Oscilloscope Calibration, Terms and Definitions

B

blueicecube

#1
Hi,

I am new here. And I found the information posted here has been really helpful.

I am writing a procedure on how to calibrate oscilloscope. However, due to my limited experience with osci. I realized there are too may variations of osci. in the market and the terminologies used are quite different.

Please help with the following questions :

1. What is the difference between the term frequency response and
bandwidth in term of testing/calibration oscilloscopes?

Some UUT manuals refer to the term as frequency response, whereas some
call it bandwidth. Is it the same thing? While the standard reference
manual call it frequency response.

2. What does it mean by pulse, rise time, trigger sensitivity? Do they
necessarily means the same thing?

I highly appreciate any helps or reference on this matter.

Thank you,
Nadhra
 
Elsmar Forum Sponsor

Jerry Eldred

Forum Moderator
Super Moderator
#3
Hi Nadhra,

First, I should mention that I visited Malaysia for a week a few years ago (Petaling Jaya and Penang). I stayed at the Sunway Lagoon which was a beautiful hotel. I am looking forward to some day having enough money to return. I visited Malacca and Batu Cave as well as touring KLM.

Enough off topic. See my answers below each question.

1. What is the difference between the term frequency response and
bandwidth in term of testing/calibration oscilloscopes?
-They are the same. Bandwidth is the highest frequency where the amplitude response of the oscilloscope degrades by <=-3 dB. It is very common in procedures to produce a 6 v deflection at a base frequency and check the upper bandwidth limit with a >=4.2 division deflection.

Some UUT manuals refer to the term as frequency response, whereas some
call it bandwidth. Is it the same thing? While the standard reference
manual call it frequency response.
- See answer above.

ALSO ---- FREQUENCY RESPONSE also includes a measure within the Bandwidth (when it is truly measured).

2. What does it mean by pulse, rise time, trigger sensitivity? Do they
necessarily means the same thing?
- Rise Time is ALMOST the same as bandwidth. Bandwidth refers to the highest frequency that the oscilloscope can accurately reproduce voltage transition. Risetime is a measurement of the 10% to 90% on the leading edge of a square or pulse wave. The formula to convert between risetime and bandwidth is BANDWIDTH = .35/RISETIME or RISETIME = .35 / BANDWIDTH.

Risetime is the method used by some to measure bandwidth. That is because a square wave is a fundamental frequency plus all of its odd order harmonics. The risetime of that square wave represents a measure of the highest odd order harmonic on that square wave (kind of a measure of the bandwidth of a square wave).

The main difference between risetime and bandwidth (frequency response) is risetime does not account for all the frequencies between the bottom and highest frequency. That is why when using risetime, overshoot and ringing are also measured (which account for the variation in response within a bandwidth).

If you want to write a generic procedure to measure bandwidth, be sure to include frequency response within the bandwidth.

This may be a little confusing, but I hope it helps.
 
B

blueicecube

#5
Thanks Harry,Jerry & Hershal,

This will take me awhile to go through on top of my current work

Looking at the references given, it shows that its more fortunate for me to be in the US to solve this problem rather than here. For instances, access to GIDEP would solve soo much problems, but I am not involved with supplying anything to the US government. We are merely a local company here in Malaysia.

As for NCSLI, I went to SIRIM (so-called malaysia standard industrial research), but they said anything related to American standard are unavailable for reference.

My background is in Mechanical Engineering. I went to school at the Gopher/Timberwolves/Twins-state (guess where). Hence, electronic is a bit fuzzy for me.

Alas, thank you for your help and I hope you won't be bored to read my postings for more questions.
 
B

blueicecube

#6
Sorry about the post. Somehow my browser hang on an empty page while waiting for posting...
 
Last edited by a moderator:
B

blueicecube

#7
Another question : why does some manufacturer's calibrate the bandwidth/frequency response of an oscilloscope with an input of dB & freq, while some with input of voltage & frequency?

or are they solely dependent on which value is used by the manufacturer to judge whether the instrument is within specification and not?

would interchanging that have any effect on the result of the measurement?
 

Jerry Eldred

Forum Moderator
Super Moderator
#8
The difference between measuring bandwidth with dB versus Volts peak to peak is just units. If you substitute units, be sure to do calculations and test per correct tolerance.
 
B

blueicecube

#9
One more question :

The termination of 50 Ohm of 1 Mega Ohm used at the oscilloscopes, does it depend on the range of measurement/calibration or does it depend strictly on the manufacturer's specification?

One of Agilent's oscilloscope manual specifically mention 50 Ohm for 100 Mhz to 500 Mhz scopes. However, on a Philips-Fluke actual oscilloscope [can't find the manual], its written 1 Mega Ohm.

What will happen if I do not have 1 Mega Ohm termination and replace it with a 50 Ohm? Will I be able to compensate the measured value in any ways (i.e when measuring the voltage peak to peak values etc).

Thanks!
 
Thread starter Similar threads Forum Replies Date
B Oscilloscope - AC gain calibration General Measurement Device and Calibration Topics 6
Ajit Basrur Should calibration range of Oscilloscope cover the test ranges? General Measurement Device and Calibration Topics 8
S MU (Measurement Uncertainty) for Oscilloscope Calibration Measurement Uncertainty (MU) 2
N CMC for Oscilloscope Other ISO and International Standards and European Regulations 2
E Oscilloscope Measurement Uncertainties - MU Components for Vertical Deflection Measurement Uncertainty (MU) 3
I Wavetek 9100 - Measurement Failure in Oscilloscope Section. Need Help & Advice. Measurement Uncertainty (MU) 5
T Eqpt needed to Calibrate Oscilloscope, Multimeter, voltage tester, Torque analizer General Measurement Device and Calibration Topics 1
B Oscilloscope Gage R&R - Laboratory Devices Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
lanley liao Question regarding the calibration of monitoring and measure equipment. Oil and Gas Industry Standards and Regulations 0
N IATF Calibration Lean in Manufacturing and Service Industries 3
Q Do these certificates of calibration meet ISO 9001 requirements for traceability to NIST? ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 10
T Plug Gage Calibration Calibration and Metrology Software and Hardware 1
M Load Cell Calibration using a totalizer on a flow meter General Measurement Device and Calibration Topics 0
E Calibration Records needed ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 1
D Limited Range Calibration - 5000 lb Industrial floor scale General Measurement Device and Calibration Topics 3
D Calibration of Small Scales General Measurement Device and Calibration Topics 26
C How to Establish the Calibration & Measurement Capability (CMC)? ISO 17025 related Discussions 1
I IQOQ or just initial calibration required? General Measurement Device and Calibration Topics 3
B Calibration in real life ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 3
J Calibration cycle for monitoring & measuring tools used in medical device manufacturing General Measurement Device and Calibration Topics 5
A Is calibration of test weight required General Measurement Device and Calibration Topics 4
S Calibration Frequency for Slip Gauge Kit used for CMM Calibration? General Measurement Device and Calibration Topics 0
S Calibration/Verification of customer fixtures IATF 16949 - Automotive Quality Systems Standard 6
Ron Rompen Calibration by manufacturer ISO 17025 related Discussions 4
Q Calibration verification records 7.1.5.2.1 IATF 16949 - Automotive Quality Systems Standard 2
B AS9100D 7.1.5.2 Calibration or Verification Method using outside cal lab AS9100, IAQG, NADCAP and Aerospace related Standards and Requirements 1
W Next Calibration Due Date Calibration Frequency (Interval) 5
S Where do l get calibration standards to run a calibration lab? Other ISO and International Standards and European Regulations 2
A OEM On-Site Calibration issues during Covid19 ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 12
D Calibration tolerance question using Pipettes Medical Device and FDA Regulations and Standards News 1
M Calibration Certificate Result issued by an accredited external laboratory General Measurement Device and Calibration Topics 9
G Calibration of "Master Parts" Used as Gauges Calibration Frequency (Interval) 5
R Calibration lab environmental monitoring General Measurement Device and Calibration Topics 4
G Calibration of Rotronic probe but not digital readout? General Measurement Device and Calibration Topics 3
F Standard Calibration Procedures: Recommended Practice ISO 17025 related Discussions 0
T Temperature Requirements For In House Calibration - AS9100 AS9100, IAQG, NADCAP and Aerospace related Standards and Requirements 16
B Gage calibration frequency, ISO and IATF - What are the requirements Calibration Frequency (Interval) 3
Crimpshrine13 Laboratory Scope - Calibration vs. Test Methods - IATF 16949 IATF 16949 - Automotive Quality Systems Standard 3
Crimpshrine13 Calibration of pH Meter Probe Calibration and Metrology Software and Hardware 3
F ESD workbench "calibration" Manufacturing and Related Processes 2
C Correct Calibration Method for Dial Depth Gage General Measurement Device and Calibration Topics 6
F Nist traceable calibration certificates General Measurement Device and Calibration Topics 1
G Tool tracebility and First calibration requirements for aerospace (AS9100) organisation AS9100, IAQG, NADCAP and Aerospace related Standards and Requirements 5
D Calibration of Digital thermometer with surface probe General Measurement Device and Calibration Topics 1
T Calibration or Verification -> Cm and Cmk, etc. Definitions, Acronyms, Abbreviations and Interpretations Listed Alphabetically 3
G Is repeatability required for equipment calibration? General Measurement Device and Calibration Topics 10
was named killer AS 9100D - Calibration Instructions - Controlled documents? AS9100, IAQG, NADCAP and Aerospace related Standards and Requirements 6
B Photovoltaic Tester Calibration General Measurement Device and Calibration Topics 0
B Temperature loop: partial calibration General Measurement Device and Calibration Topics 10
G Glass scale calibration at 74 degrees F? General Measurement Device and Calibration Topics 4

Similar threads

Top Bottom