[volt-nuts] 3458A calibration

[Bruce Griffiths]

For the 3458A integrator feedback capacitor nonlinearity isnt an issue
(as long as there is no hysteresis) as it cancels out during the rundown
phase.
For DVMs like the 34401A which use an ADC to sample the integrator
output integrator feedback capacitor nonlinearity is important.

Bruce

J. Forster wrote:
> Keeping the voltage across the integrating capacitor (0 is a special case
> of constant) is a good idea because it solves the problem of dC/dV
> (voltage coefficient of capacitance).
>
> -John
>
> ============
>
>
>   
>>> The effect of dielectric absorption can be minimised by
>>> ensuring that the average voltage across the integrator feedback
>>> capacitor remains low over the integration cycle.
>>> HP/Agilent have several patents covering this aspect of DVM
>>> integrator runup cycles.
>>>       
>> Are you referring to what HP calls their "charge-balancing" A/D converter
>> where during the run-up phase of the conversion they attempt to keep the
>> output of the integrator balanced around 0 volts?
>>     
> [snip]
>
>
>