MATLAB Answers

how to detect egde on trigger signal

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Ayle on 4 May 2017
Commented: Melwin Thomas on 8 Aug 2018
I am trying to get waveform data by connecting Tektronix Oscilloscope with PC. So far I can read the waveform data points. Problem is I want to collect data points at right time (when trigger signal goes low). Is there some MATLAB function that monitors the trigger signal and detects when it is high/low so that I can do the following
while i< N if Trigger_signal_is_low w1=getwaveform(myscope); end
I can get data points for one time trigger signal and perform required action but I have to capture 2000 signals (each time when trigger occurs). I believe interrupt handling will achieve the purpose but how to link an interrupt to trigger signal?
  1 Comment
Melwin Thomas
Melwin Thomas on 8 Aug 2018
Hi Ayle,
Did you find a solution for this. If so, can you please let me know?
Thank you.

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Answers (1)

Chaitral Date
Chaitral Date on 9 May 2017
Edited: Chaitral Date on 9 May 2017
Interrupt handling can be done in MATLAB using events and listeners. Refer to the few links given below for the reference,
Also, please refer to the below simple example which can give you an idea about how you can implement events and listeners,
classdef Test < handle
prop = 0;
function setprop(obj,value)
obj.prop = value;
if (obj.prop>5)
function testD(eventsrc,eventdata)
disp('The value of prop is overflowing');
The class 'Test' has an event 'overflow' which gets triggered when 'obj.prop>5'. Function "notify" is used to trigger the event. Function 'testD' is used to print the given message. Next, we will add a listener to the above event so that whenever the prop is greater than 5, it will print the message from function "testD". Here is the way how you can trigger the listener function,
>> A=Test;
>> addlistener(A,'overflow',@testD);
>> A.setprop(20);
As you can see, function "addlistener" is used to create an event listener.Whenever prop is greater than 5, the callback function 'testD' will get executed.
You can implement your code using similar manner. Please make a note that only handle classes can define events and listeners.

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