[time-nuts] 53230A TIC and TimeLab

Ole Petter Ronningen opronningen at gmail.com
Thu Oct 4 05:21:53 EDT 2018


On Thu, Oct 4, 2018 at 11:00 AM Magnus Danielson <magnus at rubidium.dyndns.org>
wrote:

> Regardless, the 53230A does a filtered frequency estimation, which is
> great for achieving high precision frequency measures quickly, but not
> good for ADEV measures, as it introduces a bias due to the lower
> bandwidth of the filtering as compared to the sampling interval.
> Dead-time gaps biases also comes in.
>

True - but be aware that the *first sample* returned from the instrument,
when fetched using "READ", will also be biased in an absolute sense - the
frequency reported will systematically be too high or too low (the
magnitude and direction of the error depending primarily on gate time, from
what I've seen).

So even when using this mode to only look at high resolution "absolute
frequency measurements", it is easy to get bitten if the data is collected
using a computer.

BR,
Ole


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