + phi(1);

function [] = SumaSin() fs = 44100; dur=1; N=2048; tt = [0:(1/fs):dur-(1/fs)];

A = zeros(1,4); A(1)=0.5; A(2)=0.05; A(3)=0.25; A(4)=0.1;

phi = zeros(1,4); phi(1)=0; phi(2)=pi/2; phi(3)=0; phi(4)=pi;

sin = zeros(1,4);

f = zeros(1,4); f(1) = fs/N*10; f(2) = 2*fs/N*10; f(3) = 3*fs/N*10; f(4) = 4*fs/N*10;

sin(1) = A(1)*sin(2*pi*f(1)*tt) + phi(1); sin(2) = A(2)*sin(2*pi*f(2)*tt) + phi(2); sin(3) = A(3)*sin(2*pi*f(3)*tt) + phi(3); sin(4) = A(4)*sin(2*pi*f(4)*tt) + phi(4);

sin = sin(1)+sin(2)+sin(3)+sin(4);

plot(tt,sin) end

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Answer by Iman Ansari on 8 May 2013

Hi. Use another name for your variable 'sin'. When you use it as a variable,then you can't use it as sinusoid function:

fs = 44100; dur=1; N=2048; tt = [0:(1/fs):dur-(1/fs)];

A = zeros(1,4); A(1)=0.5; A(2)=0.05; A(3)=0.25; A(4)=0.1;

phi = zeros(1,4); phi(1)=0; phi(2)=pi/2; phi(3)=0; phi(4)=pi;

f = zeros(1,4); f(1) = fs/N*10; f(2) = 2*fs/N*10; f(3) = 3*fs/N*10; f(4) = 4*fs/N*10;

s(1,:) = A(1)*sin(2*pi*f(1)*tt) + phi(1); s(2,:) = A(2)*sin(2*pi*f(2)*tt) + phi(2); s(3,:) = A(3)*sin(2*pi*f(3)*tt) + phi(3); s(4,:) = A(4)*sin(2*pi*f(4)*tt) + phi(4);

s = s(1,:)+s(2,:)+s(3,:)+s(4,:); plot(tt,s)

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