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Author Topic: 50Khz to 1Ghz Oscilloscope Calibrator  (Read 5256 times)

Offline silv3rstr3

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Re: 50Khz to 1Ghz Oscilloscope Calibrator
« Reply #15 on: 04-20-2018 -- 14:16:46 »
You definitely can use the normal calibrator outputs for doing gain and offset.  Keep in mind not everyone works in a A2LA accredited lab.  And a lot of companies that are don't even follow A2LA guidelines.  At a previous lab I worked in they made everyone list the best case scenario off the scope of accreditation.  Even when most of the time you weren't even using the specific standard listed on it.  I knew it was wrong but all they cared about is increasing the amount of money billed by the lab each month. 

I run the majority of our oscilloscope calibrations here in Met/Cal using the 9500+9530 heads.  When looking at the calibration data there isn't any TAR's < 4:1.  I'm not seeing an issue with using any of the standards we have been talking about.  Unfortunately my current employer is starting to push to get all our labs 17025 accredited.  I can foresee headaches in the future.... 
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Offline griff61

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Re: 50Khz to 1Ghz Oscilloscope Calibrator
« Reply #16 on: 04-20-2018 -- 14:29:54 »
The DC Output of the Fluke 5522A's scope output is not in the ppm range like the normal output. 
50 Ohms is -- 0.25% + 40 uV
1M Ohm is -- 0.05% +40 uV

Why would you use the scope output to perform a DC check?
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Offline silv3rstr3

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Re: 50Khz to 1Ghz Oscilloscope Calibrator
« Reply #17 on: 04-20-2018 -- 14:41:56 »
The Met/Cal procedure does those checks with the scope output like the 9500 does it straight through the active head. 
“They are in front of us, behind us, and we are flanked on both sides by an enemy that out numbers us 29:1. They can’t get away from us now!!”
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Offline CalLabSolutions

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Re: 50Khz to 1Ghz Oscilloscope Calibrator
« Reply #18 on: 04-20-2018 -- 16:15:17 »
The DC Output of the Fluke 5522A's scope output is not in the ppm range like the normal output. 
50 Ohms is -- 0.25% + 40 uV
1M Ohm is -- 0.05% +40 uV

Why would you use the scope output to perform a DC check?

Because the Normal output on the 5520A is noisy.
Connect it to a scope.  Turn the averaging on the scope off.  And you will see what I am talking about.

Mike!
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Offline silv3rstr3

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Re: 50Khz to 1Ghz Oscilloscope Calibrator
« Reply #19 on: 04-20-2018 -- 17:26:41 »
Explains why military procedures tell you to set the averaging to a sufficient number of samples.  I've never had an issue using these standards for calibrating oscilloscopes.
“They are in front of us, behind us, and we are flanked on both sides by an enemy that out numbers us 29:1. They can’t get away from us now!!”
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Offline griff61

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Re: 50Khz to 1Ghz Oscilloscope Calibrator
« Reply #20 on: 04-20-2018 -- 20:49:59 »
Because the Normal output on the 5520A is noisy.
Connect it to a scope.  Turn the averaging on the scope off.  And you will see what I am talking about.

Mike!

I've never seen noisy DC on a 5500 series that I have used since 2000 when I started in commercial cal after the Army.
Of course, you could just leave the averaging on, on your noisy one, but I would investigate what malfunction is occurring in your equipment.
Or just use a 57xx?
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Offline CalLabSolutions

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Re: 50Khz to 1Ghz Oscilloscope Calibrator
« Reply #21 on: 04-21-2018 -- 04:05:25 »
It's not a malfunction.  All of them do it.  It's like a chirp, if you play with the trigger and set the scope to wait for the trigger you can capture the signal.
Note... I haven't checked the 5522A.
And the Fluke 57xx as I know don't have this issue.

Mike
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Offline griff61

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Re: 50Khz to 1Ghz Oscilloscope Calibrator
« Reply #22 on: 04-21-2018 -- 05:06:20 »
It's not a malfunction.  All of them do it.  It's like a chirp, if you play with the trigger and set the scope to wait for the trigger you can capture the signal.
Note... I haven't checked the 5522A.
And the Fluke 57xx as I know don't have this issue.

Mike

Again, my 5520 doesn't do that nor did my 5500 at Goodrich, or the ones at National, Simco and Sypris. I would call it a malfunction and have a talk with Fluke.
But I am getting 5522As, that's what I recommended.
It must be one helluva "chirp" to change the normal DC into something worse than .25%
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Offline CalLabSolutions

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Re: 50Khz to 1Ghz Oscilloscope Calibrator
« Reply #23 on: 04-22-2018 -- 01:48:23 »
Griff,
When you write automation software, you leave an audit trail.  When there is a problem with a test, I have to figure out why.  Is it software or is it hardware.  I know a ton of little issues with equipment.

If you look at the 55xx's out with anything that averages the voltage you will not see it.  If you connect the Normal DC voltage out to a scope set to no averaging, no free run and set the trigger level just about or below the voltage you will see a small chip.

If I have time the next couple of weeks I will try to grab a scope and a calibrator and give you guys some specific settings!

Mike
Michael L. Schwartz
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Offline DaveRodda

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Re: 50Khz to 1Ghz Oscilloscope Calibrator
« Reply #24 on: 11-21-2018 -- 18:38:26 »
Hello...If you convert the dB leveling error to linearity then compare the TARs you will see it is more than accurate enough that you don't need a power meter.The Keysight MXG's are pretty impressive.  We have sold a couple to some of our customers to support the Tektronix MDO-3000 and MDO-4000 Scope / Spectrum Analyzers.

pcb assembly process
« Last Edit: 11-28-2018 -- 23:01:37 by DaveRodda »

Offline CalLabSolutions

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Re: 50Khz to 1Ghz Oscilloscope Calibrator
« Reply #25 on: 11-22-2018 -- 15:47:05 »
I am going to add to DaveRodda's comment and say those older HP 8648A/B/C/D can also do the test without the Power Meter.
Michael L. Schwartz
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