Trying to plot a periodic function

Question

Christopher Carey 2018-4-12

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/394474-trying-to-plot-a-periodic-function

评论： Star Strider 2018-4-12

Not sure how to fix this error please assist

t=0:0.1:1000
ao=0.504
for n=1:1000
an=0.504*(2/(1+16*(n^2)));
bn=0.504*((8*n)/(1+16*(n^2)));
f(t)=ao + (an*cos(2*n*t))+(bn*sin(2*n*t))
end
plot(t,f(t));

here is my error

Subscript indices must either be real positive integers or logicals.
Error in asda (line 6)
    f(t)=ao + (an*cos(2*n*t))+(bn*sin(2*n*t))

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Answer 1

Star Strider 2018-4-12

0
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https://ww2.mathworks.cn/matlabcentral/answers/394474-trying-to-plot-a-periodic-function#answer_314784

在 MATLAB Online 中打开

First, MATLAB requires that subscripts (and indices) be integers greater than zero, so using ‘t’ as an index variable will not work.

Second, your ‘f’ calculation is vectorised at each iteration, producing a (1x10001) row vector. If you want to calculate and store all of them for each iteration of ‘n’, you have to account for that in your indexing.

Try this:

f(n,:)=ao + (an*cos(2*n*t))+(bn*sin(2*n*t));

with the plot call then being simply:

plot(t,f)

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Christopher Carey 2018-4-12

I can show you the desired signal if wish to look and see if my code corresponds to that signal or now

Star Strider 2018-4-12

在 MATLAB Online 中打开

You did not define ‘t’ correctly.

Try this:

t = linspace(0, pi, 250);

as well as my earlier suggestions. You might want to extend ‘t’ for a few cycles to see that the waveform repeats periodically, as it should. I will let you experiment with that.

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