How to measure the rise time? Results are emty.

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Manfred
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Joined: Wed Mar 21, 2018 8:53 am

How to measure the rise time? Results are emty.

Post by Manfred »

Hello,

I like to calculate the rise time. The measurements are added, but I do not get a result. What wrong with the configuration?
Screenshot
Screenshot
Best regards,

Manfred
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20180417-0001.psdata
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bennog
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Location: Netherlands

Re: How to measure the rise time? Results are emty.

Post by bennog »

That is because it is measure between rulers (the white square dots) not the green ones.
And between the white square dots are no rising edges, so it can not calculate the rise time.

Just my 2c.

Benno

sbabic44
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Re: How to measure the rise time? Results are emty.

Post by sbabic44 »

You are not using time rulers (square ones, you pull them from left side). You are using phase rulers (round ones, you pulled them from right side). Check help documentation..
Regards,

Sinisa

Martyn
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Re: How to measure the rise time? Results are emty.

Post by Martyn »

Alternatively if you use the PicoScope 6.13 Beta, which will be going stable soon, you can use the Deep Measure feature
DeepMeasure
DeepMeasure
Martyn
Technical Support Manager

Manfred
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Re: How to measure the rise time? Results are emty.

Post by Manfred »

Thank you for your replays.

Now I changed the rulers and measurements. For the first measure I get no min/max values and for the second measure I get all values. What can be the reason for this different behaviour?
Screenshot
Screenshot

bennog
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Re: How to measure the rise time? Results are emty.

Post by bennog »

Can you remove the resolution enhancement.

Because i think this is smoothing your fall and rise times.

Edit:
Build test setup with 100kHz signal gen square wave.
Difference in rise time with and without is 20 fault ! this is even worse than I expected.
100khz signal without resolution enhancement
100khz signal without resolution enhancement
100khz signal with resolution enhancement
100khz signal with resolution enhancement
P.S. I noticed that when there are a lot of zero crossings between rulers the Rise time calculation stops for some strange reason, this is probably a bug in the PS software.

Benno

alan
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Re: How to measure the rise time? Results are emty.

Post by alan »

To measure rise time accurately there need to be several samples on the rising edge of the square wave. As its a vertical edge there may not be enough samples - try using a shorter timebase so there are less square waves / edges on the screen. This should increase the number of samples used to make the measurement.

As Martyn says you could also try DeepMeasure which will provide a separate measurement for each rising edge on the screen.

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