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Asked by Passband Modulation
on 5 Oct 2012

say, a file consists of a single column with 10000 rows

load file.txt a = file; k=1:10000; s = a(k,1).*cosd(3.6*k);

k=0:10000; plot(k,s) xlabel('k');

it does work at all, could anyone help?

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Answer by John
on 5 Oct 2012

Accepted answer

Try this if a is a column vector:

`load file.txt`

`a = file;`

`k = [1:size(a,1)]';`

`s = a.*(cosd(3.6*k));`

`plot(k,s)`

`xlabel('k');`

Alternatively, k can be any column vector you wish to perform element-by-element multiplication with a. Just make sure a and k are of the same size.

Passband Modulation
on 6 Oct 2012

a and k are of the same size.

and thank you for your kind reply!!

## 2 Comments

## Image Analyst

Direct link to this comment:http://www.mathworks.com/matlabcentral/answers/49991#comment_103266

Do you know how to use the debugger to step though your code? This would be easily solved if you did that.

## Passband Modulation

Direct link to this comment:http://www.mathworks.com/matlabcentral/answers/49991#comment_103268

it says:

Error in ==> Untitled3 at 5 s = a(k,1)-56.97*cosd(3.6*k)-31.98*sind(3.6*k);

how to fix it, i really have no any idea.