Elsmar Cove Forum Header Graphic The Elsmar Cove Wiki Sitemap More Free Files The Elsmar Cove Forums Discussion Thread Index Post Attachments Listing Failure Modes Services and Solutions to Problems Elsmar Cove Forums Main Page Elsmar Cove Home Page
NQA-USA
NQA-USA
Miner's MSA (Measurement Systems Analysis) Blog 
Go Back   The Elsmar Cove Forum > ISO (International Organization for Standardization) Standards > ISO 17025 - General Metrology, Measurement Device, Calibration and Test Laboratories > Measurement Uncertainty (MU)
Forum Username

Wooden Line

Oscilloscope Measurement Uncertainties - MU Components for Vertical Deflection

Search the Elsmar Cove
Search Elsmar
Monitor the Elsmar Forum
Follow Marc & Elsmar
Elsmar Cove Forum RSS Feed  Marc Smith's Google+ Page  Marc Smith's Linked In Page   Marc Smith's Elsmar Cove YouTube Page  Marc Smith's Facebook Page  Elsmar Cove Twitter Feed
Elsmar Cove Groups
Elsmar Cove Google+ Group  Elsmar Cove LinkedIn Group  Elsmar Cove Facebook Group
Donate and $ Contributor Forum Access
Courtesy Quick Links

Links that Elsmar Cove visitors will find useful in your quest for knowledge:

Howard's
International Quality Services
Marcelo Antunes'
SQR Consulting
Bob Doering's
Correct SPC - Precision Machining

NIST's Engineering Statistics Handbook
IRCA - International Register of Certified Auditors
SAE - Society of Automotive Engineers
Quality Digest Portal
IEST - Institute of Environmental Sciences and Technology
ASQ - American Society for Quality

Related Topic Tags
measurement uncertainty (mu), oscilloscopes, calibration (general topics)
Reply
 
Thread Tools Search this Thread Rate Thread Content Display Modes
  Post Number #1  
Old 18th May 2011, 12:59 AM
EMacP

 
 
Total Posts: 14
Please Help! Oscilloscope Measurement Uncertainties - MU Components for Vertical Deflection

Hi All,

Very urgent. Need your response. Currently my MU components for vertical deflection are type a and type b consists of upper and lower cursor, master std. However I think i missed out one more that is the minor division. However, how can i determine the value? Is there a specific formula? Please help me...

Sponsored Links
  Post Number #2  
Old 19th May 2011, 07:25 AM
Stijloor's Avatar
Stijloor

 
 
Total Posts: 14,703
Re: Oscilloscope Measurement Uncertainties - MU Components for Vertical Deflection

Quote:
In Reply to Parent Post by EMacP View Post

Hi All,

Very urgent. Need your response. Currently my MU components for vertical deflection are type a and type b consists of upper and lower cursor, master std. However I think i missed out one more that is the minor division. However, how can i determine the value? Is there a specific formula? Please help me...
Any Calibration/MU experts that can help?

Thank you!!

Stijloor.
Sponsored Links

  Post Number #3  
Old 20th May 2011, 04:29 AM
Hershal's Avatar
Hershal

 
 
Total Posts: 2,391
Re: Oscilloscope Measurement Uncertainties - MU Components for Vertical Deflection

Oscilloscopes have unique uncertainties. Based on the description, I presume you are discussing a digitizer which has some uncertainties the same and some different than analog scopes.

Digitizer: First and most obvious is the trace width. That will affect the measurement just a little, even if you use the cursors. There is also parallax, which in truth is included with the trace width in a digitizer. Trace width is a rectangular distribution.

Calibration of the cursors is a huge help, but you have to take the uncertainty there as a normal distribution.

Applicable to both digital and analog:

Minor division is not a huge influence, but being between minor divisions is as that cannot really be accurately eyeballed. So take the minor division as the value with rectangular distribution, if you experience that.

Also, different input impedance may have an effect. For example, 50 Ohm, 600 Ohm, 1 MOhm.

If you are near the upper end on your bandwidth (BW) then there could be additional losses. For example, if you use a 50 Ohm coax above 400 MHz.

Watch rise time. The formula is .35 over T rise equals BW, or .35 over BW equals T rise. However, the ratio is not always perfect. Check both BW and T rise, then calculate to make sure you get the same results.

Analog: Hard to get any real reading under 2% due to trace, stability, bandwidth, and so forth, so just use an uncertainty value of 0.5% of reading and you should be OK.

Hope this helps.
  Post Number #4  
Old 22nd May 2011, 12:23 AM
EMacP

 
 
Total Posts: 14
Re: Oscilloscope Measurement Uncertainties - MU Components for Vertical Deflection

Hi Hershal,

I understand your reply. for your information the MU components involving Vertical deflection is as follow:

1. Type A
2. Lower and Upper cursor
3. Lower and Upper Parralax error
4. Specs/Uncertainties of standard use.
5. Vertical resolution ---- this is the one I am stuck with.

I will explain a little further, currently the digital scope is an 8-bit scope. This mean that there is 2^8= 256 steps level for the scope to sample. Let assume I set my scope at 1V/div and I am setting my source for a 6div=6V. My problem now is how to convert this to uncertainty? Any formulae???

So whoever has any idea, please assist me.
Reply

Lower Navigation Bar
Go Back   The Elsmar Cove Forum > ISO (International Organization for Standardization) Standards > ISO 17025 - General Metrology, Measurement Device, Calibration and Test Laboratories > Measurement Uncertainty (MU)

Do you find this discussion thread helpful and informational?


Bookmarks


Visitors Currently Viewing this Thread: 1 (0 Registered Visitors (Members) and 1 Unregistered Guest Visitors)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Forum Search
Display Modes Rate Thread Content
Rate Thread Content:

Forum Posting Settings
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Similar Discussion Threads
Discussion Thread Title Thread Starter Forum Replies Last Post or Poll Vote
Wavetek 9100 - Measurement Failure in Oscilloscope Section. Need Help & Advice. izmirli Measurement Uncertainty (MU) 5 28th September 2012 05:24 AM
Gage R&R on the Center Deflection of Composite Tubes dsrsdr Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 5 30th October 2011 10:17 PM
Do we still need to Calculate Measurement Uncertainties (MU)? amanbhai Measurement Uncertainty (MU) 6 3rd August 2007 09:40 AM
Temperature Measurement Uncertainties - Verify a PRT at 0C specified 0.02C celon ISO 17025 and related Metrology Topics - Measurement Devices, Calibration and Test Laboratories 4 12th November 2004 01:06 AM
Micrometer Uncertainty - Best Measurement Uncertainties for O.D. Micrometers Dave N ISO 17025 and related Metrology Topics - Measurement Devices, Calibration and Test Laboratories 2 8th January 2003 11:52 AM



The time now is 01:41 PM. All times are GMT -4.
Your time zone can be changed in your UserCP --> Options.


   


Marc Timothy Smith - Elsmar.com
8466 LeSourdsville-West Chester Road, Olde West Chester, Ohio 45069-1929
513 341-6272
NOTE: This forum uses "cookies".