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Oscilloscopes For Modern Engineers?
Every few years someone asks this community for advice on oscilloscopes. Reader dawning writes "I've just graduated with a degree in Computer Engineering (and did a Comp Sci one while I was at it) and I'm finding myself woefully under-equipped to do some great hardware projects. I'm in major need of a good oscilloscope. I'm willing to put down $2,000 for a decent one, but there are several options and they all seem so archaic and limited. I'm happy to use something that must be controlled through a PC if that gives me more measuring features. What would you, my esteemed Slashdot colleagues, get for yourself?"
I use an R7704 at home, and a 7633 at the office.
The determined Real Programmer can write Fortran programs in any language.
Or you can get a $370 Rigol DS1052E, and software-hack it to enable 100MHz mode. Not quite as good as a Tek, but significantly cheaper and well worth the money, especially if you're on a smaller budget. I recently got one (it's about time I bought a scope) and I've been quite happy with it for my purposes.
Info on the hack here.
Not really.
If they need it accurate and traceable they'd have to pay a lab to calibrate it after it was fixed. Such a lab would reject it due to it being fixed (and charge a pretty penny with no calibrated scope at the end of the process.) So they're stuck.
(This reminds me of a story my wife tells about a lab PC that had a bad case of infant mortality. The local techs wanted to fix it themselves. She pointed out it was still in warranty - so the thing to do was send it back for fix-or-replace for free, rather than void the warranty and maybe end up with a broken machine and nothing (but wasted engineer time) to show for it.
Fixing a scope adequately for home use is another matter. Then, if you ever need serious accuracy, you can do the same sort of compensation hacks that were done back in the tube days, when stuff drifted all the time and you couldn't just have a lab tune up anything complicated and expect it to stay tuned.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
I have a very nice, for me, rackmount 350MHz 4 channel Tek scope with some very killer plugins.
The scopes I used at work today are really beyond anything needed for home use, unless you're into some extremely expensive hobbies.
The portable scope is a 3054B; 500MHz x4 channels. (~$10k, with options) The good one is an 11GHz x2ch Lecroy ($ almost 6 digits), I made picosecond-order measurements with it today.
The differential probe was $5k each; (wasn't that what gov. spitzer paid? lol.) our newb has killed two. (4Vmax) $2k each to fix.
If you can afford it for home use, I'd recommend the Tek 3054 or a lower bandwidth cousin. They're very easy to use.
If you can get surplus scopes coming out of downsized companies, you can get a deal; that's how I got my rackmount and a stack of plugins for $130. It was a production fixture at a missle plant in the 90s. :)
Digital is great, as long as you realize the limitations; digital displays lie sometimes. If you're going to base a paper on it, use multiple measurements with different equipment. :) I've seen fresh engineers embarrassed by artifacts.
Truth isn't Truth - Guliani
Yeah, but the 'scope is a dedicated application with dedicated front panel controls. Windows is merely a widget provider. I've used them, and they're very nice as they support modern hardware and printouts/screenshots are a breeze. But you have to buy the ones with the full front panels - the ones that are just PCs are just... useless and you spend way too much time mousing around clicking virtual knobs. Painful.
$2k can get you a nice basic scope. That's all you need. For the rare times you need something fancy, there are many places that'll rent you the high end scopes for days or weeks. Sure you're paying a good chunk of money for someone else's loan, but unless you can ante up the $10-100K+ for those things, it's far more economical. Get what you can (surely you should be able to find a nice 500MHz scope used?) with what you have to do most of the debugging. When it comes time to debug that obscure thing, rent it.
This way you'll get a good scope for normal use, rent a oh-so-beautiful GHz level scope when you need it or even the fancy-smancy "analog digital" combined scope plus logic analyzer. Those let you analyze bus signals in standard 0's and 1's, while seeing actual signals at the same time. Plus, they can capture the analog signals with the digital, so you can trigger on some oddball logic condition on the bus and see any odd analog waveforms at the same time. But those are expensive - your best bet is renting until you can afford to buy one 10+ years from now.
And if your scope only collects dust instead of signal, you've avoided wasting a pile of money.