I am facing this error (Attempted to access num(:,2); index out of bounds because size(num)=[14341,1]. Error in Untitled10 (line 3) rpm =num(: , 2);

filename = 'first.xlsx';
num = xlsread(filename);
rpm =num(: , 2);
time =num(: , 1);
f= rpm/60;
t=1/f;
N = length(num);
a=sin(2*pi*f)*t/N;
plot(f , a)
xlabel('Frequency (Hz)')
ylabel('Displacement');
title('Displacement Spectrum');

Answer 1

[Walter Roberson]

I suspect that your time column is being interpreted as text or non-numeric. If you have R2013b or newer consider using readtable

[arif hussain]

you mean i have to declare the data range...?

[Walter Roberson]

Please attach a sample file for us to test with.

[arif hussain]

the attached file

[Walter Roberson]

Your time data looks like '9:29:55 PM0' and has a large number of repetitions of each value. On the other hand, you do not actually use the tie.

I suggest

filename = 'first.xlsx';
num = xlsread(filename);
rpm =num(: , 1);
f = rpm/60;
t = 1 ./ f;
N = length(num);
a = sin(2*pi*f) .* t/N;
plot(f , a)
xlabel('Frequency (Hz)')
ylabel('Displacement');
title('Displacement Spectrum');