Reference waveform

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stevie44
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Reference waveform

Post by stevie44 »

Hello
If i try and capture a reference waveform, all i seem to save is the noise floor?
Any ideas?
Thanks Steve.
Attachments
Capture1.PNG

Gerry
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Re: Reference waveform

Post by Gerry »

Hi stevie44,

Could you post a psdata file, and explain exactly what you're doing, if you're not just duplicating the waveform in the Reference Waveform setup.

Regards,

Gerry
Gerry
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stevie44
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Joined: Wed Mar 31, 2021 8:12 pm

Re: Reference waveform

Post by stevie44 »

Hello Gerry,
Testing rf output of a hf transceiver, this is a audio sweep response.
i want to use the waveform as a reference. Tools, ref, double click on a. I have reinstalled the software but still no joy.
i have tried to post psdata file but it says the file is to large, 25 meg.
Can i email it to you?
Cheers Steve.

Gerry
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Re: Reference waveform

Post by Gerry »

Hi Steve,

Sure, send it to support@picotech.com and put my name in the title.

Regards,

Gerry
Gerry
Technical Specialist

Gerry
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Posts: 955
Joined: Mon Aug 11, 2014 11:14 am

Re: Reference waveform

Post by Gerry »

Hi Steve,

CORRECTED 16/4/21

I got the file and I've just auto-arranged the 2 Spectrum plots and expanded the zoom to see exactly what is going on with the original signal and the Reference waveform that you created, and also added a Scope Mode view to see if there was any more waveform information to shed some light on what is going on, as shown below:
Low level ref waveform attempt.png

Actually, what is happening here is that you are Averaging waveforms over time. This is therefore not just a single capture, but the result of many captures. Reference waveforms will can only be created from a single capture, so the reference is for the first pulse only

What exactly are you capturing here, and what are you trying to achieve?

Regards,

Gerry
Gerry
Technical Specialist

stevie44
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Joined: Wed Mar 31, 2021 8:12 pm

Re: Reference waveform

Post by stevie44 »

Hello Gerry
I have been rebuilding my hf transceivers ssb transmit audio circuits, its been interesting looking at the frequency responses of the circuits involved and then the rf output which is seen in the above, signal taken from rf sampler. I was looking for an easier way of seeing the difference in settings and parts.
Thanks for your time Gerry, I've been happy with my pico.
Steve.

Gerry
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Posts: 955
Joined: Mon Aug 11, 2014 11:14 am

Re: Reference waveform

Post by Gerry »

Hi Steve,

I've made a correction to my post, as I missed an important point (need to avoid steering people down the wrong path with that one :D ).

If you are just trying to detect a difference, clearly you can't do it with a reference waveform as the reference is moving. However, you could do that with a mask, but you can't use the automatic tools, you have to plot points around the trajectory of the pulse to create a custom mask. I have done this and posted an image of the result below, showing where the pulse going outside of the trajectory will create a Mask failure notification. You can download the data file with the custom mask from here: https://drive.google.com/file/d/1x-bY03 ... sp=sharing
Custom mask with failure.png

Regards,

Gerry
Gerry
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stevie44
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Joined: Wed Mar 31, 2021 8:12 pm

Re: Reference waveform

Post by stevie44 »

Thank you Gerry
Steve.

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