Author Topic: Rigol DG4102 - Square wave output??  (Read 3174 times)

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Offline svsalt

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Rigol DG4102 - Square wave output??
« on: December 18, 2012, 07:28:28 am »
I recently purchased a Rigol DG4102 Arbitrary waveform generator. I have been playing around and just wanted to ask the wealth of experience here about what I am seeing.

When I generate a 5 MHz square wave (or any frequency square wave for that matter) and view it on my Rigol DS2102 scope I am seeing what I think is ringing (maybe) . I have attached a screen capture of the scope and was hoping someone could comment on if this is correct or typical of a square wave produced on a function generator or if something funny is happening with my scope.

Thanks
 

Offline poodyp

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Re: Rigol DG4102 - Square wave output??
« Reply #1 on: December 18, 2012, 08:19:29 am »
Not implying you're an idiot, but, what are your connections?
 

Offline svsalt

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Re: Rigol DG4102 - Square wave output??
« Reply #2 on: December 18, 2012, 08:27:05 am »
What I am asking is if it should have the oscillation present at the top and bottom of each cycle. Sorry if this is a dumb question, but I don't have any one I can ask.
 

Offline BravoV

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Re: Rigol DG4102 - Square wave output??
« Reply #3 on: December 18, 2012, 08:42:23 am »
poodyp actually already asking the crucial aspect about the connection, cause when working at high frequency, the connection (alias the cable) between the measuring tool (your scope) and the measurement subject (dut, your generator) will affect "significantly" on the result.

Check this thread, I believe you will understand why poodyp asked that question -> https://www.eevblog.com/forum/beginners/new-video-oscilloscope-probe-ground-lead-length's-affect-on-signal-integrity/

Offline svsalt

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Re: Rigol DG4102 - Square wave output??
« Reply #4 on: December 18, 2012, 09:12:25 am »
Thanks BravoV and poodyp it was the ground lead on my scope that was causing the ringing, I swapped it for the short coil type ground connection and the signal is what I would have expected :-[  :-[

Thanks for your help, it is much appreciated, I have attached another screen capture to show the difference. Hopefully this will help someone else inexperienced like me from asking such a trivial question!  :-[ :-[
 

Offline BravoV

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Re: Rigol DG4102 - Square wave output??
« Reply #5 on: December 18, 2012, 09:17:04 am »
Glad this helps !  :-+ And don't be embarrassed, every moment had it's 1st time.

Btw, if you really want to see the "REAL" output, use coaxial cable with both BNC connectors at both ends, assuming your scope has 50 Ohm termination mode, hook them up directly, it will be an eyes opener.  ;)

Offline svsalt

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Re: Rigol DG4102 - Square wave output??
« Reply #6 on: December 18, 2012, 09:39:00 am »
The function generator was supposed to come with a bnc to bnc coax cable but somehow it didn't make it in the box. Unfortunately I live in the bush and will have to order some bnc fittings and coax to make some leads up for my new toy. I'm just starting to get back into electronics and have never had the luxury of owning a scope or a function generator. The last few weeks have been a steep learning curve!! Thanks again for your help.
 


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