OK, so I find myself needing to look at some analogue stuff to debug something I'm building. Hence, an oscilloscope.
I'm not hugely familiar with what specs are important or not, so I'm after a bit of advice.
My current project uses (digital) signals up to about 6MHz.
I also like to sometimes play around with FPGAs , and my next project is likely to be having a crack at DVI (which has a ~25MHz clock).
So I guess my questions are:
how much bandwidth do I need? I know it's good to have more than the bare minimum, so more than 25MHz seems desirable. But how much more? 50, 60, or 100MHz?
There's a fairly big price step from 50MHz to 100MHz.
"equivalent" sample rate?
this is some marketing thing, only useful for periodic signals, right?
I've been pretty much ignoring it and just looking at the real sample rate, as I'll be looking at digital signals which tend to be not very periodic.
I've been looking at the Atten ADS1102
and Rigol DS1102E
, which are both 100MHz units. The $550 Atten has 4k of memory, the $720 Rigol has 1M (or is it 16k, the ebay listing is a bit vague).
Are scope prices tending to decrease as tech improves? Should I get a just-barely-good-enough one today and upgrade down the track if I need to go faster?
I'm leaning towards a stand-alone unit rather than PC-attached, although I remain open to a USB unit if it's cheap.
Any advice would be appreciated, especially if you've used any of the cheap eBay scopes (Atten, Rigol, or Owon... have I missed any?)
Oh, and before anyone says "get a 2nd hand tektronix off craigslist", well, I'm in Australia. There doesn't seem to be much of a market for 2nd-hand scopes on craigslist or ebay, and shipping from USA is huge for those big hunks of glass and metal.
And finally, I already have a logic analyser so don't need that in the scope. LAs are really great for protocol and timing debugging, but much less so for checking signal integrity or power supplies.