Looking for advice on a USB scope/logic analyzer/spectrum analyzer/fxn gen

Hi folks,

I'm thinking about shelling out for a USB scope with data capture capabilities. I'm not an EE by trade - just a hobby, so my needs are not necessarily what everyone else's here might be.

I've looked at a few:

PicoScope -

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BitScope -
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ProScope -
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DiSco / Hobbylab -
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Most of them provide both an oscilloscope (I have a dual trace already, so good-but not a big selling point), and a logic analyzer.

Some of them have function generators with standard waveforms or arbitrary waveform output via DSP.

Finally, some of them have a spectrum analyzer, which seems like a handy thing to have.

The last one in the list seems to be the least expensive, but I worry about the quality of the software, and this thing becoming a brick when the mfr decides to stop supporting it (a few of my other PC- interfaced instruments have gone that way).

so... I figured I'd ask if you experienced folks out there had advice on a good basic USB data scope.

Here's a few more details:

I don't know what my needs will be in terms of frequency on the scope or the logic analyzer / data recorder, but I don't think I'll need anything like 200MHz any time soon. I'm still puttering around with Atmel microcontrollers.

I don't do any RF stuff, and don't plan to roll-my-own any time soon.

I mostly do low-voltage stuff. TTL, DC motor control, reading sensors, etc.

Hope that narrows things down a bit.

Thanks in advanced.

-Mr. INTJ San Diego

"I suffer from CDO. It's like OCD, but all the letters are in the right order. Like they should be."

Reply to
Mr. INTJ
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What is your budget?, that pretty much determines everything. If you can afford it, you are better off getting a "real" dual channel 50MHz DSO and a seperate logic analyser. You can get really cheap and full featured USB logic analysers. The ones that comes with with combined USB scopes are usually more of a compromise. I'd recommend a Rigol DS1052E DSO for under US$500, and a USB logic analyser will set you back another few hundred (plenty to choose from). That will be a much more versatile and better performance system than almost any PC based combi-scope. See my blog for a review of the Rigol scope:

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Yes, the quality of the software (and hardware performance) varies enounmously, you certainly get what you pay for.

The PicoScope can have quite good performance, but you really pay for it. $1300 can buy you a fantastic "real" bench scope + logic analysre + function gen.

The Bitscope? Only 40MS/s, that's a single shot bandwidth of only around

4MHz, that isn't very useful at all. For the same price you can buy a 50MHz 1GS/s Rigol with 1M memory + a cheap USB LA.

The last two are just toys really, not very good bang-per-buck.

Regards. Dave.

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Reply to
David L. Jones

scope:

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Agree.

I second the vote for Rigol. Good value for money. I question the "no need for 200MHz" part. That only works out to about a 20MHz square wave. When I was tootling around with my 16/32MHz VGA converter box, I used a 1GHz sampler to get decent measurements of the clock. It would have been unthinkable with anything less. But it was an unusual situation. 200MHz is not that luxurious anymore with higher and higher clock rates out there. I complement my 100MHz Rigol with a vintage Tektronix 547 with a whole slew of plugins. But I do not recommend that path for a beginner. It's like having an F-15 for going to the supermarket. (About the same age too)

As for the logic analyzer, I don't think it's necessary. No one I know uses one, professionally or otherwise. There's just no need for them with today's IDEs and simulators, etc. The only time I can see using one is if you are into vintage '70s-'80s computers and there's no JTAG or timing diagrams available.

Reply to
a7yvm109gf5d1

What happened with a decent analog scope?

I disagree. A logic analyzer is still a very usefull tool if you are working with FPGAs, serial busses or anything digital that involves more than 2 signals. The more memory, the better. I use my LA only a few times per year but it saves me a lot of time.

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Reply to
Nico Coesel

(snip)

Well, the more we go above the $250-300 range, the more I have to justify a real NEED for this thing. It may be (as my research so far has suggested) that you can't touch a decent scope for under $500. If that's the case, I'll adjust my expectations and re-assess whether/ when I need to get one of these.

(snip)

eevblog/?p=3D6

Enjoyed your review. That was helpful to actually see it.

Reply to
Mr. INTJ

(snip)

t a

Good point. "200MHz" was just an estimate on my part. My goal (restated) is to buy something that sits in the happy spot on the price/value curve, and not run up against limitations within the next few years.

(snip)

Another good point. I haven't used one before, but I'm starting to get into microcontrollers, and just assumed that I'd need one eventually.

Thanks.

Reply to
Mr. INTJ

(snip)

I have one (BK Precision Dual Trace 2120B). I bought it a few years ago when I started doing electronics again. Has been perfect for the stuff I've been doing.

My big incentive in getting a USB scope is the data capture. Since I have a dedicated scope and function generator already, I guess the only other feature that's significant for me is the spectrum analyzer....

(snip)

I will be doing a lot of serial communication... hmmmm.

Reply to
Mr. INTJ

I agree with your disagreement. I also use a logic analyzer rarely, but when I need it, it does really help nail things down. I don't just use it to debug things. I use it to document protocols with examples and to demonstrate precision and variability in timing, where appropriate. It's useful to show what the software and hardware are _actually_ doing, so that others looking back on the project in hindsight have some things to draw upon and some supporting evidence that those working on the project earlier really did care about and check out what they were doing.

Jon

Reply to
Jon Kirwan

That Rigol is selling for about $420/shipped-free on ebay, new, I see.

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Might be still cheaper sources I don't know about.

Jon

scope:

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Reply to
Jon Kirwan

The 1GHz sampler is an analog scope, a Tek 547 with 1S1 plugin. Works well. I even have a great P6032 active (tube based!) probe for it. Lots of fun, but BIG.

We must not be working with the same FPGAs. :) There's no space to even put probes anymore. It's all done in the simulator or with boundary scan.

Reply to
a7yvm109gf5d1

The way things are moving, it's almost not worth thinking too far into the future. What do you need right now? You can always sell and upgrade when the economy gets better.

Well, other people have disagreed and that's fine. I just prefer simulating.

Reply to
a7yvm109gf5d1

I use the passive resistive divider probes as explained on

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I always include 8 pins to connect a LA to an FPGA. Inside the FPGA I have a mux with which I can output various internal signals. Simulation is probably easier but I never got myself to walk up that hill. Old habbits... Besides, the ability to connect an LA allows to debug interaction with the outside world which is always full of surprises.

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Reply to
Nico Coesel

On a sunny day (Wed, 20 May 2009 19:47:21 GMT) it happened snipped-for-privacy@puntnl.niks (Nico Coesel) wrote in :

He we agree on something. I always say: Give me one I/O pin and I can get things working :-)

Reply to
Jan Panteltje

Pretty much been displaced by much better bang-per-buck digital scopes. Any well equipped lab will still have an analog scope as well of course, but if you had the choice of only one scope for general use, you'd make it digital for sure, just way to many advantages. If the OP has money left over I'd recommend a nice used analog scope as well.

I agree. Logic analysers are not used very often, but priceless when you actually need one. See my little rant here on this in practice:

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Dave.

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Reply to
David L. Jones

In that case, forget the PC based scopes and get the Rigol for $420 from eBay as someone else mentioned. That is by far the best value for money on the price performance curve - by a long way. You will not regret buying a "real" scope, ever. Only get the other gear when you feel you have the need and further budget down the track.

There are three limitations you will typcially run into:

1) Analog bandwidth. 50MHz is probably minium you want for general purpose use. 2) Sample rate. Given the example of your minium analog bandwidth of 50MHz, you want 10 times that, or 500MS/s, minimum for general use. 3) Sample memory. The more the better, especially when using the scope as a logic analyser. A few KB is almost useless for any serious digital troubleshooting, 50KB+ is more like it, 1MB you will wonder how you ever lived without it.

Dave.

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Reply to
David L. Jones

to: Mr. INTJ re: scope bandwidth Fri 5/22/2009 4:43 pm

Everyone has their own ideas, but I've been using a 35MHz analog Hitachi scope for years, and it works fine at least for what I do. Mostly millisecond kind of signals, but just the other day I was poking around the clock circuits of a 68HC12 circuit, and I could see a 25MHz signal.

My feeling is if you *need* to see an 80 MHz signal, you're doing something wrong. Obviously this is not "true" -- but it's still true a lot....

And I prefer analog scopes; I read an article in EETimes some years ago about how people were carrying their own scopes around simply because they *couldn't understand* the digital scopes they ran into on- site! Probably because of the lack of exotic features, the analog scope is relatively easy to figure-out; when you're hacking at circuitry, it's really annoying to have to remember how the scope works....

Nevertheless, I'm thinking of getting one of these USB things; I'm mostly attracted by the thought of capturing waveforms to a PC graphics file. ... I liked the Parallax -- it seemed to have positive vibes, good software, and was the cheapest -- but no BNC connection! ... I mean, I can get probes elsewhere (mpja.com had cheap ones, although I don't know how good), so I don't particularly want to pay the vendor markup for those; but it you can't *plug-in* standard probes. ... And oh yes the Parallax only does +/- 10 volts; for larger signals you'd have to build a divide-by-10 box -- because you can't plug-in a standard probe with a "x10" switch -- and that'd be annoying.

So so far, the multiple-function hobbylabs gadget looks better, but that's probably because I haven't researched it as much. ... Anyway,

-- good luck

j.g. owen * * * * * * * * * * * * * * * * * * * web:

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email: owen snipped-for-privacy@yahoo.com

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Reply to
owen_bda4

Many of the early digital scopes were pretty "weird" and difficult to figure out in, say, the 5 minutes or so you'd tend to have needed with an analog scope.

Since that time, though, the user interfaces are much improved, and it's a fair bet that >99% of U.S.-educated college kids today are plenty familiar with contemporary digital scopes. Indeed, many of them have never used an analog scope (or used a soldering iron :-( ).

Reply to
Joel Koltner

Do you realise that you *are* going to need that 80MHz bandwidth to see that

25MHz square wave properly? There is no substitute for analog bandwidth.

That was true a decade or two ago, but hasn't been that way for a long time. Have you used a modern digital scope? they look and drive just like an analog scope. In fact digital scopes can be easier and quicker to use than many analog scopes. Most have an auto-set button you can hit that can usually set everything up for you in a second.

They are just toys.

Dave.

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Reply to
David L. Jones

You forget about screen resolution. AFAIK the Rigols use a 320x240 screen. I'd prefer a PC/laptop scope.

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Reply to
Nico Coesel

No, it's just not a serious usability limitation for most general uses.

That's just what you get in the low end digital scopes. It's perfectly adequate for the job when you have good zoom and scroll functions. The other advantages of a real bench scope far outweigh the screen limitation for most uses IMO. Still makes the Rigol by far the best bang-per-buck solution at this end of the spectrum.

Dave.

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Reply to
David L. Jones

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