How to cut the signal

13 views (last 30 days)
djoerig Hartono
djoerig Hartono on 30 Nov 2017
Moved: Image Analyst on 7 Jul 2025
Dear All, I have waveform data in csv file in 'X' and 'Y' axis, the plot is on the figure attached. I want to remove the unneeded signal marked by arrows sign in order to get complete waveform signal. Is there any advice/better algorithm to remove the signal automatically ? My idea is to track the data in a loop then find the '0' value in the 'Y' axis and delete the rows before. Best regards.
  1 Comment
Supratim
Supratim on 29 Jun 2025

You can go to the Panner under display tab in signal analyzer app, and then you can crop out your signal

Sign in to comment.

Accepted Answer

Image Analyst
Image Analyst on 30 Nov 2017
Edited: Image Analyst on 29 Jun 2025
How about if you simply find the first and last time that y is negative?
index1 = find(y < 0, 1, 'first'); % Find left index
index2 = find(y < 0, 1, 'last'); % Find right index.
% Now crop signal
yCropped = y(index1:index2);
  3 Comments
Lokesh Chowdary Patibandla
What is the 1 value in the index 1 & 2.
Image Analyst
Image Analyst on 28 May 2018
Edited: Image Analyst on 29 Jun 2025
I don't know what that means. Please reword the question.
1 is just a number I put in the variable name index1 to distinguish it from a different variable called index2. You could use other names if you want.
The 1 that is the second argument to the find function means to return 1 value where y is negative, not multiple indexes where it's negative.

Sign in to comment.

More Answers (5)

Supratim
Supratim on 29 Jun 2025
Moved: Image Analyst on 30 Jun 2025

You can go to the Panner under display tab in signal analyzer app, and then you can crop out your signal


Supratim
Supratim on 29 Jun 2025
Moved: Image Analyst on 30 Jun 2025

You can go to the Panner under display tab in signal analyzer app, and then you can crop out your signal


Supratim
Supratim on 29 Jun 2025
Moved: Image Analyst on 7 Jul 2025

You can go to the Panner under display tab in signal analyzer app, and then you can crop out your signal


Supratim
Supratim on 29 Jun 2025
Moved: Image Analyst on 1 Jul 2025

You can go to the Panner under display tab in signal analyzer app, and then you can crop out your signal


Supratim
Supratim on 29 Jun 2025
Moved: Image Analyst on 2 Jul 2025

You can go to the Panner under display tab in signal analyzer app, and then you can crop out your signal

Categories

Find more on Time-Frequency Analysis in Help Center and File Exchange

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!