Curious, what do you tend to work on (either at home or work) that frequently needs longer sample records and larger FFT kernels?
For example, I'm doing a lot of signal analysis of complex non-standard communication signals, which probably isn't a common use case.
But that's besides the point anyways, as larger sample memory is useful in lots of standard cases as well, as it means the scope will maintain a high sample rate at much longer timebase settings.
As for FFT, the number of points used decides the frequency resolution (RBW), which is inversely proportional to the sample length.
To offer a scope like the Keysight DSOX4k in the price range it sits in with 4M memory and 64k FFT is a pretty bad joke in this day and age.
How the memory is used is much more important than how much there is, in my experience.
Sometimes you can compensate or work around sample memory limitations to an extend, but at the end of the day if the sample memory is small then this will limit a scope's performance.
Also, don't forget that we're not talking about some bottom-of-the-barrel scope or some old 2nd Tek scope in this thread, we're talking about modern mid-range scopes priced between some $7k to over $20k. Heck, even a $3k WaveSurfer 3022 offers 10Mpts sample and 1M FFT.
Everyone's application is different, but from what I've seen in the scope business, it is far too easy to get caught up in "bench racing" and specsmanship. You end up with a crappier instrument, albeit one with larger numbers on the sell sheet.
That is true to some extend (i.e. the larger Rigol scopes which have lots of sample memory but otherwise perform poorly), but generally dismissing progress made over the years is not the right answer.
The simple point is that Keysight's DSOX4k offers *today* certain specs like sample memory and FFT that were considered good for a scope in its class one and a half decade ago, at the same price or even above the price other competitors ask for while offering better specifications (and the small sample memory or the 64k FFT are not the only limitations of the DSOX4k).
It's much like the thread on microscopes, where Rupunzell points out that quality can't really be inferred from the specs alone.
I certainly don't want to go deeper into what someone who regularly refers to analog scopes as "high fidelity" instruments stated but the validity of that statement pretty much depends on your definition of "quality" (the meaning of which can vary a lot).
At the end of the day, what scope specs give you is a set of parameters and limitations the manufacturer warrants its instrument to achieve in the defined environment. So in terms of "quality" of capturing and processing signals, the specs actually tell you quite a lot about how a scope will perform. It's up to you to weight them against each other in regards to your specific use case.
What specs don't tell you of course is how well the scope is built, how cumbersome the UI is, how the decoders "feel" and stuff like that. But a lot of that is subjective anyways, and not something that can be stated in the specs.
That's why for any expensive test equipment purchase one should always try to get a loaner of the instruments that are considered for purchase.
I don't care that much about my microscope, but I rely on my oscilloscope to cover my own shortcomings as an engineer, so it's almost literally a part of me.
Not sure if it's shortcomings or just a bit of lack of self confidence
but I agree, a scope is one of the most important instruments for many EEs. Which is why doing the leg work and researching properly about all available alternatives before buying is important.
Parameters like record length aren't limited only by marketing considerations in the Agilent/Keysight scopes, the way they are in everyone else's. They are limited by the ASICs that they use to process and display data.
I know, and Keysight have painted themselves into a corner here, but at the end of the day their scopes compete on a market with other scopes, and in this day and age there are enough better alternatives on the market so they have to up their game by quite some margin to become competitive. But I guess they'll try to milk the "Tek or HP/Agilent/Keysight only" crowds for a while longer. If that works for them, fair enough.
The sample record is shorter in my MSO6000-series scope than it would be in an optioned-out Tek MDO, but the fact that I don't have to fiddle with it to get the display I want counts for a lot. Let's see, which button do I press now? Do I want a "fast acquisition" or a "long acquisition"? Gee, I dunno. How about you just show me the signal?
I agree, but that's not because of the longer memory but simply because the Tek's UI sucks. Other scopes manage memory automatically (which can be overridden by the user).
I guess you haven't had to use their high end scopes (i.e. the DSO90k) where some firmware versions suffered from jumping encoders, wrong indications (i.e. showing channels as set to GND when they weren't) and other silly things. Granted, these problems were have been fixed, but Agilent didn't exactly rush out to squash these bugs.
This is true. I've been lucky so far, in that I've been able to stick with the last generation of Agilent scopes to run VxWorks. The controls are responsive and reliable (if not the best-feeling.) Not many firmware bugs, either.
Yes, today. And that is only because they've seen a large number of firmware updates over the years to squash the many bugs these scopes came to market with. They weren't released in that state.
Don't get me wrong, I do like these VxWorks based scopes, once the major bugs were fixed they were great scopes at their time. I also liked the VxWorks based LeCroy WaveRunner2/WavePro 900 scopes, which could do a lot of advanced stuff that even today only few high end scopes can do.
But would I pay $7k (or whatever their original price was back then) for a new scope with the same specs today? Hell, no!
I don't look forward to "upgrading" to a scope running a heavyweight desktop OS...
I don't know, I really like Windows scopes. They take a bit longer to boot obviously but having access to analysis tools directly on your instrument is great, plus there are all the small benefits like not being limited to FAT formatted USB sticks (being able to use USB hard drives or exFAT formatted sticks and memory cards is nice).
Truly embedded OSes like VxWorks and such are great for low-end and entry-level scopes but for a modern upper mid-range or high-end scope I'd not want anything else than a full Windows scope.