Instek MDO-2204EG or a Separate Oscilloscope and Spectrum Analyzer

[audiogurujax]

I am considering Buying a Instek MDO-2204EG as my first nice oscilloscope, I do a lot of work on audio, Building Amps, DACs but I am now very interested in doing some research on EMI/Noise filtering of Power lines ( Power Conditioning) for that reason I feel the need of having an spectrum analyzer.

My question is: with a $1,600 +-  budget what would you get an  Instek MDO-2204EG (Oscilloscope/Spectrum Analyzer Hybrid) or would you get a nice Oscilloscope like a  Rigol DS2102A 100 MHz or an Instek GDS-2102A  and a separate spectrum analyzer like a Rigol DSA705.

BTW any suggestion on a great oscilloscope in the $800-$1,200 range.

Best,

Eric

[nctnico]

For EMC pre-compliance testing you'll need a spectrum analyser because an oscilloscope is not sensitive enough. You'll need to measure signals with an amplitude in the low uV range and a generic oscilloscope doesn't do that. IMHO the MDO2000 series from GW Instek isn't worth the extra money compared to the GDS2000E series. All the MDO seems to add is a more fancy FFT display.

[trevwhite]

I would get separates. I think there are more options and most likely better features on two separates rather than one mixed unit.



Thanks

Trev

[audiogurujax]

What confuse me is that in the MDO specs for the SA the freq. range is DC TO 500mhz. Finding an SA that can go down to DC is hard. I guess my fears where correct, better to get both and maybe for my use it will be better to put more money on the SA and less on the Oscilloscope.

Please I now need recommendations lol

Thanks a lot

[rhb]

FYI  The MDO software exists as a demo app on the entire XXX-2000 line. It needs a built in AWG to start.  But if you've got that, then the lower right corner button by the screen will take you out of the demo into the menu where you can control the software.  You can see a bunch of examples in recent posts I made to the FeelTech FY-6600 thread along with Instek FFT plots and R&S SA plots. It's limited to 500 MHz because that's the Nyquist frequency for 1 GSa/S. It's pure FFT SA.

The SA function in the MDO line is only suitable for educational lab exercises.  It's better than nothing, but you can do better simply by dumping 10 Mpts of data to a PC and using Octave to compute the spectrum.

I have an MSO-2204EA.  I considered an MDO-2204EG, but decided that the LA facility was more important.  Ironicly Instek called my attention to the SA demo and a bit of button mashing gave me control. It's reasonably useful up to about 10 MHz.  Above that the RBW gets too large.  I have urged Instek to include the software in the MSO series, but they just introduced the MDO line a few months ago.  So instead of selling a standout, they're shooting themselves in the foot by making buyers choose among the GDS, MDO & MSO lines which are all the same HW with different marketing emphases.

The Instek works fairly well, but the UI is absolutely maddening and has crashed several times in a month.  I bought a Siglent SA which I eventually returned because of the UI.  So I spent a great deal of time reading manuals for a scope purchase.  Instek had the best manual at the low end, so I bought that.  Unfortunately, the manual doesn't accurately describe the scope operation.  But it does have a good FFT which the Rigol does not. So I kept it.  I have a VNWA 3EC on order.  Not sure if I'll buy a separate SA or not.  The VNWA will serve up to 1.3 GHz.

[james_s]

With few exceptions I prefer separate instruments. The combined stuff rarely works as well for either feature as separate dedicated units.

[nctnico]

With few exceptions I prefer separate instruments. The combined stuff rarely works as well for either feature as separate dedicated units.

True but newer oscilloscopes with built in function generator seem to have some basic network analysis capabilities. I've been digging around a bit in the GW Instek firmware and it see mentioning an FRA option in the firmware as well so it seems GW Instek is working to bring network analysis to their oscilloscopes as well. Or it already exists and you have to ask for it.

[rhb]

That's interesting as I mentioned the idea when I was trying to get some prepurchase questions answered.  I mentioned I planned to work on a VNA application  and was a bit surprised when the marketing contact commented that no one offered that a couple of days later.  I had seen that the PC interface was done in Python, but had not looked at it and assumed (silly me) that it had significant  functionality. He'd obviously done some research. But with 4 inputs all it takes is the ability to properly control the instrument.

I'm rather afraid though that the result will be a new "model" like the MDO line.  He was rather adamant that the SA function would not be available on the MSO line any time soon.  And his comments also suggested that the demo might be eliminated or restricted after learning I had found out how to actually control it.

My interest in the VNA  project is somewhat diminished by having a VNWA 3EC in transit.  But with things like the FeelTech, VNA for HF is doable with a DSO, albeit with limited dynamic range.  But better than nothing.

[SWR]

I've just ordered a MDO-2204EX based on the specs and the reviews here on EEVblog.
I think the SA will be quite useful for audio work, small signal analysis like sensors etc. up to a few MHz.
Vibration analysis should also be fine.

For high frequency EMC and RF work I already have a Siglent 3,2GHz spectrum analyzer.
It works very well but doesn't cover the low frequencies below 9KHz.

I'm looking forward to getting my hands on it.
Thank you for the elaborate reviews. 

Soren