Author Topic: LCR Impedance Viewer for Picoscope+Keysight+R&S Bode Plot Data (open source)  (Read 4364 times)

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Offline _Wim_

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Wim,

Thanks for the wonderful job you did, especially with the cursor and using FRA4PS as input works fine for me.
I have a point to mention.
In the image showing the impedance, the program also shows a phase. However this is the phase that belongs to the Gain.
In the Image below I show the difference phase that belongs to the impedance.

Hans

Thanks for spotting this  :-+. Corrected version is attached to first post. In the calculations I always used the phase in radians (which was correct), but converted to degrees from the measured phase instead of the phase from the DUT, exactly like you said.
 

Offline Hans Polak

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Yep, it's working all right.

Hans
 

Offline _Wim_

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Yep, it's working all right.

Hans

Great! Hopefully in the next couple of months I will have some more time to add features like calibration and calculation...
 

Offline _Wim_

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Hi Wim,

I have used FRA4 quite a lot on and of since it was released. So yours is a really nice contribution to the tools for Picoscope,
expanding on the usability !

As for Hans in the Previous post I can't get the included measurement application to work. See attached file.

I think I found a solution for the X64 problem. Updated version in first post.
 

Offline Hans Polak

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It works like a charm, nice with this extra settling time and overlaying measurements on top of each other, great job.
The only very very small thing is that you have to start measuring twice.
The first time it contacts the Picoscope and after that you have to press measure again, not very important.

Hans

 

Offline _Wim_

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The only very very small thing is that you have to start measuring twice.
The first time it contacts the Picoscope and after that you have to press measure again, not very important.

Next to the button "abort measurement" you have the option to leave the picocontrol screen open. This way you only need a single mouseclick for each measurement (I guess this is what you want).
 

Offline Hans Polak

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Wim,
I still noticed a small anomaly. In the Modulus diagram, now having the correct phase, the cursor below the image still gives the phase of the bode diagram.

Then I have a few suggestions concerning noise fighting in noisy pictures, although I have no idea whether or in what way noise fighting is already part of your software Tool.
1) the most simple step would be when testing up to a frequency A, to limit BW of both channels to a BW of 5A or something like that.
The scope's BW in my case of 100mHz, has a noise of 100uV.
When measuring up to 100kHz, BW could be limited to 500kHz, already giving a possible noise reduction of 23dB.
2) Since it is possible to "overlay" several measurements in your program, it would help to reduce noise when they could be averaged.

Kindest regards,
Hans
 

Offline _Wim_

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I still noticed a small anomaly. In the Modulus diagram, now having the correct phase, the cursor below the image still gives the phase of the bode diagram.
 
Thanks for spotting this (again). Updated version in first post.

1) the most simple step would be when testing up to a frequency A, to limit BW of both channels to a BW of 5A or something like that.
The scope's BW in my case of 100mHz, has a noise of 100uV.
When measuring up to 100kHz, BW could be limited to 500kHz, already giving a possible noise reduction of 23dB.
 
I directly use the DLL from FRA4Picoscope, and get gain and phase results directly. A good discussion on the noise improvement for FRA4Picoscope can be found here:
https://www.picotech.com/support/topic14311.html?&start=390

2) Since it is possible to "overlay" several measurements in your program, it would help to reduce noise when they could be averaged.
 
Yes, this is on my todo list, but a little more work than simple bug fixes, and currently not so much spare time and too many other projects.

 

Offline Hans Polak

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Wim,
Thank you for the link. As I found out, there are several paramaters that can be used to reduce noise, that was very helpful.

If have another suggestion. In your Reactance plots, you are using positive and negative values, just as they are calculated.
In all Network Vector analyzers and in Spice, the absolute value of these imaginary numbers are displayed, giving the  image almost twice the resolution and a sharp transition at the point of Fres, also quite useful.
See attachment as an example.

Hans
 

Offline _Wim_

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Wim,
Thank you for the link. As I found out, there are several paramaters that can be used to reduce noise, that was very helpful.

If have another suggestion. In your Reactance plots, you are using positive and negative values, just as they are calculated.
In all Network Vector analyzers and in Spice, the absolute value of these imaginary numbers are displayed, giving the  image almost twice the resolution and a sharp transition at the point of Fres, also quite useful.
See attachment as an example.

Hans

Thanks for this suggestion, I was not aware it is commonly done different (have yet to find an affordable VNA). I will implement this in the next version.
 

Online 2N3055

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I think reactance sign is also very useful.
 

Offline _Wim_

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If have another suggestion. In your Reactance plots, you are using positive and negative values, just as they are calculated.
In all Network Vector analyzers and in Spice, the absolute value of these imaginary numbers are displayed, giving the  image almost twice the resolution and a sharp transition at the point of Fres, also quite useful.
 

I think reactance sign is also very useful.

I have added a “preferences” window under the edit menu, this way the user can choose the plot options (I expect some more options will come in the future). So both can have it your way  ;)

As always, updated version in first post.
 
The following users thanked this post: 2N3055

Online 2N3055

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If have another suggestion. In your Reactance plots, you are using positive and negative values, just as they are calculated.
In all Network Vector analyzers and in Spice, the absolute value of these imaginary numbers are displayed, giving the  image almost twice the resolution and a sharp transition at the point of Fres, also quite useful.
 

I think reactance sign is also very useful.

I have added a “preferences” window under the edit menu, this way the user can choose the plot options (I expect some more options will come in the future). So both can have it your way  ;)

As always, updated version in first post.

You're just awesome!!

All the best,
Sinisa
 

Offline Hans Polak

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Absolutely perfect addition with the positive reactance.
Thank you.

Hans
 


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