Furthermore, an analog scope cannot measure better than 1% (ie 0ne part in 100 of what is on the scope face). Now one can "cheat" by using a precision offset differenced with an input and that difference amplified to *display* (part of) that difference: note the "Z", the "W", and the more modern "7A13" type plugins. But *on the screen*, i defy anyone to consistently "read" better than one part in 100 (ie if 10 divisions on screen, read to better than 1 division on a consistent basis. Thus, for a scope, one might use standards good to 5 or more places, but the result will be no better than what has been called "slide rule accuracy". Do you believe all 15 digits of each and every number in a computer printout?
Further more, if one did this procedure using thousands of meters to "calibrate" thousands of other meters, the net resulting error is *NOT* the sum; it is the square root of the sum of the squares! But taking only *one* reference ("standard") and using it to "calibrate" only one device, the result is technically indeterminate but may be bounded by the sum of the (instrument) errors - and could be
Thanks Jim. It's nice to read something that makes me feel like I still retain some semblance of sanity. That all seems completely reasonable, and you didn't even have to curse or make threats. ;-)
On Sun, 4 Mar 2007 04:23:21 -0600, "Anthony Fremont" Gave us:
You're an idiot. If I EVER wanted to be hidden, it would be no problem, you stupid fucktard.
EVERY nym I EVER chose always held like data, so there was never an intent to hide, you retarded f*ck!
It takes a true troll retard like you to act like you have some brains, and yet prove with every post that you are more disturbed than I could ever be.
On Sun, 4 Mar 2007 04:23:21 -0600, "Anthony Fremont" Gave us:
A calibration house would NOT use a 0.03% DMM to calibrate your scope with, you pathetic piece of shit!
What part of that proves that you are a brainless, pathetic piece of shit do you not understand?
Fuck you. I read the thread. It doesn't matter who the author is, and when it is you, you retarded f*ck, it becomes glaringly obvious due to your total stupidity. Just like the "E-1 grade tech" remark. You prove with your every post that it is you that is an incompetent bastard.
Fuck you. It is you that lacks the basic understanding that errors chain together.
Did I say they would? I said I would tweak it myself and that it would be good enough. Stay on track, you're here to prove why it won't work.
Is that an apology? Where are your scematics and submissions?
Show one post where I demonstrated that I don't understand that. You can't.
The problem here is that you read something and then, in your twisted little way, you interpret it as the poster is stupid and then you go off on some totaly different train of thought. Like Don Quixote you then procede to fight a battle against an illusion. You then begin to see every response as though it's calling you a liar, even if they are just trying to put you back on track. Many of your comments were valid, but they weren't germane to the discussion at that point, just like the one you just made here.
You make it sound like the OP was going to cal some critical lab equipment at home and that lives were at stake. Then you go on to tout calibrating your home theater by using a DVD/CD. And that's fine for home theater, but for lab quality work (like you constantly brag about, and compare everything to) considering the use of a signal from a CD is just F*CKING STUPID!!! 1Hz accuracy would be atrocious and you know that very well.
Now tell us why not? Exactly what kind of standard is required to adjust a scope's vertical response to 3% as it's specs state? And why wouldn't a .03% meter with traceable certs be good enough? I'm not saying it isn't, since I never even visited a cal lab, much less worked in one. I just want to hear your expert opinion on what is required.
You need to understand the concept of ACCEPTABLE ERROR, there is no perfection only "good enough". What is "good enough" is in the eye of the beholder, not yours.
"Anthony Fremont" wrote in news: snipped-for-privacy@news.supernews.com:
0.75% or better accuracy.(4X or better) (and that would be "adjust to within 3%". the actual result may be better than 3%;you just can't depend on it staying that way for any length of time.)
Thanks Jim, I feel like I finally heard something I could put some stock into. Just to set the record straight, would it be legitimate to "certify" a device to 3% (DUT specs) using a .03% accurate DMM that has an NIST cert? Really, it's just a matter of personal curiosity now.
"Anthony Fremont" wrote in news: snipped-for-privacy@news.supernews.com:
I'd be leery of that method because vertical gain check is generally done with a dynamic signal(calibrated sq.wave),to eliminate drift of your reference (ground) position.Like a TEK PG506.(I wish I had one.) IIRC,you used a DC source "transfer calibrated" with the DMM to check the vert.gain.So,literally,the DMM was the "standard" used as the reference,and that would be listed on the cert.,along with the DC supply. You just have to be careful to recheck the 0v reference trace position to be sure it didn't drift.
Gain is usually adjusted on one attenuator setting,and the other ranges checked to see that they are WITHIN the 3% tolerance,as the attenuators themselves are usually not adjustable for gain,unless it's a differential amp,like the 7A13.(don't know about scopes other than TEK.)
I don't think it's any use, after all MassiveProng didn't know that modern scopes still only have a few percent vertical accuracy, so obviously he's not quite up to speed on all this low precision stuff :-
Perhaps that nameless 4 channel 100MHz scope of his has some astonishing vertical accuracy?
2% ain't too bad in the scope world, didn't you know? - oh that's right, you didn't know! LMAO!
We are all still anxiously awaiting your link to a scope that does better than a percent or two on the vertical... What's the matter, your frantic Google search failed you? Come on, there has to be at least one out there surely, try harder...
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.