DSO nano oscilloscope reviewed [hackaday]

[ryan_the_leach]

http://hackaday.com/2009/10/19/dso-nano-oscilloscope-reviewed/

Anyone got any opinions on this oscilloscope, I saw it and immediately thought of the eevblog forums.

[EEVblog]

I agree with the Hack-a-day summary, it's seriously limiting to the point of almost being useless. 1MS/s is only around 100KHz usable single shot bandwidth.
I'd rather have an old throwaway 20MHz dual trace analog oscilloscope any day of the week, infinitely more useful.

The reviewer is way off when he says "but most electronic signals will be easily visible on an oscilloscope of this (1MS/s) resolution". That's just silly, 100KHz bandwidth is pretty well useless for anything but the audio range.

Also, why bother with 12bit resolution in such a limited unit? Perhaps for datalogging and PC upload maybe...

Also he's way off the mark on his conclusion IMO:
"The DSO Nano is shaping up to be a real contender for your cash.  Its pocket sized, well featured and very much easier to use than an analogue scope."
I found that laughable.

It's a toy, you are just throwing your money away unless you really do need a pocket size audio bandwidth scope.

I don't understand why anyone would go to so much trouble to design a unit like this and then cripple it with a 1MS/s converter.

Dave.

[charliex]

i'd rather go with one of the PC sound card scopes, it'll do just about anything that one will, since its so limited. cept the portability  (that is if you don't want an older scope etc)
there are loads of sound card scope projects on the old web, but they're also really limited.

for a bit of fun and learning about fpga's there is this guy http://www.fpga4fun.com/digitalscope.html its also limited, especially in the input stage but you can hack an old non working scope for that. (learning about sample equivalent time too)

i built one of the usb versions, works well (for what it is)

[EEVblog]

If you want portability, there are useful portable scopes around. This one is only $110:
http://www.kitsusa.net/phpstore/html/VELLEMAN-HPS10-Hand-Held-Oscilloscope-989.html
Sure it ain't pocket size, but it's a heck of a lot more useful.

Dave.

[charliex]

i have that one for my toolbag, its great for the price, can be a little bit hard to see though.

[Mastro Gippo]

35$ in kit, + the fun of building your own,  + it's open source! 
http://www.jyetech.com/en/default.html

[slburris]

While the Nano is really cute, figure it can only really show
stuff up to about 100Khz.  Yes, I know Nyquist says 2X
sampling, or 500Khz, but that only applies if you are looking
at sine waves.

Not a sine wave?  Then you have higher order harmonics that
will blow past the sample rate.  As a kid I built a 5Mhz Heathkit
oscilloscope and didn't understand at the time that it wouldn't
show a 5Mhz square wave very well.  In fact, it came out looking
like a mangled sinewave, because the poor frequency response
above 5Mhz was acting like a low pass filter, removing the higher
order odd harmonics.

In short, I'd say the Nano is useful for audio stuff, but not much else.
My Rigol DS1052E is good up to 50Mhz, but is sampled at 1Ghz, a 20x
difference!

Scott

[santy.raghavan]

Dunno how many folks have already seen this but sounds interesting. A simple FPGA based scope kit.  Some of the numbers seem off, but definitely sounds interesting.

http://www.fpga4fun.com/Hands-on_Flashy.html

I ordered the parts and have them on hand, but haven't put it together yet. Will post it up once done.

Santy

[charliex]

i have one, i think i posted about it elsewhere on the board(actually in this thread). Its ok, the input stage makes it very limited in what it can do, pillaging something from another scope would help though.

its good for learning, but too limited for most people

[santy.raghavan]

i have one, i think i posted about it elsewhere on the board(actually in this thread). Its ok, the input stage makes it very limited in what it can do, pillaging something from another scope would help though.

its good for learning, but too limited for most people

Dang, you did too!! I should read the posts more carefully.

[Simon]

Dunno how many folks have already seen this but sounds interesting. A simple FPGA based scope kit.  Some of the numbers seem off, but definitely sounds interesting.

http://www.fpga4fun.com/Hands-on_Flashy.html

I ordered the parts and have them on hand, but haven't put it together yet. Will post it up once done.

Santy

well they say 100 MHz but they say = 100 Ms/s now thats a cheat you can hardly call 100 Ms/s 100 MHz analog bandwidth, at the absolute best 50 MHz but realistically 10 MHz

[EEVblog]

Dunno how many folks have already seen this but sounds interesting. A simple FPGA based scope kit.  Some of the numbers seem off, but definitely sounds interesting.

http://www.fpga4fun.com/Hands-on_Flashy.html

I ordered the parts and have them on hand, but haven't put it together yet. Will post it up once done.

Santy

well they say 100 MHz but they say = 100 Ms/s now thats a cheat you can hardly call 100 Ms/s 100 MHz analog bandwidth, at the absolute best 50 MHz but realistically 10 MHz

For (the much more useful) real-time sampling, yes. But for repetitive sampling your sample rate can be as low as you want, so you can have a 20GHz analog bandwidth and only 20MS/s if you want to. That's how scopes used to work before real-time scopes came along. The very high bandwidth scopes still work in repetitive mode.

Dave.

[Simon]

Yes I suppose thats and option, just means it could take a good few cycles to map the entire wave, just out of curiosity: what happens when the samplerate is exactly the measured signals frequency or a sub multiple of it ? surely the same part of each consecutive wave will get samples and so you will never get to sample the whole wave giving a false reading, or the gap be so small that the amount of time taken to measure all that is impractical ?

[EEVblog]

Yes I suppose thats and option, just means it could take a good few cycles to map the entire wave, just out of curiosity: what happens when the samplerate is exactly the measured signals frequency or a sub multiple of it ? surely the same part of each consecutive wave will get samples and so you will never get to sample the whole wave giving a false reading, or the gap be so small that the amount of time taken to measure all that is impractical ?

Yeah, it takes ages, and your trigger has to be perfect, that's why it's a crap way to do it, and the main reason why digital scopes didn't hit the mainstream until the Tek TDS-210 which was the first affordable real time digital scope. Now that almost all scopes are real-time, you don't have to worry about this sort of thing unless you roll your own or buy an old used digital scope.

They use "random" equivalent time sampling to avoid the problem you mentioned.

Dave.

[Simon]

ah yes thought that might be something to do with the solution

[walterdelbono]

awesome...

[tecman]

Take it for what it is.  Under $ 100.  If your work does not require anything HF, it works great.  Most of my work is DC to 1 KHz.  I have a NANO in my hand carry case, and I need to really look at something in the field, it's there.  Smaller and lighter than a box for a PC.

paul