RMS of non sinusoidal wave

I have a signal sampled at 5000 samples per second . and I have 5 second .please tell me how yo get the RMS of non sinusoidal wave by matlab

I knew that for sinusoidal wave we do this

ac_signal = YourSignal - mean(YourSignal(:));
rms = sqrt( mean(ac_signal.^2) );

Answer 1

[Star Strider]

You get it just the way you calculated it in your ‘rms’ assignment. It’s the square root of the mean of the squared magnitude of the signal.

[carlo mars]

but my signal is not sinusoidal?

[Star Strider]

That doesn’t make any difference.

Remember that all signals can, in Fourier space, be decomposed into a (usually finite but potentially infinite) concurrent series of sinusoids with possibly different amplitudes and possibly different phases. Put it into that context, and it doesn’t matter if your actual waveform appears to be sinusoidal. It’s simply a series of concurrent, additive sinusoids.

You would also consider the d-c offset as part of the RMS voltage of a sinusoidal waveform, for example, so it is not absolutely necessary to remove the mean from the waveform first. It depends on your application.

Answer 2

[Muhammad Usman Saleem]

in order to calculate some RMS error for your signal, you require two points

(1) YourOrginalSignal

(2) ExtimatedSignal

Then you can calculate RMS error as

RMS=sqrt(sum(YourOrginalSignal (:)-ExtimatedSignal (:))/N)

where N may be total no of samples in YourOrginalSignal