How to use helperFreq​uencyAnaly​sisPlot1 in Matlab 2018b

Hello everyone,

I am trying to use this function in Matlab 2018b: helperFrequencyAnalysisPlot1

However the function does not work. I get the following error: Undefined function or variable 'helperDFTEstimationPlot1'.

I have tried 'edit('helperFrequencyAnalysisPlot1.m') and still, it doesn't find anything.

I am following this tutorial: https://uk.mathworks.com/help/signal/examples/practical-introduction-to-frequency-domain-analysis.html

Does anybody know how can I use it?

Also, is there any specific package or tutorial on how to perform ECG frequency domain analysis?

Thank you for your time.

Best,

Gianluca