Hi
Probably also worth mentioning:
For short tau, you are probably measuring the ADEV of the counter noise floor
rather than the
ADEV of the GPSDO. Yes, there are noisy GPSDO’s out there but most of what you
run into
is not in that category.
Bob
> On Oct 4, 2018, at 8:42 AM, Ole Petter
On Thu, Oct 4, 2018 at 1:40 PM Magnus Danielson
wrote:
> Who-oh! OK. This means that one should intentionally let a number of
> samples pass before trusting it.
>
Precisely. But, crucially, discard 1-2 samples *since the last INIT* -
which may not be obvious without some investigation. It is a
Hej Ole!
On 10/4/18 11:21 AM, Ole Petter Ronningen wrote:
> On Thu, Oct 4, 2018 at 11:00 AM Magnus Danielson
> 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,
On Thu, Oct 4, 2018 at 11:00 AM Magnus Danielson
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
Somewhat longer answer; I assume you have set up a frequency measurement
(as opposed to time interval)
1. Timelab uses SCPI-command "READ" to fetch readings from the 53230a (and
most other counters *). The 53230a does not return gap free frequency
measurements in this case. There will be deadtime
You may want to have a look at http://www.efos3.com/53230A/HPAK53230A-1.html
Ole
> 4. okt. 2018 kl. 04:04 skrev AC0XU (Jim) :
>
> I have recently acquited a 53230A counter and have tried to measure ADEV of a
> GPSDO with it. I am suspicious of the ADEV numbers reported by TimeLab V1.31
>
I have recently acquited a 53230A counter and have tried to measure ADEV of a
GPSDO with it. I am suspicious of the ADEV numbers reported by TimeLab V1.31
because
1) Timelab disagrees significantly with the ADEV numbers reported by the 53230A
itself. In this case, with 1 sec sample intervals,
