DSO's

[KurtEE]

I've done a little seaching the web for info on designing digital oscilliscopes and haven't found anything helpful. Can anyone tell me where I could look for information that is "the way it's done today" technology.
I'm curious of any pro/cons of using a digital pot for the attenuation/gain stage.

Thanks.

 

[jbartos]

Suggestion:
Go to

http://www.thomasregister.com

and under Product/Services
input
Digital Oscilloscope
Then, keep on sending emails similar to you posted above. Some manufacturer could give you some home project resembling the above one with its tech support.

 

[umn]

Please see the FAQ: "Selection and use of oscilloscopes" under this forum. You can follow the link:

http://www.eng-tips.com/faq.cfm?spid=248&page=1&cfid=5385450&cftoken=88618351#6

 

[RedDerek]

Two good sources of oscilloscope information - Tektronix and HP. These two manufacturers have done a lot of publications of DSO vs. Analog. Research their web pages and then call a sales rep and ask for the pitch.

Then make up your own mind as to what you really need.

Personally, I got the TDS220 from Tek. Good sampling rate, low cost (when on sale). However, a good analog will capture those fast transients - if that is important. [sig][/sig]

 

[KurtEE]

Thanks for the advice, and now I have other question if anyone can answer.
I'd perfer to design the input section with a 10 Meg input impedence but didn't really want to design it with descrete FETs etc. to get a relatively high BW around 250 - 500KHz. Does anyone know of any neat ways to maybe cancel out the known capacitance (mainly op-amp inputs) to help with the bandwith. I've looked at some other designs and notice that the main input resistance (1M ohm) was split up and a small capacitance was shunted across one of them. Without getting out my pencil and paper and deriving the transfer function for that topology I'm guessing maybe that's how one could compensate the system.

When I figured out how to use an op-amp integrator summed with the input to simlulate AC coupling, I thought that was a cool way to do it and figured someone may know a neat way to do what I'm trying to do.

Thanks,

Kurt [sig][/sig]

 

[RedDerek]

Use a FET input probe is the quickest solution. These are higher impedance and very low capacitance probes. The only drawback is cost. Derek Koonce
DDK Interactive Consulting Services

http://www.dkoonce.com