[time-nuts] NIST frequency doubler

SAIDJACK at aol.com SAIDJACK at aol.com
Mon Jul 9 19:27:20 EDT 2007

In a message dated 7/9/2007 01:59:46 Pacific Daylight Time,  
bruce.griffiths at xtra.co.nz writes:

>It  just an RF bypass capacitor to ground.
>This circuit was embedded in a  very small section of a much larger 
>paper, so its difficult to  find.
>You may even have read the paper and not have noticed  the  mixer circuit.
>The resistor from the centre tap to ground is selected  so that the peak 
>drain current is around 28mA or so when the RF is  applied

>RF input ~ 13dBm.
>Input transformer 1:4 turns ratio  (or thereabouts) centre tapped secondary.
>Output transformer 2:1 turns  ratio (or thereabouts).
>RF bypass capacitor depends on input frequency  typically 100nF or so.


Hi Bruce,
nice circuit. Many questions:
I wonder how well it works to get a 5MHz source up to 10MHz?
Also, would you have recommendations on the transformer part numbers?  
(MiniCircuits, MaCom, etc)? I think the transformers are probably key  to getting 
good phase noise (preventing them from saturating, crosstalk,  etc).
Do you have a suggestion on who makes the best (lowest-noise) JFets?
Where could we find the original paper's PDF?
Lastly, how much fundamental attenuation would you expect from such a  

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