The HP 8082 uses ECL you can't get no mo, and looks like a PITA to repair:
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Far as I can tell its slower smaller cousin the 8012a is all discrete-on-card though, yeah? It looks that way from the service manual but I haven't checked every thing.
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A 5ns rise time is still useful for a number of jobs, and I can get a dodgy unit for next to nothing locally. I figure if I use it once a year it might be worth trying to fix up if it doesn't require exotic parts.
I generally use my P400 for that. Of course it's all synchronous to a single T0 channel, so it's completely useless for building the asynchronous chain-of-monostable hairballs so beloved of grad students of yore. ;)
I have an HP 8013B, which more or less works but is nothing special.
I should add that one proposal for our snazzy new time stretcher APD array chip was to use a 64 x 64 array of linear-mode APDs, with 25 T/Hs each, with the track-holds timed using a half-monostable each.
IOW, as I pointed out, our chip would have had _over a hundred thousand one-shots_ doing the timing. (O tempora! O mores!)
It's a lovely scope but a few other items are going to take priority this spring (cleaning) like an Agilent or similar multi-output PSU, bench DMM, and LCR meter/impedance analyzer-thing (not quite sure what to pick there and am open to suggestions), I've solidly outgrown my hand-held DMMs and China-special bench PSUs.
But a 8012a in unknown condition for $25 sure is tempting.
My girlfriend picked me up a nice present while she was looking for thrift store clothing bargains, a 1987 hardbound HP product lineup guide in mint condition, $3.99. Odd thing to find at a thrift store maybe but this is the heart of what used to be DEC & Wang etc. country near Rte
128, maybe someone was cleaning out their closet also.
You can often pick up used kit from local tech firms, universities (excellent source of kit as they often dump everything they purchased for a GRANT project when the grant is over), etc. Some firms just contract disposal of their kit to a firm; others sell at auction (which may or may not be "public"). Knowing folks at these places is a great way to get the inside track...
Yeah, I rescued an HP 3458A many years ago. After the initial "pride of rescueship" (v "ownership") wore off, I realized it was just an oversized
*4* digit DVM given that I never needed more accuracy/precision than that! And, surely wasn't going to PAY to have it calibrated to 8+ digits!
(here, bench space is far more precious than quality of kit!)
Do it with ECLinPs which is still around, and a whole lot faster than the old ECL which has now gone obsolescent.
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is a nice part - the delay is programable up to 10nsec in roughly 10psec increments, but the actual delay is temperature dependent.
My solution to the problem (back around 1998) was to measure all the delays every ten minutes of so - I'd worked out a scheme for doing it in a few milliseconds - but the project got binned before we could turn it into working hardware. Not because it wouldn't have worked, but because the customer got his grant money cut off.
Regular applications would probably have to ping-pong between two output stages and recalibrate one while the other one was serving the customer, but an ingenious designer like John Larkin should be able to come up with something even better.
There is a re-seller like that near me with several dozen "tested"
3478As bench DMMs available for $150 per (better test the AC section though as it uses an unobtaninum part) and another place will calibrate it for $50.
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I think I'll pick up a couple I used them in college & they're still nice meters.
Going off BW * tr = 0.34 as the fastest edge a DSO can even assign a sample to, much less measure the rise time of accurately, I figure a 100 MHz scope is too sluggish to calibrate a 5ns pulser on its fastest setting. /shrug
Resellers increase the price but usually don't add much "value". You want to find the guy *he* buys from (usually someone at ABC Tech Corporation).
Most of the products I've designed have intentionally NOT required close tolerances on anything. That adds cost -- in parts or calibration labor. So, we design products that rely on other means to make sense of their observations (ratiometric or other "self calibration" tricks).
[It's not uncommon to have manufacturing tolerances of -60%, +300%. Easy to accommodate if you are smart about it.]
There are precise parts around, and some that can be made very precise with nothing more than careful assembly.
The Thompson-Lampard calculable capacitor is the poster-child for that approach.
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It's usually used with a laser interferometer to get the length exactly right.
At a more mundane level, a ratio transformer can be wound by hand to give 0.1ppm ratio accuracy. A 1:1 bifilar wound inductive divider can be accurate to one part per billion.
I've not seen anybody use Litz wire to make a ratio transformer, which would probably work better than the merely twisted bundles of wire use in regular ration transformers.
It's never all that easy to get rid of all the potential errors, and it's lot safer to just buy precise parts when you can.
Lots of things don't need to be qualified in "engineering units".
How do you test that the *hammer* you are building, today, is as good as the hammers you've built in the past? Or, a screwdriver? Just how "durable" should the finish on a tape rule be?
[who, besides the manufacturer, would know how to interpret those data? What units? How to evaluate relative to other vendors' products?]
How do you verify that the (pharmaceutical) tablet that you produced NOW is as good as the one you produced 5 milliseconds earlier?
[Does the consumer care if a particular batch of tablets have a friability of 1.2%? Or, variations of hardness on the order of 2KP? Or, a dissolution time that varies by 4% in a particular sample of tablets?]
In many cases, you rely on some other (external) determinant of "acceptable quality" and the goal is just to ensure repeatability of process. E.g., those "good" tablets were produced with 4.5 bogounits of force exerted during the compression phase; make sure all of them experience a similar force. Or, a sample of those hammers struck the test anvil 1825 times, on average, before the handle snapped; the competitor's hammers broke at 1615 strikes, on average. Etc.
Statistical Process Control becomes more important than traditional control theory (use a conventional control loop and wrap SPC around that)
If it contains the same amount of the specific chemical compound that constitutes it active ingredient, it is pretty much certain to be just as good.
As long as the active dose gets into their body, they couldn't care less.
Nobody could care less how tightly squeezed the tablets were as long as they dissolved in the right bit of the digestive system.
The time it takes to break the handle of a hammer is worth worrying about, but it shouldn't ever break at all.
No amount of statistical process control can compensate fro somebody who won't think about what they are measuring, and why it matters. You just scored a massive fail on that.
Another NOLA story: we'd send drawings out to machine shops and get stuff that didn't fit. They responded that we should send them drawings with tolerances, and circle some in red with the note HOLD.
Life's too short to worry about the small stuff, I guess.
The Silicon Bayou and similar plans never seemed to work out. That's one reason why I left.
The 0.34 is a relic of the past, when scopes were gaussian. Most scopes these days are peaked to meet their bandwidth claim, so even if they do make their -3 dB spec they ring like bells.
If a scope is an honest 100 MHz, with a 3.5 ns Trr, it should be OK to measure a 5 ns edge; just math it.
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