Retrieving RMS of a signal with variable sample rate
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Hello community,
I'm using PLECS, with a variable solver, and would like to postprocess its data within matlab. Trying to extract the RMS value of signals has been a struggle, as the sampling rate increases a lot when there are transient phenomena. Therefore, using rms(values) gives me an extremely higher rms value than the expected, as I am working with pulsed values. Also changing to a discrete solver to have equal sampling rate, is not wanted because it's much slower.
I've been looking at a method to attach the timestamps in my signals somehow, to work around this problem. Yet, I'm not having any luck. Does anyone know of an available function or code snipper to figure this out, please?
Thank you for any help.
1 Comment
Mathieu NOE
on 19 Jul 2024 at 15:46
if we had the timestamps we could resample the data with fixed sampling rate and do the rms computation
I assume that if PLECS is able to plot the results, those timestamps should be available somewhere...
Answers (2)
dpb
on 19 Jul 2024 at 14:54
Straightforward, deadahead solution would be something like
y=resample(y,tx,fs);
y_rms=rms(y);
where y is your beginning signal y resampled at the time points tx using a polyphase antialiasing filter at the uniform sample rate specified in fs. tx --> [0 : 1/fs : T]. <resample> is in the Signal Processing TB.
This has the possibility of creating memory issues if the minimum dt of your solution vector is extremely small; you might be forced to more clever soutions weighting sections of the overall signal by the length in time.
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