[time-nuts] DDS, OCXO and ADEV
d0ct0r
time at patoka.org
Sun May 3 10:44:19 EDT 2015
The counter is in TIME MODE. And simple calculation could transform it
to frequency as necessary. For example:
1/(350.50824*10^-9)
2852999.97512184021693755330
OR
1/0.0000003505082409000000
2852999.96779619226350692058
Which is pretty close to my DDS VFO freq. value [2853000]
I switch counter to TIME MODE, because ADEV1 utility using times, not
frequency:
Here is from documentation:
"Adev1 works on everything from pendulum clocks to hydrogen masers. The
only restrictions are that the data must be phase (time interval) rather
than frequency; the data must be sequential (no gaps); and the data
should be free from glitches or outliers."
I am using 10 second intervals for the measurement. DDS VFO clocked by
Trimble TB and its using AD9852 chip.
Regards,
V.P.
On 2015-05-03 10:01, Bob Camp wrote:
> Hi
>
> Either the output data is with the counter set to time mode (and
> it’s in 100’s of ns) or you have it
> set to frequency mode and have a very stable system.
>
> Bob
>
>> On May 2, 2015, at 9:53 PM, d0ct0r <time at patoka.org> wrote:
>>
>>
>> Hello,
>>
>>
>> I would like to create some charts for ADEV for following setup:
>>
>> HP5386A counter connected to External REF. (OCXO). The input of
>> counter connected to my DDS VFO. The frequency on VFO is 2853000 Hz.
>>
>> Here is what I got from counter via GPIB:
>>
>> S +3.505082408E-7
>> S +3.505082408E-7
>> S +3.505082408E-7
>> S +3.505082408E-7
>> S +3.505082408E-7
>> S +3.505082408E-7
>> S +3.505082408E-7
>> S +3.505082409E-7
>> S +3.505082408E-7
>> S +3.505082409E-7
>> S +3.505082408E-7
>> S +3.505082408E-7
>> S +3.505082408E-7
>>
>> I converted it to following form:
>>
>> 0.0000003505082409000000
>> 0.0000003505082409000000
>> 0.0000003505082409000000
>> 0.0000003505082408000000
>> 0.0000003505082409000000
>> 0.0000003505082409000000
>> 0.0000003505082409000000
>> 0.0000003505082409000000
>> 0.0000003505082409000000
>> 0.0000003505082409000000
>> 0.0000003505082409000000
>> 0.0000003505082409000000
>> 0.0000003505082409000000
>> 0.0000003505082409000000
>> 0.0000003505082409000000
>>
>> Then I tried to use ADEV by tvb (long life to Tom!). See attached file
>> 1b.bmp
>>
>> And I tried to create the charts for the collected data. See attached
>> file 1a.bmp.
>>
>> But it seems I am doing something wrong. Any advises will be greatly
>> appreciated. Thanks !
>>
>>
>> --
>> WBW,
>>
>> V.P.<1a.png><1b.png>_______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
--
WBW,
V.P.
More information about the time-nuts
mailing list