Prepping to by my first oscilloscope after years of talking about it. I initally decided on the Rigol DS2072, but now it turns out they're backordered, and I have to choose again...
(Background on me: I took some basic vocational courses in electronics. I've had college physics. I put together one simple project using a
Teensy. So I'm definitely a beginner. I'm looking to do more hobbyist stuff, probably mostly digital at first. I want to buy good stuff that can grow to a number of applications as I get better.)
They do have a DS2102 in stock. Looking at the data sheet, the differences between the 2072 and the 2102 are
Analog Bandwidth (-3dB): 70MHz vs 100MHz
Rise Time: 5ns vs 3.5ns
I've read
https://www.eevblog.com/forum/testgear/frequency-response-of-your-dso/ and get the impression that the 2072 scope would be fine for viewing the shape of signals with much higher frequency than 70MHz; you just have to be aware to compensate for the attenuation. But how much higher? For example, could I meaningfully look at regular FM radio signals (87-108MHz)? What kind of work would actually
require a 100MHz bandwidth instead of 70MHz?
Both scopes have a sampling rate of 2GSa/s single-channel, 1GSa/s dual-channel. Naively, I would think a 1GSa/s could notice a voltage jump in 1ns. That the 70MHz version specs 5ns makes me think there's some input filtering (like an inductor?) to attenuate higher frequency signals. If this is the case, I would expect all the DS2000 series scopes to see the same spikes in a signal, but for the spike to be taller on the more expensive variants. Do I understand rightly? What does 5ns translate into practically? What kind of work would actually
require a 3.5ns rise time instead of 5ns?
The 200MHz version adds a couple more things, but it still seems to boil down to the same thing. Now a 200MHz bandwidth and a 1.8ns rise time. Those do seem more obviously different, but that scope is twice as expensive! Still, I'm curious what work would require the jump in capability.
(Sorry if this kind of question has been answered a zillion times already! I did see a ton of "what blah should I buy?" posts.)