Create a plot for local max peaks given a certain time range.

This is the code I am running for an ECG data.

Imagine that

sf = 399.0698; %sampling frequency (Hz), samples per second
T = 1/sf;
timeSeries = T:T:600.8122;   %time intervals

% graph with circled peaks (needs debugging)
[pks,locs] = findpeaks(y(1,:),'MinPeakDistance',0.3);
plot(timeseries,y(1,:),timeseries(locs),pks,'or'),xlabel('Time (s)'),ylabel('Amplitude(uV)')

%y(1,:)is the signal I have filtered; its points traverse horizontally on row 1
% timeSeries is my time intervals on my X axis

I have a signal y(1,:) with a sampling frequency of 399.0698 and the total length of signal is 600s. I have found the local max for the signal y(1,:) I would like to plot a graph such that the peaks are circled and I can choose which part of the signal to show. Example 590-591seconds.

Thank you!

[Image Analyst]

I imagine you don't have an answer yet because people are waiting for you to attach y in a .mat file.

[Shamus Sim]

My y.zip file is larger than 5 MB and the system wont let me upload it. Is there another file format I can use to share the file?

[Adam Danz]

We probably only need a segment of the y-data. A few hundred samples may be sufficient.

[Shamus Sim]

Hi Adam. I have already entered it as an attachment.

[Shamus Sim]

also its an EEG signal not ECG

Answer 1

[Adam Danz]

It's unclear what some of your variables are and how they relate to each other. For example, what's the second row of y? How does timeSeries (1x239766) related to y (2x100)? What is x?

Here's how to circle the peaks when (x,y(1,:)) is used to plot the data.

plot(x,y(1,:))
hold on
plot(x(locs),y(1,locs), 'ro')

To address the time cutoffs of 590-591, I'll need more info.

[Shamus Sim]

Hi Adam. Thanks for your reply. I have re-edited the question, hopefully its clearer.

y is just a shortened section of the EEG data where I concatenated its corresponding time data on row 2. Therefore, row 1 has the EEG data readings and row 2 has its corresponding time values.

[Adam Danz]

I'm not sure what you changed. Have you run the code you shared? It uses two different forms of the variable "timeSeries" vs "timeseries".

" I would like to plot a graph such that the peaks are circled and I can choose which part of the signal to show."

My answer shows you how to do the first part. You can apply that method to whatever variables you're using.

As for the second part about choosing which part of the signal to show, I don't know what your question is.