How to cut waveform

[shirin91]

Hi,

I have a waveform which is repeatting itself(out of DAC). I have added zeros at the beginning and end of the waveform as shown bellow. How can I cut only one copy of waveform. I have attached csv file of the waveform.

Here is what I have tried but every time I have to do it mannually and it is not accurate.

Thanks

[GerdW]

Hi shirin,

what's the point in multiplying with zero and one?

Why don't you search for your "added zeros" in the signal?

Suggestion:

[shirin91]

Hi GerdW,

-Just to compare original and selected size of data(It will not effect the cutting process anyway)

Thanks

[GerdW]

Hi shirin,

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@shirin91 wrote:

I have to add zeros before DAC so after DAC it will not be zero exactly, so I can not just seach for it.

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But there seems to be a clear distinction between "signal" and "gap": you just need to define this distinction and then create an algorithm to detect it in your waveform!

How do you define the "gaps"?

[JÞB]

My guess is that 0 is an absolutely valid value for a datapoint.  That makes it harder to trigger.   Options:

• Change your "fake zeros" to NaN.  That does require a change at the recording end but is soooooo much simpler.
• Envolope detection.  Absolute Value, clipping(use In Range and Coerce with a smallish positive value,) and a low pass FIR filter is the most common means.  Play with it to see how your data behaves with both GOOD and BAD data
• Assume Something.  What do you know about the waveform? Is the Duration fixed?

Good hunting!