[volt-nuts] The 3458A A/D

[John Phillips]

The other reason the price is so high is that the cost of entry for a
competitor to develop and sell a comparable unit for such low sales volume
would also cost that much if not more. The Fluke 8508 does cost more but it
is a 3458A "under the hood".


On Mon, Jan 20, 2014 at 3:09 PM, Frank Stellmach <frank.stellmach at freenet.de
> wrote:

> "3. The 3458A still has got the best linear A/D, around 0.02ppm of input."
>>>
>>
>  Is that a typo? Even 0.2 ppm would seem extremely good. I think I saw an
>> official number of 0.1ppm somewhere. Probably 0.1ppm of range. And how do
>> they implement that? Manual trimming and compensation?
>>
>
> Hello Jan,
>
> well DNL, INL, sometimes I still struggle with those terms..
>
> Those 0.02ppm were nonlinearity of input, measured with a JJ array.
> And they use a special multiple slope scheme, with glitch compensation for
> the switching FETs.
>
> Just download the April 1989 HP Journal, there's everything explained in
> detail.
>
> http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1989-04.pdf
>
>
> Frank
>
>
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-- 
John Phillips