[time-nuts] DMTI and Timelab setup

Adrian rfnuts at arcor.de
Thu Dec 13 10:06:36 UTC 2012


Hi John,

I'm running TimeLab with a Quartzlock A7 which multiplies frequency / 
phase differences in a similar way, and a HP 5370B counter. With the A7 
running in TI mode, the multiplying factor is 1E-4 and works as 
expected. I measured only stable sources that don't wrap phase within a 
few hours, but it would be nice to know how to handle phase wraps properly.

In this case, both, the reference and input frequency are normalized to 
1 Hz, so the actual input frequency makes no difference.

Adrian


John Miles schrieb:
> Hi, Luciano --
>
> The sampling interval would be whatever rate the counter is returning
> readings, as usual.  I usually let the acquisition driver estimate the rate,
> unless I know it's exactly one reading per second.
>
> In frequency mode, the scale factor should be 1E-6.   You need the program
> to treat the frequency readings as microhertz, to force the 1000000:1
> heterodyne factor to be accounted for when the frequency readings are
> integrated back to phase differences.
>
> For TI readings the scale factor should also be 1E-6, and you would enter
> 5E6 as the input frequency.  I *think* that'll make it handle phase wraps
> properly, but you might send me a few plots to make sure.  I've never tried
> a DMTD with TimeLab before.
>
> -- john
>
>> -----Original Message-----
>> From: time-nuts-bounces at febo.com [mailto:time-nuts-
>> bounces at febo.com] On Behalf Of Timeok
>> Sent: Wednesday, December 12, 2012 5:15 AM
>> To: time-nuts at febo.com
>> Subject: [time-nuts] DMTI and Timelab setup
>>
>> Hi all,
>>
>> if I will use a dual mixer TI meter, suppose to have :
>>
>> LO 5.000.005 Hz
>> Ref and Ftest 5 MHz
>> IF= 5Hz
>>
>> how do I have to setup Timelab for acquisition?
>>
>> Sampling interval = ....
>> Input frequency =  ....
>> Scale factor =  ....
>>
>> Thanks all,
>> Luciano
>> timeok
>>
>>    _______________________________________________
>>> 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.
>> --
>> timeok
>>
>> _______________________________________________
>> 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.
>
> _______________________________________________
> 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.
>




More information about the time-nuts mailing list