USB Scope Comparison - Page 1
Forum section: electronics / testgear

author: EPAIII
author_rank: Super Contributor
timestamp: January 24, 2014, 09:00:22 pm
content: My first post here so be gentle.My old Tektronix has seemingly bit the dust and I need a scope for present and future projects. My immediate needs are in the analog audio realm. I am designing some audio amplifier circuits and would like something that would do some signal quality analysis in addition to just displaying it and allowing me to do frequency response curves. Spectrum analyzer would be nice. So would noise and distortion analyzer tools. I have a laptop with Windows 7 which I plan to dedicate to my electronic bench and this scope. I also have future projects that involve switching power supplies and of course, PIC devices so digital tools are also nice to have.Cost is a major consideration and I am limited to under $500, preferably WELL under that figure.I have been searching and found several interesting models.The Analog Discovery ($219) has digital and analog channels and a dual signal generator, but does not seem to have any software for further analog signal analysis.No spectrum analyzer or harmonic distortion measurement capability. An optional adapter is available for using standard BNC probes.The BitScope BS10A ($285) with a differential probe looks nice and it does have a spectrum analyzer which would help with the audio work. I imagine I can do the equivalent of harmonic distortion and inter channel tests with it. It has only a single channel signal generator, but I have a standalone generator so I can easily use two different test signals at one time. It does not appear to have a BNC probe adapter, but perhaps I can build one.The Quant Asylum (big confidence booster there) QA100 ($349) also came to my attention. It does have BNC probe capability as well as 12 digital channels vs. the 8 or 10 of other USB DSOs. But their name and limited web site does not instill much confidence in me.I am willing to consider more traditional scopes, but all of the ones in my price range are apparently scope only and do not have any of the other tools that I need.I would appreciate any experience, thoughts, suggestions, etc. on this subject. On the above devices or on any others you may know of. I need something that will work well with a minimum of set-up trouble.

author: Pasky
author_rank: Regular Contributor
timestamp: January 24, 2014, 09:33:00 pm
content: Does it need to be USB?If not:http://www.ebay.com/itm/Tektronix-Tek-2246-working-oscilloscope-4-channel-Excellent-Working-Tested-/131094066847?pt=BI_Oscilloscopes&hash=item1e85d0b69fOh I misread your post, you're looking for a scope that will spit out analysis numbers for you...

author: EPAIII
author_rank: Super Contributor
timestamp: January 25, 2014, 01:09:09 am
content: No, it does not need to be USB. If fact, I would prefer a stand-alone scope, but I also need the other functions. I am well aware of the trade-offs with the inexpensive USB/DSOs. I even have a bias against sampling scopes. I have read the papers on what can go wrong. It is a lot easier to look at an analog waveform display that is close to the BW limitations of the scope and imagine what it actually looks like than trying to do that with a digitally sampled signal. I mean, I can quickly draw at least several different waveforms that could have produced that sampled trace.However, the world has gone to DSOs so I am probably stuck with that. At least in my price range. And I can not find any stand-alone DSOs that have the additional functionality - in my price range. Of course, I would be willing to consider two or three different instruments.

author: echen1024
author_rank: Super Contributor
timestamp: January 25, 2014, 03:50:35 am
content: Buy thiseBay auction: #251432867300(bid), spend around 225 max, and then get a logic analyzer (Intronix Logicport or Saleae)

author: phil
author_rank: Regular Contributor
timestamp: January 25, 2014, 04:05:18 am
content: Concerning the analog discover:Quote from: phil on January 23, 2014, 03:29:49 am(fromhere)Care should be taken when measuring SMPS. While you can use the analog discovery for lower frequency PSUs, it becomes increasingly difficult to use it with switching frequencys > 1MHz. The signal integrety may become a problem, but that depends on what you want to do.Phil

author: fake-name
author_rank: Regular Contributor
timestamp: January 25, 2014, 09:47:28 am
content: You don't want a USB scope. Seriously. They're all HORRIBLE.Scopes really need a actual control panel. I have played with a few USB scopes on a laptop, and actually *using* the scope has been a giant pain in the ass on ALL of them. Basically, there is no way to properly accommodate the parallel nature of a scope's UI to the serial nature of a computer mouse/trackpad.

author: phil
author_rank: Regular Contributor
timestamp: January 25, 2014, 10:01:19 am
content: Quote from: fake-name on January 25, 2014, 09:47:28 amWaveforms. Try it. Has a free demo mode and the UI is actually better than that of some of the cheap bench scopes (owon, I'm looking at you!)Phil