Q: Construction of a 8.5 digit multimeter

[Harald Noack]

Hello!

Has someone of you experience how a high precision multimeter is constructed
?

e.g.: http://www.home.agilent.com/USeng/nav/-11250.536881781/pd.html

How is the voltage reference stabilized? (by using an oven?)

Are the input voltage divider temperature stabilized ? (temp. coeff.)

How is the self calibration done?

What type of ADC is used (maybe time to digital converter) ?

How is the integral and differential non-linearity measured and compensated
?



THANKS a lot for your help

Harald Noack

 

[Andrew Tweddle]

Harald Noack wrote:

Hello!

Has someone of you experience how a high precision multimeter is constructed
?

e.g.: http://www.home.agilent.com/USeng/nav/-11250.536881781/pd.html

How is the voltage reference stabilized? (by using an oven?)

Are the input voltage divider temperature stabilized ? (temp. coeff.)

How is the self calibration done?

What type of ADC is used (maybe time to digital converter) ?

How is the integral and differential non-linearity measured and compensated
?



THANKS a lot for your help

Harald Noack



If you peruse back through old copys of the HP Journal, there was an

article on the design of the HP3458A, which should answer your questions
in detail. Mine are packed away so I can't give you the date.

Hope this helps

Andrew

 

[CJT]

Harald Noack wrote:

Hello!

Has someone of you experience how a high precision multimeter is constructed
?

e.g.: http://www.home.agilent.com/USeng/nav/-11250.536881781/pd.html

How is the voltage reference stabilized? (by using an oven?)

Are the input voltage divider temperature stabilized ? (temp. coeff.)

How is the self calibration done?

What type of ADC is used (maybe time to digital converter) ?

How is the integral and differential non-linearity measured and compensated
?



THANKS a lot for your help

Harald Noack



Careful -- precision isn't worth much without accuracy, and you're going

to have a heck of a time calibrating to a commensurate accuracy.

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