neslekkim

Oscilloscope

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Didn't find any place to do general discussions, so trying here, move if not appropriate.

 

I have been looking for an scope for some time now, and are about to shell out for an Rigol ds2102a-s or ds2202-a-s, will scopes in this range be usable for working with mcu's and fpga's?

For use as logicanalyzator I'm either using the pipistrello/ols, or this project that I backed today: http://www.kickstarter.com/projects/dreamsourcelab/dslogic-multifunction-instruments-for-everyone

 

But for checking signalquality I think an scope is nice to have, but not sure about the speeds that are required. 

I have looked a bit on the ds1000z series, but think it's maybe a bit too entry level.. and here it's still expensive (the ds2102 will be only about twice the price), and I don't want to buy something, and then later find out that the money is wasted so i need to buy an bigger one, these are not directly upgradeable (other than hacking), Agilent could be something, it can be upgraded buy purchasing licenses for bigger bandwith, but hey, who want an windows ce device on it's desk?

 

Anyone have any pointers here? 

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I have a Tektronix 465B analog scope that is my favorite piece of test gear. They're old, but you'd be hard pressed to find a finer analog scope than that or a 468. I've also got a Bitscope PC based USB DSO which admittedly is better for digital work as it can capture a portion of a waveform or transient event so you can take your time looking at it. It also offers a basic 8 channel logic analyzer function, although the prices on new ones are higher than I'd pay.

 

Honestly for FPGA work, you might get more out of a logic analyzer than a scope since FPGAs are inherently digital but it really depends on what you're trying to do. I built a Mini-LA a number of years ago which is based on a Xilinx CPLD and it has worked well, but the design connects to a parallel port so it's showing its age. That DSLogic device you linked to looks very promising, you might consider getting something like that, then pick up an older analog scope as a companion to it if necessary. For all the fancy features in the modern DSOs, there is still something about working with a good analog scope that feels more "real".

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the problem is to find analog scopes here, buying over internet will give me very expensive shipping, and the few analog ones I have found bear strange names, in fact, only scopes I find on the market here now is promax and and rigol 1052e, for way much than I want to spend on old things like that.

 

the rigol ds2000 series have 256 gradients i think, to kinda mimic the analog effekt, but of course, not like an analog one (and they are not so deep, so it will fit on my desk)

But I'm more concerned about wether I need 100 or 200mhz, I'm doing stuff with all kind of mcu's also, like avr's, pics, and so on, and from an netduino project I tried, someone helped with spi problems using LA and an scope, the la was nice enough, I hope the DSlogic will help there (and I have an clone coming from china someday), but the scope was helpfull because it allowed you to see the voltage levels on the trafic as well, and to discover that bad cables destroyed the signals somehow.

For some reason, these Rigol's arent' that much more expensive here, only like +$160 on the ds2000 series compared to batronix (eu) and rigolna.com, usually stuff costs like x2 -x3.. (like my jbs solderingstation for instance)

I'm kinda leaning to the 200mhz to be sure, but if 200mhz is not enough in the first place, it would be better to take the 100mhz I guess. (It seems like someone at eevblog forum are close at hacking this scope also now.. 

this thread is very interresting on all things rigol: http://www.eevblog.com/forum/testgear/sniffing-the-rigol's-internal-i2c-bus/

 

Yes, it was almost I fell for the pitaya, but I then saw the max sampling rate.. very low to be an oscilloscope?

 

 

[edit] oh noh.. I just found out that the dslogic uses the same spartan as the OLS, damn, that's going to be an expensive ols.. how can they get that speed from it since the ols only have 50mhz?

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About the pitaya, low sampling rate ?

 

You should have missread. If you refere to the 125MS/s it is the sample limite of the ADC, i think it is quite honorable.  As an logic analyser you can expect better performance than the dsl... because of the possibility of the HW provided (memory chip, ethernet ...)

But yes actually they don't have adaptation board to probe -30/30V logical signals. And the logical analysier application seems not to be out-of-the-box features.

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yeah, don't understand all the numbers, but I was thinking about the scope functionality for the pitaya, rigol have like 2gs/s.. but didn't think about that as an logic analyzer.

But I guess I screwed up on the dslogic since it have the same (it seems) hardware as the ols, oh, well.. 

 

[edit] probably the ram that makes the difference on the dslogic vs ols, forgot that

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