Fool'n around with DSO & AWG

[Frex]

Hi all,

The fun thing about this controversy is that the first thing
we see on the top of the thread is a Keysight banner ...
 

Frex

[Mechatrommer]

Attached is the sketch and setup images.

thanks my dear.

The fun thing about this controversy is that the first thing
we see on the top of the thread is a Keysight banner ...

thats the trap for young player.

[mawyatt]

Per suggestion here's another thread related to the Curve Tracer DSO & AWG usage:

https://www.eevblog.com/forum/projects/dso-awg-based-curve-tracer/

Best,

[tekguy]

What is an awg?,the only thing i know as awg is american wire gauge ?.

[RoGeorge]

Arbitrary Waveform Generator (AWG)
Digital Storage Oscilloscope (DSO)

[tautech]

What is an awg?,the only thing i know as awg is american wire gauge ?.

In capitals means nothing other than an Arbitrary Waveform Generator better known to old farts as a FG but a AWG is many times more useful than an FG. Study of the first post or 2 indicates we need both Staircase and Ramp/Triangle waveforms, I may be wrong but I've never seen an FG that could do a Staircase.

For this project a 2ch frequency source is required of which old school 2ch FG's are quite rare whereas 2ch AWG's are very common and for this usage perfectly suited.

[mawyatt]

What is an awg?,the only thing i know as awg is american wire gauge ?.

In capitals means nothing other than an Arbitrary Waveform Generator better known to old farts as a FG but a AWG is many times more useful than an FG. Study of the first post or 2 indicates we need both Staircase and Ramp/Triangle waveforms, I may be wrong but I've never seen an FG that could do a Staircase.

For this project a 2ch frequency source is required of which old school 2ch FG's are quite rare whereas 2ch AWG's are very common and for this usage perfectly suited.

And the two waveforms (Ramp and Stairstep) need to be synchronized. One Ramp Sweep for each Stairstep, otherwise the curve plot will likely look very messy!!

Best,

[RoGeorge]

And for those who don't have an AWG, for curve tracing the AWG can be substituted with this:
https://www.qsl.net/w2aew/youtube/curvetracer.pdf

And for those who don't have a DSO either, any analog oscilloscope with XY mode will work.  In fact, old analog oscilloscopes are working much better in XY mode than a usual DSO. 

[tekguy]

very true,i have a tek 465 and a rigol dso 50mhz 1GSa/s the 465 knocks spots off of the rigol with an octopuss in xy mode,works but only just!.

[tautech]

very true,i have a tek 465 and a rigol dso 50mhz 1GSa/s the 465 knocks spots off of the rigol with an octopuss in xy mode,works but only just!.

Please in a EE forum make the effort to have units specified correctly !
Did you mean MHz not mHz ?

[Sensorcat]

When I discovered this thread, I thought this "Ad-hoc Curve Tracer" is great for me and everyone who does not like to have another box getting dusty while waiting for the next time it is needed. Since I do not have an analog scope, the only disadvantage I see is the not-so-impressive performance of many DSOs, including mine, in XY mode. But it appeared to me that XY mode is not necessary for a curve tracer, because it has a linear function of voltage on one axis, and the usual YT mode has a linear function of time.

So I set up the circuit and my AWG as presented by @mawyatt above and played around with instrument settings on my Rigol MSO5000. For the sake of completeness, the transistor is a BC238A. What I got is shown in image 'curve_tracer_YT'.

Compare this to using XY mode, with and without HighRes activated, images 'curve_tracer_XY_HighRes' and 'curve_tracer_XY_Normal'. HighRes does not perform well (especially in XY mode), a known flaw of the MSO5000, but somewhat reduces the trace width, while producing additional artifacts in XY. I started with YT mode and later did not change channels, so the XY images are not in the commen orientation.

Clearly, YT mode produces a better result, a cleaner image without dots all over the screen. Since it does not depend on the DSOs XY performance, it is expected that using YT mode improves the result on many DSOs. Another advantage of YT mode is that the whole screen area can be used. It would be easy to expand the traces to hide the parts left and right of the actual curve tracer plot, to match the image that XY mode provides. I thought I leave it as it is, because this way it shows what's going on.

The scope settings that required attention are:

• In Display menu, 'Dots' instead of 'Vectors' to reduce line width
• In Display menu, 'Persistance' = 5s, 'Intensity' = 100%, 'ColorGrade' = OFF, 'Waveform Freeze' = ON. These settings make all lines appear similar, regardless of the plotting sequence, and all lines stay on screen if the acquisition is stopped, for instance to take a screenshot.
• In Acquisition menu, 'HighRes' = ON, 'Mem Depth' = 10k

[Aldo22]

Hi!
Thanks for the example.
I tried to reproduce that today with my humble equipment.
Would you say from the screenshots that this is how it works, or is there something missing?
I'm not sure if I'm interpreting this correctly.

[mawyatt]

Looks as you've got things setup properly and result looks good

Best

[Aldo22]

Looks as you've got things setup properly and result looks good

Thank you, I'm happy now! 
I was a bit lost for a while.
I only have the FY3200s and the DSO2000.
At first I thought it might not work with this equipment.
I had to teach the FY3200s the ramp first, as this wave form is not built in.
Then everything has to be right with the frequencies, amplitudes and offset. The resistors must also fit and then the oscilloscope settings.
At some point it looked halfway right, but I wasn't quite sure.
But it all matches the thread title: “Fool'n around with DSO & AWG”.