[time-nuts] Agilent 53220A and TimeLab

timeok at timeok.it timeok at timeok.it
Wed Feb 3 15:03:44 UTC 2016


Hi Attila,

I normally use the HP53132A in Frequency mode with the Timelab. The time interval mode, I know is more accurate but using the 1PPS as input you lost too much resolution.
looking : http://www.timeok.it/wp/wp-content/uploads/2015/09/Timeok-Time-and-Frequency-House-Standard-v-2.1.pdf page 8, the noise floor using fmode is around 2.5E-12 at1 sec and 5.2E-14 at 1000Sec.

I would like to have around 100 time more resolution capability, in particular, in the 1-1000Sec range and short to long term stability measurement possibility.


> How about implementing DMTD using ADCs? You could do something similar
> to what the TimePod does using a dual >40Msps ADC to sample both signals
> and feed that into a PC for processing. E.g. an AD9248-65 is available for
> 40USD, add some 100-200USD for a suitable FPGA board. A small PCB to glue
> the ADC and the FPGA board together, a little bit of software writing and
> you are done ;-)
>
> Of course, this would not have the short term stability (aka low noise
> floor)
> of the TimePod, but beyond a second, it should give you good results. And
> should be more than good enough to measure the ADEV of the devices we
> usually
> deal with.


I am not a "Digital Person" and I cannot approach this kind of project I have not this knowledge, so I am looking some "analog" solution or any, ready to use, solution.
Thank you for your help,


Luciano
www.timeok.it
Message sent via Atmail Open - http://atmail.org/)





On Wed 03/02/16 15:01 , Attila Kinali <attila at kinali.ch> wrote:

> Ciao Luciano,
> 
> On Wed, 03 Feb 2016 13:31:44 +0100
> timeok at timeok.it wrote:
> 
> > Unfortunately it is very difficult to measure the Allan deviation levels
> to
> > E-14 and beyond.
> > I have tried some solutions like Wavecrest and Dual mixer Time Interval
> but
> > with poor results:
> 
> Do you think this is a general problem of comparing 10MHz standards
> or just one of inadequate equipment?
> 
> > Honestly I do not see at present practical solutions and reliable low
> cost.
> 
> How about implementing DMTD using ADCs? You could do something similar
> to what the TimePod does using a dual >40Msps ADC to sample both signals
> and feed that into a PC for processing. E.g. an AD9248-65 is available for
> 40USD, add some 100-200USD for a suitable FPGA board. A small PCB to glue
> the ADC and the FPGA board together, a little bit of software writing and
> you are done ;-)
> 
> Of course, this would not have the short term stability (aka low noise
> floor)
> of the TimePod, but beyond a second, it should give you good results. And
> should be more than good enough to measure the ADEV of the devices we
> usually
> deal with.
> 
> Attila Kinali
> 
> --
> It is upon moral qualities that a society is ultimately founded. All
> the prosperity and technological sophistication in the world is of no
> use without that foundation.
> -- Miss Matheson, The Diamond Age, Neil Stephenson
> 
> 
> 
Message sent via Atmail Open - http://atmail.org/



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