How to find integral under the noise power spectrum

Hi

I am bit confused with wording. Is the integral under noise power spectrum simply the sum of all values in matrix? If not how to calculate it. Thanks

Answer 1

[Honglei Chen]

That's one way to do it, just make sure you also multiply the sum with the width of each bin.

Alternatively, you can also use the bandpower function

http://www.mathworks.com/help/signal/ref/bandpower.html

Answer 2

[Parag]

Thank you for your reply, I tried using bandpower function but it shooting me following error. Can you please let me know how to reslove it. My sampling is of 0.1 pixels and and range in power spectrum is from [-5 5]. I will appreciate your help.

if true
 b = bandpower(nps_measured,5,[-5 5]);
Error using bandpower>psdbandpower (line 127)
The frequency range must be within the range of F for the specified input.
end