waveform duration

[zhiqin]

Hello everyone,

        I have a question about how to get the start time and duration of the waves i got. The attached figure shows a sketched wave i got . Before the main wave, there's kind of disturbance that i don't need to consider.  i just need wave information from start time i marked in the attached file. And after the main wave, there's eco followed ,we don't need to considerthat . Is there any way to know the start time and duration of the waveform. I was really trapped here. Any help is appreciated. 

Thanks in advance.

[Agile]

Hi zhiqin,

The key is properly characterizing your desired signal in a way that is significantly different from the undesired portion of the signal.  (Forgive me if I'm stating the obvious.)  I can guess a few things from the image you posed, but let me ask some more questions that may help characterize it.

I'm guessing that:

1.  You set up your acquisition so that you continue reading the signal until you get the waveform you're looking for, right?

2.  Your desired signal starts when the it passes some positive y-axis threshold, right?

3.  Your desired signal ends when it is below that threshold for a given time, right?