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Have any of you seen the DSO Nano v3? http://www.seeedstud....html?cPath=174 Do you have any opinions on how good this would be for a starter scope? The portability and form factor seem very good. I know the Nano V2 got pretty good reviews from AdaFruit and Sparkfun, but I can't find anything about the v3 yet.
Steven, it's just $89, but it's also just 200kHz of bandwidth: what would you expect to see?
For making you understand, if you would try to inspect a 100kHz square-wave, you will see with rounded corners. Even worse, the inspection of a typical SPI message would be impossible.
IMHO, such a scope could be fine just for audio purposes, not for any other digital target.
Also forget the bigger brother, the DSO Quad: I own for a while but it's garbage.
If you really need a scope just think about some good hobby model: there are many. However, the price is above $300.
Have any of you seen the DSO Nano v3? http://www.seeedstud....html?cPath=174 Do you have any opinions on how good this would be for a starter scope? The portability and form factor seem very good. I know the Nano V2 got pretty good reviews from AdaFruit and Sparkfun, but I can't find anything about the v3 yet.
My experience is that unless you are desperate then save up for a better scope. Picoscope have a bottom of the range USB scope at a reasonable price. I owned one whilst I saved up for a bench scope. It served me well during the time I had it.
Like Mario, I had a look at the DS Quad - it's a bit of a novelty but not something I would use.
I bought an DSO Quad, useless imho, the interface is not usable in any way, waste of money.
I'm kinda looking at this: http://www.bitscope.com/ specially the 120, but it's kinda expensive for something usb based. It saves space though, and triples as signal generator, LA and scope.
Is USB2 good enough for such things?, I kinda hope they upgrade to USB3 soon..
Do you have any opinions on how good this would be for a starter scope?
The point here is what exactly you mean by "starter scope". DSO Nano devices are nice, but you have to understand their [serious] limitations.
Just to put things into perspective, as a rule of thumb (1), a scope’s bandwidth should be at least five times higher than the fastest digital signal rate in the system under test. So 200 kHz translates to 40 kHz signal, and that's not much - even 'normal' UART communicates at > 100 kHz (115200 baudrate), not to mention I2C, orders of magnitude faster SPI etc.
Another thing is sample rate - while 1 Msps can seem to be a lot, it really is not - for example the cheapest Rigol DS1000E series scopes have thousand times more (1 Gsps single channel).
IMVHO DSO Nano can be used to inspect low speed signals, and maybe for probing ("ok, there is some signal in here"). But you will not be able to measure anything in usual digital circuit, i.e. with a microcontroller. A logic analyzer would be much better alternative...
The point here is what exactly you mean by "starter scope". DSO Nano devices are nice, but you have to understand their [serious] limitations.
Just to put things into perspective, as a rule of thumb (1), a scope’s bandwidth should be at least five times higher than the fastest digital signal rate in the system under test. So 200 kHz translates to 40 kHz signal, and that's not much - even 'normal' UART communicates at > 100 kHz (115200 baudrate), not to mention I2C, orders of magnitude faster SPI etc.
Another thing is sample rate - while 1 Msps can seem to be a lot, it really is not - for example the cheapest Rigol DS1000E series scopes have thousand times more (1 Gsps single channel).
IMVHO DSO Nano can be used to inspect low speed signals, and maybe for probing ("ok, there is some signal in here"). But you will not be able to measure anything in usual digital circuit, i.e. with a microcontroller. A logic analyzer would be much better alternative...
Absolutely agree: that's the way I'm (very) suspicious about the Hantek. 48M samples for a 20MHz bandwidth? Seems to me something unbelievable (at least until I seen it by my eyes).
Moreover it sounds like the Quad: 72M samples, but the real bandwidth was about 3-4MHz, due the extreme un-flatness of the analog stage.
Also agree on the purpose of the tool are you looking for: if you want to deal with just "boolean" signals, the logic analyzer is enough, and far less expensive. The problem could arise when the "things aren't simple as they look", thus a scope is the right (and only) useful instrument.
As a software-perspective comparison, if your target is just creating simple apps with C#, the VS Express IDE is enough. If you need to inspect the assembler produced, the network traffic, the serial I/O etc. it's clear that you will need more than that.
Finally, bear in mind that the cost of a scope is mostly on the analog stage and the high-speed cache memory. ADCs are also expensive but not as much as the mentioned sections.
Cheers
Biggest fault of Netduino? It runs by electricity.
Wow, I could go massively in depth in this subject since this is what I do. But, there are many very thick books that also cover these subjects.
And, many subjects have been asked.
I'll try to do a very broad summary:
USB: Most of these scopes will buffer and then send the data. Some will stream, but very few. They often have a POS ARM processor (sorry Netduino , but an ARM processor as the main processor for this type of application does qualify as a POS ). That means that there is a significant delay in processing buffers.
Therefore, IMHO, USB2.0 is not the limiting factor - in fact it's far from it! Don't forget, USB2.0 is now used to stream from a video camera. USB2.0 has many modes. Very few applications/hub-chips/etc use the advances modes.
For USB performance, do not use an external hub. Connect directly to a PC. USB1.x-2.x is polled. And, chances are anything other than a high-end laptop or desktop has a semi-POS USB controller that was chosen more for cost than for performance.
A low-end laptop and/or desktop may have the graphics controller as another limiting factor.
I've done a lot of simple VB/C# Windows GUIs that connect via USB to my hardware. Amazing the differences in PC performance depending on many factors.
Bandwidth and that other device:
Over 1MHz, the grounding and probes become important. Over 20MHz, you better have 100+MHz probes.
In general, you want the 3rd, 5th, and 7th harmonic of a square wave to be "clean" to get a decent/accurate signal.
Even with a "cheap" Tek 100MHz passive probe, with a 40MHz Tek scope, and an 10MHz clock signal, if you move the probe wire around, you'll see the signal shape change on the screen. Again, grounding, ground wire length, ground connection, probe tip/connection, etc all come into play.
I have a few of the old Tek FET probes that use a 50-ohm coax cable and a separate probe power supply. I use those when I care about getting an accurate signal for something below ~100MHz.
Over that, it's stepping up to the $1K+++ FET probes. Ouch! I do not have any of those personally.
It all comes down to why a person wants a scope, and what uses they need it for.
When I verify signal integrity for high-speed signals, that's done with very short soldered on wires, and I use specially placed ground vias without solder mask. And, a scope and probes that cost $$$.
If I'm doing eye patterns, SATA, radar/etc, that's all 50-ohm direct connections to the scope.
The point here is what exactly you mean by "starter scope". DSO Nano devices are nice, but you have to understand their [serious] limitations.
Just to put things into perspective, as a rule of thumb (1), a scope’s bandwidth should be at least five times higher than the fastest digital signal rate in the system under test. So 200 kHz translates to 40 kHz signal, and that's not much - even 'normal' UART communicates at > 100 kHz (115200 baudrate), not to mention I2C, orders of magnitude faster SPI etc.
Another thing is sample rate - while 1 Msps can seem to be a lot, it really is not - for example the cheapest Rigol DS1000E series scopes have thousand times more (1 Gsps single channel).
IMVHO DSO Nano can be used to inspect low speed signals, and maybe for probing ("ok, there is some signal in here"). But you will not be able to measure anything in usual digital circuit, i.e. with a microcontroller. A logic analyzer would be much better alternative...
[color=rgb(0,0,0);font-family:verdana, arial, helvetica, sans-serif;font-size:small;]By the way, I won't waste my money on a nano DSO. They're crap oscilloscopes. They have a small screen and are unprecise. Spend a little more money and get a Rigol DS1052E if you're serious about your hobby. [/color]
I have several scopes in my home lab: Tektronix DSO 100MHz , Hantek 6082BE, two chinese USB scopes, DSO nano, several logic analysers andeach of themhas itsspecific applicability.
For USB scope you must to be very carefuly! Most of 48Ms/sec scopes mean "soft" scope -> no hardware memory buffers and fpga and most of these scopes have bad software with very very big normal/single trigger problems! Itsignificantlyreduces theirapplicability!
I use DSO nano for fast service check out of my home and it is best tool for it. DSO nano is small cheap pocket device for simple signal check, enough in 99% cases.
Depend of your money and requirements you must chose scope.