How can I fix the error "Index exceeds matrix dimension

Hell, Im NEW to Matlab and I'm trying to plot the the stem function for the decimate sequence. I got the error msg saying "Index exceeds matrix dimension". Here is my code: The question is to use the the function decimate, using factor of 4 decimal and use the stem function to plot the original signal and the decimate. Use both default IRR and FIR decimate filter.

n1=0:100;
x1=cos(.15*pi.*n1);
d=decimate(x1,4);
subplot(2,1,1);
y1-stem(0:100,x(1:101), 'filled','markersize',3);
title('original signal');
subplot(2,1,2);
y11=stem(0:100,d(1:100), 'filled','markersize',3); % ERROR MSG SHOWS HERE.
title('decimate signal);

Could someone help to explain how I select the index/range for the "statment y11"? Appreciate much for your time and help. Thank you

[jaweria kainat]

i didn't get the answer. got error in the following line

 imshow(xTrainImages{i});

Answer 1

[Star Strider]

You need to ‘decimate’ ‘n1’ to match the length and correct locations of ‘d’.

This works:

subplot(2,1,2);
n1d = 0:4:100;                                  % ‘Decimate’ ‘n1’ To Match ‘d’
y11=stem(n1d, d, 'filled','markersize',3);
title('decimate signal');

EDIT — Added plot.

[Jo]

Dear Star Strider, Thank you so much for your inputs. I have another question, hope you could help. How do you get 26 elements. Thanks again.

[Star Strider]

The 26 elements in each of ‘d’ and ‘n1d’ is the result of ‘decimating’ (here, taking every 4th element) of both vectors.

I probably should have created ‘n1d’ as:

n1d = n1(1:4:end);

that would have made it more obvious. The result is the same.

[Jo]

Got it, thank you so much!

[Star Strider]

My pleasure!

Answer 2

[Roger Stafford]

The reason for the error message is undoubtedly the fact that d has only 26 elements, not one hundred, so d(1:100) is invalid.

Answer 3

[ALAGONDA MOUNIKA]

am generating overlap save method signals in matlab am getting an error "index exceeds"as shown in picture please help me to solve this