[time-nuts] Frequency comparison

Bruce Griffiths bruce.griffiths at xtra.co.nz
Mon Feb 8 21:16:35 UTC 2010


You need to use a mixer with low dc offset for best results.
Try one of the Minicircuits phase detectors (RPD-1, MPD-1, SYPD-1 etc)
These have low dc offset and dc offset drift.

Bruce

Raj wrote:
> Hi Dan,
>
>          Low tech. Yes! IMHO I think its easier for my mind to track an analog indication of Delta-V. I am more analog oriented.. my son OTOH may be able to read a last digit flickering digital display better than me!.
>
> I am other wise thinking of a DIY gizmo:
>
>          Mix two signals in an SBL1 or Eq.
>          Take the phase/DC IF difference out
>          Make a zero crossing detector or similar
>          Timimg the event. Wait for the event in other words!
>          Twiddle the preset again and see what happens.
>
>          The human mind does a lot more processing than the above with an analog display..
>
> Cheers
> Raj, vu2zap
>
>    
>> Raj wrote:
>>      
>>> I was thinking of feeding two 10 Mhz signals to two ports of a SBL-1 or similar and taking the DC
>>> output at the IF port into an opamp or analog meter. This was visually easier to adjust the drift between two frequencies by just watching the needle move. A stationary needle over a couple of hours would be the best!
>>>
>>>
>>>        
>> Raj, I did exactly this but with an old chart recorder attached to the mixer IF port.  This allows one to leave the room and not have to watch for hours or days.   I was able to adjust my -hp- rubidium unit this way against gps to better than one cycle per day.
>>
>> Low tech but effective.
>>
>> Dan
>>
>>
>> _______________________________________________
>> 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_lists.febo.com mailing list